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Sample records for beta-globin mutation induced

  1. Targeted correction of a thalassemia-associated beta-globin mutation induced by pseudo-complementary peptide nucleic acids

    DEFF Research Database (Denmark)

    Lonkar, Pallavi; Kim, Ki-Hyun; Kuan, Jean Y

    2009-01-01

    Beta-thalassemia is a genetic disorder caused by mutations in the beta-globin gene. Triplex-forming oligonucleotides and triplex-forming peptide nucleic acids (PNAs) have been shown to stimulate recombination in mammalian cells via site-specific binding and creation of altered helical structures...

  2. Detection of Rare Beta Globin Gene Mutations in Northwestern Iran

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    M Haghi

    2007-04-01

    Full Text Available Introduction: Recent molecular studies on Iranian β-thalassemia genes revealed the presence of eight common mutations associated with thalassemia. Although these mutations are frequent, there are other rare and unknown mutations that can create large problems in designing preventive programs. We detected and explained the common mutations in north-western Iran previously and detection of the rare and unknown mutations could be useful in diagnosis and design of future preventive programs. Methods: In this study, 5ml peripheral blood from 20 Azari- β-thalassemia patients whose mutation was not revealed in the previous study was collected and DNA extraction was done by isopropanol and proteinase k method. Initially, samples were examined for the rare mutations: Codon6, Codon16, Codon41/42, Codon36/37, -88 and Codon22 by ARMS – PCR techniques and then the unknown cases were directly sequenced. Results: According to our results, Codon15(TGG-TGA, Codon16(-C, Codon36/37(-T, IVSII-848(C-A, IVSII-745(C-G, -28(A-C( and Codon25/26(+T were recognized and added to the spectrom of beta globin gene mutations in Azerbaijan and Iran. Also, we detected four SNP sites: 5’UTR+20(C-T, Codon2 (CAC-CAT , IVSII-16(C-G and IVSII-666(T-C in β-thalassemia genes. Conclusion: Our results could be useful for developing molecular screening plans and help prenatal diagnosis of beta thalassemia in Azerbaijan , Iran and other neighboring countries.

  3. Diversity of [beta]-globin mutations in Israeli ethnic groups reflects recent historic events

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    Filon, D.; Oron, V.; Krichevski, S.; Shaag, A.; Goldfarb, A.; Aker, M.; Rachmilewitz, E.A.; Rund, D.; Oppenheim, A. (Hebrew Univ. Hadassah-Medical School, Jerusalem (Israel)) (and others)

    1994-05-01

    The authors characterized nearly 500 [beta]-thalassemia genes from the Israeli population representing a variety of ethnic subgroups. They found 28 different mutations in the [beta]-globin gene, including three mutations ([beta][sup S], [beta][sup C], and [beta][sup O-Arab]) causing hemoglobinopathies. Marked genetic heterogeneity was observed in both the Arab (20 mutations) and Jewish (17 mutations) populations. On the other hand, two ethnic isolates - Druze and Samaritans - had a single mutation each. Fifteen of the [beta]-thalassemia alleles are Mediterranean in type, 5 originated in Kurdistan, 2 are of Indian origin, and 2 sporadic alleles came from Europe. Only one mutant allele-nonsense codon 37-appears to be indigenous to Israel. While human habitation in Israel dates back to early prehistory, the present-day spectrum of [beta]-globin mutations can be largely explained by migration events that occurred in the past millennium. 26 refs., 2 figs., 3 tabs.

  4. A mutation of the beta-globin gene initiation codon, ATG-->AAG, found in a French Caucasian man.

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    Lacan, Philippe; Aubry, Martine; Couprie, Nicole; Francina, Alain

    2005-01-01

    A new mutation of the beta-globin gene initiation codon, ATG-->AAG (Met-->Tyr), is reported in a man originating from the southeast of France. Typical hematological findings of beta-thalassemia (thal) trait were found. We emphasize the importance of characterizing uncommon beta-thal mutations for genetic counseling.

  5. Correction of a splice-site mutation in the beta-globin gene stimulated by triplex-forming peptide nucleic acids

    DEFF Research Database (Denmark)

    Chin, Joanna Y; Kuan, Jean Y; Lonkar, Pallavi S

    2008-01-01

    Splice-site mutations in the beta-globin gene can lead to aberrant transcripts and decreased functional beta-globin, causing beta-thalassemia. Triplex-forming DNA oligonucleotides (TFOs) and peptide nucleic acids (PNAs) have been shown to stimulate recombination in reporter gene loci in mammalian...... DNA fragments, can promote single base-pair modification at the start of the second intron of the beta-globin gene, the site of a common thalassemia-associated mutation. This single base pair change was detected by the restoration of proper splicing of transcripts produced from a green fluorescent...

  6. Molecular analysis of beta-globin gene mutations among Thai beta-thalassemia children: results from a single center study

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    Boonyawat B

    2014-12-01

    Full Text Available Boonchai Boonyawat,1 Chalinee Monsereenusorn,2 Chanchai Traivaree2 1Division of Genetics, Department of Pediatrics, Phramongkutklao Hospital and College of Medicine, Bangkok, Thailand; 2Division of Hematology/Oncology, Department of Pediatrics, Phramongkutklao Hospital and College of Medicine, Bangkok, Thailand Background: Beta-thalassemia is one of the most common genetic disorders in Thailand. Clinical phenotype ranges from silent carrier to clinically manifested conditions including severe beta-thalassemia major and mild beta-thalassemia intermedia. Objective: This study aimed to characterize the spectrum of beta-globin gene mutations in pediatric patients who were followed-up in Phramongkutklao Hospital. Patients and methods: Eighty unrelated beta-thalassemia patients were enrolled in this study including 57 with beta-thalassemia/hemoglobin E, eight with homozygous beta-thalassemia, and 15 with heterozygous beta-thalassemia. Mutation analysis was performed by multiplex amplification refractory mutation system (M-ARMS, direct DNA sequencing of beta-globin gene, and gap polymerase chain reaction for 3.4 kb deletion detection, respectively. Results: A total of 13 different beta-thalassemia mutations were identified among 88 alleles. The most common mutation was codon 41/42 (-TCTT (37.5%, followed by codon 17 (A>T (26.1%, IVS-I-5 (G>C (8%, IVS-II-654 (C>T (6.8%, IVS-I-1 (G>T (4.5%, and codon 71/72 (+A (2.3%, and all these six common mutations (85.2% were detected by M-ARMS. Six uncommon mutations (10.2% were identified by DNA sequencing including 4.5% for codon 35 (C>A and 1.1% initiation codon mutation (ATG>AGG, codon 15 (G>A, codon 19 (A>G, codon 27/28 (+C, and codon 123/124/125 (-ACCCCACC, respectively. The 3.4 kb deletion was detected at 4.5%. The most common genotype of beta-thalassemia major patients was codon 41/42 (-TCTT/codon 26 (G>A or betaE accounting for 40%. Conclusion: All of the beta-thalassemia alleles have been characterized by

  7. Molecular analysis of the beta-globin gene cluster in the Niokholo Mandenka population reveals a recent origin of the beta(S) Senegal mutation.

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    Currat, Mathias; Trabuchet, Guy; Rees, David; Perrin, Pascale; Harding, Rosalind M; Clegg, John B; Langaney, André; Excoffier, Laurent

    2002-01-01

    A large and ethnically well-defined Mandenka sample from eastern Senegal was analyzed for the polymorphism of the beta-globin gene cluster on chromosome 11. Five RFLP sites of the 5' region were investigated in 193 individuals revealing the presence of 10 different haplotypes. The frequency of the sickle-cell anemia causing mutation (beta(S)) in the Mandenka estimated from this sample is 11.7%. This mutation was found strictly associated with the single Senegal haplotype. Approximately 600 bp of the upstream region of the beta-globin gene were sequenced for a subset of 94 chromosomes, showing the presence of four transversions, five transitions, and a composite microsatellite polymorphism. The sequence of 22 beta(S) chromosomes was also identical to the previously defined Senegal haplotype, suggesting that this mutation is very recent. Monte Carlo simulations (allowing for a specific balancing selection model, a logistic growth of the population, and variable initial frequencies of the Senegal haplotype) were used to estimate the age of the beta(S) mutation. Resulting maximum-likelihood estimates are 45-70 generations (1,350-2,100 years) for very different demographic scenarios. Smallest confidence intervals (25-690 generations) are obtained under the hypothesis that the Mandenka population is large (N(e) >5,000) and stationary or that it has undergone a rapid demographic expansion to a current size of >5,000 reproducing individuals, which is quite likely in view of the great diversity found on beta(A) chromosomes.

  8. Familial Polycythemia Caused by a Novel Mutation in the Beta Globin Gene: Essential Role of P50 in Evaluation of Familial Polycythemia

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    Neeraj Agarwal, Mariluz P. Mojica-Henshaw, Elizabeth. D. Simmons, Dottie Hussey, Ching N. Ou, Josef T. Prchal

    2007-01-01

    Full Text Available Two polycythemic subjects from a family with multiple polycythemic subjects were evaluated. Estimation of oxygen affinity of Hb from venous blood gas parameters (P50 revealed low P50 suggesting a high affinity Hb variant. Further work up, which included beta globin gene sequencing, revealed a novel mutation changing a codon to the previously reported high affinity Hb - Hb Johnstown (beta109 Val->Leu. Polycythemic subjects with high affinity Hb variant are asymptomatic with normal life expectancy. Their differentiation from polycythemia vera (PV is crucial to avoid therapy which is otherwise reserved for PV patients. We provide an electronic version (in Microsoft excel program of a previously reported mathematical formula for rapid calculation of P50 from venous blood gases. Estimation of P50 is an essential initial step in the evaluation of a subject with personal and family history of polycythemia.

  9. Development of K562 cell clones expressing beta-globin mRNA carrying the beta039 thalassaemia mutation for the screening of correctors of stop-codon mutations.

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    Salvatori, Francesca; Cantale, Vera; Breveglieri, Giulia; Zuccato, Cristina; Finotti, Alessia; Bianchi, Nicoletta; Borgatti, Monica; Feriotto, Giordana; Destro, Federica; Canella, Alessandro; Breda, Laura; Rivella, Stefano; Gambari, Roberto

    2009-07-09

    Nonsense mutations, giving rise to UAA, UGA and UAG stop codons within the coding region of mRNAs, promote premature translational termination and are the leading cause of approx. 30% of inherited diseases, including cystic fibrosis, Duchenne muscular dystrophy and thalassaemia. For instance, in beta(0)39-thalassaemia the CAG (glutamine) codon is mutated to the UAG stop codon, leading to premature translation termination and to mRNA destabilization through the well-described NMD (nonsense-mediated mRNA decay). In order to develop an approach facilitating translation and, therefore, protection from NMD, aminoglycoside antibiotics have been tested on mRNAs carrying premature stop codons. These drugs decrease the accuracy in the codon-anticodon base-pairing, inducing a ribosomal read-through of the premature termination codons. Interestingly, recent papers have described drugs designed and produced for suppressing premature translational termination, inducing a ribosomal read-through of premature but not normal termination codons. These findings have introduced new hopes for the development of a pharmacological approach to the therapy of beta(0)39-thalassaemia. In this context, we started the development of a cellular model of the beta(0)39-thalassaemia mutation that could be used for the screening of a high number of aminoglycosides and analogous molecules. To this aim, we produced a lentiviral construct containing the beta(0)39-thalassaemia globin gene under a minimal LCR (locus control region) control and used this construct for the transduction of K562 cells, subsequently subcloned, with the purpose to obtain several K562 clones with different integration copies of the construct. These clones were then treated with Geneticin (also known as G418) and other aminoglycosides and the production of beta-globin was analysed by FACS analysis. The results obtained suggest that this experimental system is suitable for the characterization of correction of the beta(0

  10. Genetic Heterogeneity of Beta Globin Mutations among Asian-Indians and Importance in Genetic Counselling and Diagnosis.

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    Kumar, Ravindra; Singh, Kritanjali; Panigrahi, Inusha; Agarwal, Sarita

    2013-01-01

    There are an estimated 45 million carriers of β-thalassemia trait and about 12,000-15,000 infants with β-thalassemia major are born every year in India. Thalassemia major constitutes a significant burden on the health care system. The burden of thalassemia major can be decreased by premarital screening and prenatal diagnosis. The success of prenatal diagnosis requires proper knowledge of spectrum of β-thalassemia mutations. In present study, β-thalassemia mutations were characterized in 300 thalassemia cases from 2007 to 2010 using ARMS-PCR and DNA sequencing. The five most common mutations accounted 78.9% of the studied chromosomes that includes IVS1-5(G>C), Cod 41-42(-TCTT), Cod8-9(+G), Cod16(-C) and 619bp del. Though IVS1-5(G>C) is most common mutation in all the communities, the percentage prevalence were calculated on sub caste basis and found that IVS1-5(G>C) percentage prevalence varied from 25 to 60 in Aroras & Khatris and Thakur respectively. Interestingly Cod41-42(-TCTT) mutation which is the second commonest among the mutations reported was totally absent in Kayasthas and Muslim community. These findings have implications for providing molecular diagnosis, genetic counseling and prenatal diagnosis to high risk couples of β-thalassemia.

  11. GENETIC HETEROGENEITY OF BETA GLOBIN MUTATIONS AMONG ASIAN-INDIANS AND IMPORTANCE IN GENETIC COUNSELLING AND DIAGNOSIS

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    Ravindra Kumar

    2013-01-01

    Full Text Available There are an estimated 45 million carriers of β-thalassemia trait and about 12,000-15,000 infants with β-thalassemia major are born every year in India. The consanguinity rates are higher in India, and thalassemia major constitutes a significant burden on the health care system. In present study, β-thalassemia mutations were characterized in 300 thalassemia cases from 2007 to 2010 using ARMS-PCR and DNA sequencing. The five most common mutations accounted 79.3% of the studied chromosomes that includes IVS1-5(G>C, Cod 41-42(-TCTT, Cod8-9(+G, Cod16(-C and 619bp del. Though IVS1-5(G>C is most common mutation when all the communities were included, the percentage prevalence were calculated on sub caste basis and found that IVS1-5(G>C percentage prevalence varied from 25 to 60 in Aroras & Khatris and Thakur respectively. Interestingly Cod41-42(-TCTT mutation which is the second commonest among the mutations reported was totally absent in Kayasthas and Muslim community. These findings have implications for providing molecular diagnosis, genetic counseling and prenatal diagnosis to high risk couples of β-thalassemia.

  12. The beta-globin gene in Sardinian delta beta 0-thalassemia carries a C----T nonsense mutation at codon 39.

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    Guida, S; Giglioni, B; Comi, P; Ottolenghi, S; Camaschella, C.; Saglio, G

    1984-01-01

    Sardinian delta beta 0-thalassemia is an inherited syndrome characterized by the inactivity of the beta-globin gene and the persistent activity of the fetal gamma-globin genes, particularly the A gamma-globin gene. Previous mapping studies with restriction enzymes failed to show any abnormality in the non-alpha globin gene cluster. We have now examined the possibility that this syndrome might result from a single rather than two different defects. Restriction enzyme polymorphisms linked to th...

  13. Origin and spread of beta-globin gene mutations in India, Africa, and Mediterranea: analysis of the 5' flanking and intragenic sequences of beta S and beta C genes.

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    Trabuchet, G; Elion, J; Baudot, G; Pagnier, J; Bouhass, R; Nigon, V M; Labie, D; Krishnamoorthy, R

    1991-06-01

    Nucleotide polymorphisms of both the 5' flanking and intragenic regions of the human beta-globin gene were investigated by directly sequencing genomic DNA after amplification by the polymerase chain reaction in 47 subjects homozygous for the beta S or the beta C mutation. The sickle-cell mutation was found in the context of five different haplotypes defined by eight nucleotide substitutions and various structures of a region of the simple repeated sequence (AT) chi Ty. All subjects from the same geographic origin bear an identical chromosomal structure, defining the Senegal-, Bantu-, Benin-, Cameroon-, and Indian-type chromosomes. These results strengthen our previous conclusions about the multiple occurrence of the sickle-cell mutation. The Benin-type chromosome was also found among Algerian and Sicilian sickle-cell patients, whereas the Indian-type chromosome was observed in two geographically distant tribes, illustrating the spread of these sickle-cell genes. We also found that the intragenic sequence polymorphisms (frameworks) are not always in linkage disequilibrium with the BamH I polymorphism downstream from the beta-globin gene, as had been previously observed. Finally, we present a tentative phylogenetic tree of the different alleles at this locus. Some polymorphisms of this sequence might be contemporary with our last common ancestor, the great apes, that is, about 4-6 millions years old.

  14. Structural analysis of the 5 prime flanking region of the. beta. -globin gene in African sickle cell anemia patients: Further evidence for three origins of the sickle cell mutation in Africa

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    Chebloune, Y.; Pagnier, J.; Trabuchet, G.; Faure, C.; Verdier, G.; Labie, D.; Nigon, V. (Universite Claude Bernard-Lyon, Villeurbane (France))

    1988-06-01

    Haplotype analysis of the {beta}-globin gene cluster shows two regions of DNA characterized by nonrandom association of restriction site polymorphisms. These regions are separated by a variable segment containing the repeated sequences (ATTTT){sub n} and (AT){sub x}T{sub y}, which might be involved in recombinational events. Studies of haplotypes linked to the sickle cell gene in Africa provide strong argument for three origins of the mutation: Benin, Senegal, and the Central African Republic. The structure of the variable segment in the three African populations was studied by S1 nuclease mapping of genomic DNA, which allows a comparison of several samples. A 1080-base-pair DNA segment was sequenced for one sample from each population. S1 nuclease mapping confirmed the homogeneity of each population with regard to both (ATTTT){sub n} and (AT){sub x}T{sub y} repeats. The authors found three additional structures for (AT){sub x}T{sub y} correlating with the geographic origin of the patients. Ten other nucleotide positions, 5{prime} and 3{prime} to the (AT){sub x}T{sub y} copies, were found to be variable when compared to homologous sequences from human and monkey DNAs. These results allow us to propose an evolutionary scheme for the polymorphisms in the 5{prime} flanking region of the {beta}-globin gene. The results strongly support the hypothesis of three origins for the sickle mutation in Africa.

  15. DNA sequence analysis proves Hb M-Milwaukee-2 is due to beta-globin gene codon 92 (CAC-->TAC), the presumed mutation of Hb M-Hyde Park and Hb M-Akita.

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    Hutt, P J; Pisciotta, A V; Fairbanks, V F; Thibodeau, S N; Green, M M

    1998-01-01

    Among the causes of congenital methemoglobinemia, Hb M-Milwaukee-2 was one of the earliest described, in a patient who also had Hb E trait. The structure of Hb M-Milwaukee-2 has been elusive. DNA sequence analysis, as here reported, proves that this hemoglobin variant is due to the mutation CAC-->TAC at codon 92 of the beta-globin gene, corresponding to the substitution of tyrosine for histidine. This mutation is identical with that presumed to be the cause of Hb M-Hyde Park and Hb M-Akita. In addition, the DNA mutation of Hb E, GAG-->AAG at codon 26, was confirmed in this case.

  16. Production of beta-globin and adult hemoglobin following G418 treatment of erythroid precursor cells from homozygous beta(0)39 thalassemia patients.

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    Salvatori, Francesca; Breveglieri, Giulia; Zuccato, Cristina; Finotti, Alessia; Bianchi, Nicoletta; Borgatti, Monica; Feriotto, Giordana; Destro, Federica; Canella, Alessandro; Brognara, Eleonora; Lampronti, Ilaria; Breda, Laura; Rivella, Stefano; Gambari, Roberto

    2009-11-01

    In several types of thalassemia (including beta(0)39-thalassemia), stop codon mutations lead to premature translation termination and to mRNA destabilization through nonsense-mediated decay. Drugs (for instance aminoglycosides) can be designed to suppress premature termination, inducing a ribosomal readthrough. These findings have introduced new hopes for the development of a pharmacologic approach to the cure of this disease. However, the effects of aminoglycosides on globin mRNA carrying beta-thalassemia stop mutations have not yet been investigated. In this study, we have used a lentiviral construct containing the beta(0)39-thalassemia globin gene under control of the beta-globin promoter and a LCR cassette. We demonstrated by fluorescence-activated cell sorting (FACS) analysis the production of beta-globin by K562 cell clones expressing the beta(0)39-thalassemia globin gene and treated with G418. More importantly, after FACS and high-performance liquid chromatography (HPLC) analyses, erythroid precursor cells from beta(0)39-thalassemia patients were demonstrated to be able to produce beta-globin and adult hemoglobin after treatment with G418. This study strongly suggests that ribosomal readthrough should be considered a strategy for developing experimental strategies for the treatment of beta(0)-thalassemia caused by stop codon mutations. Am. J. Hematol., 2009. (c) 2009 Wiley-Liss, Inc.

  17. Identification and molecular characterization of four new large deletions in the beta-globin gene cluster.

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    Joly, Philippe; Lacan, Philippe; Garcia, Caroline; Couprie, Nicole; Francina, Alain

    2009-01-01

    Despite the fact that mutations in the human beta-globin gene cluster are essentially point mutations, a significant number of large deletions have also been described. We present here four new large deletions in the beta-globin gene cluster that have been identified on patients displaying an atypical hemoglobin phenotype (high HbF) at routine analysis. The first deletion, which spreads over 2.0 kb, removes the entire beta-globin gene, including its promoter, and is associated with a typical beta-thal minor phenotype. The three other deletions are larger (19.7 to 23.9 kb) and remove both the delta and beta-globin genes. Phenotypically, they look like an HPFH-deletion as they are associated with normal hematological parameters. The precise localization of their 5' and 3' breakpoints gives new insights about the differences between HPFH and (deltabeta)(0)-thalassemia at the molecular level. The importance of detection of these deletions in prenatal diagnosis and newborn screening of hemoglobinopathies is also discussed.

  18. Beta-globin gene haplotypes among cameroonians and review of the global distribution: is there a case for a single sickle mutation origin in Africa?

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    Bitoungui, Valentina J Ngo; Pule, Gift D; Hanchard, Neil; Ngogang, Jeanne; Wonkam, Ambroise

    2015-03-01

    Studies of hemoglobin S haplotypes in African subpopulations have potential implications for patient care and our understanding of genetic factors that have shaped the prevalence of sickle cell disease (SCD). We evaluated HBB gene cluster haplotypes in SCD patients from Cameroon, and reviewed the literature for a global distribution. We reviewed medical records to obtain pertinent socio-demographic and clinical features for 610 Cameroonian SCD patients, including hemoglobin electrophoresis and full blood counts. RFLP-PCR was used to determine the HBB gene haplotype on 1082 chromosomes. A systematic review of the current literature was undertaken to catalogue HBB haplotype frequencies in SCD populations around the world. Benin (74%; n = 799) and Cameroon (19%; n = 207) were the most prevalent haplotypes observed among Cameroonian patients. There was no significant association between HBB haplotypes and clinical life events, anthropometric measures, hematological parameters, or fetal hemoglobin (HbF) levels. The literature review of the global haplotype distributions was consistent with known historical migrations of the people of Africa. Previously reported data from Sudan showed a distinctly unusual pattern; all four classical haplotypes were reported, with an exceptionally high proportion of the Senegal, Cameroon, and atypical haplotypes. We did not observe any significant associations between HBB haplotype and SCD disease course in this cohort. Taken together, the data from Cameroon and from the wider literature suggest that a careful reassessment of African HBB haplotypes may shed further light on the evolutionary dynamics of the sickle allele, which could suggest a single origin of the sickle mutation.

  19. beta (+)-Thalassaemia in the Po river delta region (northern Italy): genotype and beta globin synthesis.

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    Del Senno, L; Pirastu, M; Barbieri, R; Bernardi, F; Buzzoni, D; Marchetti, G; Perrotta, C; Vullo, C; Kan, Y W; Conconi, F

    1985-01-01

    Six beta(+)-thalassaemic patients from the Po river delta region have been studied. Using synthetic oligonucleotides as specific hybridisation probes, the beta(+) IVS I mutation (G----A at position 108) was demonstrated. This lesion and the enzyme polymorphism pattern in the subjects examined are the same as have been described for other Mediterranean beta(+)-thalassaemias. Antenatal diagnosis through DNA analysis of beta(+)-thalassaemia is therefore possible. The production of beta globin in a beta(+), homozygote and in a beta (+), beta(0) 39 (nonsense mutation at codon 39) double heterozygote is approximately 20% and 10% respectively of total non-alpha globin synthesis. Despite some overlapping of the results, similar beta globin synthesis levels have been obtained in 43 beta(+)-thalassaemia patients. This suggests that in the Po river delta region the most common thalassaemic genes are beta(0) 39 and beta(+) IVS I. Images PMID:2580095

  20. beta (+)-Thalassaemia in the Po river delta region (northern Italy): genotype and beta globin synthesis.

    OpenAIRE

    del Senno, L; Pirastu, M; Barbieri, R.; De Bernardi, F.; Buzzoni, D; Marchetti, G.; Perrotta, C; Vullo, C; Kan, Y W; Conconi, F

    1985-01-01

    Six beta(+)-thalassaemic patients from the Po river delta region have been studied. Using synthetic oligonucleotides as specific hybridisation probes, the beta(+) IVS I mutation (G----A at position 108) was demonstrated. This lesion and the enzyme polymorphism pattern in the subjects examined are the same as have been described for other Mediterranean beta(+)-thalassaemias. Antenatal diagnosis through DNA analysis of beta(+)-thalassaemia is therefore possible. The production of beta globin in...

  1. A review on the origin and spread of deleterious mutants of the beta-globin gene in Indian populations.

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    Das, S K; Talukder, G

    2001-01-01

    Deleterious mutations of the human beta-globin gene are responsible for beta-thalassaemia and other haemoglobinopathies, which are the most common genetic diseases in Indian populations. A highly heterogeneous distribution of those mutations is observed in India and certain mutations are restricted to some extent to particular groups only. The reasons behind the geographical clustering and origin of the mutations in India is a highly debated issue and the evidence is conflicting. Our present article aims at tracing the origin of the deleterious beta-globin mutation and evaluates the role of different evolutionary forces responsible for the spread and present distribution of those mutations in Indian populations, using data from molecular biology and statistical methods. Mutations are generated essentially randomly, but "hot-spot" sites for mutation are reported for the beta-globin gene cluster, indicating sequence dependency of mutation. A single origin of a deleterious beta-globin mutation, followed by recombination (in a hot spot region) and/or interallelic gene conversion (within beta-globin gene) through time is the most plausible hypothesis to explain the association of those mutations with multiple haplotype backgrounds and frameworks. It is suggested that India is the place of origin of HbE and HbD mutations and that they dispersed to other parts of the would by migration. HbS mutants present in Indian populations are not of Middle East origin but rather a fresh mutation is the probable explanation for the prevalence among tribal groups. beta-thalassaemia represents a heterogeneous group of mutant alleles in India. Five common and twelve rare mutations have been reported in variable frequencies among different Indian populations. Gene flow of those mutant alleles from different populations of the world by political, military and commercial interactions possibly accounts for the heterogenous nature of beta-thalassaemia among Indians. A multiple allelic

  2. Characterization of a large deletion in the {beta}-globin gene cluster in a newborn with hemoglobin FE

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    Louie, E.; Dietz, L.; Shafer, F. [Children`s Hosptial, Oakland, CA (United States)] [and others

    1994-09-01

    A sample on a newborn with hemoglobin FE screen results was obtained to investigate whether E/E or B/{beta}{degrees} thalassemia was present using polymerase chain reaction (PCR) methodology. The newborn appeared homozygous for the hemoglobin E mutation in our initial study, but the parents` genotypes did not support this diagnosis. The father is homozygous for the absence of the hemoglobin E mutation (non E/non E) and the mother is heterozygous (E/non E) for this mutation. The limitation of PCR analysis is an assumption that the amplification of the two {beta}-globin alleles is equivalent. A large deletion on one {beta}-globin gene, which would produce E/{beta}{degrees} thalassemia, would be missed if it included part or the entire region subjected to amplification. The family results were consistent with either non-paternity, sample mix-up or such a deletion of the {beta}-globin gene in the father and child. To rule out the possibility of non-paternity, two polymorphic loci (HLA on chromosome 6 and a VNTR system of chromosome 17) that are outside of the {beta}-globin gene were analyzed and show that inheritance is consistent and the likelihood of a sample mix-up is then reduced. We therefore believe there is a gene deletion in this family. At the present time, analyses of the RFLPs that are 5{prime} of the {beta}-globin gene cluster show that the polymorphisms most distal from the 5{prime} {beta}-globin gene are not being inherited as expected. These results support our interpretation that a deletion exists in the father and was inherited by the child. The father`s clinical picture of possible HPFH (the father has 12% hemoglobin F) also supports the interpretation of a deletion in this family. Deletions of the {beta}-globin gene within this ethnic group are rare. Currently, Southern blots on the family are being probed to determine the extent of the putative deletion.

  3. Definition of the minimal requirements within the human beta-globin gene and the dominant control region for high level expression.

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    Collis, P; Antoniou, M; Grosveld, F

    1990-01-01

    The human beta-globin dominant control region (DCR) was previously identified as a region from the 5' end of the human beta-globin locus which directs high level, site of integration-independent, copy number-dependent expression on a linked human beta-globin gene in transgenic mice and stably transfected mouse erythroleukaemia (MEL) cells. We have now analysed the elements comprising the DCR by systematic deletion mutagenesis in stable MEL transfectants. We have identified two independent elements within the DNase I hypersensitive sites 2 and 3, containing fragments which direct strong transcriptional inducibility of a beta-globin gene. Whilst the remaining two hypersensitive sites do not direct significant transcriptional induction, our data suggest that all four sites may be necessary for the fully regulated expression conferred by the DCR. We have also tested a number of beta-globin minigene constructs under the control of the DCR to assess if any of the local sequences from the gene may be removed without loss of expression. We find that the 3' enhancer may be removed without affecting expression, but there is an absolute requirement for the presence of the second intron, not related to the enhancer present in that intron. Images Fig. 2. Fig. 3. Fig. 4. Fig. 5. PMID:2295312

  4. Design of retrovirus vectors for transfer and expression of the human. beta. -globin gene

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    Miller, A.D.; Bender, M.A.; Harris, E.A.S.; Kaleko, M.; Gelinas, R.E.

    1988-11-01

    Regulated expression of the human ..beta..-globin gene has been demonstrated in cultured murine erythroleukemia cells and in mice after retrovirus-mediated gene transfer. However, the low titer of recombinant viruses described to date results in relatively inefficient gene transfer, which limits their usefulness for animal studies and for potential gene therapy in humans for diseases involving defective ..beta..-globin genes. The authors found regions that interfered with virus production within intron 2 of the ..beta..-globin gene and on both sides of the gene. The flanking regions could be removed, but intron 2 was required for ..beta..-globin expression. Inclusion of ..beta..-globin introns necessitates an antisense orientation of the gene within the retrovirus vector. However, they found no effect of the antisense ..beta..-globin transcription on virus production. A region downstream of the ..beta..-globin gene that stimulates expression of the gene in transgenic mice was included in the viruses without detrimental effects on virus titer. Virus titers of over 10/sup 6/ CFU/ml were obtained with the final vector design, which retained the ability to direct regulated expression of human ..beta..-globin in murine erythroleukemia cells. The vector also allowed transfer and expression of the human ..beta..-globin gene in hematopoietic cells (CFU-S cells) in mice.

  5. Two new beta0-thalassemic mutations: a deletion (-CC) at codon 142 or overlapping codons 142-143, and an insertion (+T) at codon 45 or overlapping codons 44-45/45-46 of the beta-globin gene.

    Science.gov (United States)

    Lacan, Philippe; Aubry, Martine; Couprie, Nicole; Francina, Alain

    2007-01-01

    We report here two new beta(0)-thalassemic mutations. In the first case, a deletion of two nucleotides (-CC) at codon 142 was found in a French Caucasian woman. In the second case, an insertion of a single nucleotide (+T) at codon 45 was found in a Turkish girl. In both cases, no dominant thalassemia-like phenotype was observed.

  6. Total beta-globin gene deletion has high frequency in Filipinos

    Energy Technology Data Exchange (ETDEWEB)

    Patrick, N.; Miyakawa, F.; Hunt, J.A. [Univ. of Hawaii, Honolulu, HI (United States)] [and others

    1994-09-01

    The distribution of {beta}-thalassemia [{beta}{sup Th}] mutations is unique to each ethnic group. Most mutations affect one or a few bases; large deletions have been rare. Among families screened in Hawaii, [{beta}{sup Th}] heterozygotes were diagnosed by microcytosis, absence of abnormal hemoglobins on isoelectric focusing, and raised Hb A{sub 2} by chromatography. Gene frequency for {beta}{sup Th} was 0.02 in Filipinos. In Filipinos, polymerase chain reaction [PCR] with denaturing gradient gel electrophoresis for {beta}{sup Th} mutations detected a mutation in only 6 of 42 {beta}{sup Th} heterozygotes; an IVS2-666 C/T polymorphism showed non-heterozygosity in 37 and heterozygosity in only 5 of these {beta}{sup Th} heterozygotes. One {beta}{sup Th}/{beta}{sup Th} major patient and his mother had no mutation detected by allele-specific oligomer hybridization; PCR failed to amplify any DNA from his {beta}-globin gene. After a total {beta}-globin gene deletion [{beta}{sup Del}] was found in a Filipino family in Ontario, specific PCR amplification for {beta}{sup Del} detected this in 43 of 53 {beta}{sup Th} Filipino samples tested; the above {beta}{sup Th}/{beta}{sup Th} patient was a ({beta}{sup Del}/{beta}{sup Del}) homozygote. The {beta}{sup Del} may account for over 60% of all {beta}{sup Th} alleles in Filipinos; this is the highest proportion of a deletion {beta}{sup Th} mutation reported from any population. Most but not all {beta}{sup Del} heterozygotes had high Hb F [5.13 {plus_minus} 3.94 mean {plus_minus} 1 s.d.] compared to the codon 41/42 four base deletion common in Chinese [2.30 {plus_minus} 0.86], or to {beta}{sup Th} heterozygotes with normal {alpha}-globin genes [2.23 {plus_minus} 0.80].

  7. Cis-cotranscription of two beta globin genes during chicken primitive hematopoiesis.

    Directory of Open Access Journals (Sweden)

    Hiroki Nagai

    Full Text Available Chicken beta globin locus contains four genes, two of which, rho and epsilon, are expressed from the earliest stage of primitive hematopoiesis. Here we show that the transcription of these two genes in the nucleus engages in "on/off" phases. During each "on" phase, cotranscription of rho and epsilon in cis is favored. We propose that these two chicken beta globin genes are transcribed not by competing for a transcription initiation complex, but in a cooperative way.

  8. Transformation of frog embryos with a rabbit beta-globin gene.

    OpenAIRE

    Rusconi, S; Schaffner, W

    1981-01-01

    In order to study the fate and possible expression of foreign DNA during embryogenesis of the frog Xenopus laevis, we have injected a rabbit beta-globin gene into fertilized Xenopus eggs. Frog embryo DNA was extracted at various stages of development, fractionated by agarose gel electrophoresis, transferred to nitrocellulose filters, and hybridized to labeled beta-globin recombinant plasmid DNA. It was found that the injected DNA replicated extrachromosomally, reaching, at gastrula stage, a l...

  9. Successful treatment of murine beta-thalassemia intermedia by transfer of the human beta-globin gene.

    Science.gov (United States)

    May, Chad; Rivella, Stefano; Chadburn, Amy; Sadelain, Michel

    2002-03-15

    The beta-thalassemias are caused by more than 200 mutations that reduce or abolish beta-globin production. The severity of the resulting anemia can lead to lifelong transfusion dependency. A genetic treatment based on globin gene transfer would require that transgene expression be erythroid specific, elevated, and sustained over time. We report here that long-term synthesis of chimeric hemoglobin (mualpha(2):hubeta(A)(2)) could be achieved in mice with beta-thalassemia intermedia following engraftment with bone marrow cells transduced with a lentiviral vector encoding the human beta-globin gene. In the absence of any posttransduction selection, the treated chimeras exhibit durably increased hemoglobin levels without diminution over 40 weeks. Ineffective erythropoiesis and extramedullary hematopoiesis (EMH) regress, as reflected by normalization of spleen size, architecture, hematopoietic colony formation, and disappearance of liver EMH. These findings establish that a sustained increase of 3 to 4 g/dL hemoglobin is sufficient to correct ineffective erythropoiesis. Hepatic iron accumulation is markedly decreased in 1-year-old chimeras, indicating persistent protection from secondary organ damage. These results demonstrate for the first time that viral-mediated globin gene transfer in hematopoietic stem cells effectively treats a severe hemoglobin disorder.

  10. Beta-globin gene cluster haplotypes and HbF levels are not the only modulators of sickle cell disease in Lebanon.

    Science.gov (United States)

    Inati, A; Taher, A; Bou Alawi, W; Koussa, S; Kaspar, H; Shbaklo, H; Zalloua, P A

    2003-02-01

    Sickle cell disease (SCD) is an inherited autosomal recessive disorder of the beta-globin chain. Despite the fact that all subjects with SCD have the same single base pair mutation, the severity of the clinical and hematological manifestations is extremely variable. This study examined for the first time in Lebanon the correlation between the clinical manifestation of SCD and the beta-globin gene haplotypes. The haplotypes of 50 patients diagnosed with SCD were determined using polymerase chain reaction amplification of fragments containing nine polymorphic restriction sites around and within the epsilon-Ggamma-Agamma-psibeta-delta-beta-globin gene complex. Most reported haplotypes were found in our population with the Benin haplotype as the most prevalent one. When the patients were divided according to their HbF levels into three groups (Group A: HbF 15%), surprisingly, the highest levels of HbF were associated with the most severe clinical cases. Our findings suggest that fetal hemoglobin levels are important but not the only parameters that affect the severity of the disease. In addition, the high levels of HbF in patients with CAR haplotypes did not seem to ameliorate the severity of symptoms, suggesting that genetic factors other than haplotypes are the major determinants of increased HbF levels in Lebanon.

  11. Sequential changes in chromatin structure during transcriptional activation in the beta globin LCR and its target gene.

    Science.gov (United States)

    Kim, Kihoon; Kim, AeRi

    2010-09-01

    Chromatin structure is modulated during transcriptional activation. The changes include the association of transcriptional activators, formation of hypersensitive sites and covalent modifications of histones. To understand the order of the various changes accompanying transcriptional activation, we analyzed the mouse beta globin gene, which is transcriptionally inducible in erythroid MEL cells over a time course of HMBA treatment. Transcription of the globin genes requires the locus control region (LCR) consisting of several hypersensitive sites (HSs). Erythroid specific transcriptional activators such as NF-E2, GATA-1, TAL1 and EKLF were associated with the LCR in the uninduced state before transcriptional activation. The HSs of the LCR were formed in this state as revealed by high sensitivity to DNase I and MNase attack. However the binding of transcriptional activators and the depletion of histones were observed in the promoter of the beta globin gene only after transcriptional activation. In addition, various covalent histone modifications were sequentially detected in lysine residues of histone H3 during the activation. Acetylation of K9, K36 and K27 was notable in both LCR HSs and gene after induction but before transcriptional initiation. Inactive histone marks such as K9me2, K36me2 and K27me2 were removed coincident with transcriptional initiation in the gene region. Taken together, these results indicate that LCR has a substantially active structure in the uninduced state while transcriptional activation serially adds active marks, including histone modifications, and removes inactive marks in the target gene of the LCR.

  12. Allele-specific enzymatic amplification of. beta. -globin genomic DNA for diagnosis of sickle cell anemia

    Energy Technology Data Exchange (ETDEWEB)

    Wu, D.Y.; Ugozzoli, L.; Pal, B.K.; Wallace, B. (Beckman Research Institute of the City of Hope, Duarte, CA (USA))

    1989-04-01

    A rapid nonradioactive approach to the diagnosis of sickle cell anemia is described based on an allele-specific polymerase chain reaction (ASPCR). This method allows direct detection of the normal or the sickle cell {beta}-globin allele in genomic DNA without additional steps of probe hybridization, ligation, or restriction enzyme cleavage. Two allele-specific oligonucleotide primers, one specific for the sickle cell allele and one specific for the normal allele, together with another primer complementary to both alleles were used in the polymerase chain reaction with genomic DNA templates. The allele-specific primers differed from each other in their terminal 3{prime} nucleotide. Under the proper annealing temperature and polymerase chain reaction conditions, these primers only directed amplification on their complementary allele. In a single blind study of DNA samples from 12 individuals, this method correctly and unambiguously allowed for the determination of the genotypes with no false negatives or positives. If ASPCR is able to discriminate all allelic variation (both transition and transversion mutations), this method has the potential to be a powerful approach for genetic disease diagnosis, carrier screening, HLA typing, human gene mapping, forensics, and paternity testing.

  13. Non-random association of the Rsa I polymorphic site 5' to the beta-globin gene with major sickle cell haplotypes.

    Science.gov (United States)

    Sharon, B; Poncz, M; Surrey, S; Schwartz, E

    1988-01-01

    There are three main African haplotypes associated with the sickle mutation on chromosome 11. We have examined an Rsa I polymorphism 550 bp 5' to the beta-globin gene to study the degree of linkage disequilibrium between this Rsa I site and the three haplotypes. This Rsa I site is contained within the 10.3 kb or less area of randomization separating the 5'- and 3'-haplotype clusters. The beta S-containing chromosomes of the Benin and Senegal haplotypes are not cut, while those of the Central African Republic are cleaved by Rsa I at this site. Possible explanations of these findings are discussed.

  14. Therapeutic haemoglobin synthesis in beta-thalassaemic mice expressing lentivirus-encoded human beta-globin.

    Science.gov (United States)

    May, C; Rivella, S; Callegari, J; Heller, G; Gaensler, K M; Luzzatto, L; Sadelain, M

    2000-07-06

    The stable introduction of a functional beta-globin gene in haematopoietic stem cells could be a powerful approach to treat beta-thalassaemia and sickle-cell disease. Genetic approaches aiming to increase normal beta-globin expression in the progeny of autologous haematopoietic stem cells might circumvent the limitations and risks of allogeneic cell transplants. However, low-level expression, position effects and transcriptional silencing hampered the effectiveness of viral transduction of the human beta-globin gene when it was linked to minimal regulatory sequences. Here we show that the use of recombinant lentiviruses enables efficient transfer and faithful integration of the human beta-globin gene together with large segments of its locus control region. In long-term recipients of unselected transduced bone marrow cells, tetramers of two murine alpha-globin and two human betaA-globin molecules account for up to 13% of total haemoglobin in mature red cells of normal mice. In beta-thalassaemic heterozygous mice higher percentages are obtained (17% to 24%), which are sufficient to ameliorate anaemia and red cell morphology. Such levels should be of therapeutic benefit in patients with severe defects in haemoglobin production.

  15. Structure of the human G gamma-A gamma-delta-beta-globin gene locus

    NARCIS (Netherlands)

    Bernards, R.A.; Little, P.F.R.; Annison, F.; Williamson, R.; Flavell, R.A.

    1979-01-01

    We have constructed a physical map of the human G gamma-, A gamma-, delta-, and beta-globin genes. The previously described maps of the fetal and adult beta-like globin genes have been linked to one another by identification of a DNA fragment, generated by BamHI, that contains part of each of the A

  16. Mechanisms of developmental control of transcription in the murine alpha- and beta-globin loci

    NARCIS (Netherlands)

    T. Trimborn (Tolleiv); J.H. Gribnau (Joost); P.J. Fraser (Peter); F.G. Grosveld (Frank)

    1999-01-01

    textabstractWe have characterized mRNA expression and transcription of the mouse alpha- and beta-globin loci during development. S1 nuclease and primary transcript in situ hybridization analyses demonstrate that all seven murine globin genes (zeta, alpha1, alpha2, epsil

  17. The role of EKLF in human beta-globin gene competition.

    Science.gov (United States)

    Wijgerde, M; Gribnau, J; Trimborn, T; Nuez, B; Philipsen, S; Grosveld, F; Fraser, P

    1996-11-15

    We have investigated the role of erythroid Kruppel-like factor (EKLF) in expression of the human beta-globin genes in compound EKLF knockout/human beta-locus transgenic mice. EKLF affects only the adult mouse beta-globin genes in homozygous knockout mice; heterozygous mice are unaffected. Here we show that EKLF knockout mice express the human epsilon and gamma-globin genes normally in embryonic red cells. However, fetal liver erythropoiesis, which is marked by a period of gamma- and beta-gene competition in which the genes are alternately transcribed, exhibits an altered ratio of gamma- to beta-gene transcription. EKLF heterozygous fetal livers display a decrease in the number of transcriptionally active beta genes with a reciprocal increase in the number of transcriptionally active gamma genes. beta-Gene transcription is absent in homozygous knockout fetuses with coincident changes in chromatin structure at the beta promoter. There is a further increase in the number of transcriptionally active gamma genes and accompanying gamma gene promoter chromatin alterations. These results indicate that EKLF plays a major role in gamma- and beta-gene competition and suggest that EKLF is important in stabilizing the interaction between the Locus Control Region and the beta-globin gene. In addition, these findings provide further evidence that developmental modulation of globin gene expression within individual cells is accomplished by altering the frequency and/or duration of transcriptional periods of a gene rather than changing the rate of transcription.

  18. Allele-specific enzymatic amplification of beta-globin genomic DNA for diagnosis of sickle cell anemia.

    Science.gov (United States)

    Wu, D Y; Ugozzoli, L; Pal, B K; Wallace, R B

    1989-04-01

    A rapid nonradioactive approach to the diagnosis of sickle cell anemia is described based on an allele-specific polymerase chain reaction (ASPCR). This method allows direct detection of the normal or the sickle cell beta-globin allele in genomic DNA without additional steps of probe hybridization, ligation, or restriction enzyme cleavage. Two allele-specific oligonucleotide primers, one specific for the sickle cell allele and one specific for the normal allele, together with another primer complementary to both alleles were used in the polymerase chain reaction with genomic DNA templates. The allele-specific primers differed from each other in their terminal 3' nucleotide. Under the proper annealing temperature and polymerase chain reaction conditions, these primers only directed amplification on their complementary allele. In a single blind study of DNA samples from 12 individuals, this method correctly and unambiguously allowed for the determination of the genotypes with no false negatives or positives. If ASPCR is able to discriminate all allelic variation (both transition and transversion mutations), this method has the potential to be a powerful approach for genetic disease diagnosis, carrier screening, HLA typing, human gene mapping, forensics, and paternity testing.

  19. Inter-MAR association contributes to transcriptionally active looping events in human beta-globin gene cluster.

    Science.gov (United States)

    Wang, Li; Di, Li-Jun; Lv, Xiang; Zheng, Wei; Xue, Zheng; Guo, Zhi-Chen; Liu, De-Pei; Liang, Chi-Chuan

    2009-01-01

    Matrix attachment regions (MARs) are important in chromatin organization and gene regulation. Although it is known that there are a number of MAR elements in the beta-globin gene cluster, it is unclear that how these MAR elements are involved in regulating beta-globin genes expression. Here, we report the identification of a new MAR element at the LCR (locus control region) of human beta-globin gene cluster and the detection of the inter-MAR association within the beta-globin gene cluster. Also, we demonstrate that SATB1, a protein factor that has been implicated in the formation of network like higher order chromatin structures at some gene loci, takes part in beta-globin specific inter-MAR association through binding the specific MARs. Knocking down of SATB1 obviously reduces the binding of SATB1 to the MARs and diminishes the frequency of the inter-MAR association. As a result, the ACH establishment and the alpha-like globin genes and beta-like globin genes expressions are affected either. In summary, our results suggest that SATB1 is a regulatory factor of hemoglobin genes, especially the early differentiation genes at least through affecting the higher order chromatin structure.

  20. Beta-globin gene cluster haplotypes in Venezuelan sickle cell patients from the State of Aragua

    OpenAIRE

    Nancy Moreno; Martínez, José A.; Zorella Blanco; Leidys Osorio; Patrick Hackshaw

    2002-01-01

    Seven polymorphic sites in the beta-globin gene cluster were analyzed on a sample of 96 chromosomes of Venezuelan sickle cell patients from the State of Aragua. The Benin haplotype was predominant with a frequency of 0.479, followed by the Bantu haplotype (0.406); a minority of cases with other haplotypes was also identified: atypical Bantu A2 (0.042), Senegal (0.031), atypical Bantu A7 (0.021) and Saudi Arabia/Indian (0.021) haplotypes; however, the Cameroon haplotype was not identified in t...

  1. Generation of a genomic reporter assay system for analysis of gamma- and beta-globin gene regulation

    NARCIS (Netherlands)

    Chan, Kasey S. K.; Xu, Jian; Wardan, Hady; McColl, Bradley; Orkin, Stuart; Vadolas, Jim

    2012-01-01

    A greater understanding of the regulatory mechanisms that govern gamma-globin expression in humans, especially the switching from gamma- to beta-globin, which occurs after birth, would help to identify new therapeutic targets for patients with beta-hemoglobinopathy. To further elucidate the mechanis

  2. Beta-globin gene cluster haplotypes in Venezuelan sickle cell patients from the State of Aragua

    Directory of Open Access Journals (Sweden)

    Nancy Moreno

    2002-01-01

    Full Text Available Seven polymorphic sites in the beta-globin gene cluster were analyzed on a sample of 96 chromosomes of Venezuelan sickle cell patients from the State of Aragua. The Benin haplotype was predominant with a frequency of 0.479, followed by the Bantu haplotype (0.406; a minority of cases with other haplotypes was also identified: atypical Bantu A2 (0.042, Senegal (0.031, atypical Bantu A7 (0.021 and Saudi Arabia/Indian (0.021 haplotypes; however, the Cameroon haplotype was not identified in this study. Our results are in agreement with the historical records that establish Sudanese and Bantu origins for the African slaves brought into Venezuela.

  3. Beta-globin LCR and intron elements cooperate and direct spatial reorganization for gene therapy.

    Directory of Open Access Journals (Sweden)

    Alla Buzina

    2008-04-01

    Full Text Available The Locus Control Region (LCR requires intronic elements within beta-globin transgenes to direct high level expression at all ectopic integration sites. However, these essential intronic elements cannot be transmitted through retrovirus vectors and their deletion may compromise the therapeutic potential for gene therapy. Here, we systematically regenerate functional beta-globin intron 2 elements that rescue LCR activity directed by 5'HS3. Evaluation in transgenic mice demonstrates that an Oct-1 binding site and an enhancer in the intron cooperate to increase expression levels from LCR globin transgenes. Replacement of the intronic AT-rich region with the Igmu 3'MAR rescues LCR activity in single copy transgenic mice. Importantly, a combination of the Oct-1 site, Igmu 3'MAR and intronic enhancer in the BGT158 cassette directs more consistent levels of expression in transgenic mice. By introducing intron-modified transgenes into the same genomic integration site in erythroid cells, we show that BGT158 has the greatest transcriptional induction. 3D DNA FISH establishes that induction stimulates this small 5'HS3 containing transgene and the endogenous locus to spatially reorganize towards more central locations in erythroid nuclei. Electron Spectroscopic Imaging (ESI of chromatin fibers demonstrates that ultrastructural heterochromatin is primarily perinuclear and does not reorganize. Finally, we transmit intron-modified globin transgenes through insulated self-inactivating (SIN lentivirus vectors into erythroid cells. We show efficient transfer and robust mRNA and protein expression by the BGT158 vector, and virus titer improvements mediated by the modified intron 2 in the presence of an LCR cassette composed of 5'HS2-4. Our results have important implications for the mechanism of LCR activity at ectopic integration sites. The modified transgenes are the first to transfer intronic elements that potentiate LCR activity and are designed to facilitate

  4. Meiotic recombination in the beta globin gene cluster causing an error in prenatal diagnosis of beta thalassaemia.

    OpenAIRE

    Camaschella, C.; Serra, A.; Saglio, G; Bertero, M T; Mazza, U; Terzoli, S; Brambati, B; Cremonesi, L.; Travi, M; Ferrari, M

    1988-01-01

    In the course of a prenatal diagnosis for beta thalassaemia by linkage analysis of restriction fragment length polymorphisms, a homozygous beta thalassaemia fetus was misdiagnosed as beta thalassaemia trait. Extensive studies of the polymorphic sites within the beta globin gene cluster in all the members of the family resulted in the conclusion that the paternal chromosome 11 of the newborn was different from that expected. Paternity was confirmed by HLA typing and blood group studies. The an...

  5. Allele-specific enzymatic amplification of beta-globin genomic DNA for diagnosis of sickle cell anemia.

    OpenAIRE

    1989-01-01

    A rapid nonradioactive approach to the diagnosis of sickle cell anemia is described based on an allele-specific polymerase chain reaction (ASPCR). This method allows direct detection of the normal or the sickle cell beta-globin allele in genomic DNA without additional steps of probe hybridization, ligation, or restriction enzyme cleavage. Two allele-specific oligonucleotide primers, one specific for the sickle cell allele and one specific for the normal allele, together with another primer co...

  6. Unexpected expression of alpha- and beta-globin in mesencephalic dopaminergic neurons and glial cells.

    Science.gov (United States)

    Biagioli, Marta; Pinto, Milena; Cesselli, Daniela; Zaninello, Marta; Lazarevic, Dejan; Roncaglia, Paola; Simone, Roberto; Vlachouli, Christina; Plessy, Charles; Bertin, Nicolas; Beltrami, Antonio; Kobayashi, Kazuto; Gallo, Vittorio; Santoro, Claudio; Ferrer, Isidro; Rivella, Stefano; Beltrami, Carlo Alberto; Carninci, Piero; Raviola, Elio; Gustincich, Stefano

    2009-09-08

    The mesencephalic dopaminergic (mDA) cell system is composed of two major groups of projecting cells in the substantia nigra (SN) (A9 neurons) and the ventral tegmental area (VTA) (A10 cells). A9 neurons form the nigrostriatal pathway and are involved in regulating voluntary movements and postural reflexes. Their selective degeneration leads to Parkinson's disease. Here, we report that gene expression analysis of A9 dopaminergic neurons (DA) identifies transcripts for alpha- and beta-chains of hemoglobin (Hb). Globin immunoreactivity decorates the majority of A9 DA, a subpopulation of cortical and hippocampal astrocytes and mature oligodendrocytes. This pattern of expression was confirmed in different mouse strains and in rat and human. We show that Hb is expressed in the SN of human postmortem brain. By microarray analysis of dopaminergic cell lines overexpressing alpha- and beta-globin chains, changes in genes involved in O(2) homeostasis and oxidative phopshorylation were observed, linking Hb expression to mitochondrial function. Our data suggest that the most famed oxygen-carrying globin is not exclusively restricted to the blood, but it may play a role in the normal physiology of the brain and neurodegenerative diseases.

  7. Common 5' beta-globin RFLP haplotypes harbour a surprising level of ancestral sequence mosaicism.

    Science.gov (United States)

    Webster, Matthew T; Clegg, John B; Harding, Rosalind M

    2003-07-01

    Blocks of linkage disequilibrium (LD) in the human genome represent segments of ancestral chromosomes. To investigate the relationship between LD and genealogy, we analysed diversity associated with restriction fragment length polymorphism (RFLP) haplotypes of the 5' beta-globin gene complex. Genealogical analyses were based on sequence alleles that spanned a 12.2-kb interval, covering 3.1 kb around the psibeta gene and 6.2 kb of the delta-globin gene and its 5' flanking sequence known as the R/T region. Diversity was sampled from a Kenyan Luo population where recent malarial selection has contributed to substantial LD. A single common sequence allele spanning the 12.2-kb interval exclusively identified the ancestral chromosome bearing the "Bantu" beta(s) (sickle-cell) RFLP haplotype. Other common 5' RFLP haplotypes comprised interspersed segments from multiple ancestral chromosomes. Nucleotide diversity was similar between psibeta and R/T-delta-globin but was non-uniformly distributed within the R/T-delta-globin region. High diversity associated with the 5' R/T identified two ancestral lineages that probably date back more than 2 million years. Within this genealogy, variation has been introduced into the 3' R/T by gene conversion from other ancestral chromosomes. Diversity in delta-globin was found to lead through parts of the main genealogy but to coalesce in a more recent ancestor. The well-known recombination hotspot is clearly restricted to the region 3' of delta-globin. Our analyses show that, whereas one common haplotype in a block of high LD represents a long segment from a single ancestral chromosome, others are mosaics of short segments from multiple ancestors related in genealogies of unsuspected complexity.

  8. High-density SNP genotyping to define beta-globin locus haplotypes.

    Science.gov (United States)

    Liu, Li; Muralidhar, Shalini; Singh, Manisha; Sylvan, Caprice; Kalra, Inderdeep S; Quinn, Charles T; Onyekwere, Onyinye C; Pace, Betty S

    2009-01-01

    Five major beta-globin locus haplotypes have been established in individuals with sickle cell disease (SCD) from the Benin, Bantu, Senegal, Cameroon, and Arab-Indian populations. Historically, beta-haplotypes were established using restriction fragment length polymorphism (RFLP) analysis across the beta-locus, which consists of five functional beta-like globin genes located on chromosome 11. Previous attempts to correlate these haplotypes as robust predictors of clinical phenotypes observed in SCD have not been successful. We speculate that the coverage and distribution of the RFLP sites located proximal to or within the globin genes are not sufficiently dense to accurately reflect the complexity of this region. To test our hypothesis, we performed RFLP analysis and high-density single nucleotide polymorphism (SNP) genotyping across the beta-locus using DNA samples from healthy African Americans with either normal hemoglobin A (HbAA) or individuals with homozygous SS (HbSS) disease. Using the genotyping data from 88 SNPs and Haploview analysis, we generated a greater number of haplotypes than that observed with RFLP analysis alone. Furthermore, a unique pattern of long-range linkage disequilibrium between the locus control region and the beta-like globin genes was observed in the HbSS group. Interestingly, we observed multiple SNPs within the HindIII restriction site located in the Ggamma-globin intervening sequence II which produced the same RFLP pattern. These findings illustrated the inability of RFLP analysis to decipher the complexity of sequence variations that impacts genomic structure in this region. Our data suggest that high-density SNP mapping may be required to accurately define beta-haplotypes that correlate with the different clinical phenotypes observed in SCD.

  9. In silico mutation analysis of human beta globin gene in sickle cell disease patients

    Directory of Open Access Journals (Sweden)

    Hira Mubeen

    2016-05-01

    Conclusion: Studies suggested that there is need to maintain a primary prevention program to detect sickle cell disease at earlier stages despite having a large high risk. Preventive diagnosis and follow-up would reduce infant mortality by preventing the development of severe anemia as well as dangerous complications. In short, sickle cell disease surveillance would avert loss of life, measured as the number of years lost due to ill-health, disability or early death. [Int J Res Med Sci 2016; 4(5.000: 1673-1677

  10. Gamma rays and bleomycin nick DNA and reverse the DNase I sensitivity of beta-globin gene chromatin in vivo

    Energy Technology Data Exchange (ETDEWEB)

    Villeponteau, B.; Martinson, H.G.

    1987-05-01

    The active beta-globin genes in chicken erythrocytes, like all active genes, reside in large chromatin domains which are preferentially sensitive to digestion by DNase I. We have recently proposed that the special structure of chromatin in active domains is maintained by torsional stress in the DNA. This hypothesis predicts that nicking of the DNA within any such chromosomal domain in vivo will relax the DNA and lead to loss of the special DNase I-sensitive state. Here we have tested this prediction by using gamma irradiation and bleomycin treatment to cleave DNA within intact chicken embryo erythrocytes. Both treatments cause reversal of DNase I sensitivity. Moreover, reversal occurs at approximately one nick per 150 kilobase pairs for both agents despite their entirely unrelated modes of cell penetration and DNA attack. These results suggest that the domain of DNase I sensitivity surrounding the beta-globin genes comprises 150 kilobase pairs of chromatin under torsional stress and that a single DNA nick in this region is sufficient to reverse the DNase I sensitivity throughout the entire domain.

  11. (AC)n dinucleotide repeat polymorphism in 5' beta-globin gene in native and Mestizo Mexican populations.

    Science.gov (United States)

    Peñaloza, R; Delgado, P; Arenas, D; Barrientos, C; Buentello, L; Loeza, F; Salamanca, F

    2001-12-01

    Repeated sequences are dispersed along the human genome. These sequences are useful as markers in diagnosis of inherited diseases, in forensic medicine, and in tracking the origin and evolution of human populations. The (AC)n repeated element is the most frequent in the human genome. In this paper, the (AC)n repeated element located in the 5' flanking region of the beta-globin gene was studied by single-strand conformation polymorphism (SSCP). Four ethnic Mexican groups (Mixteca, Nahua, Otomí, Purépecha) and a Mestizo population were analyzed. We observed three alleles, A [(AC)16, B [(AC)14], and C [(AC)18], with a frequency of between 68.2% and 86.9%, 13.1% and 18.2%, and 6.7% and 13.7%, respectively. Allele C was present only in Purépecha and Mestizo groups. The absence of this allele in the other ethnic groups studied suggests that there is low genetic admixture of Purépecha and that this is a relatively isolated population. However, it could be that the C allele occurs in low frequencies in the other groups as a result of small sample sizes. The (AC)n repeat polymorphism in the beta-globin gene has not been previously studied in Amerindian populations.

  12. Classical sickle beta-globin haplotypes exhibit a high degree of long-range haplotype similarity in African and Afro-Caribbean populations

    Directory of Open Access Journals (Sweden)

    Jallow Muminatou

    2007-08-01

    Full Text Available Abstract Background The sickle (βs mutation in the beta-globin gene (HBB occurs on five "classical" βs haplotype backgrounds in ethnic groups of African ancestry. Strong selection in favour of the βs allele – a consequence of protection from severe malarial infection afforded by heterozygotes – has been associated with a high degree of extended haplotype similarity. The relationship between classical βs haplotypes and long-range haplotype similarity may have both anthropological and clinical implications, but to date has not been explored. Here we evaluate the haplotype similarity of classical βs haplotypes over 400 kb in population samples from Jamaica, The Gambia, and among the Yoruba of Nigeria (Hapmap YRI. Results The most common βs sub-haplotype among Jamaicans and the Yoruba was the Benin haplotype, while in The Gambia the Senegal haplotype was observed most commonly. Both subtypes exhibited a high degree of long-range haplotype similarity extending across approximately 400 kb in all three populations. This long-range similarity was significantly greater than that seen for other haplotypes sampled in these populations (P s mutation. Conclusion Two different classical βs haplotypes, sampled from different populations, exhibit comparable and extensive long-range haplotype similarity and strong LD. This LD extends across the adjacent recombination hotspot, and is discernable at distances in excess of 400 kb. Although the multi-centric geographic distribution of βs haplotypes indicates strong subdivision among early Holocene sub-Saharan populations, we find no evidence that selective pressures imposed by falciparum malaria varied in intensity or timing between these subpopulations. Our observations also suggest that cis-acting loci, which may influence outcomes in sickle cell disease, could lie considerable distances away from β-globin.

  13. Frequency and origin of haplotypes associated with the beta-globin gene cluster in individuals with trait and sickle cell anemia in the Atlantic and Pacific coastal regions of Colombia.

    Science.gov (United States)

    Fong, Cristian; Lizarralde-Iragorri, María Alejandra; Rojas-Gallardo, Diana; Barreto, Guillermo

    2013-12-01

    Sickle cell anemia is a genetic disease with high prevalence in people of African descent. There are five typical haplotypes associated with this disease and the haplotypes associated with the beta-globin gene cluster have been used to establish the origin of African-descendant people in America. In this work, we determined the frequency and the origin of haplotypes associated with hemoglobin S in a sample of individuals with sickle cell anemia (HbSS) and sickle cell hemoglobin trait (HbAS) in coastal regions of Colombia. Blood samples from 71 HbAS and 79 HbSS individuals were obtained. Haplotypes were determined based on the presence of variable restriction sites within the β-globin gene cluster. On the Pacific coast of Colombia the most frequent haplotype was Benin, while on the Atlantic coast Bantu was marginally higher than Benin. Eight atypical haplotypes were observed on both coasts, being more diverse in the Atlantic than in the Pacific region. These results suggest a differential settlement of the coasts, dependent on where slaves were brought from, either from the Gulf of Guinea or from Angola, where the haplotype distributions are similar. Atypical haplotypes probably originated from point mutations that lost or gained a restriction site and/or by recombination events.

  14. Frequency and origin of haplotypes associated with the beta-globin gene cluster in individuals with trait and sickle cell anemia in the Atlantic and Pacific coastal regions of Colombia

    Directory of Open Access Journals (Sweden)

    Cristian Fong

    2013-01-01

    Full Text Available Sickle cell anemia is a genetic disease with high prevalence in people of African descent. There are five typical haplotypes associated with this disease and the haplotypes associated with the beta-globin gene cluster have been used to establish the origin of African-descendant people in America. In this work, we determined the frequency and the origin of haplotypes associated with hemoglobin S in a sample of individuals with sickle cell anemia (HbSS and sickle cell hemoglobin trait (HbAS in coastal regions of Colombia. Blood samples from 71 HbAS and 79 HbSS individuals were obtained. Haplotypes were determined based on the presence of variable restriction sites within the β-globin gene cluster. On the Pacific coast of Colombia the most frequent haplotype was Benin, while on the Atlantic coast Bantu was marginally higher than Benin. Eight atypical haplotypes were observed on both coasts, being more diverse in the Atlantic than in the Pacific region. These results suggest a differential settlement of the coasts, dependent on where slaves were brought from, either from the Gulf of Guinea or from Angola, where the haplotype distributions are similar. Atypical haplotypes probably originated from point mutations that lost or gained a restriction site and/or by recombination events.

  15. A novel murine model of Cooley anemia and its rescue by lentiviral-mediated human beta-globin gene transfer.

    Science.gov (United States)

    Rivella, Stefano; May, Chad; Chadburn, Amy; Rivière, Isabelle; Sadelain, Michel

    2003-04-15

    Patients affected by beta-thalassemia major require lifelong transfusions because of insufficient or absent production of the beta chain of hemoglobin (Hb). A minority of patients are cured by allogeneic bone marrow transplantation. In the most severe of the hitherto available mouse models of beta-thalassemia, a model for human beta-thalassemia intermedia, we previously demonstrated that globin gene transfer in bone marrow cells is curative, stably raising Hb levels from 8.0-8.5 to 11.0-12.0 g/dL in long-term chimeras. To fully assess the therapeutic potential of gene therapy in the context of a lethal anemia, we now have created an adult model of beta(0)-thalassemia major. In this novel model, mice engrafted with beta-globin-null (Hbb(th3/th3)) fetal liver cells succumb to ineffective erythropoiesis within 60 days. These mice rapidly develop severe anemia (2-4 g/dL), massive splenomegaly, extramedullary hematopoiesis (EMH), and hepatic iron overload. Remarkably, most mice (11 of 13) treated by lentivirus-mediated globin gene transfer were rescued. Long-term chimeras with an average 1.0-2.4 copies of the TNS9 vector in their hematopoietic and blood cells stably produced up to 12 g/dL chimeric Hb consisting of mu alpha(2):hu beta(2) tetramers. Pathologic analyses indicated that erythroid maturation was restored, while EMH and iron overload dramatically decreased. Thus, we have established an adult animal model for the most severe of the hemoglobinopathies, Cooley anemia, which should prove useful to investigate both genetic and pharmacologic treatments. Our findings demonstrate the remarkable efficacy of lentivirus-mediated globin gene transfer in treating a fulminant blood disorder and strongly support the efficacy of gene therapy in the severe hemoglobinopathies.

  16. Effect of beta-globin gene cluster haplotype on the hematological and clinical features of sickle cell anemia.

    Science.gov (United States)

    Rieder, R F; Safaya, S; Gillette, P; Fryd, S; Hsu, H; Adams, J G; Steinberg, M H

    1991-03-01

    In 113 black American adults with sickle cell anemia (HbSS), we examined nine polymorphic restriction sites, including the Xmnl site 5' to the G gamma gene, to see whether haplotype is related to the level of HbF and the proportion of G gamma chains or if it influences the hematological and clinical features of the disease. Seventy-five percent of the patients were homozygous or heterozygous for the Benin (no. 19) or Central African Republic (Bantu, no. 20) haplotypes; 13.3% were homozygous or heterozygous for the Senegal (no. 3) haplotype, while 11.5% had other genotypes. Of the subjects, 14.2% were either homozygous or heterozygous for the Xmnl restriction site 5' to the G gamma gene. We found no effect of haplotype on HbF levels. The level of G gamma chains was 60.5% +/- 17.0% in individuals heterozygous or homozygous for haplotype no. 3 and was 46.9% +/- 11.6% in individuals with other haplotypes. Subjects with the Xmnl site 5' to the G gamma gene had G gamma globin levels of 59.5% +/- 16.7% while those lacking that site had an average of 47.2% +/- 12.1%. There were no significant differences among these groups in hemoglobin concentration, packed cell volume, mean cell volume, or clinical indicators of vaso-occlusive severity, including crises, hospitalizations per year, aseptic bone necrosis, acute chest syndrome, or leg ulcers. While the presence of haplotype 3 and the 5' G gamma Xmnl site were associated with increased G gamma chains, there was no effect on HbF level or other hematological and clinical features that might reflect disease severity. It is likely that determinants unrelated to haplotype, linked or unlinked to the beta-globin gene cluster, are the major effectors of differences in the levels of HbF in American patients with sickle cell anemia.

  17. Mutations induced in plant breeding

    Energy Technology Data Exchange (ETDEWEB)

    Barriga B, P. (Universidad Austral de Chile, Valdivia. Inst. de Produccion y Sanidad Vegetal)

    1984-10-01

    The most significant aspects of the use of ionizing radiations in plant breeding are reviewed. Aspects such as basic principles of mutation, expression and selection in obtention of mutants, methods for using induced mutations and sucess achieved with this methodology in plant breeding are reviewed. Results obtained in a program of induced mutation on wheat for high content of protein and lysine at the Universidad Austral de Chile are presented.

  18. Search for antisense copies of beta-globin mRNA in anemic mouse spleen

    Directory of Open Access Journals (Sweden)

    Taylor John M

    2001-03-01

    Full Text Available Abstract Background Previous studies by Volloch and coworkers have reported that during the expression of high levels of β-globin mRNA in the spleen of anemic mice, they could also detect small but significant levels of an antisense (AS globin RNA species, which they postulated might have somehow arisen by RNA-directed RNA synthesis. For two reasons we undertook to confirm and possibly extend these studies. First, previous studies in our lab have focussed on what is an unequivocal example of host RNA-directed RNA polymerase activity on the RNA genome of human hepatitis delta virus. Second, if AS globin species do exist they could in turn form double-stranded RNA species which might induce post-transcriptional gene silencing, a phenomenon somehow provoked in eukaryotic cells by AS RNA sequences. Results We reexamined critical aspects of the previous globin studies. We used intraperitoneal injections of phenylhydrazine to induce anemia in mice, as demonstrated by the appearance and ultimate disappearance of splenomegaly. While a 30-fold increase in globin mRNA was detected in the spleen, the relative amount of putative AS RNA could be no more than 0.004%. Conclusions Contrary to earlier reports, induction of a major increase in globin transcripts in the mouse spleen was not associated with a detectable level of antisense RNA to globin mRNA.

  19. Splice-site mutations cause Rrp6-mediated nuclear retention of the unspliced RNAs and transcriptional down-regulation of the splicing-defective genes.

    Directory of Open Access Journals (Sweden)

    Andrea B Eberle

    Full Text Available BACKGROUND: Eukaryotic cells have developed surveillance mechanisms to prevent the expression of aberrant transcripts. An early surveillance checkpoint acts at the transcription site and prevents the release of mRNAs that carry processing defects. The exosome subunit Rrp6 is required for this checkpoint in Saccharomyces cerevisiae, but it is not known whether Rrp6 also plays a role in mRNA surveillance in higher eukaryotes. METHODOLOGY/PRINCIPAL FINDINGS: We have developed an in vivo system to study nuclear mRNA surveillance in Drosophila melanogaster. We have produced S2 cells that express a human beta-globin gene with mutated splice sites in intron 2 (mut beta-globin. The transcripts encoded by the mut beta-globin gene are normally spliced at intron 1 but retain intron 2. The levels of the mut beta-globin transcripts are much lower than those of wild type (wt ss-globin mRNAs transcribed from the same promoter. We have compared the expression of the mut and wt beta-globin genes to investigate the mechanisms that down-regulate the production of defective mRNAs. Both wt and mut beta-globin transcripts are processed at the 3', but the mut beta-globin transcripts are less efficiently cleaved than the wt transcripts. Moreover, the mut beta-globin transcripts are less efficiently released from the transcription site, as shown by FISH, and this defect is restored by depletion of Rrp6 by RNAi. Furthermore, transcription of the mut beta-globin gene is significantly impaired as revealed by ChIP experiments that measure the association of the RNA polymerase II with the transcribed genes. We have also shown that the mut beta-globin gene shows reduced levels of H3K4me3. CONCLUSIONS/SIGNIFICANCE: Our results show that there are at least two surveillance responses that operate cotranscriptionally in insect cells and probably in all metazoans. One response requires Rrp6 and results in the inefficient release of defective mRNAs from the transcription site. The

  20. Axolotl hemoglobin: cDNA-derived amino acid sequences of two alpha globins and a beta globin from an adult Ambystoma mexicanum.

    Science.gov (United States)

    Shishikura, Fumio; Takeuchi, Hiro-aki; Nagai, Takatoshi

    2005-11-01

    Erythrocytes of the adult axolotl, Ambystoma mexicanum, have multiple hemoglobins. We separated and purified two kinds of hemoglobin, termed major hemoglobin (Hb M) and minor hemoglobin (Hb m), from a five-year-old male by hydrophobic interaction column chromatography on Alkyl Superose. The hemoglobins have two distinct alpha type globin polypeptides (alphaM and alpham) and a common beta globin polypeptide, all of which were purified in FPLC on a reversed-phase column after S-pyridylethylation. The complete amino acid sequences of the three globin chains were determined separately using nucleotide sequencing with the assistance of protein sequencing. The mature globin molecules were composed of 141 amino acid residues for alphaM globin, 143 for alpham globin and 146 for beta globin. Comparing primary structures of the five kinds of axolotl globins, including two previously established alpha type globins from the same species, with other known globins of amphibians and representatives of other vertebrates, we constructed phylogenetic trees for amphibian hemoglobins and tetrapod hemoglobins. The molecular trees indicated that alphaM, alpham, beta and the previously known alpha major globin were adult types of globins and the other known alpha globin was a larval type. The existence of two to four more globins in the axolotl erythrocyte is predicted.

  1. The relative importance of the X-linked FCP locus and beta-globin haplotypes in determining haemoglobin F levels: a study of SS patients homozygous for beta S haplotypes.

    Science.gov (United States)

    Chang, Y P; Maier-Redelsperger, M; Smith, K D; Contu, L; Ducroco, R; de Montalembert, M; Belloy, M; Elion, J; Dover, G J; Girot, R

    1997-03-01

    Five factors have been hypothesized to influence the 20-fold variation in fetal haemoglobin (Hb F) levels in sickle cell anaemia (SS): age sex, alpha-globin gene number, beta-globin haplotype, and the X-linked F-cell production locus (FCP) that regulates the production of Hb F containing erythrocytes (F cells). We analysed the association of these factors with Hb F levels in 112 SS patients living in France who are homozygous for the three common African beta-globin haplotypes (Benin, Bantu or Central African Republic and Senegal). We found that: (1) FCP accounts for about 40% of the overall variation in Hb F levels, (2) when the FCP influence is removed, beta-globin haplotype is associated with 14% of the remaining Hb F variation, and (3) the other factors have little influence. Comparison with our previous study of SS individuals in Jamaica leads to the following conclusions: (1) the X-linked FCP locus is a major determinant of Hb F levels in SS disease, (2) factors linked to the beta-globin haplotype have only a small effect on the variation in Hb F levels, in either the homozygous or heterozygous state, and (3)approximately half of the variation in Hb F levels still remains to be explained.

  2. Mutations induced by ultraviolet light

    Energy Technology Data Exchange (ETDEWEB)

    Pfeifer, Gerd P. [Department of Biology, Beckman Research Institute, City of Hope, Duarte, CA 91010 (United States)]. E-mail: gpfeifer@coh.org; You, Young-Hyun [Department of Biology, Beckman Research Institute, City of Hope, Duarte, CA 91010 (United States); Besaratinia, Ahmad [Department of Biology, Beckman Research Institute, City of Hope, Duarte, CA 91010 (United States)

    2005-04-01

    The different ultraviolet (UV) wavelength components, UVA (320-400 nm), UVB (280-320 nm), and UVC (200-280 nm), have distinct mutagenic properties. A hallmark of UVC and UVB mutagenesis is the high frequency of transition mutations at dipyrimidine sequences containing cytosine. In human skin cancers, about 35% of all mutations in the p53 gene are transitions at dipyrimidines within the sequence 5'-TCG and 5'-CCG, and these are localized at several mutational hotspots. Since 5'-CG sequences are methylated along the p53 coding sequence in human cells, these mutations may be derived from sunlight-induced pyrimidine dimers forming at sequences that contain 5-methylcytosine. Cyclobutane pyrimidine dimers (CPDs) form preferentially at dipyrimidines containing 5-methylcytosine when cells are irradiated with UVB or sunlight. In order to define the contribution of 5-methylcytosine to sunlight-induced mutations, the lacI and cII transgenes in mouse fibroblasts were used as mutational targets. After 254 nm UVC irradiation, only 6-9% of the base substitutions were at dipyrimidines containing 5-methylcytosine. However, 24-32% of the solar light-induced mutations were at dipyrimidines that contain 5-methylcytosine and most of these mutations were transitions. Thus, CPDs forming preferentially at dipyrimidines with 5-methylcytosine are responsible for a considerable fraction of the mutations induced by sunlight in mammalian cells. Using mouse cell lines harboring photoproduct-specific photolyases and mutational reporter genes, we showed that CPDs (rather than 6-4 photoproducts or other lesions) are responsible for the great majority of UVB-induced mutations. An important component of UVB mutagenesis is the deamination of cytosine and 5-methylcytosine within CPDs. The mutational specificity of long-wave UVA (340-400 nm) is distinct from that of the shorter wavelength UV and is characterized mainly by G to T transversions presumably arising through mechanisms

  3. Erythroid Krüppel-like factor (EKLF) is active in primitive and definitive erythroid cells and is required for the function of 5'HS3 of the beta-globin locus control region.

    Science.gov (United States)

    Tewari, R; Gillemans, N; Wijgerde, M; Nuez, B; von Lindern, M; Grosveld, F; Philipsen, S

    1998-04-15

    Disruption of the gene for transcription factor EKLF (erythroid Krüppel-like factor) results in fatal anaemia caused by severely reduced expression of the adult beta-globin gene, while other erythroid-specific genes, including the embryonic epsilon- and fetal gamma-globin genes, are expressed normally. Thus, EKLF is thought to be a stage-specific factor acting through the CACC box in the beta-gene promoter, even though it is already present in embryonic red cells. Here, we show that a beta-globin gene linked directly to the locus control region (LCR) is expressed at embryonic stages, and that this is only modestly reduced in EKLF-/- embryos. Thus, embryonic beta-globin expression is not intrinsically dependent on EKLF. To investigate whether EKLF functions in the locus control region, we analysed the expression of LCR-driven lacZ reporters. This shows that EKLF is not required for reporter activation by the complete LCR. However, embryonic expression of reporters driven by 5'HS3 of the LCR requires EKLF. This suggests that EKLF interacts directly with the CACC motifs in 5'HS3 and demonstrates that EKLF is also a transcriptional activator in embryonic erythropoiesis. Finally, we show that overexpression of EKLF results in an earlier switch from gamma- to beta-globin expression. Adult mice with the EKLF transgene have reduced platelet counts, suggesting that EKLF levels affect the balance between the megakaryocytic and erythroid lineages. Interestingly, the EKLF transgene rescues the lethal phenotype of EKLF null mice, setting the stage for future studies aimed at the analysis of the EKLF protein and its role in beta-globin gene activation.

  4. An analysis of fetal hemoglobin variation in sickle cell disease: the relative contributions of the X-linked factor, beta-globin haplotypes, alpha-globin gene number, gender, and age.

    Science.gov (United States)

    Chang, Y C; Smith, K D; Moore, R D; Serjeant, G R; Dover, G J

    1995-02-15

    Five factors have been shown to influence the 20-fold variation of fetal hemoglobin (Hb F) levels in sickle cell anemia (SS): age, sex, the alpha-globin gene number, beta-globin haplotypes, and an X-linked locus that regulates the production of Hb F-containing erythrocytes (F cells), ie, the F-cell production (FCP) locus. To determine the relative importance of these factors, we studied 257 Jamaican SS subjects from a Cohort group identified by newborn screening and from a Sib Pair study. Linear regression analyses showed that each variable, when analyzed alone, had a significant association with Hb F levels (P haplotypes, alpha-globin genes, and age accounted for less than 10% of the variation. The association between the beta-globin haplotypes and Hb F levels becomes apparent if the influence of the FCP locus is removed by analyzing only individuals with the same FCP phenotype. Thus, the FCP locus is the most important factor identified to date in determining Hb F levels. The variation within each FCP phenotype is modulated by factors associated with the three common beta-globin haplotypes and other as yet unidentified factor(s).

  5. Confirmation of the potential usefulness of two human beta globin pseudogene markers to estimate gene flows to and from sub-Saharan Africans.

    Science.gov (United States)

    Ciminelli, Bianca Maria; Pompei, Fiorenza; Relucenti, Michela; Lum, J Koji; Simporé, Jacques; Spedini, Gabriella; Martínez-Labarga, Cristina; Pardo, Miguel G

    2002-04-01

    Two polymorphic sites, -107 and -100 with respect to the "cap" site of the human beta globin pseudogene, recently discovered in our laboratory, turned out to have an ethnically complementary distribution. The first site is polymorphic in Europeans, North Africans, Indians (Hindu), and Oriental Asians, and monomorphic in sub-Saharan Africans. Conversely, the second site is polymorphic in sub-Saharan African populations and monomorphic in the aforementioned populations. Here we report the gene frequencies of these two polymorphic sites in nine additional populations (Egyptians, Spaniards, Japanese, Chinese, Filipinos, Vietnamese, Africans from Togo and from Benin, and Pygmies), confirming their ethnospecificity and, through the analysis of these two markers in Oromo and Amhara of Ethiopia (two mixed populations), their usefulness in genetic admixture studies. Moreover, we studied another marker polymorphic in sub-Saharan African populations only, a TaqI restriction fragment length polymorphism located in the same region as the present markers, demonstrating the absence of linkage disequilibrium between it and the -100 site, so that we can exclude that the information they provide is redundant.

  6. Beta-globin haplotype analysis suggests that a major source of Malagasy ancestry is derived from Bantu-speaking Negroids.

    OpenAIRE

    Hewitt, R.; Krause, A.; Goldman, A; Campbell, G.; Jenkins, T

    1996-01-01

    The origins of the inhabitants of Madagascar have not been fully resolved. Anthropological studies and preliminary genetic data point to two main sources of ancestry of the Malagasy, namely, Indonesian and African, with additional contributions from India and Arabia. The sickle-cell (beta s) mutation is found in populations of African and Indian origin. The frequency of the beta s-globin gene, derived from 1,425 Malagasy individuals, varies from 0 in some highland populations to .25 in some c...

  7. Beta-globin haplotype analysis suggests that a major source of Malagasy ancestry is derived from Bantu-speaking Negroids.

    Science.gov (United States)

    Hewitt, R; Krause, A; Goldman, A; Campbell, G; Jenkins, T

    1996-06-01

    The origins of the inhabitants of Madagascar have not been fully resolved. Anthropological studies and preliminary genetic data point to two main sources of ancestry of the Malagasy, namely, Indonesian and African, with additional contributions from India and Arabia. The sickle-cell (beta s) mutation is found in populations of African and Indian origin. The frequency of the beta s-globin gene, derived from 1,425 Malagasy individuals, varies from 0 in some highland populations to .25 in some coastal populations. The beta s mutation is thought to have arisen at least five times, on the basis of the presence of five distinct beta s-associated haplotypes, each found in a separate geographic area. Twenty-five of the 35 Malagasy beta s haplotypes were of the typical "Bantu" type, 1 "Senegal" haplotype was found, and 2 rare or atypical haplotypes were observed; the remaining 7 haplotypes were consistent with the Bantu haplotype. The Bantu beta s mutation is thought to have been introduced into Madagascar by Bantu-speaking immigrants (colonists or slaves) from central or east Africa. The Senegal beta s mutation may have been introduced to the island via Portuguese naval explorers. This study provides the first definitive biological evidence that a major component of Malagasy ancestry is derived from African populations, in particular, Bantu-speaking Negroids. beta A haplotypes are also consistent with the claim for a significant African contribution to Malagasy ancestry but are also suggestive of Asian/Oceanic and Caucasoid admixture within the Malagasy population.

  8. Hb Wilde and Hb Patagonia: two novel elongated beta-globin variants causing dominant beta-thalassemia.

    Science.gov (United States)

    Scheps, Karen G; Hasenahuer, Marcia A; Parisi, Gustavo; Fornasari, María S; Pennesi, Sandra P; Erramouspe, Beatriz; Basack, Felisa N; Veber, Ernesto S; Aversa, Luis; Elena, Graciela; Varela, Viviana

    2015-06-01

    We describe here the molecular and hematological characteristics of novel frameshift mutations in exon 2 of the HBB gene (in heterozygous state) found in two Argentinean pediatric patients with dominant β-thalassemia-like features. In Hb Wilde, HBB:c.270_273delTGAG(p.Glu90Cysfs*67), we detected the deletion of the third base of the codon 89 (T) and the codon 90 (GAG), whereas in Hb Patagonia, HBB:c.296_297dupGT(p.Asp99Trpfs*59), the frameshift mutation was due to a duplication of a 'GT' dinucleotide after the second base of codon 98 (GTG). The Hb Patagonia and Hb Wilde mutations would result in elongated β-globin chains with modified C-terminal sequences and a total of 155 and 157 amino acids residues, respectively. Based on bioinformatics and structural analysis, as well as protein modeling, we predict that the elongated β-globins would affect the formation of the αβ dimers and their stability, which would further support the mechanism for the observed clinical features in both patients.

  9. Radiation induced dynamic mutations and transgenerational effects.

    Science.gov (United States)

    Niwa, Ohtsura

    2006-01-01

    Many studies have confirmed that radiation can induce genomic instability in whole body systems. Although the molecular mechanisms underlying induced genomic instability are not known at present, this interesting phenomenon could be the manifestation of a cellular fail-safe system in which fidelity of repair and replication is down-regulated to tolerate DNA damage. Two features of genomic instability namely, delayed mutation and untargeted mutation, require two mechanisms of ;damage memory' and ;damage sensing, signal transduction and execution' to induce mutations at a non damaged-site. In this report, the phenomenon of transgenerational genomic instability and possible mechanisms are discussed using mouse data collected in our laboratory as the main bases.

  10. Heavy ion induced mutation in arabidopsis

    Energy Technology Data Exchange (ETDEWEB)

    Tano, Shigemitsu [Japan Atomic Energy Research Inst., Takasaki, Gunma (Japan). Takasaki Radiation Chemistry Research Establishment

    1997-03-01

    Heavy ions, He, C, Ar and Ne were irradiated to the seeds of Arabidopsis thaliana for inducing the new mutants. In the irradiated generation (M{sub 1}), germination and survival rate were observed to estimate the relative biological effectiveness in relation to the LET including the inactivation cross section. Mutation frequencies were compared by using three kinds of genetic loci after irradiation with C ions and electrons. Several interesting new mutants were selected in the selfed progenies of heavy ion irradiated seeds. (author)

  11. Repairing the Sickle Cell mutation. III. Effect of irradiation wavelength on the specificity and type of photoproduct formed by a 3'-terminal psoralen on a third strand directed to the mutant base pair.

    Science.gov (United States)

    Broitman, Steven L; Amosova, Olga; Fresco, Jacques R

    2003-08-15

    Using a psoralen delivery system mediated by a DNA third strand that binds selectively to linear target duplexes immediately downstream from the Sickle Cell beta-globin gene mutation and the comparable wild-type beta-globin gene sequence, the kinetics of formation and yield of psoralen monoadducts and crosslinks with pyrimidine residues at and near the mutant base pair site and its wild-type counterpart were determined. By exploiting irradiation specificities at 300, 365 and 419 nm, it was possible to evaluate the orientation equilibrium of 3'-linked intercalated psoralen and to develop conditions that lead to preferential formation of each type of photoproduct in both the mutant and wild-type sequences. This makes possible the preparation of each type of photoproduct for use as a substrate for DNA repair. In this way, the base pair change(s) that each generates can be established.

  12. DNA polymorphisms at the BCL11A, HBS1L-MYB, and beta-globin loci associate with fetal hemoglobin levels and pain crises in sickle cell disease.

    Science.gov (United States)

    Lettre, Guillaume; Sankaran, Vijay G; Bezerra, Marcos André C; Araújo, Aderson S; Uda, Manuela; Sanna, Serena; Cao, Antonio; Schlessinger, David; Costa, Fernando F; Hirschhorn, Joel N; Orkin, Stuart H

    2008-08-19

    Sickle cell disease (SCD) is a debilitating monogenic blood disorder with a highly variable phenotype characterized by severe pain crises, acute clinical events, and early mortality. Interindividual variation in fetal hemoglobin (HbF) expression is a known and potentially heritable modifier of SCD severity. High HbF levels are correlated with reduced morbidity and mortality. Common single nucleotide polymorphisms (SNPs) at the BCL11A and HBS1L-MYB loci have been implicated previously in HbF level variation in nonanemic European populations. We recently demonstrated an association between a BCL11A SNP and HbF levels in one SCD cohort [Uda M, et al. (2008) Proc Natl Acad Sci USA 105:1620-1625]. Here, we genotyped additional BCL11A SNPs, HBS1L-MYB SNPs, and an SNP upstream of (G)gamma-globin (HBG2; the XmnI polymorphism), in two independent SCD cohorts: the African American Cooperative Study of Sickle Cell Disease (CSSCD) and an SCD cohort from Brazil. We studied the effect of these SNPs on HbF levels and on a measure of SCD-related morbidity (pain crisis rate). We strongly replicated the association between these SNPs and HbF level variation (in the CSSCD, P values range from 0.04 to 2 x 10(-42)). Together, common SNPs at the BCL11A, HBS1L-MYB, and beta-globin (HBB) loci account for >20% of the variation in HbF levels in SCD patients. We also have shown that HbF-associated SNPs associate with pain crisis rate in SCD patients. These results provide a clear example of inherited common sequence variants modifying the severity of a monogenic disease.

  13. Dominant cataract mutations and specific-locus mutations in mice induced by radiation or ethylnitrosourea

    Energy Technology Data Exchange (ETDEWEB)

    Ehling, U.H.; Favor, J.; Kratochvilova, J.; Neuhaeuser-Klaus, A. (Gesellschaft fuer Strahlen- und Umweltforschung m.b.H. Muenchen, Neuherberg (Germany, F.R.). Inst. fuer Genetik)

    1982-01-01

    In a combined experiment, dominant cataract mutations and specific-locus mutations were scored in the same offspring. In radiation experiments, a total of 15 dominant cataract and 38 specific-locus mutations was scored in 29396 offspring. In experiments with ethylnitrosourea (ENU), a total of 12 dominant cataracts and 54 specific-locus mutations was observed in 12712 offspring. The control frequency for dominant cataracts was 0 in 9954 offspring and for specific-locus mutations 11 in 169955 offspring. The two characteristic features of radiation-induced specific-locus mutations - the augmenting effect of dose fractionation and the quantitative differences in the mutation rates between spermatogonial and post-spermatogonial stages - can also be demonstrated for the induction of dominant cataracts. The dominant cataract mutations recovered can be categorized into 7 phenotypic classes. The only noteworthy difference observed between the radiation- and ENU-induced mutations recovered was that, of the 2 radiation-induced total lens opacities, both were associated with an iris anomaly and microphthalmia whereas the ENU-induced total opacities were not.

  14. Acute chest syndrome is associated with single nucleotide polymorphism-defined beta globin cluster haplotype in children with sickle cell anaemia.

    Science.gov (United States)

    Bean, Christopher J; Boulet, Sheree L; Yang, Genyan; Payne, Amanda B; Ghaji, Nafisa; Pyle, Meredith E; Hooper, W Craig; Bhatnagar, Pallav; Keefer, Jeffrey; Barron-Casella, Emily A; Casella, James F; Debaun, Michael R

    2013-10-01

    Genetic diversity at the human β-globin locus has been implicated as a modifier of sickle cell anaemia (SCA) severity. However, haplotypes defined by restriction fragment length polymorphism sites across the β-globin locus have not been consistently associated with clinical phenotypes. To define the genetic structure at the β-globin locus more thoroughly, we performed high-density single nucleotide polymorphism (SNP) mapping in 820 children who were homozygous for the sickle cell mutation (HbSS). Genotyping results revealed very high linkage disequilibrium across a large region spanning the locus control region and the HBB (β-globin gene) cluster. We identified three predominant haplotypes accounting for 96% of the β(S) -carrying chromosomes in this population that could be distinguished using a minimal set of common SNPs. Consistent with previous studies, fetal haemoglobin level was significantly associated with β(S) -haplotypes. After controlling for covariates, an association was detected between haplotype and rate of hospitalization for acute chest syndrome (ACS) (incidence rate ratio 0·51, 95% confidence interval 0·29-0·89) but not incidence rate of vaso-occlusive pain or presence of silent cerebral infarct (SCI). Our results suggest that these SNP-defined β(S) -haplotypes may be associated with ACS, but not pain or SCI in a study population of children with SCA.

  15. Geographic distribution of 119 alleles of the alpha and beta globin genes detected in 432 French Caucasian carriers of haemoglobin variant.

    Science.gov (United States)

    Chami, B; Braconnier, F; Riou, J; Bardakdjian-Michau, J; Préhu, C; Blouquit, Y; Rosa, J; Wajcman, H; Galactéros, F

    1995-01-01

    The French population is the result of mixing of different peoples including the Celts, Saxons, Germans, Italians and Hispanics. Between 1981 and 1993 patients were selected during investigations in France for haematological disorders associated or otherwise with the presence of a haemoglobin (Hb) variant. Further carriers of abnormal Hb were identified by HPLC measurement of glycated Hb in diabetics and by neonatal screening. Four-hundred and thirty-two subjects were found to be heterozygous for one of the 119 different alpha and the beta gene alleles encountered. These variants were characterised by a combination of 6 electrophoretic methods and in some cases by protein structure determinations. Some mutants reflected the population movements in and into France. A few mutants are frequently described in the French Caucasian population: Hb Lepore Boston, Hb D Punjab, whereas others appear to be anthropological markers. Hb Winnipeg has only been found in the West of France (Normandy); Hb J Baltimore is mainly found in French subjects of Spanish origin. Several cases of sporadic and previously undescribed mutations of Hb were identified. The last immigration waves from Africa and Asia appear to have contributed to the evolution of the pattern of haemoglobinopathies in the French population (Hb S, Hb O Arab or Hb C).

  16. Repairing the Sickle Cell mutation. II. Effect of psoralen linker length on specificity of formation and yield of third strand-directed photoproducts with the mutant target sequence.

    Science.gov (United States)

    Amosova, Olga; Broitman, Steven L; Fresco, Jacques R

    2003-08-15

    Three identical deoxyoligonucleotide third strands with a 3'-terminal psoralen moiety attached by linkers that differ in length (N = 16, 6 and 4 atoms) and structure were examined for their ability to form triplex-directed psoralen photoproducts with both the mutant T residue of the Sickle Cell beta-globin gene and the comparable wild-type sequence in linear duplex targets. Specificity and yield of UVA (365 nm) and visible (419 nm) light-induced photoadducts were studied. The total photoproduct yield varies with the linker and includes both monoadducts and crosslinks at various available pyrimidine sites. The specificity of photoadduct formation at the desired mutant T residue site was greatly improved by shortening the psoralen linker. In particular, using the N-4 linker, psoralen interaction with the residues of the non-coding duplex strand was essentially eliminated, while modification of the Sickle Cell mutant T residue was maximized. At the same time, the proportion of crosslink formation at the mutant T residue upon UV irradiation was much greater for the N-4 linker. The photoproducts formed with the wild-type target were fully consistent with its single base pair difference. The third strand with the N-4 linker was also shown to bind to a supercoiled plasmid containing the Sickle Cell mutation site, giving photoproduct yields comparable with those observed in the linear mutant target.

  17. Mathematical Modeling of the Induced Mutation Process in Bacterial Cells

    Science.gov (United States)

    Belov, Oleg V.; Krasavin, Evgeny A.; Parkhomenko, Alexander Yu.

    2010-01-01

    A mathematical model of the ultraviolet (UV) irradiation-induced mutation process in bacterial cells Escherichia coli is developed. Using mathematical approaches, the whole chain of events is tracked from a cell exposure to the damaging factor to mutation formation in the DNA chain. An account of the key special features of the regulation of this genetic network allows predicting the effects induced by the cell exposure to certain UV energy fluence.

  18. ENU-induced phenovariance in mice: inferences from 587 mutations

    Directory of Open Access Journals (Sweden)

    Arnold Carrie N

    2012-10-01

    Full Text Available Abstract Background We present a compendium of N-ethyl-N-nitrosourea (ENU-induced mouse mutations, identified in our laboratory over a period of 10 years either on the basis of phenotype or whole genome and/or whole exome sequencing, and archived in the Mutagenetix database. Our purpose is threefold: 1 to formally describe many point mutations, including those that were not previously disclosed in peer-reviewed publications; 2 to assess the characteristics of these mutations; and 3 to estimate the likelihood that a missense mutation induced by ENU will create a detectable phenotype. Findings In the context of an ENU mutagenesis program for C57BL/6J mice, a total of 185 phenotypes were tracked to mutations in 129 genes. In addition, 402 incidental mutations were identified and predicted to affect 390 genes. As previously reported, ENU shows strand asymmetry in its induction of mutations, particularly favoring T to A rather than A to T in the sense strand of coding regions and splice junctions. Some amino acid substitutions are far more likely to be damaging than others, and some are far more likely to be observed. Indeed, from among a total of 494 non-synonymous coding mutations, ENU was observed to create only 114 of the 182 possible amino acid substitutions that single base changes can achieve. Based on differences in overt null allele frequencies observed in phenotypic vs. non-phenotypic mutation sets, we infer that ENU-induced missense mutations create detectable phenotype only about 1 in 4.7 times. While the remaining mutations may not be functionally neutral, they are, on average, beneath the limits of detection of the phenotypic assays we applied. Conclusions Collectively, these mutations add to our understanding of the chemical specificity of ENU, the types of amino acid substitutions it creates, and its efficiency in causing phenovariance. Our data support the validity of computational algorithms for the prediction of damage caused by

  19. A Fast Determination of DNA Mutation Induced by Ultraviolet Radiation

    Institute of Scientific and Technical Information of China (English)

    LuFeng; LiuLili; ZhangXiaofang; WuYutian

    2001-01-01

    Electrophoresis, chromatography, immunoassay, sequencing and other time consuming ap-proaches have been developed to determine DNA base mismatching, oxidative lesion or strand breaks. Sometimes,however, only qualitative information is enough to decide whether mutation has happened to DNA and its extent.Convolution spectrometry (CS), a new technique to discover ultrafme difference on ultraviolet (UV) absorption ofdifferent substances, is originally employed to find out any subtle mutation of DNA induced by UV radiation. Muta-tive DNA is compared with ego criteria based on the spectra of the former DNA, any difference is quantitatively ex-pressed by dispersion (5). Visible changes cannot be observed on second -derivative spectra until the mutation gets 5up to 11.48%. Dimethyl sulfoxide is an intensifier of UV 254 nm induced DNA mutation and protector at 365 nm,which is simply confirmed by increasing and decreasing 5. Every convolution procedure takes less than 1 min. Convolution spectrometry provides a fast, simple, sensitive and inexpensive alternative to determine DNA mutation, andto screen anti-mutational medicines.

  20. Inducible repair system in Haemophilus influenzae unaccompanied by mutation. [uv

    Energy Technology Data Exchange (ETDEWEB)

    Notani, N.K.; Setlow, J.K.

    1980-07-01

    Weigle reactivation of ultraviolet-irradiated HPlc1 phage was observed after ultraviolet or mitomycin C treatment of Haemophilus influenzae cells. The amount of reactivation was considerably increased when the treated cells were incubated in growth medium before infection. The presence of chloramphenicol during this incubation abolished the reactivation. No mutation of this phage accompanied the reactivation. When cells were treated so as to produce a maximal reactivation of phage, neither reactivation nor mutation of cells was observed. It is concluded that H. influenzae has an inducible repair system that is not accompanied by mutation.

  1. Hepatitis C virus induces a mutator phenotype: enhanced mutations of immunoglobulin and protooncogenes.

    Science.gov (United States)

    Machida, Keigo; Cheng, Kevin T-N; Sung, Vicky M-H; Shimodaira, Shigetaka; Lindsay, Karen L; Levine, Alexandra M; Lai, Ming-Yang; Lai, Michael M C

    2004-03-23

    Hepatitis C virus (HCV) is a nonretroviral oncogenic RNA virus, which is frequently associated with hepatocellular carcinoma (HCC) and B cell lymphoma. We demonstrated here that acute and chronic HCV infection caused a 5- to 10-fold increase in mutation frequency in Ig heavy chain, BCL-6, p53, and beta-catenin genes of in vitro HCV-infected B cell lines and HCV-associated peripheral blood mononuclear cells, lymphomas, and HCCs. The nucleotide-substitution pattern of p53 and beta-catenin was different from that of Ig heavy chain in HCV-infected cells, suggesting two different mechanisms of mutation. In addition, the mutated protooncogenes were amplified in HCV-associated lymphomas and HCCs, but not in lymphomas of nonviral origin or HBV-associated HCC. HCV induced error-prone DNA polymerase zeta, polymerase iota, and activation-induced cytidine deaminase, which together, contributed to the enhancement of mutation frequency, as demonstrated by the RNA interference experiments. These results indicate that HCV induces a mutator phenotype and may transform cells by a hit-and-run mechanism. This finding provides a mechanism of oncogenesis for an RNA virus.

  2. Precise excision of transposons and point mutations induced by chemicals.

    Science.gov (United States)

    Rusina OYu; Mirskaya, E E; Andreeva, I V; Skavronskaya, A G

    1992-11-01

    The ability of 23 chemicals (carcinogens and non-carcinogens) to induce precise excision of Tn10 and point mutations was studied in experiments with a single strain. The mutation assay was shown to detect a wider spectrum of genotoxic agents than the assay of Tn10 precise excision. The latter was induced only by potent SOS mutagens, which is in accordance with data on the SOS dependence of the induction of precise excision of Tn10. The precise excision assay as an additional test contributing to the knowledge of particular features of the action of a tested mutagen is discussed. The induction of precise excision of Tn10 by pyrene (and its failure to induce point mutations in this strain) demonstrates the value of using the transposon excision assay in cases of 'problem' mutagens.

  3. Sucrose and IQ induced mutations in rat colon by independent

    DEFF Research Database (Denmark)

    Hansen, Max; Hald, M. T.; Autrup, H.

    2004-01-01

    Sucrose-rich diets have repeatedly been observed to have co-carcinogenic actions in colon and liver of rats and to increase the number of 2-amino-3-methylimidazo[4,5-f]quinoline (IQ) induced aberrant crypt foci in rat colon. To investigate a possible interaction between sucrose and IQ...... on the genotoxicity in rat liver and colon, we gave Big Blue rats(TM) a diet containing sucrose (0%, 3.45% or 13.4% w/w) and/or IQ (70 ppm) for a period of 3 weeks. Sucrose and IQ increased the mutation frequency in the colon. The effect of combined treatments with IQ and sucrose on the mutation frequencies...... was additive indicating that sucrose and IQ act independently. This was supported by the mutation spectra where sucrose expands the background mutations in the colon, whereas IQ, in other studies, more specifically has induced G:C --> T:A transversions. In the liver IQ increased the mutation frequency, whereas...

  4. The nature of mutations induced by replication–transcription collisions.

    Science.gov (United States)

    Sankar, T Sabari; Wastuwidyaningtyas, Brigitta D; Dong, Yuexin; Lewis, Sarah A; Wang, Jue D

    2016-07-01

    The DNA replication and transcription machineries share a common DNA template and thus can collide with each other co-directionally or head-on. Replication–transcription collisions can cause replication fork arrest, premature transcription termination, DNA breaks, and recombination intermediates threatening genome integrity. Collisions may also trigger mutations, which are major contributors to genetic disease and evolution. However, the nature and mechanisms of collision-induced mutagenesis remain poorly understood. Here we reveal the genetic consequences of replication–transcription collisions in actively dividing bacteria to be two classes of mutations: duplications/deletions and base substitutions in promoters. Both signatures are highly deleterious but are distinct from the previously well-characterized base substitutions in the coding sequence. Duplications/deletions are probably caused by replication stalling events that are triggered by collisions; their distribution patterns are consistent with where the fork first encounters a transcription complex upon entering a transcription unit. Promoter substitutions result mostly from head-on collisions and frequently occur at a nucleotide that is conserved in promoters recognized by the major σ factor in bacteria. This substitution is generated via adenine deamination on the template strand in the promoter open complex, as a consequence of head-on replication perturbing transcription initiation. We conclude that replication–transcription collisions induce distinct mutation signatures by antagonizing replication and transcription, not only in coding sequences but also in gene regulatory elements.

  5. Vacuum-induced Mutations In Bacillus Subtilis Spores

    Science.gov (United States)

    Munakata, N.; Maeda, M.; Hieda, K.

    During irradiation experiments with vacuum-UV radiation using synchrotron sources, we made unexpected observation that Bacillus subtilis spores of several recombination-deficient strains lost colony-forming ability by the exposure to high vacuum alone. Since this suggested the possible injury in spore DNA, we looked for mutation induction using the spores of strains HA101 (wild-type repair capability) and TKJ6312 (excision and spore repair deficient) that did not lose survivability. It was found that the frequency of nalidixic-acid resistant mutation increased several times in both of these strains by the exposure to high vacuum (10e-4 Pa after 24 hours). The analysis of sequence changes in gyrA gene showed that the majority of mutations carried a unique allele (gyrA12) of tandem double-base substitutions from CA to TT. The observation has been extended to rifampicin resistant mutations, the majority of that carried substitutions from CA to TT or AT in rpoB gene. On the other hand, when the spores of strains PS578 and PS2319 (obtained from P. Setlow) that are defective in a group of small acidic proteins (alpha/beta-type SASP) were similarly treated, none of the mutants analyzed carried such changes. This suggests that the unique mutations might be induced by the interaction of small acidic proteins with spore DNA under forced dehydration. The results indicate that extreme vacuum causes severe damage in spore DNA, and provide additional constraint to the long-term survival of bacterial spores in the space environment.

  6. Solar-UV-signature mutation prefers TCG to CCG: extrapolative consideration from UVA1-induced mutation spectra in mouse skin.

    Science.gov (United States)

    Ikehata, Hironobu; Kumagai, Jun; Ono, Tetsuya; Morita, Akimichi

    2013-08-01

    UVA1 exerts its genotoxicity on mammalian skin by producing cyclobutane pyrimidine dimers (CPDs) in DNA and preferentially inducing solar-UV-signature mutations, C → T base substitution mutations at methylated CpG-associated dipyrimidine (Py-mCpG) sites, as demonstrated previously using a 364 nm laser as a UVA1 source and lacZ-transgenic mice that utilize the transgene as a mutational reporter. In the present study, we confirmed that a broadband UVA1 source induced the same mutation profiles in mouse epidermis as the UVA1 laser, generalizing the previous result from a single 364 nm to a wider wavelength range of UVA1 (340-400 nm). Combined with our previous data on the mutation spectra induced in mouse epidermis by UVB, UVA2 and solar UVR, we proved that the solar-UV-signature mutation is commonly observed in the wavelength range from UVB to UVA, and found that UVA1 induces this mutation more preferentially than the other shorter wavelength ranges. This finding indicates that the solar-UV-signature mutation-causing CPDs, which are known to prefer Py-mCpG sites, could be produced with the energy provided by the longer wavelength region of UVR, suggesting a photochemical reaction through the excitation of pyrimidine bases to energy states that can be accomplished by absorption of even low-energy UVR. On the other hand, the lower proportions of solar-UV-signature mutations observed in the mutation spectra for UVB and solar UVR indicate that the direct photochemical reaction through excited singlet state of pyrimidine bases, which can be accomplished only by high-energy UVR, is also involved in the mutation induction at those shorter wavelengths of UVR. We also found that the solar-UV signature prefers 5'-TCG-3' to 5'-CCG-3' as mutational target sites, consistent with the fact that UVA induces CPDs selectively at thymine-containing dipyrimidine sites and that solar UVR induces them preferably at Py-mCpG sites. However, the mutation spectrum in human p53 gene from non

  7. Activation-Induced Cytidine Deaminase Contributes to Pancreatic Tumorigenesis by Inducing Tumor-Related Gene Mutations.

    Science.gov (United States)

    Sawai, Yugo; Kodama, Yuzo; Shimizu, Takahiro; Ota, Yuji; Maruno, Takahisa; Eso, Yuji; Kurita, Akira; Shiokawa, Masahiro; Tsuji, Yoshihisa; Uza, Norimitsu; Matsumoto, Yuko; Masui, Toshihiko; Uemoto, Shinji; Marusawa, Hiroyuki; Chiba, Tsutomu

    2015-08-15

    Pancreatic ductal adenocarcinoma (PDAC) develops via an accumulation of various gene mutations. The mechanism underlying the mutations in PDAC development, however, is not fully understood. Recent insight into the close association between the mutation pattern of various cancers and specific mutagens led us to investigate the possible involvement of activation-induced cytidine deaminase (AID), a DNA editing enzyme, in pancreatic tumorigenesis. Our immunohistochemical findings revealed AID protein expression in human acinar ductal metaplasia, pancreatic intraepithelial neoplasia, and PDAC. Both the amount and intensity of the AID protein expression increased with the progression from precancerous to cancerous lesions in human PDAC tissues. To further assess the significance of ectopic epithelial AID expression in pancreatic tumorigenesis, we analyzed the phenotype of AID transgenic (AID Tg) mice. Consistent with our hypothesis that AID is involved in the mechanism of the mutations underlying pancreatic tumorigenesis, we found precancerous lesions developing in the pancreas of AID Tg mice. Using deep sequencing, we also detected Kras and c-Myc mutations in our analysis of the whole pancreas of AID Tg mice. In addition, Sanger sequencing confirmed the presence of Kras, c-Myc, and Smad4 mutations, with the typical mutational footprint of AID in precancerous lesions in AID Tg mice separated by laser capture microdissection. Taken together, our findings suggest that AID contributes to the development of pancreatic precancerous lesions by inducing tumor-related gene mutations. Our new mouse model without intentional manipulation of specific tumor-related genes provides a powerful system for analyzing the mutations involved in PDAC.

  8. Utilization of denaturing gradient gel electrophoresis for diagnosis of {beta}-thalassemia and ascertainment of new mutations

    Energy Technology Data Exchange (ETDEWEB)

    Ngo, K.Y.; Liu, D.; Lee, J. [Univ. of California, San Diego (United States)] [and others

    1994-09-01

    During the past two years we have tested 2,300 Southeast Asians for alpha- and beta-thaleassemia mutations. We found the incidence of hemoglobin E ({beta}{sup 26}) to be 47% among Laotians and 38% among Cambodians. The incidence of beta thalassemia trait is 9% for Laotians and 6% for Cambodians. Thus, the risk for hemoglobin E/{beta}{sup 26} thalassemia, a transfusion-dependent disorder, is increased in these two population groups. Denaturing gradient gel electrophoresis (DGGE) has proven to be useful in testing for beta-thalassemia carriers and identifying new mutations in the beta globin gene. DNA was extracted from venous blood obtained from patients with elevated Hgb A2 (>4%). Five DNA fragments, encompassing the beta globin gene cluster, were amplified by PCR and analyzed, along with known beta gene mutations as controls, by DGGE using different denaturing gradient concentrations. Different mutations at the same nucleotide position can be distinguished by migration pattern on the DGGE (e.g., in IVS-I-1, G{r_arrow}A and T). Compound heterozygotes for {beta}-thalassemia can be detected on the same gel (e.g., HbE/mutation codon 17). New mutations are identified by their migration pattern compared with controls and determined by subsequent sequencing. We have identified three new mutations: codon 82 CAA{r_arrow}AAA in one Cambodian patient; IVS-II-667, T{r_arrow}C and IVS-II-672, A{r_arrow}C in two Laotian patients. When the parent`s genotypes are known, prenatal diagnosis can be obtained within 24 hours. Thus, PCR/DGGE combination is a rapid and reliable diagnostic approach to clinically significant {beta}-thalassemia. The most important steps are carefully designed primers and predetermined gradient concentrations for DGGE.

  9. Molecular characterization of microbial mutations induced by ion beam irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Ichida, Hiroyuki [Graduate School of Science and Technology, Chiba University, Matsudo, Chiba 271-8510 (Japan); Accelerator Applications Research Group, Nishina Center for Accelerator-Based Science, RIKEN, Wako, Saitama 351-0198 (Japan)], E-mail: ichida@riken.jp; Matsuyama, Tomoki [Cellular Biochemistry Laboratory, Discovery Research Institute, RIKEN, Wako, Saitama 351-0198 (Japan); Ryuto, Hiromichi [Accelerator Operation Group, Nishina Center for Accelerator-Based Science, RIKEN, Wako, Saitama 351-0198 (Japan); Hayashi, Yoriko [Accelerator Applications Research Group, Nishina Center for Accelerator-Based Science, RIKEN, Wako, Saitama 351-0198 (Japan); Fukunishi, Nobuhisa [Accelerator Operation Group, Nishina Center for Accelerator-Based Science, RIKEN, Wako, Saitama 351-0198 (Japan); Abe, Tomoko [Accelerator Applications Research Group, Nishina Center for Accelerator-Based Science, RIKEN, Wako, Saitama 351-0198 (Japan); Koba, Takato [Graduate School of Science and Technology, Chiba University, Matsudo, Chiba 271-8510 (Japan)

    2008-03-01

    A positive selection system for gene disruption using a sucrose-sensitive transgenic rhizobium was established and used for the molecular characterization of mutations induced by ion beam irradiations. Single nucleotide substitutions, insertions, and deletions were found to occur in the sucrose sensitivity gene, sacB, when the reporter line was irradiated with highly accelerated carbon and iron ion beams. In all of the insertion lines, fragments of essentially the same sequence and of approximately 1188 bp in size were identified in the sacB regions. In the deletion lines, iron ions showed a tendency to induce larger deletions than carbon ions, suggesting that higher LET beams cause larger deletions. We found also that ion beams, particularly 'heavier' ion beams, can produce single gene disruptions and may present an effective alternative to transgenic approaches.

  10. [UV-induced DNA mutation of peach aphid].

    Science.gov (United States)

    Du, Erxia; Guo, Jianwen; Zhao, Huiyan

    2006-07-01

    By using PCR technique and microsatellite marks, this paper studied the DNA polymorphism of peach aphid (Myzus persicae) under UV-radiation. The fragments of three primers were amplified, and the gene diversity and the rate of loci polymorphisms of their genomic DNA, which could reflect the damage degree of DNA after UV-radiation, were measured. The results revealed that after treated with different radiation intensity (15, 30, 45 W) and duration (2, 4, 6 h) , the UV-induced DNA mutations were genetic and could be delivered to F2 generation. The mutations depended on the interaction of radiation intensity and duration. Variance analysis on the gene diversity and the rate of loci polymorphisms showed that there existed a significant difference between UV-treated and control groups, except the rate of loci polymorphisms under 2 h radiation. The average value of the control was higher than that of 2 h radiation treatment. According to the cluster analysis of the genetic distance, the aphids were divided into three groups, i. e., control group, 2 h (15, 30 W) treatment group, and the other, which was consistent with the result of variance analysis.

  11. Mutations induced by dacarbazine activated with cytochrome P-450.

    Science.gov (United States)

    Mudipalli, A; Nadadur, S S; Maccubbin, A E; Gurtoo, H L

    1995-03-01

    The mutagenicity of the antitumor drug dacarbazine (DTIC) is due to alkylation of cellular DNA by metabolites resulting from the metabolism of this drug by the mixed function oxidase system. In the present study, we used an in vitro shuttle vector assay to study the base and sequence specificity of mutagenesis by DTIC. The shuttle vector plasmid pSP189 was treated with DTIC (1-2.5 mM) in vitro in a reconstituted cytochrome P-450 system at 37 degrees C for either 30 or 60 min. SupF tRNA gene insert contained in the plasmid was sequenced after replication of the drug-treated plasmid in human Ad 293 cells followed by amplification in indicator bacteria. Mutagenesis of DTIC in this system was dependent upon the presence of the cytochrome P-450 reconstituted system and NADPH. Mutations induced by DTIC included single base substitutions (35%), single base deletions (30.5%), single base insertions (19.4%) and large deletions (13.8%). Among the substitutions, transversions and transitions were in the ratio of 1:0.7. Base pairs 108 and 127 in the SupF tRNA of the pSP189 were identified as mutational hot spots.

  12. DNA sequence analysis of X-ray induced Adh null mutations in Drosophila melanogaster

    Energy Technology Data Exchange (ETDEWEB)

    Mahmoud, J.; Fossett, N.G.; Arbour-Reily, P.; McDaniel, M.; Tucker, A.; Chang, S.H.; Lee, W.R. (Louisiana State Univ., Baton Rouge (United States))

    1991-01-01

    The mutational spectrum for 28 X-ray induced mutations and 2 spontaneous mutations, previously determined by genetic and cytogenetic methods, consisted of 20 multilocus deficiencies (19 induced and 1 spontaneous) and 10 intragenic mutations (9 induced and 1 spontaneous). One of the X-ray induced intragenic mutations was lost, and another was determined to be a recombinant with the allele used in the recovery scheme. The DNA sequence of two X-ray induced intragenic mutations has been published. This paper reports the results of DNA sequence analysis of the remaining intragenic mutations and a summary of the X-ray induced mutational spectrum. The combination of DNA sequence analysis with genetic complementation analysis shows a continuous distribution in size of deletions rather than two different types of mutations consisting of deletions and point mutations'. Sequencing is shown to be essential for detecting intragenic deletions. Of particular importance for future studies is the observation that all of the intragenic deletions consist of a direct repeat adjacent to the breakpoint with one of the repeats deleted.

  13. Concordance of a point mutation 5' to the A gamma-globin gene with A gamma beta + hereditary persistence of fetal hemoglobin in Greeks.

    Science.gov (United States)

    Waber, P G; Bender, M A; Gelinas, R E; Kattamis, C; Karaklis, A; Sofroniadou, K; Stamatoyannopoulos, G; Collins, F S; Forget, B G; Kazazian, H H

    1986-02-01

    In the Greek A gamma beta + type of hereditary persistence of fetal hemoglobin (HPFH), adult heterozygotes produce about 20% fetal hemoglobin (HbF), which is predominantly of the A gamma chain variety. The affected beta-globin gene cluster produces near normal amounts of beta-like globin, but in a A gamma to beta ratio of 20:80 instead of 0.5:99.5. Gelinas et al and Collins et al have shown a G to A change 117 nucleotides 5' to the A gamma gene in two Greeks with A gamma beta + HPFH. To demonstrate that this change is not a neutral polymorphism, we carried out hybridization with oligonucleotide probes (19mers) specific for the normal and the mutant sequences. While normal probe identified the A gamma fragment in genomic DNA of all subjects studied, mutant probe was positive only in Greeks with A gamma beta + HPFH. In sum, 108 beta-globin gene clusters of individuals without HPFH were negative when tested with mutant probe, but all 11 affected individuals of six families with Greek A gamma beta + HPFH (two previously sequenced and four new families) were positive with mutant probe. These data support the conclusion that the -117 mutation is causative of A gamma beta + HPFH in Greeks.

  14. Identification of pathways controlling DNA damage induced mutation in Saccharomyces cerevisiae.

    Science.gov (United States)

    Lis, Ewa T; O'Neill, Bryan M; Gil-Lamaignere, Cristina; Chin, Jodie K; Romesberg, Floyd E

    2008-05-01

    Mutation in response to most types of DNA damage is thought to be mediated by the error-prone sub-branch of post-replication repair and the associated translesion synthesis polymerases. To further understand the mutagenic response to DNA damage, we screened a collection of 4848 haploid gene deletion strains of Saccharomyces cerevisiae for decreased damage-induced mutation of the CAN1 gene. Through extensive quantitative validation of the strains identified by the screen, we identified ten genes, which included error-prone post-replication repair genes known to be involved in induced mutation, as well as two additional genes, FYV6 and RNR4. We demonstrate that FYV6 and RNR4 are epistatic with respect to induced mutation, and that they function, at least partially, independently of post-replication repair. This pathway of induced mutation appears to be mediated by an increase in dNTP levels that facilitates lesion bypass by the replicative polymerase Pol delta, and it is as important as error-prone post-replication repair in the case of UV- and MMS-induced mutation, but solely responsible for EMS-induced mutation. We show that Rnr4/Pol delta-induced mutation is efficiently inhibited by hydroxyurea, a small molecule inhibitor of ribonucleotide reductase, suggesting that if similar pathways exist in human cells, intervention in some forms of mutation may be possible.

  15. Specificity of mutations induced by carbon ions in budding yeast Saccharomyces cerevisiae

    Energy Technology Data Exchange (ETDEWEB)

    Matuo, Youichirou [Graduate School of Engineering, Osaka University, Yamada-oka 2-1, Suita, Osaka 565-0871 (Japan); Nishijima, Shigehiro [Graduate School of Engineering, Osaka University, Yamada-oka 2-1, Suita, Osaka 565-0871 (Japan); Hase, Yoshihiro [Radiation-Applied Biology Division, Quantum Beam Science Directorate, Japan Atomic Energy Agency (JAEA), Watanuki-machi 1233, Takasaki, Gunma 370-1292 (Japan); Sakamoto, Ayako [Radiation-Applied Biology Division, Quantum Beam Science Directorate, Japan Atomic Energy Agency (JAEA), Watanuki-machi 1233, Takasaki, Gunma 370-1292 (Japan); Tanaka, Atsushi [Radiation-Applied Biology Division, Quantum Beam Science Directorate, Japan Atomic Energy Agency (JAEA), Watanuki-machi 1233, Takasaki, Gunma 370-1292 (Japan); Shimizu, Kikuo [Radioisotope Research Center, Osaka University, Yamada-oka 2-4, Suita, Osaka 565-0871 (Japan)]. E-mail: shimizu@rirc.osaka-u.ac.jp

    2006-12-01

    To investigate the nature of mutations induced by accelerated ions in eukaryotic cells, the effects of carbon-ion irradiation were compared with those of {gamma}-ray irradiation in the budding yeast Saccharomyces cerevisiae. The mutational effect and specificity of carbon-ion beams were studied in the URA3 gene of the yeast. Our experiments showed that the carbon ions generated more than 10 times the number of mutations induced by {gamma}-rays, and that the types of base changes induced by carbon ions include transversions (68.7%), transitions (13.7%) and deletions/insertions (17.6%). The transversions were mainly G:C {sup {yields}} T:A, and all the transitions were G:C {sup {yields}} A:T. In comparison with the surrounding sequence context of mutational base sites, the C residues in the 5'-AC(A/T)-3' sequence were found to be easily changed. Large deletions and duplications were not observed, whereas ion-induced mutations in Arabidopsis thaliana were mainly short deletions and rearrangements. The remarkable feature of yeast mutations induced by carbon ions was that the mutation sites were localized near the linker regions of nucleosomes, whereas mutations induced by {gamma}-ray irradiation were located uniformly throughout the gene.

  16. TP53 mutations predict decitabine-induced complete responses in patients with myelodysplastic syndromes.

    Science.gov (United States)

    Chang, Chun-Kang; Zhao, You-Shan; Xu, Feng; Guo, Juan; Zhang, Zheng; He, Qi; Wu, Dong; Wu, Ling-Yun; Su, Ji-Ying; Song, Lu-Xi; Xiao, Chao; Li, Xiao

    2017-02-01

    To identify the molecular signatures that predict responses to decitabine (DAC), we examined baseline gene mutations (28 target genes) in 109 myelodysplastic syndrome (MDS) patients at diagnosis. We determined that TP53 mutations predicted complete response (CR), as 10 of 15 patients (66·7%) who possessed TP53 mutations achieved a CR. Univariate and multivariate analyses showed that TP53 mutations are the only molecular signatures predictive of a CR to DAC in MDS. Among the ten patients with TP53 mutations who achieved a CR, nine presented with complex karyotypes due to abnormalities involving chromosome 5 and/or chromosome 7, and eight possessed monosomies. Although TP53 mutations were associated with a higher frequency of CRs, they were not associated with improved survival. Poor outcomes were attributed to early relapses and transformation to acute myeloid leukaemia after CR. Post-DAC therapy patient gene mutation profiles showed that most CR patients exhibited fewer gene mutations after achieving a CR. It seems that suppression of these gene mutations was facilitated by DAC, resulting in a CR. In summary, TP53 mutations might predict decitabine-induced complete responses in patients with MDS. DAC-induced responses may result from partial suppression of malignant clones containing mutated TP53 genes.

  17. Insight on Mutation-Induced Resistance from Molecular Dynamics Simulations of the Native and Mutated CSF-1R and KIT

    Science.gov (United States)

    Da Silva Figueiredo Celestino Gomes, Priscila; Chauvot De Beauchêne, Isaure; Panel, Nicolas; Lopez, Sophie; De Sepulveda, Paulo; Geraldo Pascutti, Pedro; Solary, Eric; Tchertanov, Luba

    2016-01-01

    The receptors tyrosine kinases (RTKs) for the colony stimulating factor-1, CSF-1R, and for the stem cell factor, SCFR or KIT, are important mediators of signal transduction. The abnormal function of these receptors, promoted by gain-of-function mutations, leads to their constitutive activation, associated with cancer or other proliferative diseases. A secondary effect of the mutations is the alteration of receptors’ sensitivity to tyrosine kinase inhibitors, compromising effectiveness of these molecules in clinical treatment. In particular, the mutation V560G in KIT increases its sensitivity to Imatinib, while the D816V in KIT, and D802V in CSF-1R, triggers resistance to the drug. We analyzed the Imatinib binding affinity to the native and mutated KIT (mutations V560G, S628N and D816V) and CSF-1R (mutation D802V) by using molecular dynamics simulations and energy calculations of Imatinib•target complexes. Further, we evaluated the sensitivity of the studied KIT receptors to Imatinib by measuring the inhibition of KIT phosphorylation. Our study showed that (i) the binding free energy of Imatinib to the targets is highly correlated with their experimentally measured sensitivity; (ii) the electrostatic interactions are a decisive factor affecting the binding energy; (iii) the most deleterious impact to the Imatinib sensitivity is promoted by D802V (CSF-1R) and D816V (KIT) mutations; (iv) the role of the juxtamembrane region, JMR, in the imatinib binding is accessory. These findings contribute to a better description of the mutation-induced effects alternating the targets sensitivity to Imatinib. PMID:27467080

  18. The effect of induced mutations on quantitative traits in Arabidopsis thaliana: Natural versus artificial conditions.

    Science.gov (United States)

    Stearns, Frank W; Fenster, Charles B

    2016-12-01

    Mutations are the ultimate source of all genetic variations. New mutations are expected to affect quantitative traits differently depending on the extent to which traits contribute to fitness and the environment in which they are tested. The dogma is that the preponderance of mutations affecting fitness will be skewed toward deleterious while their effects on nonfitness traits will be bidirectionally distributed. There are mixed views on the role of stress in modulating these effects. We quantify mutation effects by inducing mutations in Arabidopsis thaliana (Columbia accession) using the chemical ethylmethane sulfonate. We measured the effects of new mutations relative to a premutation founder for fitness components under both natural (field) and artificial (growth room) conditions. Additionally, we measured three other quantitative traits, not expected to contribute directly to fitness, under artificial conditions. We found that induced mutations were equally as likely to increase as decrease a trait when that trait was not closely related to fitness (traits that were neither survivorship nor reproduction). We also found that new mutations were more likely to decrease fitness or fitness-related traits under more stressful field conditions than under relatively benign artificial conditions. In the benign condition, the effect of new mutations on fitness components was similar to traits not as closely related to fitness. These results highlight the importance of measuring the effects of new mutations on fitness and other traits under a range of conditions.

  19. Particle-induced chromosome aberrations and mutations: an overview

    Energy Technology Data Exchange (ETDEWEB)

    Ritter, S. [Gesellschaft fuer Schwerionenforschung, Darmstadt (Germany)

    1997-09-01

    This overview will focus on progress in chromosome and mutation studies achieved by the application of new techniques. Furthermore, recent relevant data on longterm genetic effects of densely ionizing radiation will be summarized. (orig./MG)

  20. Induced mutations in yeast cell populations adapting to an unforeseen challenge.

    Science.gov (United States)

    Moore, Lindsay S; Wei, Wu; Stolovicki, Elad; Benbenishty, Tamar; Wilkening, Stefan; Steinmetz, Lars M; Braun, Erez; David, Lior

    2014-01-01

    The modern evolutionary synthesis assumes that mutations occur at random, independently of the environment in which they confer an advantage. However, there are indications that cells facing challenging conditions can adapt rapidly, utilizing processes beyond selection of pre-existing genetic variation. Here, we show that a strong regulatory challenge can induce mutations in many independent yeast cells, in the absence of general mutagenesis. Whole genome sequencing of cell lineages reveals a repertoire of independent mutations within a single lineage that arose only after the cells were exposed to the challenging environment, while other cells in the same lineage adapted without any mutation in their genomes. Thus, our experiments uncovered multiple alternative routes for heritable adaptation that were all induced in the same lineage during a short time period. Our results demonstrate the existence of adaptation mechanisms beyond random mutation, suggesting a tight connection between physiological and genetic processes.

  1. Cellular and deafness mechanisms underlying connexin mutation induced hearing loss – A common hereditary deafness

    Directory of Open Access Journals (Sweden)

    Jeffrey C Wingard

    2015-05-01

    Full Text Available Hearing loss due to mutations in the connexin gene family which encodes gap junctional proteins is a common form of hereditary deafness. In particular, connexin 26 (Cx26, GJB2 mutations are responsible for ~50% of nonsyndromic hearing loss, which is the highest incidence of genetic disease. In the clinic, Cx26 mutations cause various auditory phenotypes ranging from profound congenital deafness at birth to mild, progressive hearing loss in late childhood. Recent experiments demonstrate that congenital deafness mainly results from cochlear developmental disorders rather than hair cell degeneration and endocochlear potential (EP reduction, while late-onset hearing loss results from reduction of active cochlear amplification, even though cochlear hair cells have no connexin expression. Moreover, new experiments further demonstrate that the hypothesized K+-recycling disruption is not a principal deafness mechanism for connexin deficiency induced hearing loss. Additionally, there is no clear relationship between specific changes in connexin (channel functions and the phenotypes of mutation-induced hearing loss. Cx30, Cx29, Cx31, and Cx43 mutations can also cause hearing loss with distinct pathological changes in the cochlea. These new studies provide invaluable information about deafness mechanisms underlying connexin mutation induced hearing loss and also provide important information for developing new protective and therapeutic strategies for this common deafness. However, the detailed cellular mechanisms underlying these pathological changes and pathogeneses of specific-mutation induced hearing loss remain unclear. Finally, little information is available for humans. Further studies to address these deficiencies are urgently required.

  2. Target cell APOBEC3C can induce limited G-to-A mutation in HIV-1.

    Directory of Open Access Journals (Sweden)

    Khaoula Bourara

    2007-10-01

    Full Text Available The evolutionary success of primate lentiviruses reflects their high capacity to mutate and adapt to new host species, immune responses within individual hosts, and, in recent years, antiviral drugs. APOBEC3G (A3G and APOBEC3F (A3F are host cell DNA-editing enzymes that induce extensive HIV-1 mutation that severely attenuates viral replication. The HIV-1 virion infectivity factor (Vif, expressed in vivo, counteracts the antiviral activity of A3G and A3F by inducing their degradation. Other APOBECs may contribute more to viral diversity by inducing less extensive mutations allowing viral replication to persist. Here we show that in APOBEC3C (A3C-expressing cells infected with the patient-derived HIV-1 molecular clones 210WW, 210WM, 210MW, and 210MM, and the lab-adapted molecular clone LAI, viral G-to-A mutations were detected in the presence of Vif expression. Mutations occurred primarily in the GA context and were relatively infrequent, thereby allowing for spreading infection. The mutations were absent in cells lacking A3C but were induced after transient expression of A3C in the infected target cell. Inhibiting endogenous A3C by RNA interference in Magi cells prevented the viral mutations. Thus, A3C is necessary and sufficient for G-to-A mutations in some HIV-1 strains. A3C-induced mutations occur at levels that allow replication to persist and may therefore contribute to viral diversity. Developing drugs that inhibit A3C may be a novel strategy for delaying viral escape from immune or antiretroviral inhibition.

  3. Target Cell APOBEC3C Can Induce Limited G-to-A Mutation in HIV-1

    Science.gov (United States)

    Bourara, Khaoula; Liegler, Teri J; Grant, Robert M

    2007-01-01

    The evolutionary success of primate lentiviruses reflects their high capacity to mutate and adapt to new host species, immune responses within individual hosts, and, in recent years, antiviral drugs. APOBEC3G (A3G) and APOBEC3F (A3F) are host cell DNA-editing enzymes that induce extensive HIV-1 mutation that severely attenuates viral replication. The HIV-1 virion infectivity factor (Vif), expressed in vivo, counteracts the antiviral activity of A3G and A3F by inducing their degradation. Other APOBECs may contribute more to viral diversity by inducing less extensive mutations allowing viral replication to persist. Here we show that in APOBEC3C (A3C)-expressing cells infected with the patient-derived HIV-1 molecular clones 210WW, 210WM, 210MW, and 210MM, and the lab-adapted molecular clone LAI, viral G-to-A mutations were detected in the presence of Vif expression. Mutations occurred primarily in the GA context and were relatively infrequent, thereby allowing for spreading infection. The mutations were absent in cells lacking A3C but were induced after transient expression of A3C in the infected target cell. Inhibiting endogenous A3C by RNA interference in Magi cells prevented the viral mutations. Thus, A3C is necessary and sufficient for G-to-A mutations in some HIV-1 strains. A3C-induced mutations occur at levels that allow replication to persist and may therefore contribute to viral diversity. Developing drugs that inhibit A3C may be a novel strategy for delaying viral escape from immune or antiretroviral inhibition. PMID:17967058

  4. Genome-wide survey of artificial mutations induced by ethyl methanesulfonate and gamma rays in tomato.

    Science.gov (United States)

    Shirasawa, Kenta; Hirakawa, Hideki; Nunome, Tsukasa; Tabata, Satoshi; Isobe, Sachiko

    2016-01-01

    Genome-wide mutations induced by ethyl methanesulfonate (EMS) and gamma irradiation in the tomato Micro-Tom genome were identified by a whole-genome shotgun sequencing analysis to estimate the spectrum and distribution of whole-genome DNA mutations and the frequency of deleterious mutations. A total of ~370 Gb of paired-end reads for four EMS-induced mutants and three gamma-ray-irradiated lines as well as a wild-type line were obtained by next-generation sequencing technology. Using bioinformatics analyses, we identified 5920 induced single nucleotide variations and insertion/deletion (indel) mutations. The predominant mutations in the EMS mutants were C/G to T/A transitions, while in the gamma-ray mutants, C/G to T/A transitions, A/T to T/A transversions, A/T to G/C transitions and deletion mutations were equally common. Biases in the base composition flanking mutations differed between the mutagenesis types. Regarding the effects of the mutations on gene function, >90% of the mutations were located in intergenic regions, and only 0.2% were deleterious. In addition, we detected 1,140,687 spontaneous single nucleotide polymorphisms and indel polymorphisms in wild-type Micro-Tom lines. We also found copy number variation, deletions and insertions of chromosomal segments in both the mutant and wild-type lines. The results provide helpful information not only for mutation research, but also for mutant screening methodology with reverse-genetic approaches.

  5. Mutator suppression and escape from replication error-induced extinction in yeast.

    Directory of Open Access Journals (Sweden)

    Alan J Herr

    2011-10-01

    Full Text Available Cells rely on a network of conserved pathways to govern DNA replication fidelity. Loss of polymerase proofreading or mismatch repair elevates spontaneous mutation and facilitates cellular adaptation. However, double mutants are inviable, suggesting that extreme mutation rates exceed an error threshold. Here we combine alleles that affect DNA polymerase δ (Pol δ proofreading and mismatch repair to define the maximal error rate in haploid yeast and to characterize genetic suppressors of mutator phenotypes. We show that populations tolerate mutation rates 1,000-fold above wild-type levels but collapse when the rate exceeds 10⁻³ inactivating mutations per gene per cell division. Variants that escape this error-induced extinction (eex rapidly emerge from mutator clones. One-third of the escape mutants result from second-site changes in Pol δ that suppress the proofreading-deficient phenotype, while two-thirds are extragenic. The structural locations of the Pol δ changes suggest multiple antimutator mechanisms. Our studies reveal the transient nature of eukaryotic mutators and show that mutator phenotypes are readily suppressed by genetic adaptation. This has implications for the role of mutator phenotypes in cancer.

  6. MOLECULAR ANALYSIS OF RADIATION-INDUCED MUTATION IN EXON 7/8 OF RAT HPRT GENE

    Institute of Scientific and Technical Information of China (English)

    任晓庆; 黄定九; 黄钢; 王利民

    2003-01-01

    Objective To investigate the relationship between the radiation dose and the HPRT gene locus mutation in rat smooth muscle cells, and provide the molecular basis for prevention of restenosis after percutaneous transluminal coronary angioplasty (PTCA).MethodsThe smooth muscle cells cultured in vitro were irradiated by radionuclide 188Re in different doses. HPRT gene mutation colonies were selected and isolated by 6 thioguanine. Analysis of mutation in exon 7/8 of HPRT gene were accomplished by polymerase chain reaction and single strand conformation polymorphism.ResultsThe HPRT gene mutation frequency of rat smooth muscle cells that were irradiated by radionuclide 188Re ranged from 5.5×10-6 to 13×10-6. Of 91 HPRT gene mutation colonies, 13(14.3%) contained exon 7/8 deletion and 15(16.5%) had point mutation. The exon 7/8 mutation frequency was 30.8%. There were significant relationships between radiation dose and mutation frequency of HPRT gene and exon 7/8.ConclusionThe DNA damage and gene mutation induced by radiation has positive relationship with radiation dose, and is a basis of proliferation inhibition and apoptosis of smooth muscle cells.

  7. Ethambutol-induced optic neuropathy linked to OPA1 mutation and mitochondrial toxicity.

    Science.gov (United States)

    Guillet, Virginie; Chevrollier, Arnaud; Cassereau, Julien; Letournel, Franck; Gueguen, Naïg; Richard, Laurence; Desquiret, Valérie; Verny, Christophe; Procaccio, Vincent; Amati-Bonneau, Patrizia; Reynier, Pascal; Bonneau, Dominique

    2010-03-01

    Ethambutol (EMB), widely used in the treatment of tuberculosis, has been reported to cause Leber's hereditary optic neuropathy in patients carrying mitochondrial DNA mutations. We study the effect of EMB on mitochondrial metabolism in fibroblasts from controls and from a man carrying an OPA1 mutation, in whom the drug induced the development of autosomal dominant optic atrophy (ADOA). EMB produced a mitochondrial coupling defect together with a 25% reduction in complex IV activity. EMB induced the formation of vacuoles associated with decreased mitochondrial membrane potential and increased fragmentation of the mitochondrial network. Mitochondrial genetic variations may therefore be predisposing factors in EMB-induced ocular injury.

  8. Optimization of crop productivity in tomato using induced mutations in the florigen pathway.

    Science.gov (United States)

    Park, Soon Ju; Jiang, Ke; Tal, Lior; Yichie, Yoav; Gar, Oron; Zamir, Dani; Eshed, Yuval; Lippman, Zachary B

    2014-12-01

    Naturally occurring genetic variation in the universal florigen flowering pathway has produced major advancements in crop domestication. However, variants that can maximize crop yields may not exist in natural populations. Here we show that tomato productivity can be fine-tuned and optimized by exploiting combinations of selected mutations in multiple florigen pathway components. By screening for chemically induced mutations that suppress the bushy, determinate growth habit of field tomatoes, we isolated a new weak allele of the florigen gene SINGLE FLOWER TRUSS (SFT) and two mutations affecting a bZIP transcription factor component of the 'florigen activation complex' (ref. 11). By combining heterozygous mutations, we pinpointed an optimal balance of flowering signals, resulting in a new partially determinate architecture that translated to maximum yields. We propose that harnessing mutations in the florigen pathway to customize plant architecture and flower production offers a broad toolkit to boost crop productivity.

  9. Inducible repair system in Haemophilus influenzae unaccompanied by mutation.

    OpenAIRE

    Notani, N. K.; Setlow, J K

    1980-01-01

    Weigle reactivation of ultraviolet-irradiated HPlc1 phage was observed after ultraviolet or mitomycin C treatment of Haemophilus influenzae cells. The amount of reactivation was considerably increased when the treated cells were incubated in growth medium before infection. The presence of chloramphenicol during this incubation abolished the reactivation. No mutation of this phage accompanied the reactivation. When cells were treated so as to produce a maximal reactivation of phage, neither re...

  10. Myostatin gene mutated mice induced with tale nucleases.

    Science.gov (United States)

    Zhou, Fangfang; Sun, Ruilin; Chen, Hongyan; Fei, Jian; Lu, Daru

    2015-01-01

    Myostain gene (MSTN) is expressed primarily in skeletal muscle, and negatively regulates skeletal muscle mass; it has been suggested that mice with MSTN inhibition have reduced adiposity and improved insulin sensitivity. Therefore, it is important to establish a fast and effective gene editing method. In this report, we established the myostatin mutated-mouse model by microinjection of Transcription Activator-Like Effector Nucleases (TALENs) mRNA within the mouse fertilized oocytes and achieved high rates of mutagenesis of the mouse MSTN in C57BL/6J. Six of 45 born mice carried target mutations and we appointed one as the parental mating with wild mouse to produce the F1 and backcross to produce the F2 generation. All the mutations of the mice were examined quickly and efficiently by high-resolution melting curve analysis (HRMA) and then verified by direct sequencing. We obtained the homozygous of the F2 generation which transmitted the mutant alleles to the progeny with 100% efficiency. Mutant mice exhibited increases in muscle mass comparable to those observed in wild-type mice. Therefore, combining TALEN-mediated gene targeting with HRMA technology is a superior method of constructing genetically modified mice through microinjection in the mouse fertilized oocytes with high efficiency and short time of selection.

  11. Congenital erythropoietic porphyria due to a mutation in GATA1: the first trans-acting mutation causative for a human porphyria.

    Science.gov (United States)

    Phillips, John D; Steensma, David P; Pulsipher, Michael A; Spangrude, Gerald J; Kushner, James P

    2007-03-15

    Congenital erythropoietic porphyria (CEP), an autosomal recessive disorder, is due to mutations of uroporphyrinogen III synthase (UROS). Deficiency of UROS results in excess uroporphyrin I, which causes photosensitization. We evaluated a 3-year-old boy with CEP. A hypochromic, microcytic anemia was present from birth, and platelet counts averaged 70 x 10(9)/L (70,000/microL). Erythrocyte UROS activity was 21% of controls. Red cell morphology and globin chain labeling studies were compatible with beta-thalassemia. Hb electrophoresis revealed 36.3% A, 2.4% A(2), 59.5% F, and 1.8% of an unidentified peak. No UROS or alpha- and beta-globin mutations were found in the child or the parents. The molecular basis of the phenotype proved to be a mutation of GATA1, an X-linked transcription factor common to globin genes and heme biosynthetic enzymes in erythrocytes. A mutation at codon 216 in the child and on one allele of his mother changed arginine to tryptophan (R216W). This is the first report of a human porphyria due to a mutation in a trans-acting factor and the first association of CEP with thalassemia and thrombocytopenia. The Hb F level of 59.5% suggests a role for GATA-1 in globin switching. A bone marrow allograft corrected both the porphyria and the thalassemia.

  12. Characterization of beta-thalassemia mutations in patients from the state of Rio Grande do Norte, Brazil

    Directory of Open Access Journals (Sweden)

    Zama Messala Luna da Silveira

    2011-01-01

    Full Text Available 35 unrelated individuals were studied for characterization as either heterozygous or homozygous for beta-thalassemia. Molecular analysis was done by PCR/RFLP to detect the mutations most commonly associated with beta-thalassemia (β0IVS-I-1, β+IVS-I-6, and β039. In the patients who showed none of these mutations, the beta-globin genes were sequenced. Of the 31 heterozygous patients, 13 (41.9% had the β+IVS-I-6 mutation, 15 (48.4% the β0IVS-I-1 mutation, 2 (6.5% the β+IVS-I-110 mutation and 1 (3.2% the β+IVS-I-5 mutation. IVS-I-6 was detected in the four homozygotes. The mutation in codon 39, often found in previous studies in Brazil, was not detected in the present case. This is the first study aiming at identifying mutations that determine beta-thalassemia in the state of Rio Grande do Norte.

  13. Personalized prediction of EGFR mutation-induced drug resistance in lung cancer

    OpenAIRE

    Wang, Debby D.; Weiqiang Zhou; Hong Yan; Maria Wong; Victor Lee

    2013-01-01

    EGFR mutation-induced drug resistance has significantly impaired the potency of small molecule tyrosine kinase inhibitors in lung cancer treatment. Computational approaches can provide powerful and efficient techniques in the investigation of drug resistance. In our work, the EGFR mutation feature is characterized by the energy components of binding free energy (concerning the mutant-inhibitor complex), and we combine it with specific personal features for 168 clinical subjects to construct a...

  14. Beta-Globin Gene Regulation and Nuclear Organisation

    NARCIS (Netherlands)

    J.A. Kooren (Jurgen)

    2007-01-01

    textabstractAll genetic information required for the development and functioning of an organism is stored in billions of base pairs of deoxyribonucleic acid (or DNA). In eukaryotes, DNA is organised in large units called chromosomes that are located inside the cells nucleus. On these chromosomes res

  15. Mutational History of a Human Cell Lineage from Somatic to Induced Pluripotent Stem Cells.

    Directory of Open Access Journals (Sweden)

    Foad J Rouhani

    2016-04-01

    Full Text Available The accuracy of replicating the genetic code is fundamental. DNA repair mechanisms protect the fidelity of the genome ensuring a low error rate between generations. This sustains the similarity of individuals whilst providing a repertoire of variants for evolution. The mutation rate in the human genome has recently been measured to be 50-70 de novo single nucleotide variants (SNVs between generations. During development mutations accumulate in somatic cells so that an organism is a mosaic. However, variation within a tissue and between tissues has not been analysed. By reprogramming somatic cells into induced pluripotent stem cells (iPSCs, their genomes and the associated mutational history are captured. By sequencing the genomes of polyclonal and monoclonal somatic cells and derived iPSCs we have determined the mutation rates and show how the patterns change from a somatic lineage in vivo through to iPSCs. Somatic cells have a mutation rate of 14 SNVs per cell per generation while iPSCs exhibited a ten-fold lower rate. Analyses of mutational signatures suggested that deamination of methylated cytosine may be the major mutagenic source in vivo, whilst oxidative DNA damage becomes dominant in vitro. Our results provide insights for better understanding of mutational processes and lineage relationships between human somatic cells. Furthermore it provides a foundation for interpretation of elevated mutation rates and patterns in cancer.

  16. Mutations induced by monofunctional and bifunctional phosphoramide mustards in supF tRNA gene.

    Science.gov (United States)

    Mudipalli, A; Maccubbin, A E; Nadadur, S S; Struck, R F; Gurtoo, H L

    1997-11-19

    The relative mutagenicity, nature of the mutations and the sequence specificity of mutations induced by the bifunctional alkylating agent, phosphoramide mustard (PM) and a monofunctional derivative, dechloroethyl phosphoramide mustard (dePM), were analyzed by the Ames test and by an in vitro shuttle vector mutagenesis assay. Both PM and dePM increased the mutation frequency above background in either assay. However, on an equimolar basis, dePM was less mutagenic than PM. In the in vitro shuttle vector mutagenesis assay, sequencing demonstrated that about 40% of the mutant plasmids contained more than one mutation in the supF tRNA gene segment of the plasmid. About 70% of the mutations observed in dePM-treated plasmids were single base substitutions with A:T and G:C base pairs being mutated at equivalent rates. In contrast, only about 50% of the mutations observed in PM-treated plasmids were single base substitutions, 80% of which involved G:C base pairs. Single base deletions and insertions were found in approximately equal proportions with both compounds; however, these lesions were in greater abundance in PM-treated plasmids. Putative hot-spots for mutation in the supF tRNA gene included base pairs at position 102 and 110 for PM and positions 170 and 171 for dePM.

  17. Inducing mutations in the mouse genome with the chemical mutagen ethylnitrosourea

    Directory of Open Access Journals (Sweden)

    S.M.G. Massironi

    2006-09-01

    Full Text Available When compared to other model organisms whose genome is sequenced, the number of mutations identified in the mouse appears extremely reduced and this situation seriously hampers our understanding of mammalian gene function(s. Another important consequence of this shortage is that a majority of human genetic diseases still await an animal model. To improve the situation, two strategies are currently used: the first makes use of embryonic stem cells, in which one can induce knockout mutations almost at will; the second consists of a genome-wide random chemical mutagenesis, followed by screening for mutant phenotypes and subsequent identification of the genetic alteration(s. Several projects are now in progress making use of one or the other of these strategies. Here, we report an original effort where we mutagenized BALB/c males, with the mutagen ethylnitrosourea. Offspring of these males were screened for dominant mutations and a three-generation breeding protocol was set to recover recessive mutations. Eleven mutations were identified (one dominant and ten recessives. Three of these mutations are new alleles (Otop1mlh, Foxn1sepe and probably rodador at loci where mutations have already been reported, while 4 are new and original alleles (carc, eqlb, frqz, and Sacc. This result indicates that the mouse genome, as expected, is far from being saturated with mutations. More mutations would certainly be discovered using more sophisticated phenotyping protocols. Seven of the 11 new mutant alleles induced in our experiment have been localized on the genetic map as a first step towards positional cloning.

  18. Most ultraviolet irradiation induced mutations in the nematode Caenorhabditis elegans are chromosomal rearrangements

    Energy Technology Data Exchange (ETDEWEB)

    Stewart, H.I.; Rosenbluth, R.E.; Baillie, D.L. (Simon Fraser University, Burnaby, BC (Canada). Department of Biological Sciences, Institute of Molecular Biology)

    1991-07-01

    In this study the utility of 254-nm ultraviolet light (UV) as a magnetic tool in C.elegans is determined. It is demonstrated that irradiation of adult hermaphrodites provides a simple method for the induction of heritable chromosomal rearrangements. A screening protocol was employed that identifies either recessive lethal mutations in the 40 map unit region balanced by the translocation eT1(III;V), or unc-36(III) duplications. Mutations were recovered in 3% of the chromosomes screened after a dose of 120 J/m{sup 2}. This rate resembles that for 1500 R {gamma}-ray-induced mutations selected in a similar manner. The mutations were classified either as lethals (mapping to Linkage Group (LG)III or LGV) or as putative unc-36 duplications. In contrast to the majority of UV-induced mutations analysed in micro-organisms, a large fraction of the C.elegans UV-induced mutations were found to be not simple intragenic lesions, but deficiencies for more than one adjacent gene or more complex events. Preliminary evidence for this conclusion came from the high frequency of mutations that had a dominant effect causing reduced numbers of adult progeny. Subsequently 6 out of 9 analysed LGV mutations were found to be deficiencies. Other specific rearrangements also identified were: one translocation, sT5(II;III), and two unc-36 duplications, sDp8 and sDp9. It was concluded that UV irradiation can easily be used as an additional tool for the analysis of C.elegans chromosomes, and that C.elegans should prove to be a useful organism in which to study the mechanisms whereby UV acts as a mutagen in cells of complex eukaryotes. (author). 46 refs.; 5 figs.; 4 tabs.

  19. Transposon-induced nuclear mutations that alter chloroplast gene expression

    Energy Technology Data Exchange (ETDEWEB)

    Barkan, A.

    1992-01-01

    The goal of this project is to use mutant phenotypes as a guide to nuclear genes that determine the timing and localization of chloroplast development The immediate goals are to identify nuclear mutants with defects in chloroplast gene expression from maize lines harboring active Mu transposons; characterize their phenotypes to determine the precise defect in gene expression; clone several of the most interesting mutations by exploiting the transposon tag; and use the clones to further define the roles of these genes in modulating chloroplast gene expression. Three mutants were described earlier that had global defects in chloroplast gene expression. We have found that two of these mutations are allelic. Both alleles have global defects in chloroplast translation initiation, as revealed by the failure to assemble chloroplast mRNAs into polysomes. We have isolated and characterized three new mutants from Mu lines that have novel defects in chloroplast RNA metabolism. We are now ready to begin the task of cloning several of these genes, by using the Mu transposon tag.

  20. Cellular and Deafness Mechanisms Underlying Connexin Mutation-Induced Hearing Loss - A Common Hereditary Deafness.

    Science.gov (United States)

    Wingard, Jeffrey C; Zhao, Hong-Bo

    2015-01-01

    Hearing loss due to mutations in the connexin gene family, which encodes gap junctional proteins, is a common form of hereditary deafness. In particular, connexin 26 (Cx26, GJB2) mutations are responsible for ~50% of non-syndromic hearing loss, which is the highest incidence of genetic disease. In the clinic, Cx26 mutations cause various auditory phenotypes ranging from profound congenital deafness at birth to mild, progressive hearing loss in late childhood. Recent experiments demonstrate that congenital deafness mainly results from cochlear developmental disorders rather than hair cell degeneration and endocochlear potential reduction, while late-onset hearing loss results from reduction of active cochlear amplification, even though cochlear hair cells have no connexin expression. However, there is no apparent, demonstrable relationship between specific changes in connexin (channel) functions and the phenotypes of mutation-induced hearing loss. Moreover, new experiments further demonstrate that the hypothesized K(+)-recycling disruption is not a principal deafness mechanism for connexin deficiency induced hearing loss. Cx30 (GJB6), Cx29 (GJC3), Cx31 (GJB3), and Cx43 (GJA1) mutations can also cause hearing loss with distinct pathological changes in the cochlea. These new studies provide invaluable information about deafness mechanisms underlying connexin mutation-induced hearing loss and also provide important information for developing new protective and therapeutic strategies for this common deafness. However, the detailed cellular mechanisms underlying these pathological changes remain unclear. Also, little is known about specific mutation-induced pathological changes in vivo and little information is available for humans. Such further studies are urgently required.

  1. Spectrum of Glycidyl Methacrylate—induced Mutation in Plasmid—Escherichia coli System

    Institute of Scientific and Technical Information of China (English)

    GAOHui-Lan; ZuoJin; 等

    1994-01-01

    In order to characterize the spectrum of mutation induced by glycidyl methacrylate(GMA),the plasmid pBR322 was modified with this mutagen in vitro.transfected into appropriate Escherichia coli host HB101.The mutants were then screned and defined by DNA sequencing.Sequence analysis reveals that GMA induces two classes of mutations:deletion of the mono-,di-or tetra-base or the insertion of mono-or di-base.Both types of muations,with about 10% frequency,occur predominantly at C.G runs and at 5'-CNCCN-3' sequence,which are hotspots for GMA damage and may cause frameshift muation.

  2. A Novel SCN5A Mutation Associated with Drug Induced Brugada Type ECG

    OpenAIRE

    Isik, Turker; Takeru, Makiyama; Matteo, Vatta; Hideki, Itoh; Takeshi, Ueyama; Akihiko, Shimizu; Tomohiko, Ai; Minoru, Horie

    2016-01-01

    Background: Class IC antiarrhythmic agents may induce acquired forms of Brugada Syndrome. We have identified a novel mutation in SCN5A, the gene that encodes the α-subunit of the human cardiac sodium channel (hNav1.5), in a patient who exhibited Brugada- type ECG changes during pharmacotherapy of atrial arrhythmias. Objective: To assess whether the novel mutation p.V1328M can cause drug induced Brugada Syndrome. Methods: Administration of pilsicainide, a class IC antiarrhythmic agent, caused ...

  3. Break-Induced Replication Is a Source of Mutation Clusters Underlying Kataegis

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    Cynthia J. Sakofsky

    2014-06-01

    Full Text Available Clusters of simultaneous multiple mutations can be a source of rapid change during carcinogenesis and evolution. Such mutation clusters have been recently shown to originate from DNA damage within long single-stranded DNA (ssDNA formed at resected double-strand breaks and dysfunctional replication forks. Here, we identify double-strand break (DSB-induced replication (BIR as another powerful source of mutation clusters that formed in nearly half of wild-type yeast cells undergoing BIR in the presence of alkylating damage. Clustered mutations were primarily formed along the track of DNA synthesis and were frequently associated with additional breakage and rearrangements. Moreover, the base specificity, strand coordination, and strand bias of the mutation spectrum were consistent with mutations arising from damage in persistent ssDNA stretches within unconventional replication intermediates. Altogether, these features closely resemble kataegic events in cancers, suggesting that replication intermediates during BIR may be the most prominent source of mutation clusters across species.

  4. Obtaining induced mutations of drought tolerance in sorghum

    Energy Technology Data Exchange (ETDEWEB)

    Hoeman, S.; Razzak, M.T. [National Atomic Energy Agency, Batan (Indonesia). Center for Application of Isotopes and Radiation; Nakanishi, Tomoko M. [Tokyo Univ. (Japan). Graduate School of Agricultural and Life Sciences

    2003-01-01

    Since sorghum plant (Sorghum bicolor L.) has a big potential to be cultivated in Indonesia especially in drought-prone areas, improvement of sorghum had been carried out through mutation breeding methods. The seeds of the sorghum plant was irradiated by gamma rays emitted from cobalt-60 source. The total dose was 0.4 kGy. Through selection process in the M2 generation, a number of promising mutant lines of sorghum have been obtained and registered in the M3 generation. In the M4, a number of 100 mutant lines were tested against drought in Gunung Kidul District during the dry season in 2000. Results of the test showed that mutant line DU/20/Psj/1, DU/20/Psj/4, DU/20/Psj/24, JA/30/Cty/21, ET/40/Psj/4 and DU/20/Psj/10 had relatively high grain yield compared to the control variety. (author)

  5. Analysis of human transforming growth factor β-induced gene mutation in corneal dystrophy

    Institute of Scientific and Technical Information of China (English)

    李杨; 孙旭光; 任慧媛; 董冰; 王智群; 孙秀英

    2004-01-01

    Background Corneal dystrophy is a group of inherited blinding diseases of the cornea. This study was to identify the mutations of the keratoepithelin (KE) gene for proper diagnosis of corneal dystrophy. Methods Three families with corneal dystrophy were analysed. Thirteen individuals at risk for corneal dystrophy in family A, the proband and her son in family B, and the proband in family C were examined after their blood samples were obtained. Mutation screening of human transforming growth factor β-induced gene (BIGH3 gene) was performed. Results Five individuals in family A were found by clinical evaluation to be affected with granular corneal dystrophy and carried the BIGH3 mutation W555R. However, both probands in families B and C, also diagnosed with granular corneal dystrophy, harboured the BIGH3 mutation R124H. Conclusion Molecular genetic analysis can improve accurate diagnosis of corneal dystrophy.

  6. Development of herbicide resistant crops through induced mutations

    Directory of Open Access Journals (Sweden)

    Muhammad Rizwan

    2015-11-01

    Full Text Available Herbicide resistance is an innate characteristic of crop plants. It enables them to survive and propagate even in the presence of lethal doses of herbicides in the surroundings. Genetic tolerance in crops towards herbicides may have several benefits. It may increases safety margins between weed and crop sensitivity and also expands applicability of a particular herbicide. Besides, it can also lower the operating cost for weed control as compared to manual weeding and crop rotation which is normally prohibited by herbicide persistence. Herbicide resistant crops are developed through transformation of a plant with either native or mutant resistant genes, seed mutagenesis, plant cell or tissue culture and through other traditional plant breeding techniques. Seed mutagenesis is a non-transgenic approach, which is found to be most economical and perfect approach. Moreover, all commercial herbicide tolerant crops were derived from single nucleotide substitution of genes and trait can be incorporated into elite varieties because of incomplete dominance and non-pleiotropic effect of the alleles of all commercial herbicide tolerant mutations.

  7. Somatic mutations in stilbene estrogen-induced Syrian hamster kidney tumors identified by DNA fingerprinting

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    Roy Deodutta

    2004-01-01

    Full Text Available Abstract Kidney tumors from stilbene estrogen (diethylstilbestrol-treated Syrian hamsters were screened for somatic genetic alterations by Random Amplified Polymorphic DNA-polymerase chain-reaction (RAPD-PCR fingerprinting. Fingerprints from tumor tissue were generated by single arbitrary primers and compared with fingerprints for normal tissue from the same animal, as well as normal and tumor tissues from different animals. Sixty one of the arbitrary primers amplified 365 loci that contain approximately 476 kbp of the hamster genome. Among these amplified DNA fragments, 44 loci exhibited either qualitative or quantitative differences between the tumor tissues and normal kidney tissues. RAPD-PCR loci showing decreased and increased intensities in tumor tissue DNA relative to control DNA indicate that loci have undergone allelic losses and gains, respectively, in the stilbene estrogen-induced tumor cell genome. The presence or absence of the amplified DNA fragments indicate homozygous insertions or deletions in the kidney tumor DNA compared to the age-matched normal kidney tissue DNA. Seven of 44 mutated loci also were present in the kidney tissues adjacent to tumors (free of macroscopic tumors. The presence of mutated loci in uninvolved (non-tumor surrounding tissue adjacent to tumors from stilbene estrogen-treated hamsters suggests that these mutations occurred in the early stages of carcinogenesis. The cloning and sequencing of RAPD amplified loci revealed that one mutated locus had significant sequence similarity with the hamster Cyp1A1 gene. The results show the ability of RAPD-PCR to detect and isolate, in a single step, DNA sequences representing genetic alterations in stilbene estrogen-induced cancer cells, including losses of heterozygosity, and homozygous deletion and insertion mutations. RAPD-PCR provides an alternative molecular approach for studying cancer cytogenetics in stilbene estrogen-induced tumors in humans and experimental

  8. Multiplex Chromosomal Exome Sequencing Accelerates Identification of ENU-Induced Mutations in the Mouse.

    Science.gov (United States)

    Sun, Miao; Mondal, Kajari; Patel, Viren; Horner, Vanessa L; Long, Alyssa B; Cutler, David J; Caspary, Tamara; Zwick, Michael E

    2012-01-01

    Forward genetic screens in Mus musculus have proved powerfully informative by revealing unsuspected mechanisms governing basic biological processes. This approach uses potent chemical mutagens, such as N-ethyl-N-nitrosourea (ENU), to randomly induce mutations in mice, which are then bred and phenotypically screened to identify lines that disrupt a specific biological process of interest. Although identifying a mutation using the rich resources of mouse genetics is straightforward, it is unfortunately neither fast nor cheap. Here we show that detecting newly induced causal variants in a forward genetic screen can be accelerated dramatically using a methodology that combines multiplex chromosome-specific exome capture, next-generation sequencing, rapid mapping, sequence annotation, and variation filtering. The key innovation of our method is multiplex capture and sequence that allows the simultaneous survey of both mutant, parental, and background strains in a single experiment. By comparing variants identified in mutant offspring with those found in dbSNP, the unmutagenized background strains, and parental lines, induced causative mutations can be distinguished immediately from preexisting variation or experimental artifact. Here we demonstrate this approach to find the causative mutations induced in four novel ENU lines identified from a recent ENU screen. In all four cases, after applying our method, we found six or fewer putative mutations (and sometimes only a single one). Determining the causative variant was then easily achieved through standard segregation approaches. We have developed this process into a community resource that will speed up individual labs' ability to identify the genetic lesion in mutant mouse lines; all of our reagents and software tools are open source and available to the broader scientific community.

  9. Inflammation, gene mutation and photoimmunosuppression in response to UVR-induced oxidative damage contributes to photocarcinogenesis

    Energy Technology Data Exchange (ETDEWEB)

    Halliday, Gary M. [Dermatology Research Laboratories, Division of Medicine, Melanoma and Skin Cancer Research Institute, Royal Prince Alfred Hospital at the University of Sydney, Sydney, NSW (Australia)]. E-mail: garyh@med.usyd.edu.au

    2005-04-01

    Ultraviolet (UV) radiation causes inflammation, gene mutation and immunosuppression in the skin. These biological changes are responsible for photocarcinogenesis. UV radiation in sunlight is divided into two wavebands, UVB and UVA, both of which contribute to these biological changes, and therefore probably to skin cancer in humans and animal models. Oxidative damage caused by UV contributes to inflammation, gene mutation and immunosuppression. This article reviews evidence for the hypothesis that UV oxidative damage to these processes contributes to photocarcinogenesis. UVA makes a larger impact on oxidative stress in the skin than UVB by inducing reactive oxygen and nitrogen species which damage DNA, protein and lipids and which also lead to NAD+ depletion, and therefore energy loss from the cell. Lipid peroxidation induces prostaglandin production that in association with UV-induced nitric oxide production causes inflammation. Inflammation drives benign human solar keratosis (SK) to undergo malignant conversion into squamous cell carcinoma (SCC) probably because the inflammatory cells produce reactive oxygen species, thus increasing oxidative damage to DNA and the immune system. Reactive oxygen or nitrogen appears to cause the increase in mutational burden as SK progress into SCC in humans. UVA is particularly important in causing immunosuppression in both humans and mice, and UV lipid peroxidation induced prostaglandin production and UV activation of nitric oxide synthase is important mediators of this event. Other immunosuppressive events are likely to be initiated by UV oxidative stress. Antioxidants have also been shown to reduce photocarcinogenesis. While most of this evidence comes from studies in mice, there is supporting evidence in humans that UV-induced oxidative damage contributes to inflammation, gene mutation and immunosuppression. Available evidence implicates oxidative damage as an important contributor to sunlight-induced carcinogenesis in humans.

  10. Inflammation, gene mutation and photoimmunosuppression in response to UVR-induced oxidative damage contributes to photocarcinogenesis.

    Science.gov (United States)

    Halliday, Gary M

    2005-04-01

    Ultraviolet (UV) radiation causes inflammation, gene mutation and immunosuppression in the skin. These biological changes are responsible for photocarcinogenesis. UV radiation in sunlight is divided into two wavebands, UVB and UVA, both of which contribute to these biological changes, and therefore probably to skin cancer in humans and animal models. Oxidative damage caused by UV contributes to inflammation, gene mutation and immunosuppression. This article reviews evidence for the hypothesis that UV oxidative damage to these processes contributes to photocarcinogenesis. UVA makes a larger impact on oxidative stress in the skin than UVB by inducing reactive oxygen and nitrogen species which damage DNA, protein and lipids and which also lead to NAD+ depletion, and therefore energy loss from the cell. Lipid peroxidation induces prostaglandin production that in association with UV-induced nitric oxide production causes inflammation. Inflammation drives benign human solar keratosis (SK) to undergo malignant conversion into squamous cell carcinoma (SCC) probably because the inflammatory cells produce reactive oxygen species, thus increasing oxidative damage to DNA and the immune system. Reactive oxygen or nitrogen appears to cause the increase in mutational burden as SK progress into SCC in humans. UVA is particularly important in causing immunosuppression in both humans and mice, and UV lipid peroxidation induced prostaglandin production and UV activation of nitric oxide synthase is important mediators of this event. Other immunosuppressive events are likely to be initiated by UV oxidative stress. Antioxidants have also been shown to reduce photocarcinogenesis. While most of this evidence comes from studies in mice, there is supporting evidence in humans that UV-induced oxidative damage contributes to inflammation, gene mutation and immunosuppression. Available evidence implicates oxidative damage as an important contributor to sunlight-induced carcinogenesis in humans.

  11. Herpesvirus telomerase RNA (vTR with a mutated template sequence abrogates herpesvirus-induced lymphomagenesis.

    Directory of Open Access Journals (Sweden)

    Benedikt B Kaufer

    2011-10-01

    Full Text Available Telomerase reverse transcriptase (TERT and telomerase RNA (TR represent the enzymatically active components of telomerase. In the complex, TR provides the template for the addition of telomeric repeats to telomeres, a protective structure at the end of linear chromosomes. Human TR with a mutation in the template region has been previously shown to inhibit proliferation of cancer cells in vitro. In this report, we examined the effects of a mutation in the template of a virus encoded TR (vTR on herpesvirus-induced tumorigenesis in vivo. For this purpose, we used the oncogenic avian herpesvirus Marek's disease virus (MDV as a natural virus-host model for lymphomagenesis. We generated recombinant MDV in which the vTR template sequence was mutated from AATCCCAATC to ATATATATAT (vAU5 by two-step Red-mediated mutagenesis. Recombinant viruses harboring the template mutation replicated with kinetics comparable to parental and revertant viruses in vitro. However, mutation of the vTR template sequence completely abrogated virus-induced tumor formation in vivo, although the virus was able to undergo low-level lytic replication. To confirm that the absence of tumors was dependent on the presence of mutant vTR in the telomerase complex, a second mutation was introduced in vAU5 that targeted the P6.1 stem loop, a conserved region essential for vTR-TERT interaction. Absence of vTR-AU5 from the telomerase complex restored virus-induced lymphoma formation. To test if the attenuated vAU5 could be used as an effective vaccine against MDV, we performed vaccination-challenge studies and determined that vaccination with vAU5 completely protected chickens from lethal challenge with highly virulent MDV. Taken together, our results demonstrate 1 that mutation of the vTR template sequence can completely abrogate virus-induced tumorigenesis, likely by the inhibition of cancer cell proliferation, and 2 that this strategy could be used to generate novel vaccine candidates

  12. Gene Mutation as Biomarker of Radiation Induced Cell Injury and Genomic Instability

    Directory of Open Access Journals (Sweden)

    M Syaifudin

    2006-07-01

    Full Text Available Gene expression profiling and its mutation has become one of the most widely used approaches to identify genes and their functions in the context of identify and categorize genes to be used as radiation effect markers including cell and tissue sensitivities. Ionizing radiation produces genetic damage and changes in gene expression that may lead to cancer due to specific protein that controlling cell proliferation altered the function, its expression or both. P53 protein encoded by p53 gene plays an important role in protecting cell by inducing growth arrest and or cell suicide (apoptosis after deoxyribonucleic acid (DNA damage induced by mutagen such as ionizing radiation. The mutant and thereby dysfunctional of this gene was found in more than 50% of various human cancers, but it is as yet unclear how p53 mutations lead to neoplastic development. Wild-type p53 has been postulated to play a role in DNA repair, suggesting that expression of mutant forms of p53 might alter cellular resistance to the DNA damage caused by radiation. Moreover, p53 is thought to function as a cell cycle checkpoint after irradiation, also suggesting that mutant p53 might change the cellular proliferative response to radiation. p53 mutations affect the cellular response to DNA damage, either by increasing DNA repair processes or, possibly, by increasing cellular tolerance to DNA damage. The association of p53 mutations with increased radioresistance suggests that alterations in the p53 gene might lead to oncogenic transformation. Current attractive model of carcinogenesis also showed that p53 gene is the major target of radiation. The majority of p53 mutations found so far is single base pairchanges (point mutations, which result in amino acid substitutionsor truncated forms of the P53 protein, and are widely distributedthroughout the evolutionarily conserved regions of the gene. Examination of p53 mutations in human cancer also shows an association between particular

  13. Mutations induced in a shuttle vector plasmid exposed to monofunctionally activated mitomycin C.

    Science.gov (United States)

    Maccubbin, A E; Mudipalli, A; Nadadur, S S; Ersing, N; Gurtoo, H L

    1997-01-01

    Reductive activation of mitomycin C leads to its covalent binding to DNA, forming monoadducts and cross-links. The cytotoxicity of mitomycin C has been attributed to cross-link formation, whereas monoadducts are assumed to cause mutagenicity. We have developed a 32P-postlabeling technique to measure mitomycin C DNA adducts. Using this technique, we have measured monoadduct formation in the shuttle vector plasmid pSP189 and have determined mutations induced by monoadduct formation. The shuttle vector plasmid was incubated with mitomycin C under conditions favoring monofunctional activation of mitomycin C. The plasmid was then replicated in human Ad293 cells, rescued in bacteria, and analyzed for mutations in the supF tRNA gene sequence of pSP189. One major mitomycin C/DNA adduct was observed by 32P-postlabeling and was characterized as a monoadduct of guanine. When pSP189 was exposed to monofunctionally activated mitomycin C, increases in adduct levels and mutation frequency were found to be related to mitomycin C concentration. The majority of the mutations involved single bases, with base substitutions making up 59.1% of the total mutations observed. Of the base substitutions, 67.2% were transversions and 32.8% were transitions, with nearly 80% of all base substitutions involving G:C base pairs. Deletions, either as single bases or large deletions, also involved G:C base pairs the majority of the time. The observed bias of mutations at G:C and the formation of a mitomycin C/DNA monoadduct involving guanine suggests that monoadduct formation may be responsible for the mutations.

  14. Point Mutations in Centromeric Histone Induce Post-zygotic Incompatibility and Uniparental Inheritance.

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    Sundaram Kuppu

    2015-09-01

    Full Text Available The centromeric histone 3 variant (CENH3, aka CENP-A is essential for the segregation of sister chromatids during mitosis and meiosis. To better define CENH3 functional constraints, we complemented a null allele in Arabidopsis with a variety of mutant alleles, each inducing a single amino acid change in conserved residues of the histone fold domain. Many of these transgenic missense lines displayed wild-type growth and fertility on self-pollination, but exhibited frequent post-zygotic death and uniparental inheritance when crossed with wild-type plants. The failure of centromeres marked by these missense mutation in the histone fold domain of CENH3 reproduces the genome elimination syndromes described with chimeric CENH3 and CENH3 from diverged species. Additionally, evidence that a single point mutation is sufficient to generate a haploid inducer provide a simple one-step method for the identification of non-transgenic haploid inducers in existing mutagenized collections of crop species. As proof of the extreme simplicity of this approach to create haploid-inducing lines, we performed an in silico search for previously identified point mutations in CENH3 and identified an Arabidopsis line carrying the A86V substitution within the histone fold domain. This A87V non-transgenic line, while fully fertile on self-pollination, produced postzygotic death and uniparental haploids when crossed to wild type.

  15. Induced Mutations Unleash the Potentials of Plant Genetic Resources for Food and Agriculture

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    Chikelu Mba

    2013-03-01

    Full Text Available The options for increasing food production by at least 70% over the next four decades so as to keep pace with a rapidly increasing human population are bedeviled by erratic climatic conditions, depleted arable lands, dwindling water resources and by the significant environmental and health costs for increasing the use of agrochemicals. Enhanced productivities through “smart” crop varieties that yield more with fewer inputs is a viable option. However, the genetic similarities amongst crop varieties—which render entire cropping systems vulnerable to the same stresses—coupled with unvarying parental materials limit the possibilities for uncovering novel alleles of genes and, hence, assembling new gene combinations to break yield plateaux and enhance resilience. Induced mutation unmasks novel alleles that are harnessed to breed superior crop varieties. The historical antecedents, theoretical and practical considerations, and the successes of induced mutations in crop improvement are reviewed along with how induced mutagenesis underpins plant functional genomics. The roles of cell and molecular biology techniques in enhancing the efficiencies for the induction, detection and deployment of mutation events are also reviewed. Also, the integration of phenomics into induced mutagenesis and the use of pre-breeding for facilitating the incorporation of mutants into crop improvement are advocated.

  16. Mutational spectra of Salmonella typhimurium revertants induced by chlorohydroxyfuranones, byproducts of chlorine disinfection of drinking water.

    Science.gov (United States)

    Knasmüller, S; Zöhrer, E; Kronberg, L; Kundi, M; Franzén, R; Schulte-Hermann, R

    1996-03-01

    The base substitution specificities of 3-chloro-4-(dichloromethyl)-5-hydroxy-2(5H)-furanone (MX), 3-chloro-4-(chloromethyl)-5-hydroxy-2(5H)-furanone (CMCF), 3,4-dichloro-5-hydroxy-2(5H)-furanone (MCA), and chloromalonaldehyde (CMA), a putative breakdown product of MCA, were examined in the hisG46 gene and in the hisG428 gene of Salmonella typhimurium using allele specific oligonucleotide hybridization. Although the compounds are structurally closely related, they induced substantially different mutation spectra: MCA and CMA caused primarily GC-->AT transitions in the hisG46 allele (target sequence CCC), in particular, at the second position of the codon in strain TA100. In TA100 the mutation spectrum of MCA was similar to that of CMA. The mutational specificity of MCA can be explained as a consequence of misincorporation opposite to cyclic etheno adducts identical to those formed by the carcinogen vinyl chloride. The spectra induced by MX and CMCF in TA100 were almost identical but distinctively different from the spectra of MCA and CMA. Both compounds induced primarily GC-->TA transversions, in particular, at the second position of the codon, and to a lesser extent in the first position of the codon. An identical site bias is induced by carcinogens such as polycyclic aromatic hydrocarbons and heterocyclic amines as a consequence of formation of (noncyclic) guanosine adducts. In hisG428 (target sequence TAA) MX induced again primarily GC-->TA transversions in Tyr tRNA genes (supC/M) and, to a lesser extent, intragenic AT-->TA transversions (TAA-->AAA). The possible involvement of guanosine and adenosine adducts in the mutational specificity of MX is addressed.

  17. Nucleic acid template and the risk of a PCR-Induced HIV-1 drug resistance mutation.

    Directory of Open Access Journals (Sweden)

    Vici Varghese

    Full Text Available BACKGROUND: The HIV-1 nucleoside RT inhibitor (NRTI-resistance mutation, K65R confers intermediate to high-level resistance to the NRTIs abacavir, didanosine, emtricitabine, lamivudine, and tenofovir; and low-level resistance to stavudine. Several lines of evidence suggest that K65R is more common in HIV-1 subtype C than subtype B viruses. METHODS AND FINDINGS: We performed ultra-deep pyrosequencing (UDPS and clonal dideoxynucleotide sequencing of plasma virus samples to assess the prevalence of minority K65R variants in subtype B and C viruses from untreated individuals. Although UDPS of plasma samples from 18 subtype C and 27 subtype B viruses showed that a higher proportion of subtype C viruses contain K65R (1.04% vs. 0.25%; p1.5% of UDPS reads. We therefore performed UDPS on clones and site-directed mutants containing subtype B- and C-specific patterns of silent mutations in the conserved KKK motif encompassing RT codons 64 to 66 and found that subtype-specific nucleotide differences were responsible for increased PCR-induced K65R mutation in subtype C viruses. CONCLUSIONS: This study shows that the RT KKK nucleotide template in subtype C viruses can lead to the spurious detection of K65R by highly sensitive PCR-dependent sequencing techniques. However, the study is also consistent with the subtype C nucleotide template being inherently responsible for increased polymerization-induced K65R mutations in vivo.

  18. Repairing the sickle cell mutation. I. Specific covalent binding of a photoreactive third strand to the mutated base pair.

    Science.gov (United States)

    Broitman, S; Amosova, O; Dolinnaya, N G; Fresco, J R

    1999-07-30

    A DNA third strand with a 3'-psoralen substituent was designed to form a triplex with the sequence downstream of the T.A mutant base pair of the human sickle cell beta-globin gene. Triplex-mediated psoralen modification of the mutant T residue was sought as an approach to gene repair. The 24-nucleotide purine-rich target sequence switches from one strand to the other and has four pyrimidine interruptions. Therefore, a third strand sequence favorable to two triplex motifs was used, one parallel and the other antiparallel to it. To cope with the pyrimidine interruptions, which weaken third strand binding, 5-methylcytosine and 5-propynyluracil were used in the third strand. Further, a six residue "hook" complementary to an overhang of a linear duplex target was added to the 5'-end of the third strand via a T(4) linker. In binding to the overhang by Watson-Crick pairing, the hook facilitates triplex formation. This third strand also binds specifically to the target within a supercoiled plasmid. The psoralen moiety at the 3'-end of the third strand forms photoadducts to the targeted T with high efficiency. Such monoadducts are known to preferentially trigger reversion of the mutation by DNA repair enzymes.

  19. Deficiency of the DNA repair protein nibrin increases the basal but not the radiation induced mutation frequency in vivo

    Energy Technology Data Exchange (ETDEWEB)

    Wessendorf, Petra [Institute of Medical and Human Genetics, Charité – Universitätsmedizin Berlin, Augustenburger Platz 1, D-13353 Berlin (Germany); Vijg, Jan [Albert Einstein College of Medicine, Michael F. Price Center, 1301 Morris Park Avenue, Bronx, NY 10461 (United States); Nussenzweig, André [Laboratory of Genome Integrity, National Cancer Institute, National Institute of Health, 37 Convent Drive, Room 1106, Bethesda, MD 20892 (United States); Digweed, Martin, E-mail: martin.digweed@charite.de [Institute of Medical and Human Genetics, Charité – Universitätsmedizin Berlin, Augustenburger Platz 1, D-13353 Berlin (Germany)

    2014-11-15

    Highlights: • lacZ mutant frequencies measured in vivo in mouse models of radiosensitive Nijmegen Breakage Syndrome. • Spontaneous mutation frequencies are increased in lymphatic tissue due to Nbn mutation. • Single base transitions, not deletions, dominate the mutation spectrum. • Radiation induced mutation frequencies are not increased due to Nbn mutation. - Abstract: Nibrin (NBN) is a member of a DNA repair complex together with MRE11 and RAD50. The complex is associated particularly with the repair of DNA double strand breaks and with the regulation of cell cycle check points. Hypomorphic mutation of components of the complex leads to human disorders characterised by radiosensitivity and increased tumour occurrence, particularly of the lymphatic system. We have examined here the relationship between DNA damage, mutation frequency and mutation spectrum in vitro and in vivo in mouse models carrying NBN mutations and a lacZ reporter plasmid. We find that NBN mutation leads to increased spontaneous DNA damage in fibroblasts in vitro and high basal mutation rates in lymphatic tissue of mice in vivo. The characteristic mutation spectrum is dominated by single base transitions rather than the deletions and complex rearrangements expected after abortive repair of DNA double strand breaks. We conclude that in the absence of wild type nibrin, the repair of spontaneous errors, presumably arising during DNA replication, makes a major contribution to the basal mutation rate. This applies also to cells heterozygous for an NBN null mutation. Mutation frequencies after irradiation in vivo were not increased in mice with nibrin mutations as might have been expected considering the radiosensitivity of NBS patient cells in vitro. Evidently apoptosis is efficient, even in the absence of wild type nibrin.

  20. Spontaneous and induced chromosomal damage and mutations in Bloom Syndrome mice.

    Science.gov (United States)

    Wang, Yanping; Heddle, John A

    2004-10-04

    Bloom Syndrome (BS) is characterized by both cancer and genomic instability, including chromosomal aberrations, sister chromosome exchanges, and mutations. Since BS heterozygotes are much more frequent than homozygotes, the issue of the sensitivity of heterozygotes to cancer is an important one. This and many other questions concerning the effects of BLM (the gene responsible for the BS) are more easily studied in mice than in humans. To gain insight into genomic instability associated with loss of function of BLM, which codes for a DNA helicase, we compared frequencies of micronuclei, somatic mutations, and loss of heterozygosity (LOH) in Blmtm3Brd homozygous, heterozygous, and wild-type mice carrying a cII transgenic reporter gene. It should be noted that the Blmtm3Brd is inserted into the endogenous locus with a partial duplication of the gene, so some function of the locus may be retained. The cII reporter gene was introduced from the Big Blue mouse by crossing them with Blmtm3Brd mice. All measurements were made on F2 mice from this cross. The reticulocytes of Blmtm3Brd homozygous mice had more micronuclei than heterozygous or wild-type mice (4.5, 2.7, and 2.5 per thousand, respectively; P 0.05). Mutation measurements were also made on mice that had been treated with ethyl-nitrosourea (ENU) because Bloom Syndrome cells are sensitive to ethylating agents. The ENU-induced mutation frequency in Blmtm3Brd homozygous, heterozygous, and wild mice were 54 x 10(-5), 35 x 10(-5), and 25 x 10(-5) mutants/plaques, respectively. ENU induced more mutations in Blmtm3Brd homozygous mice than in wild-type mice (P Bloom Syndrome except that they have normal frequencies of spontaneous mutation. The fact that these mice have elevated rates of both cancer and chromosomal aberrations (as shown by more micronuclei and LOH) but normal rates of spontaneous mutation, shows the greater importance of chromosomal events than mutations in the origin of their cancers.

  1. Mutations in BALB mitochondrial DNA induce CCL20 up-regulation promoting tumorigenic phenotypes

    Energy Technology Data Exchange (ETDEWEB)

    Sligh, James [Department of Medicine—Dermatology Division, University of Arizona, Tucson, AZ 857 24 (United States); University of Arizona Cancer Center, Tucson, AZ 85724 (United States); Janda, Jaroslav [University of Arizona Cancer Center, Tucson, AZ 85724 (United States); Jandova, Jana, E-mail: jjandova@email.arizona.edu [Department of Medicine—Dermatology Division, University of Arizona, Tucson, AZ 857 24 (United States); University of Arizona Cancer Center, Tucson, AZ 85724 (United States)

    2014-11-15

    Highlights: • Alterations in mitochondrial DNA are commonly found in various human cancers. • Mutations in BALB mitochondrial DNA induce up-regulation of chemokine CCL20. • Increased growth and motility of mtBALB cells is associated with CCL20 levels. • mtDNA changes in BALB induce in vivo tumor growth through CCL20 up-regulation. • Mutations in mitochondrial DNA play important roles in keratinocyte neoplasia. - Abstract: mtDNA mutations are common in human cancers and are thought to contribute to the process of neoplasia. We examined the role of mtDNA mutations in skin cancer by generating fibroblast cybrids harboring a mutation in the gene encoding the mitochondrial tRNA for arginine. This somatic mutation (9821insA) was previously reported in UV-induced hyperkeratotic skin tumors in hairless mice and confers specific tumorigenic phenotypes to mutant cybrids. Microarray analysis revealed and RT-PCR along with Western blot analysis confirmed the up-regulation of CCL20 and its receptor CCR6 in mtBALB haplotype containing the mt-Tr 9821insA allele compared to wild type mtB6 haplotype. Based on reported role of CCL20 in cancer progression we examined whether the hyper-proliferation and enhanced motility of mtBALB haplotype would be associated with CCL20 levels. Treatment of both genotypes with recombinant CCL20 (rmCCL20) resulted in enhanced growth and motility of mtB6 cybrids. Furthermore, the acquired somatic alteration increased the in vivo tumor growth of mtBALB cybrids through the up-regulation of CCL20 since neutralizing antibody significantly decreased in vivo tumor growth of these cells; and tumors from anti-CCL20 treated mice injected with mtBALB cybrids showed significantly decreased CCL20 levels. When rmCCL20 or mtBALB cybrids were used as chemotactic stimuli, mtB6 cybrids showed increased motility while anti-CCL20 antibody decreased the migration and in vivo tumor growth of mtBALB cybrids. Moreover, the inhibitors of MAPK signaling and NF

  2. Intersex (ix) mutations of Drosophila melanogaster cause nonrandom cell death in genital disc and can induce tumours in genitals in response to decapentaplegic (dppdisk) mutations

    Indian Academy of Sciences (India)

    R. N. chatterjee; P. Chatterjee; S. Kuthe; M. Acharyya-Ari; R. Chatterjee

    2015-06-01

    In Drosophila melanogaster, the intersex (ix) is a terminally positioned gene in somatic sex determination hierarchy and function with the female specific product of double sex (DSXF) to implement female sexual differentiation. The null phenotype of ix is to transform diplo-X individuals into intersexes while leaving haplo-X animals unaffected. This study on the effect of different intersex mutations on genital disc development provides the following major results: (i) similar range of a characteristic array of morphological structures (from almost double sex terminalia to extreme reduction of terminal appendages) was displayed by the terminalia of XX ix1/ix1, XX ix2/ix2 and XX ix5/ix5 individuals; (ii) an increased number of apoptotic cells were found to occur in a localized manner in mature third instar larval genital discs of ix individuals; (iii) ix mutations can induce high frequency of neoplastic tumours in genitals in the presence of decapentaplegic (dppdisk) mutations; and (iv) heteroallelic combinations of dppdisk mutations can also induce tumours in intersex genitals with variable expressivity. On the basis of these findings, we suggest that: (i) loss of function of ix causes massive cell death in both male and female genital primordia of genital discs, resulting phenotype mimicking in male and female characteristics in genitals; and (ii) at the discs, the apoptotic cells persist as ‘undead’ cells that can induce oncogenic transformation in the neighbouring disc cells when dpp signalling is blocked or reduced by dppdisk mutations.

  3. Repeat induced point mutation in two asexual fungi, Aspergillus niger and Penicillium chrysogenum.

    Science.gov (United States)

    Braumann, Ilka; van den Berg, Marco; Kempken, Frank

    2008-05-01

    Repeat induced point mutation (RIP) is a gene silencing mechanism present in fungal genomes. During RIP, duplicated sequences are efficiently and irreversibly mutated by transitions from C:G to T:A. For the first time, we have identified traces of RIP in transposable elements of Aspergillus niger and Penicillium chrysogenum, two biotechnologically relevant fungi. We found that RIP in P. chrysogenum has affected a large set of sequences, which also contain other mutations. On the other hand, RIP in A. niger is limited to only few sequences, but literally all mutations are RIP-like. Surprisingly, RIP occurred only in transposon sequences that have disrupted open reading frames in A. niger, a phenomenon not yet reported for other fungi. In both fungal species, we identified two sequences with strong sequence similarity to Neurospora crassa RID. RID is a putative DNA methyltransferase and the only known enzyme involved in the RIP process. Our findings suggest that both A. niger and P. chrysogenum either had a sexual past or have a sexual potential. These findings have important implications for future strain development of these fungi.

  4. Src mutation induces acquired lapatinib resistance in ERBB2-amplified human gastroesophageal adenocarcinoma models.

    Directory of Open Access Journals (Sweden)

    Yong Sang Hong

    Full Text Available ERBB2-directed therapy is now a routine component of therapy for ERBB2-amplified metastatic gastroesophageal adenocarcinomas. However, there is little knowledge of the mechanisms by which these tumors develop acquired resistance to ERBB2 inhibition. To investigate this question we sought to characterize cell line models of ERBB2-amplified gastroesophageal adenocarcinoma with acquired resistance to ERBB2 inhibition. We generated lapatinib-resistant (LR subclones from an initially lapatinib-sensitive ERBB2-amplified esophageal adenocarcinoma cell line, OE19. We subsequently performed genomic characterization and functional analyses of resistant subclones with acquired lapatinib resistance. We identified a novel, acquired SrcE527K mutation in a subset of LR OE19 subclones. Cells with this mutant allele harbour increased Src phosphorylation. Genetic and pharmacologic inhibition of Src resensitized these subclones to lapatinib. Biochemically, Src mutations could activate both the phosphatidylinositol 3-kinase and mitogen activated protein kinase pathways in the lapatinib-treated LR OE19 cells. Ectopic expression of SrcE527K mutation also was sufficient to induce lapatinib resistance in drug-naïve cells. These results indicate that pathologic activation of Src is a potential mechanism of acquired resistance to ERBB2 inhibition in ERBB2-amplified gastroesophageal cancer. Although Src mutation has not been described in primary tumor samples, we propose that the Src hyperactivation should be investigated in the settings of acquired resistance to ERBB2 inhibition in esophageal and gastric adenocarcinoma.

  5. Stability Test For Sorghum Mutant Lines Derived From Induced Mutations with Gamma-Ray Irradiation

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    S. Human

    2011-12-01

    Full Text Available Sorghum breeding program had been conducted at the Center for the Application of Isotopes and Radiation Technology, BATAN. Plant genetic variability was increased through induced mutations using gamma-ray irradiation. Through selection process in successive generations, some promising mutant lines had been identified to have good agronomic characteristics with high grain yield. These breeding lines were tested in multi location trials and information of the genotypic stability was obtained to meet the requirements for officially varietal release by the Ministry of Agriculture. A total of 11 sorghum lines and varieties consisting of 8 mutant lines derived from induced mutations (B-100, B-95, B-92, B-83, B-76, B-75, B-69 and Zh-30 and 3 control varieties (Durra, UPCA-S1 and Mandau were included in the experiment. All materials were grown in 10 agro-ecologically different locations namely Gunungkidul, Bantul, Citayam, Garut, Lampung, Bogor, Anyer, Karawaci, Cianjur and Subang. In each location, the local adaptability test was conducted by randomized block design with 3 replications. Data of grain yield was used for evaluating genotypic stability using AMMI approach. Results revealed that sorghum mutation breeding had generated 3 mutant lines (B-100, B-76 and Zh-30 exhibiting grain yield significantly higher than the control varieties. These mutant lines were genetically stable in all locations so that they would be recommended for official release as new sorghum varieties to the Ministry of Agriculture

  6. A PCR based protocol for detecting indel mutations induced by TALENs and CRISPR/Cas9 in zebrafish.

    Directory of Open Access Journals (Sweden)

    Chuan Yu

    Full Text Available Genome editing techniques such as the zinc-finger nucleases (ZFNs, transcription activator-like effecter nucleases (TALENs and clustered regularly interspaced short palindromic repeats (CRISPR/CRISPR-associated (Cas system Cas9 can induce efficient DNA double strand breaks (DSBs at the target genomic sequence and result in indel mutations by the error-prone non-homologous end joining (NHEJ DNA repair system. Several methods including sequence specific endonuclease assay, T7E1 assay and high resolution melting curve assay (HRM etc have been developed to detect the efficiency of the induced mutations. However, these assays have some limitations in that they either require specific sequences in the target sites or are unable to generate sequencing-ready mutant DNA fragments or unable to distinguish induced mutations from natural nucleotide polymorphism. Here, we developed a simple PCR-based protocol for detecting indel mutations induced by TALEN and Cas9 in zebrafish. We designed 2 pairs of primers for each target locus, with one putative amplicon extending beyond the putative indel site and the other overlapping it. With these primers, we performed a qPCR assay to efficiently detect the frequencies of newly induced mutations, which was accompanied with a T-vector-based colony analysis to generate single-copy mutant fragment clones for subsequent DNA sequencing. Thus, our work has provided a very simple, efficient and fast assay for detecting induced mutations, which we anticipate will be widely used in the area of genome editing.

  7. Utilization of induced mutation techniques in rice improvement in the Philippines

    Energy Technology Data Exchange (ETDEWEB)

    Asencion, A.B.; Santos, I.S.; Barrida, A.C.; Medina, F.I.S. III [Philippine Nuclear Research Institute, Atomic Research Center (Philippines)

    2001-03-01

    Rice is one of the most important food crops in the Philippines, as such, efforts have been made consistently to improve the varieties released to the farmers for planting. Both conventional and induced mutation techniques were utilized to solve some of the problems. Varieties with improved qualities, resistance to pests and diseases, reduced height, early maturity and non-photoperiod sensitive were developed using either physical or chemical mutagen. Other methods were also tried to enhance variability like combination of gamma irradiation and biotechnology. Irradiation of F1 seeds was also initiated including the use of mutants in crosses to transfer their improved mutated characters. Promising selections were already tested and six lines from the F1 irradiation out-yielded both C4-63G and IR 1561-288-3, their parents. (author)

  8. Development of radiation-induced mutation techniques and functional genomics studies

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Dong Sub; Kang, Si Yong; Kim, Jin Baek [KAERI, Daejeon (Korea, Republic of); and others

    2012-01-15

    This project has been performed to develop plant genetic resources using radiation (gamma-rays, ion-beam, space environments), to conduct functional genomics studies with mutant resources, and to develop new radiation plant breeding techniques using various radiation sources during 3 years. In the first section, we developed flower genetic resources, functional crop resources, and bio-industrial plant resources. In the second section, we cloned several mutated genes and studied mechanisms of gene expression and genetic diversity of mutations induced by gamma-rays. In the third section, we developed new plant breeding techniques using gamma-phytotron, heavy ion-beam, and space environments. Based on these results, a total of 8 cultivars containing Chrysanthemum, Hibiscus, kenaf, rice, and soybean were applied for plant variety protection (PVP) and a total of 4 cultivars were registered for PVP. Also, license agreement for the dwarf type Hibiscus mutant 'Ggoma' was conducted with Supro co. and the manufacturing technology for natural antioxidant pear-grape vinegar was transferred into Enzenic co. Also, 8 gene sequences, such as F3'H and LDOX genes associated with flower color in Chrysanthemum and EPSPS gene from Korean lawn grass, were registered in the database of National Center for Biotechnology Information (NCBI). In the future study, we will develop new radiation mutation breeding techniques through the mutation spectrum induced by various radiation sources, the studies for mechanism of the cellular response to radiation, and the comparative{center_dot}structural{center_dot}functional genomics studies for useful traits.

  9. A rapid method for detection of five known mutations associated with aminoglycoside-induced deafness

    Directory of Open Access Journals (Sweden)

    Greinwald John H

    2009-01-01

    Full Text Available Abstract Background South Africa has one of the highest incidences of multidrug-resistant tuberculosis (MDR-TB in the world. Concomitantly, aminoglycosides are commonly used in this country as a treatment against MDR-TB. To date, at least five mutations are known to confer susceptibility to aminoglycoside-induced hearing loss. The aim of the present study was to develop a rapid screening method to determine whether these mutations are present in the South African population. Methods A multiplex method using the SNaPshot technique was used to screen for five mutations in the MT-RNR1 gene: A1555G, C1494T, T1095C, 961delT+C(n and A827G. A total of 204 South African control samples, comprising 98 Mixed ancestry and 106 Black individuals were screened for the presence of the five mutations. Results A robust, cost-effective method was developed that detected the presence of all five sequence variants simultaneously. In this pilot study, the A1555G mutation was identified at a frequency of 0.9% in the Black control samples. The 961delT+C(n variant was present in 6.6% of the Black controls and 2% of the Mixed ancestry controls. The T1095C, C1494T and A827G variants were not identified in any of the study participants. Conclusion The frequency of 0.9% for the A1555G mutation in the Black population in South Africa is of concern given the high incidence of MDR-TB in this particular ethnic group. Future larger studies are warranted to determine the true frequencies of the aminoglycoside deafness mutations in the general South African population. The high frequencies of the 961delT+C(n variant observed in the controls suggest that this change is a common non-pathogenic polymorphism. This genetic method facilitates the identification of individuals at high risk of developing hearing loss prior to the start of aminoglycoside therapy. This is important in a low-resource country like South Africa where, despite their adverse side-effects, aminoglycosides will

  10. Locus control region HS2 point mutations are generally not responsible for elevated fetal hemoglobin expression of sickle cell patients

    Energy Technology Data Exchange (ETDEWEB)

    Gilman, J.G. [Montefiore Medical Center/Albert Einstein College of Medicine, Bronx, NY (United States); Brinson, E.C.; Milner, P.M. [Medical College of Georgia, Augusta (United States)] [and others

    1994-09-01

    The locus control region (LCR), composed of four hypersensitive sites (HS1-4) 5{prime} of the {epsilon} globin gene, confers strong, copy-number dependent expression on globin genes in transgenic mice. Several {beta}-globin gene cluster haplotypes carry the sickle cell gene, and show variable levels of fetal hemoglobin (Hb F) expression in association with DNA sequence differences in HS2, {gamma} and {beta} globin promoters, and {gamma}IVSII: The Senegal (SEN or No. 3) haplotype generally has high (>10%) Hb F, Benin (BEN or No. 19) has intermediate Hb F (but some low and some high), and Banu (BAN or No. 20) generally has low Hb F. Huisman and colleagues have proposed that `factors produced under conditions of hematopoietic stress, together with genetic determinants on the haplotype-3 like LCR sequences, allow for high level expression of {gamma} globin genes`. We have now used slot blot to screen high Hb F (>9.5%) and low Hb F cases for two of the three HS2 point mutations described by Oener et al. Comparing eight high Hb F BEN/BEN with two low Hb F BEN/BEN, all ten had the BEN mutations considered by Oener et al. to be associated with low Hb F. Comparing three high Hb F BEN/BAN with two low Hb F BEN/BAN, all five were heterozygous at three positions; this is consistent with BEN having G and T and BAN having A at both positions. DNA sequencing of HS2 for BAN, which is generally associated with low HB F, showed that the point mutations at all three positions were those seen in SEN (generally high Hb F); only the AT repeat region showed major differences, confirming results of Huisman and colleagues. Hence, if there is any effect of HS2 of the Senegal sickle cell haplotype in causing elevated Hb F under hematopoietic stress, it must be due to specific variation in the AT repeat region, which Oener et al. have suggested may bind a silencer.

  11. Genome-wide mutation avalanches induced in diploid yeast cells by a base analog or an APOBEC deaminase.

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    Artem G Lada

    Full Text Available Genetic information should be accurately transmitted from cell to cell; conversely, the adaptation in evolution and disease is fueled by mutations. In the case of cancer development, multiple genetic changes happen in somatic diploid cells. Most classic studies of the molecular mechanisms of mutagenesis have been performed in haploids. We demonstrate that the parameters of the mutation process are different in diploid cell populations. The genomes of drug-resistant mutants induced in yeast diploids by base analog 6-hydroxylaminopurine (HAP or AID/APOBEC cytosine deaminase PmCDA1 from lamprey carried a stunning load of thousands of unselected mutations. Haploid mutants contained almost an order of magnitude fewer mutations. To explain this, we propose that the distribution of induced mutation rates in the cell population is uneven. The mutants in diploids with coincidental mutations in the two copies of the reporter gene arise from a fraction of cells that are transiently hypersensitive to the mutagenic action of a given mutagen. The progeny of such cells were never recovered in haploids due to the lethality caused by the inactivation of single-copy essential genes in cells with too many induced mutations. In diploid cells, the progeny of hypersensitive cells survived, but their genomes were saturated by heterozygous mutations. The reason for the hypermutability of cells could be transient faults of the mutation prevention pathways, like sanitization of nucleotide pools for HAP or an elevated expression of the PmCDA1 gene or the temporary inability of the destruction of the deaminase. The hypothesis on spikes of mutability may explain the sudden acquisition of multiple mutational changes during evolution and carcinogenesis.

  12. Genetic and molecular analyses of UV radiation-induced mutations in the fem-3 gene of Caenorhabditis elegans

    Energy Technology Data Exchange (ETDEWEB)

    Hartman, P.S.; De Wilde, D.; Dwarakanath, V.N. [Texas Christian Univ., Fort Worth, TX (United States). Dept. of Biology

    1995-06-01

    The utility of a new target gene (fem-3) is described for investigating the molecular nature of mutagenesis in the nematode Caenorhabditis elegans. As a principal attribute, this system allows for the selection, maintenance and molecular analysis of any type of mutation that disrupts the gene, including deletions. In this study, 86 mutant strains were isolated, of which 79 proved to have mutations in fem-3. Twenty of these originally tested as homozygous inviable. Homozygous inviability was expected, as Stewart and coworkers had previously observed that, unlike in other organisms, most UV radiation-induced mutations in C. elegans are chromosomal rearrangements of deficiencies (Mutat. Res 249, 37-54, 1991). However, additional data, including Southern blot analyses on 49 of the strains, indicated that most of the UV radiation-induced fem-3 mutations were not deficiencies, as originally inferred from their homozygous inviability. Instead, the lethals were most likely ``coincident mutations`` in linked, essential genes that were concomitantly induced. As such, they were lost owing to genetic recombination during stock maintenance. As in mammalian cells, yeast and bacteria, the frequency of coincident mutations was much higher than would be predicted by chance. (Author).

  13. Detection of four beta-thalassemia point mutations in Iranians using a PCR-ELISA genotyping system.

    Science.gov (United States)

    Gill, Pooria; Forouzandeh, Mehdi; Eshraghi, Naser; Ghalami, Mostafa; Safa, Majid; Noori-Daloii, Mohammad-Reza

    2008-04-01

    Development of molecular techniques with analytical capability of mutation detection can realize the medical diagnosis of diseases and improve people's health. beta-Thalassemia is one of the most prevalent genetic disorders in Iran and using a simple and rapid test in laboratories for the mass screening and prenatal diagnosis is essential. Here, we described a simple method for rapid detection of four common beta-thalassemia point mutations in Iranians (IVS-II-1 (G-->A), IVS-I-5 (G-->C), FSC 8/9 (+G), IVS-I-110 (G-->A)) using a PCR-ELISA genotyping system. After DNA isolation from whole blood, a segment of beta-globin gene was amplified by DIG-labeling PCR. The DIG-labeled PCR amplicons were denatured and added to biotinylated normal probe (for normal gene allele) and mutant probe (for mutant gene allele). The hybrids were detected by colorimetric ELISA method. The optical densities obtained using normal and mutant probes with heterozygous PCR products were very similar. The optical densities obtained using mutant probes were higher than normal probes with homozygous PCR products. In vice versa, the optical densities obtained using normal probes were higher than mutant probes with normal PCR products. All the results demonstrated that the PCR-ELISA has similar specificity in comparison to the amplification refractory mutation system.

  14. Modeling the induced mutation process in bacterial cells with defects in excision repair system

    Science.gov (United States)

    Bugay, A. N.; Vasilyeva, M. A.; Krasavin, E. A.; Parkhomenko, A. Yu.

    2015-12-01

    A mathematical model of the UV-induced mutation process in Escherichia coli cells with defects in the uvrA and polA genes has been developed. The model describes in detail the reaction kinetics for the excision repair system. The number of mismatches as a result of translesion synthesis is calculated for both wild-type and mutant cells. The effect of temporal modulation of the number of single-stranded DNA during postreplication repair has been predicted. A comparison of effectiveness of different repair systems has been conducted.

  15. Inactivation and inducible oncogenic mutation of p53 in gene targeted pigs.

    Directory of Open Access Journals (Sweden)

    Simon Leuchs

    Full Text Available Mutation of the tumor suppressor p53 plays a major role in human carcinogenesis. Here we describe gene-targeted porcine mesenchymal stem cells (MSCs and live pigs carrying a latent TP53(R167H mutant allele, orthologous to oncogenic human mutant TP53(R175H and mouse Trp53(R172H, that can be activated by Cre recombination. MSCs carrying the latent TP53(R167H mutant allele were analyzed in vitro. Homozygous cells were p53 deficient, and on continued culture exhibited more rapid proliferation, anchorage independent growth, and resistance to the apoptosis-inducing chemotherapeutic drug doxorubicin, all characteristic of cellular transformation. Cre mediated recombination activated the latent TP53(R167H allele as predicted, and in homozygous cells expressed mutant p53-R167H protein at a level ten-fold greater than wild-type MSCs, consistent with the elevated levels found in human cancer cells. Gene targeted MSCs were used for nuclear transfer and fifteen viable piglets were produced carrying the latent TP53(R167H mutant allele in heterozygous form. These animals will allow study of p53 deficiency and expression of mutant p53-R167H to model human germline, or spontaneous somatic p53 mutation. This work represents the first inactivation and mutation of the gatekeeper tumor suppressor gene TP53 in a non-rodent mammal.

  16. Target DNA sequence directly regulates the frequency of activation-induced deaminase-dependent mutations.

    Science.gov (United States)

    Chen, Zhangguo; Viboolsittiseri, Sawanee S; O'Connor, Brian P; Wang, Jing H

    2012-10-15

    Activation-induced deaminase (AID) catalyses class switch recombination (CSR) and somatic hypermutation (SHM) in B lymphocytes to enhance Ab diversity. CSR involves breaking and rejoining highly repetitive switch (S) regions in the IgH (Igh) locus. S regions appear to be preferential targets of AID. To determine whether S region sequence per se, independent of Igh cis regulatory elements, can influence AID targeting efficiency and mutation frequency, we established a knock-in mouse model by inserting a core Sγ1 region into the first intron of proto-oncogene Bcl6, which is a non-Ig target of SHM. We found that the mutation frequency of the inserted Sγ1 region was dramatically higher than that of the adjacent Bcl6 endogenous sequence. Mechanistically, S region-enhanced SHM was associated with increased recruitment of AID and RNA polymerase II, together with Spt5, albeit to a lesser extent. Our studies demonstrate that target DNA sequences influence mutation frequency via regulating AID recruitment. We propose that the nucleotide sequence preference may serve as an additional layer of AID regulation by restricting its mutagenic activity to specific sequences despite the observation that AID has the potential to access the genome widely.

  17. Vincristine-induced central neurotoxicity in a collie homozygous for the ABCB1Δ mutation.

    Science.gov (United States)

    Krugman, L; Bryan, J N; Mealey, K L; Chen, A

    2012-03-01

    A six-year-old, neutered, female collie was presented to an oncology specialty service after developing tetraparesis and self-mutilation that progressively worsened while receiving chemotherapy for lymphoma. Neurologic examination revealed ataxia, paresis and diminished conscious proprioception in all limbs with entire spinal reflexes. Magnetic resonance imaging of the brain and spinal cord was normal. Electromyography of the limbs ruled out a vincristine-induced peripheral neuropathy. Cerebrospinal fluid analysis and cerebrospinal fluid and serum testing for Neospora and Toxoplasma were normal. Results of MDR1 genotyping revealed that the dog was homozygous for the ABCB1-1Δ (MDR1) mutation. This clinical presentation strongly resembled the effects seen from inadvertent intrathecal administration of vincristine in humans. Dogs that are homozygous for the ABCB1-1Δ (MDR1) mutation should not receive standard dosages of chemotherapy drugs known to be eliminated by P-glycoprotein, the gene product of ABCB1. Testing for this mutation is strongly recommended before chemotherapy initiation for at-risk breeds.

  18. Heterodimeric TALENs induce targeted heritable mutations in the crustacean Daphnia magna.

    Science.gov (United States)

    Naitou, Akiko; Kato, Yasuhiko; Nakanishi, Takashi; Matsuura, Tomoaki; Watanabe, Hajime

    2015-02-13

    Transcription activator-like effector nucleases (TALENs) are artificial nucleases harboring a customizable DNA-binding domain and a FokI nuclease domain. The high specificity of the DNA-binding domain and the ease of design have enabled researchers to use TALENs for targeted mutagenesis in various organisms. Here, we report the development of TALEN-dependent targeted gene disruption in the crustacean Daphnia magna, the emerging model for ecological and toxicological genomics. First, a reporter transgene DsRed2 (EF1α-1::DsRed2) was targeted. Using the Golden Gate method with a GoldyTALEN scaffold, we constructed homodimeric and heterodimeric TALENs containing wild-type and ELD/KKR FokI domains. mRNAs that coded for either the customized homodimeric or heterodimeric TALENs were injected into one-cell-stage embryos. The high mortality of embryos injected with homodimeric TALEN mRNAs prevented us from detecting mutations. In contrast, embryos injected with heterodimeric TALEN mRNAs survived and 78%-87% of the adults lost DsRed2 fluorescence in a large portion of cells throughout the body. In addition, these adults produced non-fluorescent progenies, all of which carried mutations at the dsRed2 locus. We also tested heterodimeric TALENs targeted for the endogenous eyeless gene and found that biallelic mutations could be transmitted through germ line cells at a rate of up to 22%. Both somatic and heritable mutagenesis efficiencies of TALENs were higher than those of the CRISPR/Cas9 system that we recently developed. These results suggest that the TALEN system may efficiently induce heritable mutations into the target genes, which will further contribute to the progress of functional genomics in D. magna.

  19. Heterodimeric TALENs induce targeted heritable mutations in the crustacean Daphnia magna

    Directory of Open Access Journals (Sweden)

    Akiko Naitou

    2015-02-01

    Full Text Available Transcription activator-like effector nucleases (TALENs are artificial nucleases harboring a customizable DNA-binding domain and a FokI nuclease domain. The high specificity of the DNA-binding domain and the ease of design have enabled researchers to use TALENs for targeted mutagenesis in various organisms. Here, we report the development of TALEN-dependent targeted gene disruption in the crustacean Daphnia magna, the emerging model for ecological and toxicological genomics. First, a reporter transgene DsRed2 (EF1α-1::DsRed2 was targeted. Using the Golden Gate method with a GoldyTALEN scaffold, we constructed homodimeric and heterodimeric TALENs containing wild-type and ELD/KKR FokI domains. mRNAs that coded for either the customized homodimeric or heterodimeric TALENs were injected into one-cell-stage embryos. The high mortality of embryos injected with homodimeric TALEN mRNAs prevented us from detecting mutations. In contrast, embryos injected with heterodimeric TALEN mRNAs survived and 78%–87% of the adults lost DsRed2 fluorescence in a large portion of cells throughout the body. In addition, these adults produced non-fluorescent progenies, all of which carried mutations at the dsRed2 locus. We also tested heterodimeric TALENs targeted for the endogenous eyeless gene and found that biallelic mutations could be transmitted through germ line cells at a rate of up to 22%. Both somatic and heritable mutagenesis efficiencies of TALENs were higher than those of the CRISPR/Cas9 system that we recently developed. These results suggest that the TALEN system may efficiently induce heritable mutations into the target genes, which will further contribute to the progress of functional genomics in D. magna.

  20. Afatinib induces apoptosis in NSCLC without EGFR mutation through Elk-1-mediated suppression of CIP2A

    OpenAIRE

    Chao, Ting-Ting; Wang, Cheng-Yi; Chen, Yen-Lin; Lai, Chih-Cheng; Chang, Fang-Yu; Tsai, Yi-Ting; Chao, Chung-Hao H.; Shiau, Chung-Wai; Huang, Yuh-Chin T.; Yu, Chong-Jen; Chen, Kuen-Feng

    2014-01-01

    Afatinib has anti-tumor effect in non-small cell lung carcinoma (NSCLC) with epidermal growth factor receptor (EGFR) mutation. We found afatinib can also induce apoptosis in NSCLC cells without EGFR mutation through CIP2A pathway. Four NSCLC cell lines (H358 H441 H460 and A549) were treated with afatinib to determine their sensitivity to afatinib-induced cell death and apoptosis. The effects of CIP2A on afatinib-induced apoptosis were confirmed by overexpression and knockdown of CIP2A express...

  1. A comparison of mutations induced by accelerated iron particles versus those induced by low earth orbit space radiation in the FEM-3 gene of Caenorhabditis elegans

    Science.gov (United States)

    Hartman, P. S.; Hlavacek, A.; Wilde, H.; Lewicki, D.; Schubert, W.; Kern, R. G.; Kazarians, G. A.; Benton, E. V.; Benton, E. R.; Nelson, G. A.

    2001-01-01

    The fem-3 gene of Caenorhabditis elegans was employed to determine the mutation frequency as well as the nature of mutations induced by low earth orbit space radiation ambient to Space Shuttle flight STS-76. Recovered mutations were compared to those induced by accelerated iron ions generated by the AGS synchrotron accelerator at Brookhaven National Laboratory. For logistical reasons, dauer larvae were prepared at TCU, transported to either Kennedy Space Center or Brookhaven National Laboratory, flown in space or irradiated, returned to TCU and screened for mutants. A total of 25 fem-3 mutants were recovered after the shuttle flight and yielded a mutation frequency of 2.1x10(-5), roughly 3.3-fold higher than the spontaneous rate of 6.3x10(-6). Four of the mutations were homozygous inviable, suggesting that they were large deletions encompassing fem-3 as well as neighboring, essential genes. Southern blot analyses revealed that one of the 25 contained a polymorphism in fem-3, further evidence that space radiation can induce deletions. While no polymorphisms were detected among the iron ion-induced mutations, three of the 15 mutants were homozygous inviable, which is in keeping with previous observations that high LET iron particles generate deficiencies. These data provide evidence, albeit indirect, that an important mutagenic component of ambient space radiation is high LET charged particles such as iron ions.

  2. Reduced Tyk2 gene expression in β-cells due to natural mutation determines susceptibility to virus-induced diabetes

    OpenAIRE

    Izumi, Kenichi; Mine, Keiichiro; Inoue, Yoshitaka; Teshima, Miho; Ogawa, Shuichiro; Kai, Yuji; Kurafuji, Toshinobu; Hirakawa, Kanako; Miyakawa, Daiki; Ikeda, Haruka; Inada, Akari; Hara, Manami; Yamada, Hisakata; Akashi, Koichi; Niho, Yoshiyuki

    2015-01-01

    Accumulating evidence suggests that viruses play an important role in the development of diabetes. Although the diabetogenic encephalomyocarditis strain D virus induces diabetes in restricted lines of inbred mice, the susceptibility genes to virus-induced diabetes have not been identified. We report here that novel Tyrosine kinase 2 (Tyk2) gene mutations are present in virus-induced diabetes-sensitive SJL and SWR mice. Mice carrying the mutant Tyk2 gene on the virus-resistant C57BL/6 backgrou...

  3. The dioxin TCDD protects against aflatoxin-induced mutation in female rats, but not in male rats.

    Science.gov (United States)

    Thornton, A S; Oda, Y; Stuart, G R; Holcroft, J; de Boer, J G

    2004-07-11

    2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) is an environmental contaminant and a potent carcinogen in laboratory rodents. When combined with other environmental toxins, it has been shown to increase the (geno)toxicity of some compounds. In this study, the effect of TCDD on the mutagenicity of aflatoxin-B1 (AFB1) was examined in the rat liver using a lacI transgenic rodent mutation assay. AFB1 induces GC-->TA transversions. Since TCDD is known to have a differential effect in male and female rodents, both sexes were studied. The data showed that a 6-week pre-exposure to TCDD had no significant effect on the frequency of aflatoxin-induced mutation in the liver of male rats. However, the TCDD treatment completely prevented the aflatoxin-induced transversion mutations in female animals.

  4. Nickel may contribute to EGFR mutation and synergistically promotes tumor invasion in EGFR-mutated lung cancer via nickel-induced microRNA-21 expression.

    Science.gov (United States)

    Chiou, Yu-Hu; Liou, Saou-Hsing; Wong, Ruey-Hong; Chen, Chih-Yi; Lee, Huei

    2015-08-19

    We recently reported that nickel accumulation in lung tissues may be associated with an increased in p53 mutation risk via reduced DNA repair activity. Here, we hypothesized that nickel accumulation in lung tissues could contribute to EGFR mutations in never-smokers with lung cancer. We enrolled 76 never-smoking patients to evaluate nickel level in adjacent normal lung tissues by ICP-MS. The prevalence of EGFR mutations was significantly higher in the high-nickel subgroup than in the low-nickel subgroup. Intriguingly, the OR for the occurrence of EGFR mutations in female, adenocarcinoma, and female adenocarcinoma patients was higher than that of all patients. Mechanistically, SPRY2 and RECK expressions were decreased by nickel-induced miR-21 via activation of the EGFR/NF-κB signaling pathway, which promoted invasiveness in lung cancer cells, and particularly in the cells with EGFR L858R expression vector transfection. The patients' nickel levels were associated with miR-21 expression levels. Kaplan-Meier analysis revealed poorer overall survival (OS) and shorter relapse free survival (RFS) in the high-nickel subgroup than in low-nickel subgroup. The high-nickel/high-miR-21 subgroup had shorter OS and RFS periods when compared to the low-nickel/low-miR-21 subgroup. Our findings support previous epidemiological studies indicating that nickel exposure may not only contribute to cancer incidence but also promote tumor invasion in lung cancer.

  5. A triple-helix forming oligonucleotide targeting genomic DNA fails to induce mutation.

    Science.gov (United States)

    Reshat, Reshat; Priestley, Catherine C; Gooderham, Nigel J

    2012-11-01

    Purine tracts in duplex DNA can bind oligonucleotide strands in a sequence specific manner to form triple-helix structures. Triple-helix forming oligonucleotides (TFOs) targeting supFG1 constructs have previously been shown to be mutagenic raising safety concerns for oligonucleotide-based pharmaceuticals. We have engineered a TFO, TFO27, to target the genomic Hypoxanthine-guanine phosphoribosyltransferase (HPRT) locus to define the mutagenic potential of such structures at genomic DNA. We report that TFO27 was resistant to nuclease degradation and readily binds to its target motif in a cell free system. Contrary to previous studies using the supFG1 reporter construct, TFO27 failed to induce mutation within the genomic HPRT locus. We suggest that it is possible that previous reports of triplex-mediated mutation using the supFG1 reporter construct could be confounded by DNA quadruplex formation. Although the present study indicates that a TFO targeting a genomic locus lacks mutagenic activity, it is unclear if this finding can be generalised to all TFOs and their targets. For the present, we suggest that it is prudent to avoid large purine stretches in oligonucleotide pharmaceutical design to minimise concern regarding off-target genotoxicity.

  6. Rice improvement through radiation-induced mutation for cultivation in South Vietnam

    Energy Technology Data Exchange (ETDEWEB)

    Do Khac Thinh; Hung Phi Oanh; Nguyen Thi Cuc; Nguyen Ngoc Quynh [Institute of Agricultural Science of South Vietnam, Ho Chi Minh (Viet Nam)

    2001-03-01

    For past years, rice varieties cultivated in South Vietnam originated from domestic hybridisation or from IRRI. Rice mutation breeding has been initiated for recent years. To meet the requirement of rice production diversification in different agro-ecological areas and rice genetic resources, from 1993 Institute of Agricultural Science of South Vietnam has carried out rice improvement by induced mutation of radiation. The mutagen was gamma rays of {sup 60}Co. The goal is to create inherited variations, which cannot be obtained from other breeding methods, specially important characters of rice varieties (high tolerance to acid sulfate soil, lodging resistance combined with early maturity), which were difficult to gain by hybridisation. With {sup 60}Co gamma rays, doses of 10-20 krad, dose rate of 280 krad/h, dry and germinated seeds of introduced and local rice varieties (IR 64, IR 9729, IR 50404, IR 59606, Jasmine 85, Nang Huong, Tam Xoan) were irradiated. The irradiated seeds were immediately sown within 24 and 94 hrs for wet seeds and dry seeds after treatment, respectively. Population of 10,000-15,000 plants were established and evaluated by IRRI evaluation standard from M2-M7 generations. 365 lines, varieties were selected with better behaviours than original varieties as lodging resistance, earliness, potential yield, leaf characters, tolerant ability to adverse conditions etc. Some good varieties (VND95-19, VND95-20) have been approved as leading national varieties and released for large-scale production in South Vietnam. (author)

  7. PKA regulatory subunit 1A inactivating mutation induces serotonin signaling in primary pigmented nodular adrenal disease.

    Science.gov (United States)

    Bram, Zakariae; Louiset, Estelle; Ragazzon, Bruno; Renouf, Sylvie; Wils, Julien; Duparc, Céline; Boutelet, Isabelle; Rizk-Rabin, Marthe; Libé, Rossella; Young, Jacques; Carson, Dennis; Vantyghem, Marie-Christine; Szarek, Eva; Martinez, Antoine; Stratakis, Constantine A; Bertherat, Jérôme; Lefebvre, Hervé

    2016-09-22

    Primary pigmented nodular adrenocortical disease (PPNAD) is a rare cause of ACTH-independent hypercortisolism. The disease is primarily caused by germline mutations of the protein kinase A (PKA) regulatory subunit 1A (PRKAR1A) gene, which induces constitutive activation of PKA in adrenocortical cells. Hypercortisolism is thought to result from PKA hyperactivity, but PPNAD tissues exhibit features of neuroendocrine differentiation, which may lead to stimulation of steroidogenesis by abnormally expressed neurotransmitters. We hypothesized that serotonin (5-HT) may participate in the pathophysiology of PPNAD-associated hypercortisolism. We show that PPNAD tissues overexpress the 5-HT synthesizing enzyme tryptophan hydroxylase type 2 (Tph2) and the serotonin receptors types 4, 6, and 7, leading to formation of an illicit stimulatory serotonergic loop whose pharmacological inhibition in vitro decreases cortisol production. In the human PPNAD cell line CAR47, the PKA inhibitor H-89 decreases 5-HT4 and 5-HT7 receptor expression. Moreover, in the human adrenocortical cell line H295R, inhibition of PRKAR1A expression increases the expression of Tph2 and 5-HT4/6/7 receptors, an effect that is blocked by H-89. These findings show that the serotonergic process observed in PPNAD tissues results from PKA activation by PRKAR1A mutations. They also suggest that Tph inhibitors may represent efficient treatments of hypercortisolism in patients with PPNAD.

  8. bfb, a novel ENU-induced blebs mutant resulting from a missense mutation in Fras1.

    Directory of Open Access Journals (Sweden)

    Kerry A Miller

    Full Text Available Fras1 is an extracellular matrix associated protein with essential roles in adhesion of epithelia and mesenchyme during early embryonic development. The adhesive function of Fras1 is achieved through interaction with a group of related proteins, Frem 1-3, and a cytoplasmic adaptor protein Grip1. Mutation of each of these proteins results in characteristic epithelial blistering and have therefore become known as "blebs" proteins. Human Fraser syndrome presents with a similar phenotype and the blebs mice have been instrumental in identification of the genetic basis of Fraser syndrome. We have identified a new ENU-induced blebs allele resulting from a novel missense mutation in Fras1. The resulting mouse strain, blood filled blisters (bfb, presents with a classic blebs phenotype but does not exhibit embryonic lethality typical of other blebs mutants and in addition, we report novel palate and sternal defects. Analysis of the bfb phenotype confirms the presence of epithelial-mesenchymal adhesion defects but also supports the emerging role of blebs proteins in regulating signalling during organogenesis. The bfb strain provides new opportunities to investigate the role of Fras1 in development.

  9. Improvement of penicillin G acylase expression in Escherichia coli through UV induced mutations

    Directory of Open Access Journals (Sweden)

    Rubina Arshad

    2010-12-01

    Full Text Available We used ultraviolet (UV radiation to induce mutation in three locally isolated strains of Escherichia coli. Different dilutions of bacterial cultures were exposed to UV lamp of 254 nm wavelength for different time intervals at varied distances ranging from 5 to 210 sec and 5 to 100 cm. Viable colonies were screened for mutants with an increased production of penicillin G acylase (PGA and a reduced production of β-lactamase, which are the desired properties of PGA producing industrial strains. A survival curve was made to get optimum exposure time and distance. The survival percentage for each exposure period was calculated and 1-5% survival was found useful for obtaining mutants with desired change. Screening for PGA and β-lactamase constitutive and/or deficient mutants was made by Serratia marcescens overlay test. A total of 100 survivors were selected of which 49% expressed PGA activity higher than the parent strain. Frequency of β-lactamase constitutive and deficient mutants was 48 and 52%, respectively. The best hyper-producing mutant (BDCS-N-M74, with almost negligible expression of β-lactamase, exhibited three-fold (22.5 mg 6-APA h-1 mg-1 wet cells increase in PGA activity compared with that in the parent strain (6.7 mg 6-APA h-1 mg-1 wet cells. The results indicated the successful induction of UV mediated mutation in E. coli for PGA hyper-producing mutants lacking β-lactamase activity.

  10. PKA regulatory subunit 1A inactivating mutation induces serotonin signaling in primary pigmented nodular adrenal disease

    Science.gov (United States)

    Bram, Zakariae; Louiset, Estelle; Renouf, Sylvie; Duparc, Céline; Boutelet, Isabelle; Rizk-Rabin, Marthe; Libé, Rossella; Young, Jacques; Carson, Dennis; Vantyghem, Marie-Christine; Szarek, Eva; Martinez, Antoine; Stratakis, Constantine A.; Bertherat, Jérôme

    2016-01-01

    Primary pigmented nodular adrenocortical disease (PPNAD) is a rare cause of ACTH-independent hypercortisolism. The disease is primarily caused by germline mutations of the protein kinase A (PKA) regulatory subunit 1A (PRKAR1A) gene, which induces constitutive activation of PKA in adrenocortical cells. Hypercortisolism is thought to result from PKA hyperactivity, but PPNAD tissues exhibit features of neuroendocrine differentiation, which may lead to stimulation of steroidogenesis by abnormally expressed neurotransmitters. We hypothesized that serotonin (5-HT) may participate in the pathophysiology of PPNAD-associated hypercortisolism. We show that PPNAD tissues overexpress the 5-HT synthesizing enzyme tryptophan hydroxylase type 2 (Tph2) and the serotonin receptors types 4, 6, and 7, leading to formation of an illicit stimulatory serotonergic loop whose pharmacological inhibition in vitro decreases cortisol production. In the human PPNAD cell line CAR47, the PKA inhibitor H-89 decreases 5-HT4 and 5-HT7 receptor expression. Moreover, in the human adrenocortical cell line H295R, inhibition of PRKAR1A expression increases the expression of Tph2 and 5-HT4/6/7 receptors, an effect that is blocked by H-89. These findings show that the serotonergic process observed in PPNAD tissues results from PKA activation by PRKAR1A mutations. They also suggest that Tph inhibitors may represent efficient treatments of hypercortisolism in patients with PPNAD. PMID:27699247

  11. Magnetic separation and antibiotics selection enable enrichment of cells with ZFN/TALEN-induced mutations.

    Directory of Open Access Journals (Sweden)

    Hyojin Kim

    Full Text Available The ability to enrich cells with targeted mutations greatly facilitates the process of using engineered nucleases, including zinc-finger nucleases and transcription activator-like effector nucleases, to construct such cells. We previously used surrogate reporters to enrich cells containing nuclease-induced mutations via flow cytometry. This method is, however, limited by the availability of flow cytometers. Furthermore, sorted cells occasionally fail to form colonies after exposure to a strong laser and hydrostatic pressure. Here we describe two different types of novel reporters that enable mutant cell enrichment without the use of flow cytometers. We designed reporters that express H-2K(k, a surface antigen, and the hygromycin resistance protein (Hygro(R, respectively, when insertions or deletions are generated at the target sequences by the activity of engineered nucleases. After cotransfection of these reporters and the engineered nuclease-encoding plasmids, H-2K(k- and Hygro(R-expressing cells were isolated using magnetic separation and hygromycin treatment, respectively. We found that mutant cells were drastically enriched in the isolated cells, suggesting that these two reporters enable efficient enrichment of mutants. We propose that these two reporters will greatly facilitate the use of engineered nucleases in a wider range of biomedical research.

  12. Study on mutation induced effect of gamma ray and DES on black bean phaseolus vulgaris

    Energy Technology Data Exchange (ETDEWEB)

    Le Thi Dinh; Pham Le Ha; Nguyen Van Toan; Le Xuan Tham [Nuclear Research Institute, Radiobiology Department, Dalat (Viet Nam)

    2001-03-01

    The study on mutation induced effect of gamma ray and DES on black bean Phaseolus vulgaris was carried out at Radiobiology Department, Nuclear Research Institute of Dalat. Dry seeds of variety No.1847 - Bonita - Cuba in set of 13 black bean varieties were irradiated with gamma ray from {sup 60}Co source at dose range from 150 Gy to 350 Gy and treated with DES at concentration from 0.1% to 0.3% in 2 hours for experiments in laboratory. The doses of 200, 250, 300 Gy and concentration of 0.2% DES in 2 hours were selected to treat dry seeds for experiments on the field. In populations of M{sub 1} generation, the height, number of branches and fruits per plant, number of seeds per fruit were decreased with increasing of irradiation doses. In populations of M{sub 2} generation, individual variants in leaf shape, chlorophyll, short stem, dwarf, early maturity, flowering in very short time were obtained and selected in all treatment cases. Mutation frequency at dose of 300 Gy was higher than that in other treatment cases, but ratio of sterility is also largest. The mutant lines of early maturity and short stem with flowering in very short time are promised materials for further studies. (author)

  13. Attempts to induce mutations in Haemophilus influenzae with the base analogues 5-bromodeoxyuridine and 2-aminopurine

    Energy Technology Data Exchange (ETDEWEB)

    Kimball, R.F.; Perdue, S.W.

    1977-01-01

    Attempts were made to induce mutations in Haemophilus influenzae with the base analogues 5-bromodeoxyuridine and 2-aminopurine. These attempts were unsuccessful. Incorporation studies with BrdUrd showed, in agreement with earlier studies on Escherichia coli, that BrdUrd was discriminated against when dThd was also present but was incorporated to essentially the same extent as dThd when only BrdUrd was present. In this latter case, strands fully substituted with BrdUrd were produced, but survival data suggest that bacteria deriving their DNA by replication on such fully substituted templates were inviable. However, bacteria with about 20% of the thymine substituted with bromouracil were usually viable. No mutations could be detected in the descendants of such bacteria. The reasons for this are discussed and it is concluded that in all probability the replication system in species rarely if ever treats incorporated bromouracil as anything except a thymine analogue. The alternative possibility, that the negative results are a consequence of the absence of the reclex (SOS) error-prone repair system in this species, is considered much less likely.

  14. Ribosomal protein mutations induce autophagy through S6 kinase inhibition of the insulin pathway.

    Directory of Open Access Journals (Sweden)

    Harry F Heijnen

    Full Text Available Mutations affecting the ribosome lead to several diseases known as ribosomopathies, with phenotypes that include growth defects, cytopenia, and bone marrow failure. Diamond-Blackfan anemia (DBA, for example, is a pure red cell aplasia linked to the mutation of ribosomal protein (RP genes. Here we show the knock-down of the DBA-linked RPS19 gene induces the cellular self-digestion process of autophagy, a pathway critical for proper hematopoiesis. We also observe an increase of autophagy in cells derived from DBA patients, in CD34+ erythrocyte progenitor cells with RPS19 knock down, in the red blood cells of zebrafish embryos with RP-deficiency, and in cells from patients with Shwachman-Diamond syndrome (SDS. The loss of RPs in all these models results in a marked increase in S6 kinase phosphorylation that we find is triggered by an increase in reactive oxygen species (ROS. We show that this increase in S6 kinase phosphorylation inhibits the insulin pathway and AKT phosphorylation activity through a mechanism reminiscent of insulin resistance. While stimulating RP-deficient cells with insulin reduces autophagy, antioxidant treatment reduces S6 kinase phosphorylation, autophagy, and stabilization of the p53 tumor suppressor. Our data suggest that RP loss promotes the aberrant activation of both S6 kinase and p53 by increasing intracellular ROS levels. The deregulation of these signaling pathways is likely playing a major role in the pathophysiology of ribosomopathies.

  15. A novel radiation-induced p53 mutation is not implicated in radiation resistance via a dominant-negative effect.

    Directory of Open Access Journals (Sweden)

    Yunguang Sun

    Full Text Available Understanding the mutations that confer radiation resistance is crucial to developing mechanisms to subvert this resistance. Here we describe the creation of a radiation resistant cell line and characterization of a novel p53 mutation. Treatment with 20 Gy radiation was used to induce mutations in the H460 lung cancer cell line; radiation resistance was confirmed by clonogenic assay. Limited sequencing was performed on the resistant cells created and compared to the parent cell line, leading to the identification of a novel mutation (del at the end of the DNA binding domain of p53. Levels of p53, phospho-p53, p21, total caspase 3 and cleaved caspase 3 in radiation resistant cells and the radiation susceptible (parent line were compared, all of which were found to be similar. These patterns held true after analysis of p53 overexpression in H460 cells; however, H1299 cells transfected with mutant p53 did not express p21, whereas those given WT p53 produced a significant amount, as expected. A luciferase assay demonstrated the inability of mutant p53 to bind its consensus elements. An MTS assay using H460 and H1299 cells transfected with WT or mutant p53 showed that the novel mutation did not improve cell survival. In summary, functional characterization of a radiation-induced p53 mutation in the H460 lung cancer cell line does not implicate it in the development of radiation resistance.

  16. Imidacloprid and Thiamethoxam Induced Mutations in Internal Transcribed Spacer 2 (ITS2) of Anopheles stephensi.

    Science.gov (United States)

    Bhinder, Preety; Chaudhry, Asha; Barna, Bhupinder; Kaur, Satvinderjeet

    2012-05-01

    The present article deals with the polymerase chain reaction (PCR)-based genotoxicity evaluation of neonicotinoid pesticides, imidacloprid and thiamethoxam, by using the genome of a mosquito Anopheles stephensi taken as an experimental model. After treatment of the second instar larvae with LC(20) of the pesticides for 24 h, the induced nucleotide sequence variations in the internal transcribed spacer 2 (ITS2) of freshly hatched unfed control and treated individuals was studied from the sequence alignment data and the mutations in the form of insertion, deletion and substitution of bases were recorded. Measurable differences, indicative of the genetic damage due to imidacloprid and thiamethoxam were observed when ITS2 sequences of control and treated individuals were compared. It was found that imidacloprid-treated individual had 8 deletions, 29 insertions, 18 transitions and 33 transversions, whereas thiamethoxam-treated individual had 10 deletions, 8 insertions, 47 transitions and 68 transversions.

  17. The use of induced mutation combined with crossing in high quality rice breeding

    Energy Technology Data Exchange (ETDEWEB)

    Do Huu At; Bui Huy Thuy; Nguyen Van Bich; Tran Duy Quy [Agricultural Genetics Institute, Division of Genetics and Hybrid Rice Technology, Hanoi (Viet Nam); Nguyen Minh Cong [Hanoi No. 1 Teacher Training Univ., Department of Genetics (Viet Nam)

    2001-03-01

    The high quality rice varieties: Tam thom mutant rice Var., DT17 rice Var, DT21 glutinous rice Var were formed by induced mutation combined with crossing. Tam thom mutant rice Var. lost photosensitivity, could be planted 2 crops/year. DT17 rice Var with high yielding capacity, suitable for growth on lowland in summer crop, is replacing step-by-step Moctuyen rice Var. in North Vietnam. DT21 glutinous rice Var. could be planted 2 crops/year and had short growth duration, average yield was 4.0-4.5 tons/ha. These three ones had good quality, soft and scent cooked rice, suitable for customers and export requirements. Tam thom mutant rice Var. DT17 rice Var., DT21 and glutinous rice Var. were adopted for regional production by Ministry of Agriculture and Rural Development and allowed to be in trial production. (author)

  18. Next-Gen Sequencing-Based Mapping and Identification of Ethyl Methanesulfonate-Induced Mutations in Arabidopsis thaliana.

    Science.gov (United States)

    Zhang, Xue-Cheng; Millet, Yves; Ausubel, Frederick M; Borowsky, Mark

    2014-10-01

    Forward genetic analysis using ethyl methanesulfonate (EMS) mutagenesis has proven to be a powerful tool in biological research, but identification and cloning of causal mutations by conventional genetic mapping approaches is a painstaking process. Recent advances in next-gen sequencing have greatly invigorated the process of identifying EMS-induced mutations corresponding to a specific phenotype in model genetic hosts, including the plant Arabidopsis thaliana and the nematode Caenorhabditis elegans. Next-gen sequencing of bulked F2 mutant recombinants produces a wealth of high-resolution genetic data, provides enhanced delimitation of the genomic location of mutations, and greatly reduces hands-on time while maintaining high accuracy and reproducibility. In this unit, a detailed procedure to simultaneously map and identify EMS mutations in Arabidopsis is described.

  19. Molecular analysis of THH-induced mutations at HPRT locus in human promyelocytic leukemia cells with multiplex polymerase chain reaction

    Institute of Scientific and Technical Information of China (English)

    LIU Sheng-xue; CAO Jia; AN Hui

    2002-01-01

    Objective: To study the genotoxicity and antitumor activity of a Chinese medicinal herb, Tripterygium Hypoglaucum (Level) Hutch (THH). Methods: The genotoxicity and antitumor activity of TH-H were investigated in human promyelocytic leukemia cells on the mutation of hypoxanthine-guanine phosphoribosyl transferase (HPRT) gene by using single cell clone culture, two-way screening counting, multiplex PCR amplification and gel electrophoresis. Results: The results showed that different mutant spectra existed between the spontaneous mutation and induced mutation by THH. Only 7. 7% (1/13) of spontaneous mutants showed deletion mutations, whereas the induced mutants included 46.6% (27/58) deletions. Mapping of all intragenic deletion breakpoints showed a random distribution in all 9 exons, but toward the 3'-end of the HPRT gene. Deletion of exon 1 only appeared when whole gene was deleted. Deletions of exon 7/8 and 9 often showed linkage deletions (71.4%). Conclusion: THH can induce the mutation, mainly deletions, of HPRT gene in human promyelocytic leukemia cells.

  20. Evidence that in xeroderma pigmentosum variant cells, which lack DNA polymerase eta, DNA polymerase iota causes the very high frequency and unique spectrum of UV-induced mutations.

    Science.gov (United States)

    Wang, Yun; Woodgate, Roger; McManus, Terrence P; Mead, Samantha; McCormick, J Justin; Maher, Veronica M

    2007-04-01

    Xeroderma pigmentosum variant (XPV) patients have normal DNA excision repair, yet are predisposed to develop sunlight-induced cancer. They exhibit a 25-fold higher than normal frequency of UV-induced mutations and very unusual kinds (spectrum), mainly transversions. The primary defect in XPV cells is the lack of functional DNA polymerase (Pol) eta, the translesion synthesis DNA polymerase that readily inserts adenine nucleotides opposite photoproducts involving thymine. The high frequency and striking difference in kinds of UV-induced mutations in XPV cells strongly suggest that, in the absence of Pol eta, an abnormally error-prone polymerase substitutes. In vitro replication studies of Pol iota show that it replicates past 5'T-T3' and 5'T-U3' cyclobutane pyrimidine dimers, incorporating G or T nucleotides opposite the 3' nucleotide. To test the hypothesis that Pol iota causes the high frequency and abnormal spectrum of UV-induced mutations in XPV cells, we identified an unlimited lifespan XPV cell line expressing two forms of Pol iota, whose frequency of UV-induced mutations is twice that of XPV cells expressing one form. We eliminated expression of one form and compared the parental cells and derivatives for the frequency and kinds of UV-induced mutations. All exhibited similar sensitivity to the cytotoxicity of UV((254 nm)), and the kinds of mutations induced were identical, but the frequency of mutations induced in the derivatives was reduced to UV-induced mutations, and ultimately their malignant transformation.

  1. Simple methods for generating and detecting locus-specific mutations induced with TALENs in the zebrafish genome.

    Directory of Open Access Journals (Sweden)

    Timothy J Dahlem

    Full Text Available The zebrafish is a powerful experimental system for uncovering gene function in vertebrate organisms. Nevertheless, studies in the zebrafish have been limited by the approaches available for eliminating gene function. Here we present simple and efficient methods for inducing, detecting, and recovering mutations at virtually any locus in the zebrafish. Briefly, double-strand DNA breaks are induced at a locus of interest by synthetic nucleases, called TALENs. Subsequent host repair of the DNA lesions leads to the generation of insertion and deletion mutations at the targeted locus. To detect the induced DNA sequence alterations at targeted loci, genomes are examined using High Resolution Melt Analysis, an efficient and sensitive method for detecting the presence of newly arising sequence polymorphisms. As the DNA binding specificity of a TALEN is determined by a custom designed array of DNA recognition modules, each of which interacts with a single target nucleotide, TALENs with very high target sequence specificities can be easily generated. Using freely accessible reagents and Web-based software, and a very simple cloning strategy, a TALEN that uniquely recognizes a specific pre-determined locus in the zebrafish genome can be generated within days. Here we develop and test the activity of four TALENs directed at different target genes. Using the experimental approach described here, every embryo injected with RNA encoding a TALEN will acquire targeted mutations. Multiple independently arising mutations are produced in each growing embryo, and up to 50% of the host genomes may acquire a targeted mutation. Upon reaching adulthood, approximately 90% of these animals transmit targeted mutations to their progeny. Results presented here indicate the TALENs are highly sequence-specific and produce minimal off-target effects. In all, it takes about two weeks to create a target-specific TALEN and generate growing embryos that harbor an array of germ line

  2. Absence of p53 gene mutations in mice colon pre-cancerous stage induced by o-nitrotoluene

    Directory of Open Access Journals (Sweden)

    Nahed A Hussien

    2014-01-01

    Conclusion: The results from the present study indicate that point mutations in the p53 gene, in the coding region (exons 5-8 and outside it (exons 10, 11, are not involved in the development of the colon precancerous stage induced by o-nt in mice.

  3. Absence of missense mutations in activated c-myc genes in avian leukosis virus-induced B-cell lymphomas

    Energy Technology Data Exchange (ETDEWEB)

    Hahn, M.; Hayward, W.S.

    1988-06-01

    The authors determined the nucleotide sequences of two independent DNA clones which contained the activated c-myc genes from avian leukosis virus-induced B-cell lymphomas. Neither of these c-myce genes contained missense mutations. This strongly supports the notion that the c-myc photo-oncogene in avian leukosis virus-induced B-cell lymphomas can be oncogenically activated by altered expression of the gene without a change in the primary structure of the gene product.

  4. UV-induced mutations in epidermal cells of mice defective in DNA polymerase η and/or ι.

    Science.gov (United States)

    Kanao, Rie; Yokoi, Masayuki; Ohkumo, Tsuyoshi; Sakurai, Yasutaka; Dotsu, Kantaro; Kura, Shinobu; Nakatsu, Yoshimichi; Tsuzuki, Teruhisa; Masutani, Chikahide; Hanaoka, Fumio

    2015-05-01

    Xeroderma pigmentosum variant (XP-V) is a human rare inherited recessive disease, predisposed to sunlight-induced skin cancer, which is caused by deficiency in DNA polymerase η (Polη). Polη catalyzes accurate translesion synthesis (TLS) past pyrimidine dimers, the most prominent UV-induced lesions. DNA polymerase ι (Polι) is a paralog of Polη that has been suggested to participate in TLS past UV-induced lesions, but its function in vivo remains uncertain. We have previously reported that Polη-deficient and Polη/Polι double-deficient mice showed increased susceptibility to UV-induced carcinogenesis. Here, we investigated UV-induced mutation frequencies and spectra in the epidermal cells of Polη- and/or Polι-deficient mice. While Polη-deficient mice showed significantly higher UV-induced mutation frequencies than wild-type mice, Polι deficiency did not influence the frequencies in the presence of Polη. Interestingly, the frequencies in Polη/Polι double-deficient mice were statistically lower than those in Polη-deficient mice, although they were still higher than those of wild-type mice. Sequence analysis revealed that most of the UV-induced mutations in Polη-deficient and Polη/Polι double-deficient mice were base substitutions at dipyrimidine sites. An increase in UV-induced mutations at both G:C and A:T pairs associated with Polη deficiency suggests that Polη contributes to accurate TLS past both thymine- and cytosine-containing dimers in vivo. A significant decrease in G:C to A:T transition in Polη/Polι double-deficient mice when compared with Polη-deficient mice suggests that Polι is involved in error-prone TLS past cytosine-containing dimers when Polη is inactivated.

  5. Radiation-induced mutation at tandem repeat DNA Loci in the mouse germline: spectra and doubling doses.

    Science.gov (United States)

    Dubrova, Yuri E

    2005-02-01

    The spectra and dose response for mutations at expanded simple tandem repeat (ESTR) loci in the germline of male mice acutely exposed to low-LET X or gamma rays at pre-meiotic stages of spermatogenesis were compared in five strains of laboratory mice. Most mutation events involved the gain or loss of a relatively small number of repeat units, and the distributions of length changes were indistinguishable between the exposed and control males. Overall, a significant bias toward gains of repeats was detected, with approximately 60% of mutants showing gains. The values for ESTR mutation induction did not differ substantially between strains. The highest values of doubling dose were obtained for two genetically related strains, BALB/c and C.B17 (mean value 0.98 Gy). The estimates of doubling dose for three other strains (CBA/H, C57BL/6 x CBA/H F1 and 129SVJ x C57BL/6) were lower, with a mean value of 0.44 Gy. The dose response for ESTR mutation across all five strains was very close to that for the specific loci (Russell 7-locus test). The mechanisms of ESTR mutation induction and applications of this system for monitoring radiation-induced mutation in the mouse germline are discussed.

  6. STAT3 mutations identified in human hematologic neoplasms induce myeloid malignancies in a mouse bone marrow transplantation model

    Science.gov (United States)

    Couronné, Lucile; Scourzic, Laurianne; Pilati, Camilla; Valle, Véronique Della; Duffourd, Yannis; Solary, Eric; Vainchenker, William; Merlio, Jean-Philippe; Beylot-Barry, Marie; Damm, Frederik; Stern, Marc-Henri; Gaulard, Philippe; Lamant, Laurence; Delabesse, Eric; Merle-Beral, Hélène; Nguyen-Khac, Florence; Fontenay, Michaëla; Tilly, Hervé; Bastard, Christian; Zucman-Rossi, Jessica; Bernard, Olivier A.; Mercher, Thomas

    2013-01-01

    STAT3 protein phosphorylation is a frequent event in various hematologic malignancies and solid tumors. Acquired STAT3 mutations have been recently identified in 40% of patients with T-cell large granular lymphocytic leukemia, a rare T-cell disorder. In this study, we investigated the mutational status of STAT3 in a large series of patients with lymphoid and myeloid diseases. STAT3 mutations were identified in 1.6% (4 of 258) of patients with T-cell neoplasms, in 2.5% (2 of 79) of patients with diffuse large B-cell lymphoma but in no other B-cell lymphoma patients (0 of 104) or patients with myeloid malignancies (0 of 96). Functional in vitro assays indicated that the STAT3Y640F mutation leads to a constitutive phosphorylation of the protein. STA21, a STAT3 small molecule inhibitor, inhibited the proliferation of two distinct STAT3 mutated cell lines. Using a mouse bone marrow transplantation assay, we observed that STAT3Y640F expression leads to the development of myeloproliferative neoplasms with expansion of either myeloid cells or megakaryocytes. Together, these data indicate that the STAT3Y640F mutation leads to constitutive activation of STAT3, induces malignant hematopoiesis in vivo, and may represent a novel therapeutic target in some lymphoid malignancies. PMID:23872306

  7. Single point mutation in tick-borne encephalitis virus prM protein induces a reduction of virus particle secretion.

    Science.gov (United States)

    Yoshii, Kentarou; Konno, Akihiro; Goto, Akiko; Nio, Junko; Obara, Mayumi; Ueki, Tomotaka; Hayasaka, Daisuke; Mizutani, Tetsuya; Kariwa, Hiroaki; Takashima, Ikuo

    2004-10-01

    Flaviviruses are assembled to bud into the lumen of the endoplasmic reticulum (ER) and are secreted through the vesicle transport pathway. Virus envelope proteins play important roles in this process. In this study, the effect of mutations in the envelope proteins of tick-borne encephalitis (TBE) virus on secretion of virus-like particles (VLPs), using a recombinant plasmid expression system was analysed. It was found that a single point mutation at position 63 in prM induces a reduction in secretion of VLPs. The mutation in prM did not affect the folding of the envelope proteins, and chaperone-like activity of prM was maintained. As observed by immunofluorescence microscopy, viral envelope proteins with the mutation in prM were scarce in the Golgi complex, and accumulated in the ER. Electron microscopic analysis of cells expressing the mutated prM revealed that many tubular structures were present in the lumen. The insertion of the prM mutation at aa 63 into the viral genome reduced the production of infectious virus particles. This data suggest that prM plays a crucial role in the virus budding process.

  8. Conformational changes induced by the A21G Flemish mutation in the amyloid precursor protein lead to increased Aβ production.

    Science.gov (United States)

    Tang, Tzu-Chun; Hu, Yi; Kienlen-Campard, Pascal; El Haylani, Laetitia; Decock, Marie; Van Hees, Joanne; Fu, Ziao; Octave, Jean-Noel; Constantinescu, Stefan N; Smith, Steven O

    2014-03-04

    Proteolysis of the β C-terminal fragment (β-CTF) of the amyloid precursor protein generates the Aβ peptides associated with Alzheimer's disease. Familial mutations in the β-CTF, such as the A21G Flemish mutation, can increase Aβ secretion. We establish how the Flemish mutation alters the structure of C55, the first 55 residues of the β-CTF, using FTIR and solid-state NMR spectroscopy. We show that the A21G mutation reduces β sheet structure of C55 from Leu17 to Ala21, an inhibitory region near the site of the mutation, and increases α-helical structure from Gly25 to Gly29, in a region near the membrane surface and thought to interact with cholesterol. Cholesterol also increases Aβ peptide secretion, and we show that the incorporation of cholesterol into model membranes enhances the structural changes induced by the Flemish mutant, suggesting a common link between familial mutations and the cellular environment.

  9. An induced mutation in tomato eIF4E leads to immunity to two potyviruses.

    Directory of Open Access Journals (Sweden)

    Florence Piron

    Full Text Available BACKGROUND: The characterization of natural recessive resistance genes and Arabidopsis virus-resistant mutants have implicated translation initiation factors of the eIF4E and eIF4G families as susceptibility factors required for virus infection and resistance function. METHODOLOGY/PRINCIPAL FINDINGS: To investigate further the role of translation initiation factors in virus resistance we set up a TILLING platform in tomato, cloned genes encoding for translation initiation factors eIF4E and eIF4G and screened for induced mutations that lead to virus resistance. A splicing mutant of the eukaryotic translation initiation factor, S.l_eIF4E1 G1485A, was identified and characterized with respect to cap binding activity and resistance spectrum. Molecular analysis of the transcript of the mutant form showed that both the second and the third exons were miss-spliced, leading to a truncated mRNA. The resulting truncated eIF4E1 protein is also impaired in cap-binding activity. The mutant line had no growth defect, likely because of functional redundancy with others eIF4E isoforms. When infected with different potyviruses, the mutant line was immune to two strains of Potato virus Y and Pepper mottle virus and susceptible to Tobacco each virus. CONCLUSIONS/SIGNIFICANCE: Mutation analysis of translation initiation factors shows that translation initiation factors of the eIF4E family are determinants of plant susceptibility to RNA viruses and viruses have adopted strategies to use different isoforms. This work also demonstrates the effectiveness of TILLING as a reverse genetics tool to improve crop species. We have also developed a complete tool that can be used for both forward and reverse genetics in tomato, for both basic science and crop improvement. By opening it to the community, we hope to fulfill the expectations of both crop breeders and scientists who are using tomato as their model of study.

  10. Insertional mutation of marA vitiates inducible multiple antimicrobial resistance in Salmonella enterica subsp. enterica serovar Choleraesuis.

    Science.gov (United States)

    Tibbetts, Robert J; Lin, Tsang Long; Wu, Ching Ching

    2005-08-30

    marA has been shown to mediate a multiple antimicrobial resistance (MAR) phenotype following induction in some members of the Enterobacteriaceae. When Salmonella Choleraesuis was exposed to inducing agents they displayed higher minimal inhibitory concentrations (MIC) to multiple antimicrobial agents and an increase in marA expression as determined by northern hybridization analysis. The objective of the present study was to determine if mutation of marA vitiated multiple antimicrobial resistance inducibility in S. Choleraesuis. A loss-of-function mutation of marA in a single S. Choleraesuis isolate was created by insertion of the dihydrofolate reductase (DHFR) gene cassette within marA using double homologous recombination. This mutation was complemented with an expression plasmid possessing marA under the control of an IPTG-inducible promoter. Mutation and complementation of marA was verified using polymerase chain reaction, Northern hybridization, and Western blotting assays. Minimum inhibitory concentrations (MICs) of tetracycline, chloramphenicol, nalidixic acid, and rifampin were determined against induced and uninduced wildtype, marA-disrupted and marA-complemented strains using a microbroth dilution assay. Minimum inhibitory concentrations against induced wildtype and marA-complemented strains increased four- to eight-fold for all antimicrobials tested when compared to the uninduced strains while the MICs of the induced marA-disrupted mutant remained the same. However, this increase was abrogated when the cells were grown in the presence of the efflux pump inhibitor compound EPI phe-arg-naphthylamide. The results indicate that a functional marA is solely required for an inducible multiple antimicrobial resistance phenotype in S. Choleraesuis.

  11. Efficient Generation of Gene-Modified Pigs Harboring Precise Orthologous Human Mutation via CRISPR/Cas9-Induced Homology-Directed Repair in Zygotes.

    Science.gov (United States)

    Zhou, Xiaoyang; Wang, Lulu; Du, Yinan; Xie, Fei; Li, Liang; Liu, Yu; Liu, Chuanhong; Wang, Shiqiang; Zhang, Shibing; Huang, Xingxu; Wang, Yong; Wei, Hong

    2016-01-01

    Precise genetic mutation of model animals is highly valuable for functional investigation of human mutations. Clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated 9 (Cas9)-induced homology-directed repair (HDR) is usually used for precise genetic mutation, being limited by the relatively low efficiency compared with that of non-homologous end joining (NHEJ). Although inhibition of NHEJ was shown to enhance HDR-derived mutation, in this work, without inhibition of NHEJ, we first generated gene-modified pigs harboring precise orthologous human mutation (Sox10 c.A325>T) via CRISPR/Cas9-induced HDR in zygotes using single-strand oligo DNA (ssODN) as template with an efficiency as high as 80%, indicating that pig zygotes exhibited high activities of HDR relative to NHEJ and were highly amendable to genetic mutation via CIRSPR/Cas9-induced HDR. Besides, we found a higher concentration of ssODN remarkably reduced HDR-derived mutation in pig zygotes, suggesting a possible balance for optimal HDR-derived mutation in zygotes between the excessive accessibility to HDR templates and the activities of HDR relative to NHEJ which appeared to be negatively correlated to ssODN concentration. In addition, the HDR-derived mutation, as well as those from NHEJ, extensively integrated into various tissues including gonad of founder pig without detected off-targeting, suggesting CRISPR/Cas9-induced HDR in zygotes is a reliable approach for precise genetic mutation in pigs.

  12. Single point mutation in tick-borne encephalitis virus prM protein induces a reduction of virus particle secretion

    OpenAIRE

    Yoshii, Kentarou; Konno, Akihiro; Goto, Akiko; Nio, Junko; Obara, Mayumi; Ueki, Tomotaka; Hayasaka, Daisuke; Mizutani, Tetsuya; Kariwa, Hiroaki; Takashima, Ikuo

    2004-01-01

    Flaviviruses are assembled to bud into the lumen of the endoplasmic reticulum (ER) and are secreted through the vesicle transport pathway. Virus envelope proteins play important roles in this process. In this study, the effect of mutations in the envelope proteins of tick-borne encephalitis (TBE) virus on secretion of virus-like particles (VLPs), using a recombinant plasmid expression system was analysed. It was found that a single point mutation at position 63 in prM induces a reduction in s...

  13. Human APOBEC3 induced mutation of human immunodeficiency virus type-1 contributes to adaptation and evolution in natural infection.

    Directory of Open Access Journals (Sweden)

    Eun-Young Kim

    2014-07-01

    Full Text Available Human APOBEC3 proteins are cytidine deaminases that contribute broadly to innate immunity through the control of exogenous retrovirus replication and endogenous retroelement retrotransposition. As an intrinsic antiretroviral defense mechanism, APOBEC3 proteins induce extensive guanosine-to-adenosine (G-to-A mutagenesis and inhibit synthesis of nascent human immunodeficiency virus-type 1 (HIV-1 cDNA. Human APOBEC3 proteins have additionally been proposed to induce infrequent, potentially non-lethal G-to-A mutations that make subtle contributions to sequence diversification of the viral genome and adaptation though acquisition of beneficial mutations. Using single-cycle HIV-1 infections in culture and highly parallel DNA sequencing, we defined trinucleotide contexts of the edited sites for APOBEC3D, APOBEC3F, APOBEC3G, and APOBEC3H. We then compared these APOBEC3 editing contexts with the patterns of G-to-A mutations in HIV-1 DNA in cells obtained sequentially from ten patients with primary HIV-1 infection. Viral substitutions were highest in the preferred trinucleotide contexts of the edited sites for the APOBEC3 deaminases. Consistent with the effects of immune selection, amino acid changes accumulated at the APOBEC3 editing contexts located within human leukocyte antigen (HLA-appropriate epitopes that are known or predicted to enable peptide binding. Thus, APOBEC3 activity may induce mutations that influence the genetic diversity and adaptation of the HIV-1 population in natural infection.

  14. Afatinib induces apoptosis in NSCLC without EGFR mutation through Elk-1-mediated suppression of CIP2A.

    Science.gov (United States)

    Chao, Ting-Ting; Wang, Cheng-Yi; Chen, Yen-Lin; Lai, Chih-Cheng; Chang, Fang-Yu; Tsai, Yi-Ting; Chao, Chung-Hao H; Shiau, Chung-Wai; Huang, Yuh-Chin T; Yu, Chong-Jen; Chen, Kuen-Feng

    2015-02-10

    Afatinib has anti-tumor effect in non-small cell lung carcinoma (NSCLC) with epidermal growth factor receptor (EGFR) mutation. We found afatinib can also induce apoptosis in NSCLC cells without EGFR mutation through CIP2A pathway. Four NSCLC cell lines (H358 H441 H460 and A549) were treated with afatinib to determine their sensitivity to afatinib-induced cell death and apoptosis. The effects of CIP2A on afatinib-induced apoptosis were confirmed by overexpression and knockdown of CIP2A expression in the sensitive and resistant cells, respectively. Reduction of Elk-1 binding to the CIP2A promoter and suppression of CIP2A transcription were analyzed. In vivo efficacy of afatinib against H358 and H460 xenografts tumors were also determined in nude mice. Afatinib induced significant cell death and apoptosis in H358 and H441 cells, but not in H460 or A549 cells. The apoptotic effect of afatinib in sensitive cells was associated with downregulation of CIP2A, promotion of PP2A activity and decrease in AKT phosphorylation. Afatinib suppressed CIP2A at the gene transcription level by reducing the promoter binding activity of Elk-1. Clinical samples showed that higher CIP2A expression predicted a poor prognosis and Elk-1 and CIP2A expressions were highly correlated. In conclusion, afatinib induces apoptosis in NSCLC without EGFR mutations through Elk-1/CIP2A/PP2A/AKT pathway.

  15. NanoTIO2 (UV-Titan) does not induce ESTR mutations in the germline of prenatally exposed female mice

    DEFF Research Database (Denmark)

    Boisen, Anne Mette Zenner; Shipley, Thomas; Hougaard, Karin Sørig

    2012-01-01

    Particulate air pollution has been linked to an increased risk of cardiovascular disease and cancer. Animal studies have shown that inhalation of air particulates induces mutations in the male germline. Expanded simple tandem repeat (ESTR) loci in mice are sensitive markers of mutagenic effects...... on male germ cells resulting from environmental exposures; however, female germ cells have received little attention. Oocytes may be vulnerable during stages of active cell division (e.g., during fetal development). Accordingly, an increase in germline ESTR mutations in female mice prenatally exposed...... exposed by whole-body inhalation to the nanoTiO2 UV-Titan L181 (~42.4 mg UV-Titan/m3) or filtered clean air on gestation days (GD) 8–18. Female C57BL/6 F1 offspring were raised to maturity and mated with unexposed CBA males. The F2 descendents were collected and ESTR germline mutation rates...

  16. Point mutations induced by 1,2-epoxy-3-butene N1 deoxyinosine adducts.

    Science.gov (United States)

    Rodriguez, D A; Kowalczyk, A; Ward, J B; Harris, C M; Harris, T M; Lloyd, R S

    2001-01-01

    The National Toxicology Program has recently classified 1,3-butadiene (BD) as a human carcinogen. BD is metabolized to the intermediates 1,2-epoxy-3-butene (EB), 1,2:3,4-diepoxybutane (DEB), and 1,2-dihydroxy-3,4-epoxybutane. All three metabolites have been implicated in producing specific types of DNA damage and as genotoxic agents in mice, rat, and human cells. This study has focused on EB-induced N1 deoxyinosine lesions that are formed by deamination of deoxyadenosine following reaction of the epoxide at the N(1) position. The R and S stereoisomers of this lesion were incorporated site-specifically within the context of an 11-mer oligodeoxynucleotide, incorporated into M13mp7L2 single-stranded DNA, and transfected into E. coli. Both stereoisomers modestly reduced plaque-forming ability, indicating that neither lesion presents a base modification that cannot be bypassed. The resulting plaques were assessed for point mutations using differential hybridization and DNA sequence analyses. The overall mutagenic spectrum revealed that the N1 adducts were highly mutagenic (approximately 90% per replication cycle), causing a predominance of A --> G transitions.

  17. Improvement of traditional local rice varieties through induced mutations using nuclear techniques

    Energy Technology Data Exchange (ETDEWEB)

    Pham Van Ro; Do Huu At [Cuu Long Delta Rice Research Institute (Viet Nam)

    2001-03-01

    'Improvement of local rice varieties for high yield, resistance to disease and insect pests (brown plant hopper and rice blast) and export quality through induced mutations for the Mekong Delta' started in 1993. After six years, it showed effecting on the field in the MD as well as at the south of Vietnam. TNDB-100 manifest very wide adaptation and yield stable variety. THDB is suitable for deepwater rice region, coastal area, where rice cultivation effected by acid sulphate and salinity conditions. Both varieties are good example for the method. Thank to good Co-operation from extension center from provinces, hundred classes of extension were organized to recommend to the farmers. And thank to the strongly supporting from IAEA so that nearly 400,000 ha of TNDB-100 occupied at the south of Vietnam as well as nearly 15,000 ha of THDB grown in the coastal as well as rainfed lowland rice areas at the South of Vietnam. To continue the rice improvement by this technique, seeds of six traditional local varieties were exposed under different dose of gamma rays to create new mutants. At present day hundred improved breeding lines were selected, a dozen of uniform lines were isolated and entranced the yield trail as well as regional testing program. From these improved varieties would be selected to contribute to the rice cultivation at the south of Vietnam in the next years. (author)

  18. Induced mutations in tomato SlExp1 alter cell wall metabolism and delay fruit softening.

    Science.gov (United States)

    Minoia, Silvia; Boualem, Adnane; Marcel, Fabien; Troadec, Christelle; Quemener, Bernard; Cellini, Francesco; Petrozza, Angelo; Vigouroux, Jacqueline; Lahaye, Marc; Carriero, Filomena; Bendahmane, Abdelhafid

    2016-01-01

    Fruit ripening and softening are key traits for many fleshy fruit. Since cell walls play a key role in the softening process, expansins have been investigated to control fruit over ripening and deterioration. In tomato, expression of Expansin 1 gene, SlExp1, during fruit ripening was associated with fruit softening. To engineer tomato plants with long shelf life, we screened for mutant plants impaired in SlExp1 function. Characterization of two induced mutations, Slexp1-6_W211S, and Slexp1-7_Q213Stop, showed that SlExp1 loss of function leads to enhanced fruit firmness and delayed fruit ripening. Analysis of cell wall polysaccharide composition of Slexp1-7_Q213Stop mutant pointed out significant differences for uronic acid, neutral sugar and total sugar contents. Hemicelluloses chemistry analysis by endo-β-1,4-d-glucanase hydrolysis and MALDI-TOF spectrometry revealed that xyloglucan structures were affected in the fruit pericarp of Slexp1-7_Q213Stop mutant. Altogether, these results demonstrated that SlExp1 loss of function mutants yield firmer and late ripening fruits through modification of hemicellulose structure. These SlExp1 mutants represent good tools for breeding long shelf life tomato lines with contrasted fruit texture as well as for the understanding of the cell wall polysaccharide assembly dynamics in fleshy fruits.

  19. Resistance to adenovirally induced hyperleptinemia in rats. Comparison of ventromedial hypothalamic lesions and mutated leptin receptors.

    Science.gov (United States)

    Koyama, K; Shimabukuro, M; Chen, G; Wang, M Y; Lee, Y; Kalra, P S; Dube, M G; Kalra, S P; Newgard, C B; Unger, R H

    1998-01-01

    Leptin regulates appetite and body weight via hypothalamic targets, but it can act directly on cultured pancreatic islets to regulate their fat metabolism. To obtain in vivo evidence that leptin may act peripherally as well as centrally, we compared the effect of adenovirally induced hyperleptinemia on food intake, body weight, and islet fat content in ventromedial hypothalamic-lesioned (VMHL) rats, sham-lesioned (SL) controls, and Zucker Diabetic Fatty (ZDF) rats in which the leptin receptor is mutated. Infusion with recombinant adenovirus containing the rat leptin cDNA increased plasma leptin by approximately 20 ng/ml in VMHL and ZDF rats but had no effect on their food intake, body weight, or fat tissue weight. Caloric matching of hyperphagic VMHL rats to SL controls did not reduce their resistance to hyperleptinemia. Whereas prediabetic ZDF rats had a fourfold elevation in islet fat, in VMHL rats islet fat was normal and none of them became diabetic. Isolated islets from ZDF rats were completely resistant to the lipopenic action of leptin, while VMHL islets exhibited 50% of the normal response; caloric matching of VMHL rats to SL controls increased leptin responsiveness of their islets to 92% of controls. We conclude that leptin regulation of adipocyte fat requires an intact VMH but that islet fat content is regulated independently of the VMH. PMID:9710441

  20. Identification of an mtDNA mutation hot spot in UV-induced mouse skin tumors producing altered cellular biochemistry.

    Science.gov (United States)

    Jandova, Jana; Eshaghian, Alex; Shi, Mingjian; Li, Meiling; King, Lloyd E; Janda, Jaroslav; Sligh, James E

    2012-02-01

    There is increasing awareness of the role of mtDNA alterations in the development of cancer, as mtDNA point mutations are found at high frequency in a variety of human tumors. To determine the biological effects of mtDNA mutations in UV-induced skin tumors, hairless mice were irradiated to produce tumors, and the tumor mtDNAs were screened for single-nucleotide changes using temperature gradient capillary electrophoresis (TGCE), followed by direct sequencing. A mutation hot spot (9821insA) in the mitochondrially encoded tRNA arginine (mt-Tr) locus (tRNA(Arg)) was discovered in approximately one-third of premalignant and malignant skin tumors. To determine the functional relevance of this particular mutation in vitro, cybrid cell lines containing different mt-Tr (tRNA(Arg)) alleles were generated. The resulting cybrid cell lines contained the same nuclear genotype and differed only in their mtDNAs. The biochemical analysis of the cybrids revealed that the mutant haplotype is associated with diminished levels of complex I protein (CI), resulting in lower levels of baseline oxygen consumption and lower cellular adenosine triphosphate (ATP) production. We hypothesize that this specific mtDNA mutation alters cellular biochemistry, supporting the development of keratinocyte neoplasia.

  1. Ribosomal protein mutations induce autophagy through S6 kinase inhibition of the insulin pathway

    NARCIS (Netherlands)

    Heijnen, Harry F; van Wijk, Richard; Pereboom, Tamara C; Goos, Yvonne J; Seinen, Cor W; van Oirschot, Brigitte A; van Dooren, Rowie; Gastou, Marc; Giles, Rachel H; van Solinge, Wouter; Kuijpers, Taco W; Gazda, Hanna T; Bierings, Marc B; Da Costa, Lydie; MacInnes, Alyson W

    2014-01-01

    Mutations affecting the ribosome lead to several diseases known as ribosomopathies, with phenotypes that include growth defects, cytopenia, and bone marrow failure. Diamond-Blackfan anemia (DBA), for example, is a pure red cell aplasia linked to the mutation of ribosomal protein (RP) genes. Here we

  2. Tbc1d1 mutation in lean mouse strain confers leanness and protects from diet-induced obesity

    DEFF Research Database (Denmark)

    Chadt, Alexandra; Leicht, Katja; Deshmukh, Atul;

    2008-01-01

    We previously identified Nob1 as a quantitative trait locus for high-fat diet-induced obesity and diabetes in genome-wide scans of outcross populations of obese and lean mouse strains. Additional crossbreeding experiments indicated that Nob1 represents an obesity suppressor from the lean Swiss Jim...... and reduced glucose uptake in isolated skeletal muscle. Our data strongly suggest that mutation of Tbc1d1 suppresses high-fat diet-induced obesity by increasing lipid use in skeletal muscle....... Lambert (SJL) strain. Here we identify a SJL-specific mutation in the Tbc1d1 gene that results in a truncated protein lacking the TBC Rab-GTPase-activating protein domain. TBC1D1, which has been recently linked to human obesity, is related to the insulin signaling protein AS160 and is predominantly...

  3. Oncogenic CARD11 mutations induce hyperactive signaling by disrupting autoinhibition by the PKC-responsive inhibitory domain.

    Science.gov (United States)

    Lamason, Rebecca L; McCully, Ryan R; Lew, Stefanie M; Pomerantz, Joel L

    2010-09-28

    The regulated activation of NF-κB by antigen receptor signaling is required for normal B and T lymphocyte activation during the adaptive immune response. Dysregulated NF-κB activation is associated with several types of lymphoma, including diffuse large B cell lymphoma (DLBCL). During normal antigen receptor signaling, the multidomain scaffold protein CARD11 undergoes a transition from a closed, inactive state to an open, active conformation that recruits several signaling proteins into a complex, leading to IKK kinase activation. This transition is regulated by the CARD11 inhibitory domain (ID), which participates in intramolecular interactions that prevent cofactor binding to CARD11 prior to signaling, but which is neutralized after receptor engagement by phosphorylation. Several oncogenic CARD11 mutations have been identified in DLBCL that enhance activity and that are mostly found in the coiled-coil domain. However, the mechanisms by which these mutations cause CARD11 hyperactivity and spontaneous NF-κB activation are poorly understood. In this report, we provide several lines of evidence that oncogenic mutations F123I and L225LI induce CARD11 hyperactivity by disrupting autoinhibition by the CARD11 ID. These mutations disrupt ID-mediated intramolecular interactions and ID-dependent inhibition and bypass the requirement for ID phosphorylation during T cell receptor signaling. Intriguingly, these mutations selectively enhance the apparent affinity of CARD11 for Bcl10, but not for other signaling proteins that are recruited to CARD11 in an ID-dependent manner during normal antigen receptor signaling. Our results establish a mechanism that explains how DLBCL-associated mutations in CARD11 can initiate spontaneous, receptor-independent activation of NF-κB.

  4. Molecular structural analysis of HPRT mutations induced by thermal and epithermal neutrons in Chinese hamster ovary cells.

    Science.gov (United States)

    Kinashi, Y; Sakurai, Y; Masunaga, S; Suzuki, M; Takagaki, M; Akaboshi, M; Ono, K

    2000-09-01

    Chinese hamster ovary (CHO) cells were exposed to thermal and epithermal neutrons, and the occurrence of mutations at the HPRT locus was investigated. The Kyoto University Research Reactor (KUR), which has been improved for use in neutron capture therapy, was the neutron source. Neutron energy spectra ranging from nearly pure thermal to epithermal can be chosen using the spectrum shifters and thermal neutron filters. To determine mutant frequency and cell survival, cells were irradiated with thermal and epithermal neutrons under three conditions: thermal neutron mode, mixed mode with thermal and epithermal neutrons, and epithermal neutron mode. The mutagenicity was different among the three irradiation modes, with the epithermal neutrons showing a mutation frequency about 5-fold that of the thermal neutrons and about 1.5-fold that of the mixed mode. In the thermal neutron and mixed mode, boron did not significantly increase the frequency of the mutants at the same dose. Therefore, the effect of boron as used in boron neutron capture therapy (BNCT) is quantitatively minimal in terms of mutation induction. Over 300 independent neutron-induced mutant clones were isolated from 12 experiments. The molecular structure of HPRT mutations was determined by analysis of all nine exons by multiplex polymerase chain reaction. In the thermal neutron and mixed modes, total and partial deletions were dominant and the fraction of total deletions was increased in the presence of boron. In the epithermal neutron mode, more than half of the mutations observed were total deletions. Our results suggest that there are clear differences between thermal and epithermal neutron beams in their mutagenicity and in the structural pattern of the mutants that they induce. Mapping of deletion breakpoints of 173 partial-deletion mutants showed that regions of introns 3-4, 7/8-9 and 9-0 are sensitive to the induction of mutants by neutron irradiation.

  5. Complete Spectrum of CRISPR/Cas9-induced Mutations on HBV cccDNA

    Science.gov (United States)

    Seeger, Christoph; Sohn, Ji A

    2016-01-01

    Hepatitis B virus (HBV) causes chronic infections that cannot yet be cured. The virus persists in infected hepatocytes, because covalently closed circular DNA (cccDNA), the template for the transcription of viral RNAs, is stable in nondividing cells. Antiviral therapies with nucleoside analogues inhibit HBV DNA synthesis in capsids in the cytoplasm of infected hepatocytes, but do not destroy nuclear cccDNA. Because over 200 million people are still infected, a cure for chronic hepatitis B (CHB) has become one of the major challenges in antiviral therapy. As a first step toward the development of curative therapies, we previously demonstrated that the CRISPR/Cas9 system can be used to functionally inactivate cccDNA derived from infectious HBV. Moreover, some evidence suggests that certain cytokines might induce an APOBEC-mediated cascade leading to the destruction of cccDNA. In this report we investigated whether a combination of the two mechanisms could act synergistically to inactivate cccDNA. Using next generation sequencing (NGS), we determined the complete spectrum of mutations in cccDNA following Cas9 cleavage and repair by nonhomologous end joining (NHEJ). We found that over 90% of HBV DNA was cleaved by Cas9. In addition our results showed that editing of HBV DNA after Cas9 cleavage is at least 15,000 times more efficient that APOBEC-mediated cytosine deamination following treatment of infected cells with interferon alpha (IFNα). We also found that a previously used method to detect cytosine deaminated DNA, termed 3D-PCR, overestimates the amount and frequency of edited HBV DNA. Taken together, our results demonstrated that the CRISPR/Cas9 system is so far the best method to functionally inactivate HBV cccDNA and provide a cure for CHB. PMID:27203444

  6. Somatic mutation in larvae of the silkworm, Bombyx mori, induced by heavy ion irradiation to diapause eggs

    Energy Technology Data Exchange (ETDEWEB)

    Kotani, Eiji; Furusawa, Toshiharu [Kyoto Inst. of Tech. (Japan). Faculty of Textile Science; Nagaoka, Shunji [Fujita Health Univ., Toyoake, Aichi (Japan). School of Health Sciences] [and others

    2002-12-01

    In order to investigate whether eggs of the black-striped strain (P{sup S}) of the silkworm, Bombyx mori, represent an appropriate model for estimating the biological effect of cosmic radiation, radiosensitivity of the eggs against X-rays and heavy ion particles was examined as ground-based experiments. The exposure of diapause eggs to X-rays or heavy ion particles resulted in somatic mutations appearing as a white spot on the black integument during larval stage. Irradiation of non-diapause eggs with X-rays demonstrated a significant difference in frequency of the mutation between fractionated and single administration doses, but no difference was observed in diapause eggs. Incidence of the mutation as induced by carbon ion beams for 15-day old eggs was higher for eggs that had been kept at 15 deg C than those kept at 25 deg C. Neon beam irradiation of diapause eggs displayed dose- and linear energy transfer (LET)-dependent effects, causing a maximal rate of the mutation at 150 keV/{mu}m. These results confirm that B. mori eggs represent valid models for estimating the biological effects of cosmic radiation. (author)

  7. A novel activation-induced cytidine deaminase (AID) mutation in Brazilian patients with hyper-IgM type 2 syndrome.

    Science.gov (United States)

    Caratão, Nadine; Cortesão, Catarina S; Reis, Pedro H; Freitas, Raquel F; Jacob, Cristina M A; Pastorino, Antonio C; Carneiro-Sampaio, Magda; Barreto, Vasco M

    2013-08-01

    Activation-induced cytidine deaminase (AID) is a DNA editing protein that plays an essential role in three major events of immunoglobulin (Ig) diversification: somatic hypermutation, class switch recombination and Ig gene conversion. Mutations in the AID gene (AICDA) have been found in patients with autosomal recessive Hyper-IgM (HIGM) syndrome type 2. Here, two 9- and 14-year-old Brazilian sisters, from a consanguineous family, were diagnosed with HIGM2 syndrome. Sequencing analysis of the exons from AICDA revealed that both patients are homozygous for a single C to G transversion in the third position of codon 15, which replaces a conserved Phenylalanine with a Leucine. To our knowledge, this is a new AICDA mutation found in HIGM2 patients. Functional studies confirm that the homologous murine mutation leads to a dysfunctional protein with diminished intrinsic cytidine deaminase activity and is unable to rescue CSR when introduced in Aicda(-/-)stimulated murine B cells. We briefly discuss the relevance of AICDA mutations found in patients for the biology of this molecule.

  8. Mutation Induced Extinction in Finite Populations: Lethal Mutagenesis and Lethal Isolation

    OpenAIRE

    C Scott Wylie; Shakhnovich, Eugene I.

    2012-01-01

    Reproduction is inherently risky, in part because genomic replication can introduce new mutations that are usually deleterious toward fitness. This risk is especially severe for organisms whose genomes replicate “semi-conservatively,” e.g. viruses and bacteria, where no master copy of the genome is preserved. Lethal mutagenesis refers to extinction of populations due to an unbearably high mutation rate (U), and is important both theoretically and clinically, where drugs can extinguish pathoge...

  9. Relationship of p53 Mutations to Epidermal Cell Proliferation and Apoptosis in Human UV-Induced Skin Carcinogenesis

    Directory of Open Access Journals (Sweden)

    Janine G. Einspahr

    1999-11-01

    Full Text Available Human skin is continually subjected to UV-irradiation with the p53 gene playing a pivotal role in repair of UV-induced DNA damage and apoptosis. Consequently, p53 alterations are early events in human UV-induced skin carcinogenesis. We studied 13 squamous cell carcinomas (SCC, 16 actinic keratoses (AK, 13 samples adjacent to an AK (chronically sun-damaged, and 14 normal-appearing skin samples for p53 mutation, p53 immunostaining (IHC, apoptosis (in situ TUNEL and morphology, and proliferation (PCNA. The frequency of p53 mutation increased from 14% in normal skin, to 38.5% in sun-damaged skin, 63% in AK, and 54% in SCC. p53 IHC increased similarly. Apoptosis (TUNEL increased from 0.06 ± 0.02%, to 0.1 ± 0.2, 0.3 ± 0.3, and 0.4 ± 0.3 in normal skin, sun-damaged skin, AK, and SCC, respectively. Apoptosis was strongly correlated with proliferation (i.e., TUNEL and PCNA, r = 0.7, P < 0.0001, and proliferation was significantly increased in the progression from normal skin to SCC. Bax was significantly increased in SCC compared to AK. These data imply that apoptosis in samples with a high frequency of p53 mutation may not necessarily be p53-dependent. We suggest that there is a mechanism for apoptosis in response to increased cellular proliferation that is p53-independent.

  10. Multipotent genetic suppression of retrotransposon-induced mutations by Nxf1 through fine-tuning of alternative splicing.

    Directory of Open Access Journals (Sweden)

    Dorothy Concepcion

    2009-05-01

    Full Text Available Cellular gene expression machinery has coevolved with molecular parasites, such as viruses and transposons, which rely on host cells for their expression and reproduction. We previously reported that a wild-derived allele of mouse Nxf1 (Tap, a key component of the host mRNA nuclear export machinery, suppresses two endogenous retrovirus-induced mutations and shows suggestive evidence of positive selection. Here we show that Nxf1(CAST suppresses a specific and frequent class of intracisternal A particle (IAP-induced mutations, including Ap3d1(mh2J, a model for Hermansky-Pudlak syndrome, and Atcay(hes, an orthologous gene model for Cayman ataxia, among others. The molecular phenotype of suppression includes approximately two-fold increase in the level of correctly-spliced mRNA and a decrease in mutant-specific, alternatively-processed RNA accumulating from the inserted allele. Insertional mutations involving ETn and LINE elements are not suppressed, demonstrating a high degree of specificity to this suppression mechanism. These results implicate Nxf1 in some instances of pre-mRNA processing, demonstrate the useful range of Nxf1(CAST alleles for manipulating existing mouse models of disease, and specifically imply a low functional threshold for therapeutic benefit in Cayman ataxia.

  11. CHARACTERIZATION OF ENU-INDUCED MUTATIONS IN RED BLOOD CELL STRUCTURAL PROTEINS

    Directory of Open Access Journals (Sweden)

    Katrina Kildey

    2013-03-01

    Full Text Available Murine models with modified gene function as a result of N-ethyl-N-nitrosourea (ENU mutagenesis have been used to study phenotypes resulting from genetic change. This study investigated genetic factors associated with red blood cell (RBC physiology and structural integrity that may impact on blood component storage and transfusion outcome. Forward and reverse genetic approaches were employed with pedigrees of ENU-treated mice using a homozygous recessive breeding strategy. In a “forward genetic” approach, pedigree selection was based upon identification of an altered phenotype followed by exome sequencing to identify a causative mutation. In a second strategy, a “reverse genetic” approach based on selection of pedigrees with mutations in genes of interest was utilised and, following breeding to homozygosity, phenotype assessed. Thirty-three pedigrees were screened by the forward genetic approach. One pedigree demonstrated reticulocytosis, microcytic anaemia and thrombocytosis. Exome sequencing revealed a novel single nucleotide variation (SNV in Ank1 encoding the RBC structural protein ankyrin-1 and the pedigree was designated Ank1EX34. The reticulocytosis and microcytic anaemia observed in the Ank1EX34 pedigree were similar to clinical features of hereditary spherocytosis in humans. For the reverse genetic approach three pedigrees with different point mutations in Spnb1 encoding RBC protein spectrin-1β, and one pedigree with a mutation in Epb4.1, encoding band 4.1 were selected for study. When bred to homozygosity two of the spectrin-1β pedigrees (a, b demonstrated increased RBC count, haemoglobin (Hb and haematocrit (HCT. The third Spnb1 mutation (spectrin-1β c and mutation in Epb4.1 (band 4.1 did not significantly affect the haematological phenotype, despite these two mutations having a PolyPhen score predicting the mutation may be damaging. Exome sequencing allows rapid identification of causative mutations and development of

  12. Molecular nature of mutations induced by high-LET irradiation with argon and carbon ions in Arabidopsis thaliana

    Energy Technology Data Exchange (ETDEWEB)

    Hirano, Tomonari; Kazama, Yusuke [Nishina Center for Accelerator-Based Science, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Innovation Center, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Ohbu, Sumie; Shirakawa, Yuki; Liu Yang; Kambara, Tadashi; Fukunishi, Nobuhisa [Nishina Center for Accelerator-Based Science, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Abe, Tomoko, E-mail: tomoabe@riken.jp [Nishina Center for Accelerator-Based Science, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Innovation Center, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan)

    2012-07-01

    Linear energy transfer (LET) is an important parameter to be considered in heavy-ion mutagenesis. However, in plants, no quantitative data are available on the molecular nature of the mutations induced with high-LET radiation above 101-124 keV {mu}m{sup -1}. In this study, we irradiated dry seeds of Arabidopsis thaliana with Ar and C ions with an LET of 290 keV {mu}m{sup -1}. We analyzed the DNA alterations caused by the higher-LET radiation. Mutants were identified from the M{sub 2} pools. In total, 14 and 13 mutated genes, including bin2, egy1, gl1, gl2, hy1, hy3-5, ttg1, and var2, were identified in the plants derived from Ar- and C-ions irradiation, respectively. In the mutants from both irradiations, deletion was the most frequent type of mutation; 13 of the 14 mutated genes from the Ar ion-irradiated plants and 11 of the 13 mutated genes from the C ion-irradiated plants harbored deletions. Analysis of junction regions generated by the 2 types of irradiation suggested that alternative non-homologous end-joining was the predominant pathway of repair of break points. Among the deletions, the proportion of large deletions (>100 bp) was about 54% for Ar-ion irradiation and about 64% for C-ion irradiation. Both current results and previously reported data revealed that the proportions of the large deletions induced by 290-keV {mu}m{sup -1} radiations were higher than those of the large deletions induced by lower-LET radiations (6% for 22.5-30.0 keV {mu}m{sup -1} and 27% for 101-124 keV {mu}m{sup -1}). Therefore, the 290 keV {mu}m{sup -1} heavy-ion beams can effectively induce large deletions and will prove useful as novel mutagens for plant breeding and analysis of gene functions, particularly tandemly arrayed genes.

  13. Protective effect of curcumin and chlorophyllin against DNA mutation induced by cyclophosphamide or benzo[a]pyrene

    Energy Technology Data Exchange (ETDEWEB)

    Ibrahim, M.A.; Elbehairy, A.M.; Ghoneim, M.A.; Amer, H.A. [Cairo Univ., Giza (Egypt). Biochemistry Dept. and Biotechnology Center

    2007-03-15

    The current study was carried out to evaluate the potency of curcumin and chlorophyllin as natural antioxidants to reduce the oxidative stress markers induced by cyclophosphamide (CP) and benzo[a]pyrene [B(a)P] which were used as free radical inducers. For this purpose, 126 male albino rats were used. The animals were assigned into 4 main groups: negative control group; oxidant-treated group (subdivided into two subgroups: cyclophosphamide- treated group and benzo[a]pyrene-treated group); curcumin-treated group; and chlorophyllin-treated group. Liver samples were collected after two days post the oxidant inoculation and at the end of the experimental period (10 weeks). These samples were examined for determination of liver microsomal malondialdehyde (MDA), DNA fragmentation, restriction fragment length polymorphism (RFLP) and 8-hydroxy deoxyguanosine (8-OHdG) concentration. Both CP and B(a)P caused increments in DNA fragmentation percentages, liver microsomal MDA, concentration of 8-OHdG and induced point mutation. Treatment of rats with either curcumin or chlorophyllin revealed lower DNA fragmentation percentages, liver microsomal MDA concentration, concentration of 8-OHdG and prevented induction of mutations, i. e., reversed the oxidative stress induced by CP and B(a)P and proved that they were capable of protecting rats against the oxidative damage evoked by these oxidants. (orig.)

  14. Protective effect of curcumin and chlorophyllin against DNA mutation induced by cyclophosphamide or benzo[a]pyrene.

    Science.gov (United States)

    Ibrahim, Marwa A; Elbehairy, Adel M; Ghoneim, Magdy A; Amer, Hassan A

    2007-01-01

    The current study was carried out to evaluate the potency of curcumin and chlorophyllin as natural antioxidants to reduce the oxidative stress markers induced by cyclophosphamide (CP) and benzo[a]pyrene [B(a)P] which were used as free radical inducers. For this purpose, 126 male albino rats were used. The animals were assigned into 4 main groups: negative control group; oxidant-treated group (subdivided into two subgroups: cyclophosphamide-treated group and benzo[a]pyrene-treated group); curcumin-treated group; and chlorophyllin-treated group. Liver samples were collected after two days post the oxidant inoculation and at the end of the experimental period (10 weeks). These samples were examined for determination of liver microsomal malondialdehyde (MDA), DNA fragmentation, restriction fragment length polymorphism (RFLP) and 8-hydroxy deoxyguanosine (8-OHdG) concentration. Both CP and B(a)P caused increments in DNA fragmentation percentages, liver microsomal MDA, concentration of 8-OHdG and induced point mutation. Treatment of rats with either curcumin or chlorophyllin revealed lower DNA fragmentation percentages, liver microsomal MDA concentration, concentration of 8-OHdG and prevented induction of mutations, i.e., reversed the oxidative stress induced by CP and B(a)P and proved that they were capable of protecting rats against the oxidative damage evoked by these oxidants.

  15. Reduced ciliary polycystin-2 in induced pluripotent stem cells from polycystic kidney disease patients with PKD1 mutations.

    Science.gov (United States)

    Freedman, Benjamin S; Lam, Albert Q; Sundsbak, Jamie L; Iatrino, Rossella; Su, Xuefeng; Koon, Sarah J; Wu, Maoqing; Daheron, Laurence; Harris, Peter C; Zhou, Jing; Bonventre, Joseph V

    2013-10-01

    Heterozygous mutations in PKD1 or PKD2, which encode polycystin-1 (PC1) and polycystin-2 (PC2), respectively, cause autosomal dominant PKD (ADPKD), whereas mutations in PKHD1, which encodes fibrocystin/polyductin (FPC), cause autosomal recessive PKD (ARPKD). However, the relationship between these proteins and the pathogenesis of PKD remains unclear. To model PKD in human cells, we established induced pluripotent stem (iPS) cell lines from fibroblasts of three ADPKD and two ARPKD patients. Genetic sequencing revealed unique heterozygous mutations in PKD1 of the parental ADPKD fibroblasts but no pathogenic mutations in PKD2. Undifferentiated PKD iPS cells, control iPS cells, and embryonic stem cells elaborated primary cilia and expressed PC1, PC2, and FPC at similar levels, and PKD and control iPS cells exhibited comparable rates of proliferation, apoptosis, and ciliogenesis. However, ADPKD iPS cells as well as somatic epithelial cells and hepatoblasts/biliary precursors differentiated from these cells expressed lower levels of PC2 at the cilium. Additional sequencing confirmed the retention of PKD1 heterozygous mutations in iPS cell lines from two patients but identified possible loss of heterozygosity in iPS cell lines from one patient. Furthermore, ectopic expression of wild-type PC1 in ADPKD iPS-derived hepatoblasts rescued ciliary PC2 protein expression levels, and overexpression of PC1 but not a carboxy-terminal truncation mutant increased ciliary PC2 expression levels in mouse kidney cells. Taken together, these results suggest that PC1 regulates ciliary PC2 protein expression levels and support the use of PKD iPS cells for investigating disease pathophysiology.

  16. TAL effector nucleases induce mutations at a pre-selected location in the genome of primary barley transformants.

    Science.gov (United States)

    Wendt, Toni; Holm, Preben Bach; Starker, Colby G; Christian, Michelle; Voytas, Daniel F; Brinch-Pedersen, Henrik; Holme, Inger Bæksted

    2013-10-01

    Transcription activator-like effector nucleases (TALENs) enable targeted mutagenesis in a variety of organisms. The primary advantage of TALENs over other sequence-specific nucleases, namely zinc finger nucleases and meganucleases, lies in their ease of assembly, reliability of function, and their broad targeting range. Here we report the assembly of several TALENs for a specific genomic locus in barley. The cleavage activity of individual TALENs was first tested in vivo using a yeast-based, single-strand annealing assay. The most efficient TALEN was then selected for barley transformation. Analysis of the resulting transformants showed that TALEN-induced double strand breaks led to the introduction of short deletions at the target site. Additional analysis revealed that each barley transformant contained a range of different mutations, indicating that mutations occurred independently in different cells.

  17. Induced pluripotent stem cells (iPSCs derived from cerebrotendinous xanthomatosis (CTX patient's fibroblasts carrying a R395S mutation

    Directory of Open Access Journals (Sweden)

    Philip Höflinger

    2016-09-01

    Full Text Available Induced pluripotent stem cells (iPSCs were generated from dermal fibroblasts from a 60-year-old cerebrotendinous xanthomatosis (CTX patient, carrying a homozygous mutation c. [1183C>A]; p. R395S in CYP27A1. Episomal plasmids encoding the pluripotency genes OCT4, SOX2, KLF4, L-MYC and LIN28 were introduced via electroporation. The generated line iPS-CTX-R395S has no sign of plasmid integration or chromosomal aberration and retained the mutation site in CYP27A1. Furthermore, iPSCs express pluripotency markers and are able to differentiate in all germ layers in vitro. The generated line may be a useful tool for disease modelling of CTX.

  18. Codon 64 of K-ras gene mutation pattern in hepatocellular carcinomas induced by bleomycin and 1-nitropyrene in A/J mice.

    Science.gov (United States)

    Bai, Feng; Nakanishi, Yoichi; Takayama, Koichi; Pei, Xin-Hai; Inoue, Koji; Harada, Taishi; Izumi, Miiru; Hara, Nobuyuki

    2003-01-01

    Bleomycin is a radiomimetic antitumor agent with unique genotoxic properties. 1-nitropyrene is an environmental mutagen and carcinogen that undergoes both oxidative and reductive metabolism. In the present study, hepatocellular carcinomas were induced in male A/J mice by the intraperitoneal injection of bleomycin (120 mg/kg) followed by the intraperitoneal administration of 1-nitropyrene (total dose: 1,575 mg/kg). In order to understand the mechanism by which these two compounds induce hepatocellular carcinomas, the incidence and spectrum of mutations in the K-ras proto-oncogene in these hepatocellular carcinomas were analyzed. The hepatocellular carcinomas were induced by the administration of bleomycin and 1-nitropyrene were evaluated for point mutations in exon 1 and exon 2 of the K-ras gene by the polymerase chain reaction and a sequencing analysis. No mutation was found in the hotspots regions of the K-ras gene codon 12, 13, or 61. However, the codon 64 of the K-ras gene mutation was identified in 10 of 10 (100%) hepatocellular carcinomas. All mutations showed the same pattern, which was TAC-CAC transition. Codon 64 of the K-ras gene mutation may thus play an important role in the induction of hepatocellular carcinomas by bleomycin in the existence of 1-nitropyrene. As far as we know, this is the first report of a codon 64 mutation in the K-ras gene in a chemically induced tumor.

  19. Disruption of Transcriptional Coactivator Sub1 Leads to Genome-Wide Re-distribution of Clustered Mutations Induced by APOBEC in Active Yeast Genes.

    Science.gov (United States)

    Lada, Artem G; Kliver, Sergei F; Dhar, Alok; Polev, Dmitrii E; Masharsky, Alexey E; Rogozin, Igor B; Pavlov, Youri I

    2015-05-01

    Mutations in genomes of species are frequently distributed non-randomly, resulting in mutation clusters, including recently discovered kataegis in tumors. DNA editing deaminases play the prominent role in the etiology of these mutations. To gain insight into the enigmatic mechanisms of localized hypermutagenesis that lead to cluster formation, we analyzed the mutational single nucleotide variations (SNV) data obtained by whole-genome sequencing of drug-resistant mutants induced in yeast diploids by AID/APOBEC deaminase and base analog 6-HAP. Deaminase from sea lamprey, PmCDA1, induced robust clusters, while 6-HAP induced a few weak ones. We found that PmCDA1, AID, and APOBEC1 deaminases preferentially mutate the beginning of the actively transcribed genes. Inactivation of transcription initiation factor Sub1 strongly reduced deaminase-induced can1 mutation frequency, but, surprisingly, did not decrease the total SNV load in genomes. However, the SNVs in the genomes of the sub1 clones were re-distributed, and the effect of mutation clustering in the regions of transcription initiation was even more pronounced. At the same time, the mutation density in the protein-coding regions was reduced, resulting in the decrease of phenotypically detected mutants. We propose that the induction of clustered mutations by deaminases involves: a) the exposure of ssDNA strands during transcription and loss of protection of ssDNA due to the depletion of ssDNA-binding proteins, such as Sub1, and b) attainment of conditions favorable for APOBEC action in subpopulation of cells, leading to enzymatic deamination within the currently expressed genes. This model is applicable to both the initial and the later stages of oncogenic transformation and explains variations in the distribution of mutations and kataegis events in different tumor cells.

  20. Development of Sorghum Tolerant to Acid Soil Using Induced Mutation with Gamma Irradiation

    Directory of Open Access Journals (Sweden)

    S. Human

    2010-04-01

    Full Text Available Water scarcity still becomes a problem in some dryland agricultural areas in Indonesia. Development of dryland farming system may be focused on crops that are required less water such as sorghum. Sorghum is a cereal crop that is usually grown under hot and dry condition and it is ideal for Indonesia. Sorghum is a good source of food, animal feed and raw material for ethanol. Indonesia is currently looking for alternative renewable energy resources and sorghum is regarded as one of the promising source of bioethanol as bioenergy. Unfortunately, most agricultural land in western part of the country particularly in Sumatera and Kalimantan is dryland and dominated by acid soil. The main constraint of crop production in acid soil is deficiency and Al toxicity. Therefore, development of sorghum cultivation in dryland farming system requires a variety which is tolerant to such conditions. Sorghum breeding for acid soil tolerance had been conducted at PATIR-BATAN by using induced mutations with gamma irradiation. The breeding objective was to search for sorghum genotypes tolerant to acid soil condition and with regard to sorghum use for bioethanol production. A number of 66 breeding materials, including the mutants, had been screened for acid soil tolerance on land with soil pH of 4.2 and 39% Al saturation in Lampung Province. Ten sorghum genotypes had been identified as high yielding in the acid soil condition. The mutant lines GH-ZB-41-07, YT30-39-07, B-76 and B-92 had grain yield higher (>4.5 t/ha than the control plants (Durra, Mandau and Numbu. Sorghum mutants ZH30-29-07, ZH30-30-07 and ZH30-35-07 were promising for grain-base bioethanol production with ethanol yield exceeded 2,000 l/ha. Meanwhile, the sweet sorghum mutants ZH30-35-07, ZH30-30-07 and ZH30-29-07 had brix content of 11.59, 11.95 and 10.50%, respectively. These mutant lines are promising to be developed further in sorghum breeding since they are highly tolerant to acid soils.

  1. A sucrose-rich diet induces mutations in the rat colon

    DEFF Research Database (Denmark)

    Dragsted, Lars O.; Daneshvar, Bahram; Vogel, Ulla

    2002-01-01

    affecting the overall energy and carbohydrate intake. We observed a dose-dependent increase in the mutation frequency at the cII site in the colonic mucosa with increased sucrose levels, reaching a 129% increase at the highest dose level. This would indicate a direct or indirect genotoxic effect...... of a sucrose-rich diet. No significant increase in mutations was observed in the liver. To seek an explanation for this finding, a variety of parameters were examined representing different mechanisms, including increased oxidative stress, changes in oxidative defense, effects on DNA repair, or changes......, but the background level of DNA adducts (I-compounds) as determined by (32)P postlabeling was significantly decreased in colon. This decrease in colon I-compounds correlated inversely with both mutation frequency and ERCC1 DNA repair gene expression. Dietary sucrose did not change liver apoptosis or cell turnover...

  2. Low-energy (30 keV) carbon ion induced mutation spectrum in the LacZ{alpha} gene of M13mp18 double-stranded DNA

    Energy Technology Data Exchange (ETDEWEB)

    Wang Quan; Zhang Gang; Du Yanhua; Zhao Yong; Qiu Guanying

    2003-07-25

    Double-stranded M13mp18 DNA was irradiated with 30 keV carbon ions in dry state under vacuum to investigate the low-energy heavy ion induced mutation spectra. When the irradiated DNA was used to transfect Escherichia coli JM105, 3.6-5.7-fold increases in mutation frequency were observed, in contrast to the spontaneous group. Sequences of the 92 induced mutants showed that the carbon ions in this study could induce an interesting mutation spectrum in the lacZ{alpha} gene. One-base mutations (96.8%) and base pair substitutions (56.4%) were predominant, most of which involved G:C base pairs (90.6%), especially G:C {yields} T:A transversions (49.6%) and G:C {yields} A:T transitions (39.6%). This is similar to the spectra induced by {gamma}-rays in the same ds M13, wild type E. coli system. We also found a considerable amount of carbon ion induced one-base deletion (38.5%) and the mutation sites distribution on the target lacZ{alpha} gene was obviously non-random. We compared this study with previous data employing {gamma}-rays to discuss the possible causes of the mutation spectrum.

  3. 27. Molecular spectra of acrylamide-induced mutation at hprt locus in human promyelocytic leukemia HL-60 and NB4. cell lines

    Institute of Scientific and Technical Information of China (English)

    刘胜学; 曹佳; 杨梦苏; 方志俊; 安辉

    2001-01-01

    The genotoxicity of acrylamide was investigated by methods of single cell clone culturing, two-way screening count, multiplex PCR amplification and electrophoresis technique. Acrylamide only showed clear mutagenesis until dose raised 700 mg*L-1 in HL-60 cells. The most frequent spontaneous mutation were point mutation (≥90.0%) and acrylamide-induced mutation mainly included partial deletion and point mutation (respectively 40.0%~66.7%/33.3%~60.0%). Total gene deletion wasn't discovered in both of cells. There were deletion mutation in all exons of hprt gene(except 7/8 exon), and toward the 3' end of the hprt gene. The most frequent acrylamide-induced mutation were point mutation and single exon deletion (93.3%/86.1%). There were not clear difference in both of cells. The results suggest that the spectra of spontaneous and acrylamide-induced mutants were different. and the smaller changes in genetic structure have something to do with mechanism.

  4. Application of Two- and Four-Mutation Carcinogenesis Models to UV induced Skin Tumours in Mice

    NARCIS (Netherlands)

    Venema LB; Leenhouts HP; LSO

    1995-01-01

    Dit rapport bevat de resultaten van de analyse van de incidentie van huidtumoren bij muizen na blootstelling aan ultra-violette straling (UV). Twee soorten modellen, gebaseerd op het meerstadiumkarakter van het carcinogenese proces, werden gebruikt om de incidentie te beschrijven: een twee-mutat

  5. Evolution of metastasis revealed by mutational landscapes of chemically induced skin cancers

    Science.gov (United States)

    McCreery, Melissa Q; Halliwill, Kyle D; Chin, Douglas; Delrosario, Reyno; Hirst, Gillian; Vuong, Peter; Jen, Kuang-Yu; Hewinson, James; Adams, David J; Balmain, Allan

    2016-01-01

    Human tumors show a high level of genetic heterogeneity, but the processes that influence the timing and route of metastatic dissemination of the subclones are unknown. Here we have used whole-exome sequencing of 103 matched benign, malignant and metastatic skin tumors from genetically heterogeneous mice to demonstrate that most metastases disseminate synchronously from the primary tumor, supporting parallel rather than linear evolution as the predominant model of metastasis. Shared mutations between primary carcinomas and their matched metastases have the distinct A-to-T signature of the initiating carcinogen dimethylbenzanthracene, but non-shared mutations are primarily G-to-T, a signature associated with oxidative stress. The existence of carcinomas that either did or did not metastasize in the same host animal suggests that there are tumor-intrinsic factors that influence metastatic seeding. We also demonstrate the importance of germline polymorphisms in determining allele-specific mutations, and we identify somatic genetic alterations that are specifically related to initiation of carcinogenesis by Hras or Kras mutations. Mouse tumors that mimic the genetic heterogeneity of human cancers can aid our understanding of the clonal evolution of metastasis and provide a realistic model for the testing of novel therapies. PMID:26523969

  6. Seamless correction of the sickle cell disease mutation of the HBB gene in human induced pluripotent stem cells using TALENs.

    Science.gov (United States)

    Sun, Ning; Zhao, Huimin

    2014-05-01

    Sickle cell disease (SCD) is the most common human genetic disease which is caused by a single mutation of human β-globin (HBB) gene. The lack of long-term treatment makes the development of reliable cell and gene therapies highly desirable. Disease-specific patient-derived human induced pluripotent stem cells (hiPSCs) have great potential for developing novel cell and gene therapies. With the disease-causing mutations corrected in situ, patient-derived hiPSCs can restore normal cell functions and serve as a renewable autologous cell source for the treatment of genetic disorders. Here we successfully utilized transcription activator-like effector nucleases (TALENs), a recently emerged novel genome editing tool, to correct the SCD mutation in patient-derived hiPSCs. The TALENs we have engineered are highly specific and generate minimal off-target effects. In combination with piggyBac transposon, TALEN-mediated gene targeting leaves no residual ectopic sequences at the site of correction and the corrected hiPSCs retain full pluripotency and a normal karyotype. Our study demonstrates an important first step of using TALENs for the treatment of genetic diseases such as SCD, which represents a significant advance toward hiPSC-based cell and gene therapies.

  7. Proteomic analysis of the low mutation rate of diploid male gametes induced by colchicine in Ginkgo biloba L.

    Directory of Open Access Journals (Sweden)

    Nina Yang

    Full Text Available Colchicine treatment of G. biloba microsporocytes results in a low mutation rate in the diploid (2n male gamete. The mutation rate is significantly lower as compared to other tree species and impedes the breeding of new economic varieties. Proteomic analysis was done to identify the proteins that influence the process of 2n gamete formation in G. biloba. The microsporangia of G. biloba were treated with colchicine solution for 48 h and the proteins were analyzed using 2-D gel electrophoresis and compared to protein profiles of untreated microsporangia. A total of 66 proteins showed difference in expression levels. Twenty-seven of these proteins were identified by mass spectrometry. Among the 27 proteins, 14 were found to be up-regulated and the rest 13 were down-regulated. The identified proteins belonged to five different functional classes: ATP generation, transport and carbohydrate metabolism; protein metabolism; ROS scavenging and detoxifying enzymes; cell wall remodeling and metabolism; transcription, cell cycle and signal transduction. The identification of these differentially expressed proteins and their function could help in analysing the mechanism of lower mutation rate of diploid male gamete when the microsporangium of G. biloba was induced by colchicine.

  8. Mutation induced extinction in finite populations: lethal mutagenesis and lethal isolation.

    Directory of Open Access Journals (Sweden)

    C Scott Wylie

    Full Text Available Reproduction is inherently risky, in part because genomic replication can introduce new mutations that are usually deleterious toward fitness. This risk is especially severe for organisms whose genomes replicate "semi-conservatively," e.g. viruses and bacteria, where no master copy of the genome is preserved. Lethal mutagenesis refers to extinction of populations due to an unbearably high mutation rate (U, and is important both theoretically and clinically, where drugs can extinguish pathogens by increasing their mutation rate. Previous theoretical models of lethal mutagenesis assume infinite population size (N. However, in addition to high U, small N can accelerate extinction by strengthening genetic drift and relaxing selection. Here, we examine how the time until extinction depends jointly on N and U. We first analytically compute the mean time until extinction (τ in a simplistic model where all mutations are either lethal or neutral. The solution motivates the definition of two distinct regimes: a survival phase and an extinction phase, which differ dramatically in both how τ scales with N and in the coefficient of variation in time until extinction. Next, we perform stochastic population-genetics simulations on a realistic fitness landscape that both (i features an epistatic distribution of fitness effects that agrees with experimental data on viruses and (ii is based on the biophysics of protein folding. More specifically, we assume that mutations inflict fitness penalties proportional to the extent that they unfold proteins. We find that decreasing N can cause phase transition-like behavior from survival to extinction, which motivates the concept of "lethal isolation." Furthermore, we find that lethal mutagenesis and lethal isolation interact synergistically, which may have clinical implications for treating infections. Broadly, we conclude that stably folded proteins are only possible in ecological settings that support sufficiently

  9. Sp1 regulates Raf/MEK/ERK-induced p21(CIP1) transcription in TP53-mutated cancer cells.

    Science.gov (United States)

    Karkhanis, Mansi; Park, Jong-In

    2015-03-01

    We previously reported that the upregulation of mortalin, an Hsp70 family chaperone, is important for B-Raf(V600E) tumor cells to bypass p21(CIP1) expression, which is activated as a tumor-suppressive mechanism in response to aberrant MEK/ERK activation (Wu et al., 2013). Interestingly, mortalin depletion induced p21(CIP1) transcription not only in wild-type TP53 but also in TP53-mutated B-Raf(V600E) cancer cells, suggesting the presence of an additional mechanism for p21(CIP1) regulation. In the present study, using luciferase reporter truncation analysis in a TP53-mutated B-Raf(V600E) cancer cell line, SK-MEL28, we identified a proximal p21(CIP1) promoter region responsive to mortalin depletion. Interestingly, when Sp1-like cis-elements in this promoter region were mutagenized, the p21(CIP1) promoter luciferase reporter was no longer responsive to mortalin depletion. Consistent with this, our ChIP analysis revealed that mortalin knockdown could induce Sp1 binding to p21(CIP1) promoter in a MEK/ERK-dependent manner. Moreover, RNA interference of Sp1 substantially attenuated p21(CIP1) expression induced by mortalin depletion in SK-MEL28 cells. Consistent with this observation in SK-MEL28 cells, Sp1 was necessary for the tamoxifen-regulated ∆Raf-1:ER to induce p21(CIP1) transcription in U251 cells, in which TP53 is mutated. However, in contrast, Sp1 was not necessary for ∆Raf-1:ER to induce p21(CIP1) transcription in LNCaP cells, in which TP53 is wild type. These data suggest that Sp1 may address TP53-independent p21(CIP1) transcription in Raf/MEK/ERK-activated cancer cells and that its requirement in Raf/MEK/ERK-induced p21(CIP1) transcription is subject to TP53 status.

  10. Hypoxia-inducible factor-1α polymorphisms and TSC1/2 mutations are complementary in head and neck cancers

    Directory of Open Access Journals (Sweden)

    Nikitakis Nikolaos G

    2006-01-01

    Full Text Available Abstract Background Polymorphisms or mutations in hypoxia inducible factor-1 alpha (HIF-1alpha that increases its activity and stability under normoxia have recently been identified. Likewise, disruption of the TSC1/TSC2 complex through loss of TSC1 or TSC2 has been shown to result in abnormal accumulation of HIF-1α. Here, we investigate the novel polymorphisms in exon 12, that approximate the oxygen-dependent degradation domain of HIF-1alpha in five cell lines and 28 patients with oral squamous carcinomas. Moreover, we assess for the presence of polymorphisms and mutations in TSC1 and TSC2, to ascertain if dysregulation of such might complement HIF-1alpha expression. Results Denaturing high pressure liquid chromatography (DHPLC analysis on PCR fragments in exon 12 of HIF-1alpha from 28 patients with OSCC revealed that 6 of 28 patients had mismatched heteroduplex patterns. Genomic DNA was extracted from peripheral blood leukocytes and direct sequencing showed that in 5 of the six cases these changes represented polymorphisms while, one case was a somatic mutation. Analyses of TSC1 and TSC2 revealed heteroduplexes in exons: TSC1 exon 17; TSC2 exons 36,40, and 41. The relative levels of HIF-1alpha were significantly greater for tumors possessing a HIF-1alpha polymorphism or mutation within exon 12, whereas tumors possessing a deletion or polymorphism in TSC1/TSC2 displayed a trend for higher levels of HIF-1alpha. Western blot analyses for HIF-1alpha, TSC1 and TSC2 in five SCC cell lines revealed high levels of HIF-1alpha in SCC cells possessing TSC1 and/or TSC2 mutations. Wild-type TSC2 cells targeted with siRNA to TSC2 exhibited increased levels of HIF-1alpha. Transfection of a HIF-1alpha mutant produced higher levels of HIF-1alpha in TSC1/TSC2 mutant cell lines than in wild type cells. TSC1/TSC2 mutant cell lines administered Rapamycin blocked S6 phorphorylation and diminished the levels of HIF-1alpha to those observed in cell lines with wild

  11. Functional and cellular characterization of human Retinoic Acid Induced 1 (RAI1 mutations associated with Smith-Magenis Syndrome

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    Carmona-Mora Paulina

    2010-08-01

    Full Text Available Abstract Background Smith-Magenis Syndrome is a contiguous gene syndrome in which the dosage sensitive gene has been identified: the Retinoic Acid Induced 1 (RAI1. Little is known about the function of human RAI1. Results We generated the full-length cDNA of the wild type protein and five mutated forms: RAI1-HA 2687delC, RAI1-HA 3103delC, RAI1 R960X, RAI1-HA Q1562R, and RAI1-HA S1808N. Four of them have been previously associated with SMS clinical phenotype. Molecular weight, subcellular localization and transcription factor activity of the wild type and mutant forms were studied by western blot, immunofluorescence and luciferase assays respectively. The wild type protein and the two missense mutations presented a higher molecular weight than expected, localized to the nucleus and activated transcription of a reporter gene. The frameshift mutations generated a truncated polypeptide with transcription factor activity but abnormal subcellular localization, and the same was true for the 1-960aa N-terminal half of RAI1. Two different C-terminal halves of the RAI1 protein (1038aa-end and 1229aa-end were able to localize into the nucleus but had no transactivation activity. Conclusion Our results indicate that transcription factor activity and subcellular localization signals reside in two separate domains of the protein and both are essential for the correct functionality of RAI1. The pathogenic outcome of some of the mutated forms can be explained by the dissociation of these two domains.

  12. A modified TILLING approach to detect induced mutations in tetraploid and hexaploid wheat

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    Tsai Helen

    2009-08-01

    Full Text Available Abstract Background Wheat (Triticum ssp. is an important food source for humans in many regions around the world. However, the ability to understand and modify gene function for crop improvement is hindered by the lack of available genomic resources. TILLING is a powerful reverse genetics approach that combines chemical mutagenesis with a high-throughput screen for mutations. Wheat is specially well-suited for TILLING due to the high mutation densities tolerated by polyploids, which allow for very efficient screens. Despite this, few TILLING populations are currently available. In addition, current TILLING screening protocols require high-throughput genotyping platforms, limiting their use. Results We developed mutant populations of pasta and common wheat and organized them for TILLING. To simplify and decrease costs, we developed a non-denaturing polyacrylamide gel set-up that uses ethidium bromide to detect fragments generated by crude celery juice extract digestion of heteroduplexes. This detection method had similar sensitivity as traditional LI-COR screens, suggesting that it represents a valid alternative. We developed genome-specific primers to circumvent the presence of multiple homoeologous copies of our target genes. Each mutant library was characterized by TILLING multiple genes, revealing high mutation densities in both the hexaploid (~1/38 kb and tetraploid (~1/51 kb populations for 50% GC targets. These mutation frequencies predict that screening 1,536 lines for an effective target region of 1.3 kb with 50% GC content will result in ~52 hexaploid and ~39 tetraploid mutant alleles. This implies a high probability of obtaining knock-out alleles (P = 0.91 for hexaploid, P = 0.84 for tetraploid, in addition to multiple missense mutations. In total, we identified over 275 novel alleles in eleven targeted gene/genome combinations in hexaploid and tetraploid wheat and have validated the presence of a subset of them in our seed stock

  13. Dependence of mutation spectrum on physiological state of Pen. Chrysogenum cells. Auxotrophic mutants induced with UV rays at various stages of DNA replication

    Energy Technology Data Exchange (ETDEWEB)

    Zakharova, G.M.; Bartoshevich, Yu.Eh.; Lebed, Eh.S.; Domracheva, A.G.

    1981-01-01

    The effect of UV-rays on non-activated and activated conidia of penicillin producers Pen, chryrogenum, strain 39, has been studied. It has been established that 2 doses of UV-rays - 4000 and 6000 erg/mm/sup 2/ - induce in non-activated conidia approximately equal quantity of mutations with broken synthesis of amino acids and nitrous bases of nucleic acids. The spectrum of auxotrophic mutations induced during the DNA replication changes depending on the mutagen dose and replication stage. No distinct periodicity in the mutation yield has been observed. Schemes of the induction of mutations during the DNA replication under the effect of both doses of UV-rays have been made.

  14. MUTATION OF p53 GENE IN TRANSFORMED RAT TRACHEAL EPITHELIAL CELLS INDUCED BY RADIATION

    Institute of Scientific and Technical Information of China (English)

    赵永良; 吴德昌; 刘国廉; 项晓琼

    1998-01-01

    The highly conserved domain (exon 5-8) of p53 gene in transformed rat tracheal epithelial (RTE) cells was analyzed by means of polymerase chain reaction and single strand conformation polymorphism (PCR-SSCP). The result showed that single strand of exon 8 gene had mobility shift in polyacrylamide nondenaturing gel. DNA sequencing proved the mutation was G→C transversion at condon 265.

  15. Insights into the mutation-induced HHH syndrome from modeling human mitochondrial ornithine transporter-1.

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    Jing-Fang Wang

    Full Text Available Human mitochondrial ornithine transporter-1 is reported in coupling with the hyperornithinemia-hyperammonemia-homocitrullinuria (HHH syndrome, which is a rare autosomal recessive disorder. For in-depth understanding of the molecular mechanism of the disease, it is crucially important to acquire the 3D structure of human mitochondrial ornithine transporter-1. Since no such structure is available in the current protein structure database, we have developed it via computational approaches based on the recent NMR structure of human mitochondrial uncoupling protein (Berardi MJ, Chou JJ, et al. Nature 2011, 476:109-113. Subsequently, we docked the ligand L-ornithine into the computational structure to search for the favorable binding mode. It was observed that the binding interaction for the most favorable binding mode is featured by six remarkable hydrogen bonds between the receptor and ligand, and that the most favorable binding mode shared the same ligand-binding site with most of the homologous mitochondrial carriers from different organisms, implying that the ligand-binding sites are quite conservative in the mitochondrial carriers family although their sequences similarity is very low with 20% or so. Moreover, according to our structural analysis, the relationship between the disease-causing mutations of human mitochondrial ornithine transporter-1 and the HHH syndrome can be classified into the following three categories: (i the mutation occurs in the pseudo-repeat regions so as to change the region of the protein closer to the mitochondrial matrix; (ii the mutation is directly affecting the substrate binding pocket so as to reduce the substrate binding affinity; (iii the mutation is located in the structural region closer to the intermembrane space that can significantly break the salt bridge networks of the protein. These findings may provide useful insights for in-depth understanding of the molecular mechanism of the HHH syndrome and

  16. Insights into the mutation-induced HHH syndrome from modeling human mitochondrial ornithine transporter-1.

    Science.gov (United States)

    Wang, Jing-Fang; Chou, Kuo-Chen

    2012-01-01

    Human mitochondrial ornithine transporter-1 is reported in coupling with the hyperornithinemia-hyperammonemia-homocitrullinuria (HHH) syndrome, which is a rare autosomal recessive disorder. For in-depth understanding of the molecular mechanism of the disease, it is crucially important to acquire the 3D structure of human mitochondrial ornithine transporter-1. Since no such structure is available in the current protein structure database, we have developed it via computational approaches based on the recent NMR structure of human mitochondrial uncoupling protein (Berardi MJ, Chou JJ, et al. Nature 2011, 476:109-113). Subsequently, we docked the ligand L-ornithine into the computational structure to search for the favorable binding mode. It was observed that the binding interaction for the most favorable binding mode is featured by six remarkable hydrogen bonds between the receptor and ligand, and that the most favorable binding mode shared the same ligand-binding site with most of the homologous mitochondrial carriers from different organisms, implying that the ligand-binding sites are quite conservative in the mitochondrial carriers family although their sequences similarity is very low with 20% or so. Moreover, according to our structural analysis, the relationship between the disease-causing mutations of human mitochondrial ornithine transporter-1 and the HHH syndrome can be classified into the following three categories: (i) the mutation occurs in the pseudo-repeat regions so as to change the region of the protein closer to the mitochondrial matrix; (ii) the mutation is directly affecting the substrate binding pocket so as to reduce the substrate binding affinity; (iii) the mutation is located in the structural region closer to the intermembrane space that can significantly break the salt bridge networks of the protein. These findings may provide useful insights for in-depth understanding of the molecular mechanism of the HHH syndrome and developing effective

  17. Induced Mutations for Improved Lycopene, Total Antioxidant Properties and Other Quality Factors in Wild Tomato (Solanum pimpinellifolium L

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    Emmanuel K. Quartey

    2012-08-01

    Full Text Available The objective of the study was to determine biochemical changes in (5 gamma radiation induced variant lines of wild tomato after mutation induction. Five gamma radiation-induced variant lines of wild tomato (Solanum pimpinellifolium L., selected in the M3 generation following mutagenic treatment of seeds using three doses (150, 300 and 450 Gy, respectively of gamma radiation from a Co-60 gamma source, were analysed for their lycopene content, total antioxidant properties, total and soluble solids as well as pH. Fruits of variant line BV-21 (deep red fruits recorded higher lycopene contents of 146.1 mg/kg on fresh weight basis and 156.7 mg/kg on dry weight basis compared to 136 and 152 mg/kg, respectively for the control. They also recorded higher total antioxidant properties compared to the control. Fruits of variant line BV-40 (yellow fruits recorded higher total solids of 17.9% and the lowest pH value of 4.17 compared to 12.8% and 4.36 for fruits from unirradiated plants. The highest amounts of total soluble solids (7% were contained in fruits harvested from variant lines BV-27 (light red fruits and BV-23 (deep red fruits as against 5.6% for fruits from control plants. The study indicates that wild tomato has immense nutritional properties which can be further improved through mutation breeding.

  18. In Vivo Spectrum of UVC-induced Mutation in Mouse Skin Epidermis May Reflect the Cytosine Deamination Propensity of Cyclobutane Pyrimidine Dimers.

    Science.gov (United States)

    Ikehata, Hironobu; Mori, Toshio; Yamamoto, Masayuki

    2015-11-01

    Although ultraviolet radiation (UVR) has a genotoxicity for inducing skin cancers, the skin may tolerate UVC component because the epidermal layer prevents this short wavelength range from passing through. Here, UVC genotoxicity for mouse skin was evaluated in terms of DNA damage formation and mutagenicity. UVC induced UVR photolesions and mutations remarkably in the epidermis but poorly in the dermis, confirming the barrier ability of the epidermis against shorter UVR wavelengths. Moreover, the epidermis itself responded to UVC mutagenicity with mutation induction suppression, which suppressed the mutant frequencies to a remarkably low, constant level regardless of UVC dose. The mutation spectrum observed in UVC-exposed epidermis showed a predominance of UV-signature mutation, which occurred frequently in 5'-TCG-3', 5'-TCA-3' and 5'-CCA-3' contexts. Especially, for the former two contexts, the mutations recurred at several sites with more remarkable recurrences at the 5'-TCG-3' sites. Comparison of the UVC mutation spectrum with those observed in longer UVR wavelength ranges led us to a mechanism that explains why the sequence context preference of UV-signature mutation changes according to the wavelength, which is based on the difference in the mCpG preference of cyclobutane pyrimidine dimer (CPD) formation among UVR ranges and the sequence context-dependent cytosine deamination propensity of CPD.

  19. Site-specific analysis of UV-induced cyclobutane pyrimidine dimers in nucleotide excision repair-proficient and -deficient hamster cells: Lack of correlation with mutational spectra

    Energy Technology Data Exchange (ETDEWEB)

    Vreeswijk, Maaike P.G., E-mail: vreeswijk@lumc.nl [Department of Toxicogenetics, Leiden University Medical Center, Einthovenweg 20, P.O. Box 9600, Postzone S4-P, 2300 RC Leiden (Netherlands); Department of Human Genetics, Center for Human and Clinical Genetics, Leiden University Medical Center, Building 2, Postzone S-04, P.O. Box 9600, 2300 RC Leiden (Netherlands); Meijers, Caro M.; Giphart-Gassler, Micheline; Vrieling, Harry; Zeeland, Albert A. van; Mullenders, Leon H.F.; Loenen, Wil A.M. [Department of Toxicogenetics, Leiden University Medical Center, Einthovenweg 20, P.O. Box 9600, Postzone S4-P, 2300 RC Leiden (Netherlands)

    2009-04-26

    Irradiation of cells with UVC light induces two types of mutagenic DNA photoproducts, i.e. cyclobutane pyrimidine dimers (CPD) and pyrimidine (6-4) pyrimidone photoproducts (6-4PP). To investigate the relationship between the frequency of UV-induced photolesions at specific sites and their ability to induce mutations, we quantified CPD formation at the nucleotide level along exons 3 and 8 of the hprt gene using ligation-mediated PCR, and determined the mutational spectrum of 132 UV-induced hprt mutants in the AA8 hamster cell line and of 165 mutants in its nucleotide excision repair-defective derivative UV5. In AA8 cells, transversions predominated with a strong strand bias towards thymine-containing photolesions in the non-transcribed strand. As hamster AA8 cells are proficient in global genome repair of 6-4PP but selectively repair CPD from the transcribed strand of active genes, most mutations probably resulted from erroneous bypass of CPD in the non-transcribed strand. However, the relative incidence of CPD and the positions where mutations most frequently arose do not correlate. In fact some major damage sites hardly gave rise to the formation of mutations. In the repair-defective UV5 cells, mutations were almost exclusively C > T transitions caused by photoproducts at PyC sites in the transcribed strand. Even though CPD were formed at high frequencies at some TT sites in UV5, these photoproducts did not contribute to mutation induction at all. We conclude that, even in the absence of repair, large variations in the level of induction of CPD at different sites throughout the two exons do not correspond to frequencies of mutation induction.

  20. Site-specific analysis of UV-induced cyclobutane pyrimidine dimers in nucleotide excision repair-proficient and -deficient hamster cells: Lack of correlation with mutational spectra.

    Science.gov (United States)

    Vreeswijk, Maaike P G; Meijers, Caro M; Giphart-Gassler, Micheline; Vrieling, Harry; van Zeeland, Albert A; Mullenders, Leon H F; Loenen, Wil A M

    2009-04-26

    Irradiation of cells with UVC light induces two types of mutagenic DNA photoproducts, i.e. cyclobutane pyrimidine dimers (CPD) and pyrimidine (6-4) pyrimidone photoproducts (6-4 PP). To investigate the relationship between the frequency of UV-induced photolesions at specific sites and their ability to induce mutations, we quantified CPD formation at the nucleotide level along exons 3 and 8 of the hprt gene using ligation-mediated PCR, and determined the mutational spectrum of 132 UV-induced hprt mutants in the AA8 hamster cell line and of 165 mutants in its nucleotide excision repair-defective derivative UV5. In AA8 cells, transversions predominated with a strong strand bias towards thymine-containing photolesions in the non-transcribed strand. As hamster AA8 cells are proficient in global genome repair of 6-4 PP but selectively repair CPD from the transcribed strand of active genes, most mutations probably resulted from erroneous bypass of CPD in the non-transcribed strand. However, the relative incidence of CPD and the positions where mutations most frequently arose do not correlate. In fact some major damage sites hardly gave rise to the formation of mutations. In the repair-defective UV5 cells, mutations were almost exclusively C>T transitions caused by photoproducts at PyC sites in the transcribed strand. Even though CPD were formed at high frequencies at some TT sites in UV5, these photoproducts did not contribute to mutation induction at all. We conclude that, even in the absence of repair, large variations in the level of induction of CPD at different sites throughout the two exons do not correspond to frequencies of mutation induction.

  1. Proportionality between variances in gene expression induced by noise and mutation: consequence of evolutionary robustness

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    Kaneko Kunihiko

    2011-01-01

    Full Text Available Abstract Background Characterization of robustness and plasticity of phenotypes is a basic issue in evolutionary and developmental biology. The robustness and plasticity are concerned with changeability of a biological system against external perturbations. The perturbations are either genetic, i.e., due to mutations in genes in the population, or epigenetic, i.e., due to noise during development or environmental variations. Thus, the variances of phenotypes due to genetic and epigenetic perturbations provide quantitative measures for such changeability during evolution and development, respectively. Results Using numerical models simulating the evolutionary changes in the gene regulation network required to achieve a particular expression pattern, we first confirmed that gene expression dynamics robust to mutation evolved in the presence of a sufficient level of transcriptional noise. Under such conditions, the two types of variances in the gene expression levels, i.e. those due to mutations to the gene regulation network and those due to noise in gene expression dynamics were found to be proportional over a number of genes. The fraction of such genes with a common proportionality coefficient increased with an increase in the robustness of the evolved network. This proportionality was generally confirmed, also under the presence of environmental fluctuations and sexual recombination in diploids, and was explained from an evolutionary robustness hypothesis, in which an evolved robust system suppresses the so-called error catastrophe - the destabilization of the single-peaked distribution in gene expression levels. Experimental evidences for the proportionality of the variances over genes are also discussed. Conclusions The proportionality between the genetic and epigenetic variances of phenotypes implies the correlation between the robustness (or plasticity against genetic changes and against noise in development, and also suggests that

  2. Radiation-Induced Germ Cell Mutations-Their Detection and Modification.

    Science.gov (United States)

    1987-06-30

    cell population in adult rats . I. Their morphology, proliferation, and maturation. Anat. Rec. 169: 553, 1971. 28. Erickson, B.H. Survival and renewal...mice. Mutation Res. 9: 137-145, 1970. 57. Borum, K. Oogenesis in the mouse. A study of the meiotic prophase. Exp. Cell Res. 24: 495-508, 1968. 58...Beaumont, H.M. and A.M. Mandl. A quantitative and cytological study of oogonia and oocytes in the feotal and neonatal rat . Proc. Roy Soc. B. 155: 557-565

  3. Mutation breedings in ornamental plants. Technique used for radiation induced mutant in begonia, chrysanthemum, aberia and winter daphne

    Energy Technology Data Exchange (ETDEWEB)

    Matsubara, Hisao

    1984-03-01

    Several methods of obtaining somatic mutant plants by el-ray irradiation on pieces of tissues as in vitro adventitious bud technique or small cutting methods with repeated pruning are described. The irradiation to the adventitious buds in the small pieces of organ cultured in vitro and to the small cuttings are employed. Culture beds of agar or of Japanese Kanuma soil were used in vitro culture. In these experiments, Japanese Kanuma soil bed in in vitro culture worked well for root development and transplant of the induced mutants. Combination with in vitro culture and repeated pruning technique were used for isolation and fixation of solid somatic mutant from small sectorial mutation induced by irradiation. This method was successful for begonia, chrysanthemum, aberia and winter daphne. These data indicates that most of the induced mutant plants were non-chimeric, while a few others were chimeric. Among the new varieties, ''Gin-Sei'', ''Ryoku-Ha'', ''Big-Cross'', ''Kaede-Iron'', ''Mei-Fu-Hana-Tsukubane-Utsugi'' and ''Daphne-el-3'' are non-chimeric, and ''Mini-Mini-Iron'' and ''Orange-Iron'' are chimeric. Moreover, these new varieties have remarkably differed in size and in color pattern from original variety. From the experimental results of somatic mutation, it is indicated that plant tissue culture have enormous potential in radiation breeding and in rapid propagation of the somatic mutant. (author).

  4. Antimutagenic effect of essential oil of sage (Salvia officinalis L. and its fractions against UV-induced mutations in bacterial and yeast cells

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    Knežević-Vukčević Jelena B.

    2005-01-01

    Full Text Available The inhibition of spontaneous and UV-induced mutations by essential oil (EO of sage (Salvia officinalis L. and its fractions F1-F5 containing different proportions of mono- and sesquiterpenes was studied with the Salmonella/microsome, E. coli K12, and S. cerevisiae D7 reversion assays. The EO, F1, and F2 exhibited antimutagenic potential against UV-induced mutations in all tests. Fractions F3 and F4 produced a toxic, mutagenic, or antimutagenic response, depend­ing on the test organism used. Reduction of spontaneous and UV-induced mutations by F5 was detected only in permeable strains of E. coli. The obtained results demonstrate antimutagenic activity of volatile sage terpenes and recommend them for further antimutagenesis and anticarcinogenesis studies.

  5. 7-(1-Methyl-3-Pyrrolyl--4,6-Dinitrobenzofuroxan Reduces the Frequency of Antibiotic Resistance Mutations Induced by Ciprofloxacin in Bacteria

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    Vladimir A. Chistyakov

    2016-09-01

    Full Text Available The aim of the present study was to investigate biological properties of the novel nitrobenzoxadiazole derivative 7-(1-methyl-3-pyrrolyl--4,6-dinitrobenzofuroxan. Materials and Methods: We used a bioluminescent test based on a set of lux-biosensors, which are genetically modified E.coli strains able to react on different types of factors that can induce an SOS-response with light emission. The spontaneous and induced mutation frequencies of antibiotic resistance in E. coli were determined by methods of classical genetics of microorganisms. Results: 7-(1-methyl-3-pyrrolyl--4,6-dinitrobenzofuroxan demonstrated inhibition of SOS-response in a biosensor model system and significantly reduced the frequency of spontaneous mutations and mutations induced by ciprofloxacin of antibiotic resistance. Conclusion: Based on our data, we can recommend using compound-1 as a starting point for the development of drugs that block mutagenesis associated with the emergence of antibiotic-resistant bacteria.

  6. TP53 mutations induced by BPDE in Xpa-WT and Xpa-Null human TP53 knock-in (Hupki) mouse embryo fibroblasts.

    Science.gov (United States)

    Kucab, Jill E; van Steeg, Harry; Luijten, Mirjam; Schmeiser, Heinz H; White, Paul A; Phillips, David H; Arlt, Volker M

    2015-03-01

    Somatic mutations in the tumour suppressor gene TP53 occur in more than 50% of human tumours; in some instances exposure to environmental carcinogens can be linked to characteristic mutational signatures. The Hupki (human TP53 knock-in) mouse embryo fibroblast (HUF) immortalization assay (HIMA) is a useful model for studying the impact of environmental carcinogens on TP53 mutagenesis. In an effort to increase the frequency of TP53-mutated clones achievable in the HIMA, we generated nucleotide excision repair (NER)-deficient HUFs by crossing the Hupki mouse with an Xpa-knockout (Xpa-Null) mouse. We hypothesized that carcinogen-induced DNA adducts would persist in the TP53 sequence of Xpa-Null HUFs leading to an increased propensity for mismatched base pairing and mutation during replication of adducted DNA. We found that Xpa-Null Hupki mice, and HUFs derived from them, were more sensitive to the environmental carcinogen benzo[a]pyrene (BaP) than their wild-type (Xpa-WT) counterparts. Following treatment with the reactive metabolite of BaP, benzo[a]pyrene-7,8-diol-9,10-epoxide (BPDE), Xpa-WT and Xpa-Null HUF cultures were subjected to the HIMA. A significant increase in TP53 mutations on the transcribed strand was detected in Xpa-Null HUFs compared to Xpa-WT HUFs, but the TP53-mutant frequency overall was not significantly different between the two genotypes. BPDE induced mutations primarily at G:C base pairs, with approximately half occurring at CpG sites, and the predominant mutation type was G:C>T:A in both Xpa-WT and Xpa-Null cells. Further, several of the TP53 mutation hotspots identified in smokers' lung cancer were mutated by BPDE in HUFs (codons 157, 158, 245, 248, 249, 273). Therefore, the pattern and spectrum of BPDE-induced TP53 mutations in the HIMA are consistent with TP53 mutations detected in lung tumours of smokers. While Xpa-Null HUFs exhibited increased sensitivity to BPDE-induced damage on the transcribed strand, NER-deficiency did not enhance TP53

  7. Mutation of isocitrate dehydrogenase 1 induces glioma cell proliferation via nuclear factor-κB activation in a hypoxia-inducible factor 1-α dependent manner.

    Science.gov (United States)

    Wang, Guoliang; Sai, Ke; Gong, Fanghe; Yang, Qunying; Chen, Furong; Lin, Jian

    2014-05-01

    Recently, mutations of the isocitrate dehydrogenase (IDH) 1 gene, which specifically occur in the majority of low-grade and secondary high-grade gliomas, have drawn particular attention of neuro-oncologists. Mutations of the IDH1 gene have been proposed to have significant roles in the tumorigenesis, progression and prognosis of gliomas. However, the molecular mechanism of the role of IDH1 mutants in gliomagenesis remains to be elucidated. The present study, showed that forced expression of an IDH1 mutant, of which the 132th amino acid residue arginine is substituted by histidine (IDH1R132H), promoted cell proliferation in cultured cells, while wild-type IDH1 overexpression had no effect on cell proliferation. Consistent with previous studies, it was also observed that expression of hypoxia-inducible factor 1-α (HIF1-α) was upregulated in IDH1R132H expressing cells with the induction of vascular endothelial growth factor (VEGF) expression. However, knockdown of VEGF via small RNA interference had no significant influence on the cell proliferation induced by overexpression of IDH1R132H, implying that another signaling pathway may be involved. Next, forced expression of IDH1R132H was found to activate nuclear factor-κB (NF-κB), since the inhibitory IκB protein (IκBα) was highly phosphorylated and the NF-κB p65 subunit was translocated into the nucleus. Notably, knockdown of HIF1-α significantly blocked NF-κB activation, which was induced by the overexpression of IDH1 mutants. In addition, expression of IDH1 mutants markedly induced the NF-κB target gene expression, including cyclin D1 and E and c-myc, which were involved in the regulation of cell proliferation. In conclusion, it was demonstrated that the IDH1 mutant activated NF-κB in a HIF1-α‑dependent manner and was involved in the regulation of cell proliferation.

  8. SCN5A mutation in patients with Brugada electrocardiographic pattern induced by fever

    Institute of Scientific and Technical Information of China (English)

    俞建华

    2014-01-01

    Objective To explore the relationship between SCN5A,SCN1b,SCN3b and GPD1L genotypes and the risk of malignant arrhythmia in patients with Brugada electrocardiographic pattern induced by fever.Methods The clinical data and peripheral blood of patients with Brugada electrocardiographic pattern induced by fever were

  9. Multiplex polymerase chain reaction analysis of UV-A- and UV-B-induced delayed and early mutations in V79 Chinese hamster cells.

    Science.gov (United States)

    Dahle, Jostein; Noordhuis, Paul; Stokke, Trond; Svendsrud, Debbie Hege; Kvam, Egil

    2005-01-01

    We previously reported that approximately 10% of V79 Chinese hamster fibroblast populations clonally derived from single cells immediately after irradiation with either ultraviolet B (UV-B, 290-320 nm, mainly 311 nm) or ultraviolet A (UV-A, 320-400 nm, mainly 350-390 nm) radiation exhibit genomic instability. The instability is revealed by relatively high mutation frequencies in the hypoxanthine phosphoribosyl transferase (hprt) gene up to 23 cell generations after irradiation. These delayed mutant clones exhibited higher levels of oxidative stress than normal cells. Therefore, persistently increased oxidative stress has been proposed as a mechanism for UV-induced genomic instability. This study investigates whether this mechanism is reflected in the deletion spectrum of delayed mutant clones. Eighty-eight percent of the delayed mutant clones derived from UV-A-irradiated populations were found to have total deletion of the hprt gene. Correspondingly, 81% of UV-A-induced early mutations (i.e. detected shortly after irradiation) also had total deletions. Among delayed UV-B-induced mutant clones, 23% had total deletions and 8% had deletion of one exon, whereas all early UV-B events were either point mutations or small deletions or insertions. In conclusion, the multiplex polymerase chain reaction deletion screen showed that there were explicit differences in the occurrence of large gene alterations between early and delayed mutations induced by UV-B radiation. For UV-A radiation the deletion spectra were similar for delayed and early mutations. UV-A radiation is, in contrast to UV-B radiation, only weakly absorbed by DNA and probably induces mutation almost solely via production of reactive oxygen species. Therefore, the present results support the hypothesis that persistent increase in oxidative stress is involved in the mechanism of UV-induced genomic instability.

  10. Radiation-induced mutations in sweet cherry (Prunus avium L. ) cvs Napoleon and Bing

    Energy Technology Data Exchange (ETDEWEB)

    Saamin, S.

    1987-01-01

    Experiments were conducted using gamma radiation to determine radiosensitivities of main and accessory buds, to increase the proportion of mutant tissue, and to determine the type of damage and mode of recovery in irradiated shoot spices of sweet cherry cvs Napoleon and Bin. Survival, growth, and the types of mutations of V/sub 1/ (primary) shoots and V/sub 2/ plants were observed. LD/sub 50/ values, based on survival of forced buds were about 5kR for both acute and fractionated irradiation in air, 5.5kR for acute exposure in water, and 6kR for fractionated dose in water. 0.39-0.69 accessory buds/site on non-irradiated Napoleon had forced after 30 days in the glasshouse. In the Bing field experiment with main buds, the LD/sub 50/ for both acute and fractionated irradiation in air was 3.5kR. In water, the LD/sub 50/ was 5kR for acute treatment and 6.5kR for fractionated dose. The overall mutation frequency in Napoleon V/sub 2/ shoots derived from main buds was 7.6%: 0.04% growth-reduced mutants, 0.4% total leaf mutants, and7.1% partial leaf mutants.

  11. Oncogenic AKT1(E17K) mutation induces mammary hyperplasia but prevents HER2-driven tumorigenesis.

    Science.gov (United States)

    Mancini, Maria L; Lien, Evan C; Toker, Alex

    2016-04-05

    One of the most frequently deregulated signaling pathways in breast cancer is the PI 3-K/Akt cascade. Genetic lesions are commonly found in PIK3CA, PTEN, and AKT, which lead to excessive and constitutive activation of Akt and downstream signaling that results in uncontrolled proliferation and increased cellular survival. One such genetic lesion is the somatic AKT1(E17K) mutation, which has been identified in 4-8% of breast cancer patients. To determine how this mutation contributes to mammary tumorigenesis, we constructed a genetically engineered mouse model that conditionally expresses human AKT1(E17K) in the mammary epithelium. Although AKT1(E17K) is only weakly constitutively active and does not promote proliferation in vitro, it is capable of escaping negative feedback inhibition to exhibit sustained signaling dynamics in vitro. Consistently, both virgin and multiparous AKT1(E17K) mice develop mammary gland hyperplasia that do not progress to carcinoma. This hyperplasia is accompanied by increased estrogen receptor expression, although exposure of the mice to estrogen does not promote tumor development. Moreover, AKT1(E17K) prevents HER2-driven mammary tumor formation, in part through negative feedback inhibition of RTK signaling. Analysis of TCGA breast cancer data revealed that the mRNA expression, total protein levels, and phosphorylation of various RTKs are decreased in human tumors harboring AKT1(E17K).

  12. Spontaneous mutation 7B-1 in tomato impairs blue light-induced stomatal opening.

    Science.gov (United States)

    Hlavinka, Jan; Nauš, Jan; Fellner, Martin

    2013-08-01

    It was reported earlier that 7B-1 mutant in tomato (Solanum lycopersicum L.), an ABA overproducer, is defective in blue light (BL) signaling leading to BL-specific resistance to abiotic and biotic stresses. In this work, we examine responses of stomata to blue, red and white lights, fusicoccin, anion channel blockers (anthracene-9-carboxylic acid; 9-AC and niflumic acid; NIF) and ABA. Our results showed that the aperture of 7B-1 stomata does not increase in BL, suggesting that 7B-1 mutation impairs an element of BL signaling pathway involved in stomatal opening. Similar stomatal responses of 7B-1 and wild type (WT) to fusicoccin or 9-AC points out that activity of H(+)-ATPase and 9-AC-sensitive anion channels per se is not likely affected by the mutation. Since 9-AC restored stomatal opening of 7B-1 in BL, it seems that 9-AC and BL could block similar type of anion channels. The stomata of both genotypes did not respond to NIF neither in darkness nor in any light conditions tested. In light, 9-AC but not NIF restored stomatal opening inhibited by ABA in WT and 7B-1. We suggest that in comparison to WT, the activity of S-type anion channels in 7B-1 is more promoted by increased ABA content, and less reduced by BL, because of the mutant resistance to BL.

  13. Precise Correction of Disease Mutations in Induced Pluripotent Stem Cells Derived From Patients With Limb Girdle Muscular Dystrophy.

    Science.gov (United States)

    Turan, Soeren; Farruggio, Alfonso P; Srifa, Waracharee; Day, John W; Calos, Michele P

    2016-04-01

    Limb girdle muscular dystrophies types 2B (LGMD2B) and 2D (LGMD2D) are degenerative muscle diseases caused by mutations in the dysferlin and alpha-sarcoglycan genes, respectively. Using patient-derived induced pluripotent stem cells (iPSC), we corrected the dysferlin nonsense mutation c.5713C>T; p.R1905X and the most common alpha-sarcoglycan mutation, missense c.229C>T; p.R77C, by single-stranded oligonucleotide-mediated gene editing, using the CRISPR/Cas9 gene-editing system to enhance the frequency of homology-directed repair. We demonstrated seamless, allele-specific correction at efficiencies of 0.7-1.5%. As an alternative, we also carried out precise gene addition strategies for correction of the LGMD2B iPSC by integration of wild-type dysferlin cDNA into the H11 safe harbor locus on chromosome 22, using dual integrase cassette exchange (DICE) or TALEN-assisted homologous recombination for insertion precise (THRIP). These methods employed TALENs and homologous recombination, and DICE also utilized site-specific recombinases. With DICE and THRIP, we obtained targeting efficiencies after selection of ~20%. We purified iPSC corrected by all methods and verified rescue of appropriate levels of dysferlin and alpha-sarcoglycan protein expression and correct localization, as shown by immunoblot and immunocytochemistry. In summary, we demonstrate for the first time precise correction of LGMD iPSC and validation of expression, opening the possibility of cell therapy utilizing these corrected iPSC.

  14. A novel ENU-induced ankyrin-1 mutation impairs parasite invasion and increases erythrocyte clearance during malaria infection in mice

    Science.gov (United States)

    Huang, Hong Ming; Bauer, Denis C.; Lelliott, Patrick M.; Greth, Andreas; McMorran, Brendan J.; Foote, Simon J.; Burgio, Gaetan

    2016-01-01

    Genetic defects in various red blood cell (RBC) cytoskeletal proteins have been long associated with changes in susceptibility towards malaria infection. In particular, while ankyrin (Ank-1) mutations account for approximately 50% of hereditary spherocytosis (HS) cases, an association with malaria is not well-established, and conflicting evidence has been reported. We describe a novel N-ethyl-N-nitrosourea (ENU)-induced ankyrin mutation MRI61689 that gives rise to two different ankyrin transcripts: one with an introduced splice acceptor site resulting a frameshift, the other with a skipped exon. Ank-1(MRI61689/+) mice exhibit an HS-like phenotype including reduction in mean corpuscular volume (MCV), increased osmotic fragility and reduced RBC deformability. They were also found to be resistant to rodent malaria Plasmodium chabaudi infection. Parasites in Ank-1(MRI61689/+) erythrocytes grew normally, but red cells showed resistance to merozoite invasion. Uninfected Ank-1(MRI61689/+) erythrocytes were also more likely to be cleared from circulation during infection; the “bystander effect”. This increased clearance is a novel resistance mechanism which was not observed in previous ankyrin mouse models. We propose that this bystander effect is due to reduced deformability of Ank-1(MRI61689/+) erythrocytes. This paper highlights the complex roles ankyrin plays in mediating malaria resistance. PMID:27848995

  15. Epigenetic Characterization of the FMR1 Promoter in Induced Pluripotent Stem Cells from Human Fibroblasts Carrying an Unmethylated Full Mutation

    Science.gov (United States)

    de Esch, Celine E.F.; Ghazvini, Mehrnaz; Loos, Friedemann; Schelling-Kazaryan, Nune; Widagdo, W.; Munshi, Shashini T.; van der Wal, Erik; Douben, Hannie; Gunhanlar, Nilhan; Kushner, Steven A.; Pijnappel, W.W.M. Pim; de Vrij, Femke M.S.; Geijsen, Niels; Gribnau, Joost; Willemsen, Rob

    2014-01-01

    Summary Silencing of the FMR1 gene leads to fragile X syndrome, the most common cause of inherited intellectual disability. To study the epigenetic modifications of the FMR1 gene during silencing in time, we used fibroblasts and induced pluripotent stem cells (iPSCs) of an unmethylated full mutation (uFM) individual with normal intelligence. The uFM fibroblast line carried an unmethylated FMR1 promoter region and expressed normal to slightly increased FMR1 mRNA levels. The FMR1 expression in the uFM line corresponds with the increased H3 acetylation and H3K4 methylation in combination with a reduced H3K9 methylation. After reprogramming, the FMR1 promoter region was methylated in all uFM iPSC clones. Two clones were analyzed further and showed a lack of FMR1 expression, whereas the presence of specific histone modifications also indicated a repressed FMR1 promoter. In conclusion, these findings demonstrate that the standard reprogramming procedure leads to epigenetic silencing of the fully mutated FMR1 gene. PMID:25358783

  16. Epigenetic Characterization of the FMR1 Promoter in Induced Pluripotent Stem Cells from Human Fibroblasts Carrying an Unmethylated Full Mutation

    Directory of Open Access Journals (Sweden)

    Celine E.F. de Esch

    2014-10-01

    Full Text Available Silencing of the FMR1 gene leads to fragile X syndrome, the most common cause of inherited intellectual disability. To study the epigenetic modifications of the FMR1 gene during silencing in time, we used fibroblasts and induced pluripotent stem cells (iPSCs of an unmethylated full mutation (uFM individual with normal intelligence. The uFM fibroblast line carried an unmethylated FMR1 promoter region and expressed normal to slightly increased FMR1 mRNA levels. The FMR1 expression in the uFM line corresponds with the increased H3 acetylation and H3K4 methylation in combination with a reduced H3K9 methylation. After reprogramming, the FMR1 promoter region was methylated in all uFM iPSC clones. Two clones were analyzed further and showed a lack of FMR1 expression, whereas the presence of specific histone modifications also indicated a repressed FMR1 promoter. In conclusion, these findings demonstrate that the standard reprogramming procedure leads to epigenetic silencing of the fully mutated FMR1 gene.

  17. Functional analysis of the ABCs of eye color in Helicoverpa armigera with CRISPR/Cas9-induced mutations

    Science.gov (United States)

    Khan, Sher Afzal; Reichelt, Michael; Heckel, David G.

    2017-01-01

    Many insect pigments are localized in subcellular pigment granules, and transport of pigment precursors from the cytoplasm is accomplished by ABC proteins. Drosophila melanogaster has three half-transporter genes (white, scarlet, and brown, all affecting eye pigments) and Bombyx mori has a fourth (ok). The White, Brown, Scarlet and Ok proteins each have one transmembrane and one cytoplasmic domain and they heterodimerize to form functional transporters with different substrate specificities. We used CRISPR/Cas9 to create somatic and germ-line knockout mutations of these four genes in the noctuid moth Helicoverpa armigera. Somatic knockouts of white block pigmentation of the egg, first instar larva and adult eye, but germ-line knockouts of white are recessive lethal in the embryo. Knockouts of scarlet are viable and produce pigmentless first instar larvae and yellow adult eyes lacking xanthommatin. Knockouts of brown show no phenotypic effects on viability or pigmentation. Knockouts of ok are viable and produce translucent larval cuticle and black eyes. CRISPR/Cas9-induced mutations are a useful tool for analyzing how essential and non-essential genes interact to produce the diversity of insect pigmentation patterns found in nature. PMID:28053351

  18. Comparative evolutionary analyses of beta globin gene in eutherian, dinosaurian and neopterygii taxa

    Directory of Open Access Journals (Sweden)

    Gauri Awasthi, Garima Srivastava & Aparup Das

    2011-03-01

    Full Text Available Background & objectives: Comparative genomics and evolutionary analyses of conserved genes have enabled usto understand the complexity of genomes of closely related species. For example: -globin gene present inhuman hemoglobin is one such gene that has experienced many genetic changes in many related taxa andproduced more than 600 variants. One of the variant, HBS causes sickle-cell anemia in humans but offersprotection against severe malaria due to Plasmodium falciparum. In the present study, we characterized andperformed evolutionary comparative analyses of the -globin gene in different related and unrelated taxa tohave a comprehensive view of its evolution.Methods: DNA and protein sequences of -globin gene were downloaded from NCBI and characterized in detailin nine eutherian (Homo sapiens, Pan troglodytes, Macaca mulatta, Mus musculus, Rattus norvegicus, Bostaurus, Canis familiaris, Equus caballus, Oryctolagus cuniculus, a dinosaurian (Gallus gallus and a neopterygii(Danio rerio taxa. Three more eutherian (Papio anubis, Ovis aries and Sus scrofa taxa were included for ananalysis at the protein level but not included at the gene level owing to lack of genomic information. Computationaland phylogenetic analyses were performed using evolutionary comparative approach.Results: Results of comparative and phylogenetic analyses revealed less conservation of genetic architecture of-globin compared to its protein architecture in all eutherian taxa. Both dinosaurian and neopterygii taxa servedas outgroups and varied at gene and protein levels.Interpretation & conclusion: Most remarkably, all primates from eutherian taxa including P. anubis showedonly nine codon position differences and an absolute similarity between H. sapiens and P. troglodytes. Absoluteconservation of coding region in Equus caballus (horse was observed. The results were discussed with aninference on the role of evolutionary forces in maintaining such close similarities and variations across closelyrelated taxa. Further, the need to utilize more comparative approaches in understanding the disease causinggenes’ evolution in closely related taxa is hoped for.

  19. Beta-globin gene cluster haplotypes in sickle cell patients from southwest Iran.

    Science.gov (United States)

    Rahimi, Z; Karimi, M; Haghshenass, M; Merat, A

    2003-11-01

    Sickle cell anemia in Iran is accompanied by a high level of HbF and mild clinical presentation. Here we report haplotypes of the beta gene cluster found in 81 randomly selected sickle cell patients, including 47 sickle cell anemia (SS), 17 sickle cell trait (AS), and 17 sickle/thalassemia (S/thal) from southwest Iran. We found all five common typical haplotypes as well as five atypical haplotypes in our patients. Except for four patients with homozygous Benin haplotype, none of the other African typical haplotypes were found in a homozygous state. Arab-Indian was found to be the most prevalent haplotype in the study population. This haplotype accounted for 51.1% as the homozygous form in SS patients, where 69.1% of chromosomes in these patients had the Arab-Indian haplotype. Bantu A2 was the second most prevalent haplotype among all patients. The mean %HbF in SS patients was 27.83 and in the homozygous Arab-Indian haplotype it was still higher (30.40%), while in AS patients the %HbF was only 1.20. The high %Ggamma chain (71.81) in the Arab-Indian homozygous haplotype was concomitant with the presence of an Xmn I site in both chromosomes. The presence of the Arab-Indian haplotype as the predominant haplotype might be suggestive of a gene flow to/from Saudi Arabia or India. More haplotype investigations of a normal population can clarify the high incidence of Bantu A2 haplotype in our population.

  20. Gain-of-function mutations of Ptpn11 (Shp2) cause aberrant mitosis and increase susceptibility to DNA damage-induced malignancies.

    Science.gov (United States)

    Liu, Xia; Zheng, Hong; Li, Xiaobo; Wang, Siying; Meyerson, Howard J; Yang, Wentian; Neel, Benjamin G; Qu, Cheng-Kui

    2016-01-26

    Gain-of-function (GOF) mutations of protein tyrosine phosphatase nonreceptor type 11 Ptpn11 (Shp2), a protein tyrosine phosphatase implicated in multiple cell signaling pathways, are associated with childhood leukemias and solid tumors. The underlying mechanisms are not fully understood. Here, we report that Ptpn11 GOF mutations disturb mitosis and cytokinesis, causing chromosomal instability and greatly increased susceptibility to DNA damage-induced malignancies. We find that Shp2 is distributed to the kinetochore, centrosome, spindle midzone, and midbody, all of which are known to play critical roles in chromosome segregation and cytokinesis. Mouse embryonic fibroblasts with Ptpn11 GOF mutations show a compromised mitotic checkpoint. Centrosome amplification and aberrant mitosis with misaligned or lagging chromosomes are significantly increased in Ptpn11-mutated mouse and patient cells. Abnormal cytokinesis is also markedly increased in these cells. Further mechanistic analyses reveal that GOF mutant Shp2 hyperactivates the Polo-like kinase 1 (Plk1) kinase by enhancing c-Src kinase-mediated tyrosine phosphorylation of Plk1. This study provides novel insights into the tumorigenesis associated with Ptpn11 GOF mutations and cautions that DNA-damaging treatments in Noonan syndrome patients with germ-line Ptpn11 GOF mutations could increase the risk of therapy-induced malignancies.

  1. [Malignant transformation of human fibroblasts by neutrons and by gamma radiation: Relationship to mutations induced

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1993-12-31

    A brief overview if provided of selected reports presented at the International Symposium on Molecular Mechanisms of Radiation- and Chemical Carcinogen-Induced Cell Transformation held at Mackinac Island, Michigan on September 19-23, 1993.

  2. The investigation of resveratrol and analogs as potential inducers of fetal hemoglobin.

    Science.gov (United States)

    Theodorou, Andria; Phylactides, Marios; Forti, Luca; Cramarossa, Maria Rita; Spyrou, Pantelis; Gambari, Roberto; Thein, Swee Lay; Kleanthous, Marina

    2016-05-01

    Βeta-thalassemia, is a hemoglobinopathy characterized by reduced beta-globin chain synthesis, leading to imbalanced globin chain production, ineffective erythropoiesis and anemia. Increasing gamma-globin gene expression is a promising therapeutic approach as it reduces this imbalance by combining with the excess alpha globin chains and producing fetal hemoglobin (HbF). Furthermore, increased iron absorption and repeated blood transfusions lead to iron overload and tissue damage secondary to reactive oxygen species. Compounds exhibiting both antioxidant and HbF inducing activities are, therefore, highly desirable therapeutic agents. Resveratrol, a natural phytoalexin, combines these two activities but is also cytotoxic. Nine hydroxystilbenic resveratrol derivatives were synthesized in an attempt to identify compounds that retain the HbF-inducing and antioxidant activities of resveratrol but exhibit reduced cytotoxicity. Three derivatives (P1, P4 and P11) exhibited similar hemoglobin-inducing properties to resveratrol in K562 cells, however, only P11 showed reduced cytotoxicity. All three derivatives demonstrated variable HbF-inducing activity in primary erythroid progenitor cells from healthy donors. Resveratrol and P11 increased HbF induction significantly, with P11 having the highest activity. Additionally, P4 significantly increased progenitor numbers. A combinatorial treatment in K562 cells using resveratrol and decitabine resulted in a statistically significant increase in hemoglobin-inducing activity only above the level shown by resveratrol alone.

  3. Mutational analysis of VAMP domains implicated in Ca2+-induced insulin exocytosis.

    Science.gov (United States)

    Regazzi, R; Sadoul, K; Meda, P; Kelly, R B; Halban, P A; Wollheim, C B

    1996-01-01

    Vesicle-associated membrane protein-2 (VAMP-2) and cellubrevin are associated with the membrane of insulin-containing secretory granules and of gamma-aminobutyric acid (GABA)-containing synaptic-like vesicles of pancreatic beta-cells. We found that a point mutation in VAMP-2 preventing targeting to synaptic vesicles also impairs the localization on insulin-containing secretory granules, suggesting a similar requirement for vesicular targeting. Tetanus toxin (TeTx) treatment of permeabilized HIT-T15 cells leads to the proteolytic cleavage of VAMP-2 and cellubrevin and causes the inhibition of Ca2+-triggered insulin exocytosis. Transient transfection of HIT-T15 cells with VAMP-1, VAMP-2 or cellubrevin made resistant to the proteolytic action of TeTx by amino acid replacements in the cleavage site restored Ca2+-stimulated secretion. Wild-type VAMP-2, wild-type cellubrevin or a mutant of VAMP-2 resistant to TeTx but not targeted to secretory granules were unable to rescue Ca2+-evoked insulin release. The transmembrane domain and the N-terminal region of VAMP-2 were not essential for the recovery of stimulated exocytosis, but deletions preventing the binding to SNAP-25 and/or to syntaxin I rendered the protein inactive in the reconstitution assay. Mutations of putative phosphorylation sites or of negatively charged amino acids in the SNARE motif recognized by clostridial toxins had no effect on the ability of VAMP-2 to mediate Ca2+-triggered secretion. We conclude that: (i) both VAMP-2 and cellubrevin can participate in the exocytosis of insulin; (ii) the interaction of VAMP-2 with syntaxin and SNAP-25 is required for docking and/or fusion of secretory granules with the plasma membrane; and (iii) the phosphorylation of VAMP-2 is not essential for Ca2+-stimulated insulin exocytosis. Images PMID:9003771

  4. Alzheimer's disease presenilin-1 exon 9 deletion and L250S mutations sensitize SH-SY5Y neuroblastoma cells to hyperosmotic stress-induced apoptosis

    DEFF Research Database (Denmark)

    Tanii, H; Ankarcrona, M; Flood, F

    2000-01-01

    mutation-related increases in number of apoptotic cells at 24 h following high glucose treatment were not accompanied by significant differences in cell viability at this time-point. Our results indicate that PS1......Mutations in the presenilin-1 (PS1) and presenilin-2 (PS2) genes account for the majority of early-onset familial Alzheimer's disease cases. Recent studies suggest that presenilin gene mutations predispose cells to apoptosis by mechanisms involving altered calcium homeostasis and oxidative damage....... In the present study, we determined whether PS1 mutations also sensitize cells to hyperosmotic stress-induced apoptosis. For this, we established SH-SY5Y neuroblastoma cell lines stably transfected with wild-type PS1 or either the PS1 exon 9 deletion (deltaE9) or PS1 L250S mutants. Cultured cells were exposed...

  5. Pharmacological coal tar induces G:C to T:A transversion mutations in the skin of Muta{trademark} mouse

    Energy Technology Data Exchange (ETDEWEB)

    Vogel, U.; Thein, N.; Moller, P.; Wallin, H. [National Institute of Occupational Health, Copenhagen (Denmark)

    2001-07-01

    Coal tar is a by-product of the distillation of coal. It consists of a complex chemical mixture of aromatic and aliphatic hydrocarbons, with high concentrations of polycyclic aromatic hydrocarbons such as benzo(a)pyrene. It has previously been shown that single painting on skin of mice increases the mutation frequency 16 times in murine epidermis cells. Here, the mutations by DNA sequencing are determined. Coal tar was found to primarily induce G:C to T:A transversions and one-base pair deletions of G:C base pairs. More than half of the mutations were at CpG sites. The mutational spectrum is in agreement with that of benzo(a)pyrene and other polycyclic aromatic hydrocarbon mixtures.

  6. Modulatory effects of Tabebuia impetiginosa (Lamiales, Bignoniaceae) on doxorubicin-induced somatic mutation and recombination in Drosophila melanogaster.

    Science.gov (United States)

    de Sousa, Neila C; de Rezende, Alexandre A A; da Silva, Regildo M G; Guterres, Zaira R; Graf, Ulrich; Kerr, Warwick E; Spanó, Mário A

    2009-04-01

    The wing Somatic Mutation and Recombination Test (SMART) in D. melanogaster was used to study genotoxicity of the medicinal plant Tabebuia impetiginosa. Lapachol (naphthoquinone) and β-lapachone (quinone) are the two main chemical constituents of T. impetiginosa. These compounds have several biological properties. They induce apoptosis by generating oxygen-reactive species, thereby inhibiting topoisomerases (I and II) or inducing other enzymes dependent on NAD(P)H:quinone oxidoreductase 1, thus affecting cell cycle checkpoints. The SMART was used in the standard (ST) version, which has normal levels of cytochrome P450 (CYP) enzymes, to check the direct action of this compound, and in the high bioactivation (HB) version, which has a high constitutive level of CYP enzymes, to check for indirect action in three different T. impetiginosa concentrations (10%, 20% or 40% w/w). It was observed that T. impetiginosa alone did not modify the spontaneous frequencies of mutant spots in either cross. The negative results observed prompted us to study this phytotherapeuticum in association with the reference mutagen doxorubicin (DXR). In co-treated series, T. impetiginosa was toxic in both crosses at higher concentration, whereas in the HB cross, it induced a considerable potentiating effect (from ~24.0 to ~95.0%) on DXR genotoxity. Therefore, further research is needed to determine the possible risks associated with the exposure of living organisms to this complex mixture.

  7. Modulatory effects of Tabebuia impetiginosa (Lamiales, Bignoniaceae on doxorubicin-induced somatic mutation and recombination in Drosophila melanogaster

    Directory of Open Access Journals (Sweden)

    Neila C. de Sousa

    2009-01-01

    Full Text Available The wing Somatic Mutation and Recombination Test (SMART in D. melanogaster was used to study genotoxicity of the medicinal plant Tabebuia impetiginosa. Lapachol (naphthoquinone and β-lapachone (quinone are the two main chemical constituents of T. impetiginosa. These compounds have several biological properties. They induce apoptosis by generating oxygen-reactive species, thereby inhibiting topoisomerases (I and II or inducing other enzymes dependent on NAD(PH:quinone oxidoreductase 1, thus affecting cell cycle checkpoints. The SMART was used in the standard (ST version, which has normal levels of cytochrome P450 (CYP enzymes, to check the direct action of this compound, and in the high bioactivation (HB version, which has a high constitutive level of CYP enzymes, to check for indirect action in three different T. impetiginosa concentrations (10%, 20% or 40% w/w. It was observed that T. impetiginosa alone did not modify the spontaneous frequencies of mutant spots in either cross. The negative results observed prompted us to study this phytotherapeuticum in association with the reference mutagen doxorubicin (DXR. In co-treated series, T. impetiginosa was toxic in both crosses at higher concentration, whereas in the HB cross, it induced a considerable potentiating effect (from ~24.0 to ~95.0% on DXR genotoxity. Therefore, further research is needed to determine the possible risks associated with the exposure of living organisms to this complex mixture.

  8. Diabetes (db/db mutation-induced endometrial epithelial lipoapoptosis: Ultrastructural and cytochemical analysis of reproductive tract atrophy

    Directory of Open Access Journals (Sweden)

    Garris David R

    2005-04-01

    Full Text Available Abstract Background The diabetes (db/db mutation in C57BL/KsJ mice promotes a progressive cytolipidemia within the endometrial epithelial (EE layer of the female reproductive tract which results in premature cellular and organ atrophy. The current studies focus on the ultrastructural and cytochemical changes which promote nuclear apoptosis and cytostructural disruption following the expression of endometrial hypercytolipidemia which promotes diabetes-associated organoinvolution and manifest infertility. Methods Control (normal:+/+ and diabetes (db/db genotype groups were prepared for high resolution light microscopic analysis of cytolipidemia and nuclear apoptosis (TUNEL-labeled 3'-DNA fragmentation indices and compared to the transmission electron (TEM microscopic analysis of endometrial tissue samples collected from 8–16 week-old groups. Results Compared to controls, db/db mutation expression induced a dramatic increase in EE cytolipid vacuole volume and density within the epithelial endometrial layer. TEM analysis revealed that cytolipid vacuole accumulations initially aggregated at the baso-polar regions of UEE cells in response to the systemic hyperglycemic/hypertriglyceridemic conditions which characterized the (db/db groups. Progressive cytoplasmic movement of the lipid pools into perinuclear compartments of affected EE cells induced nuclear isolation from organelles that were displaced towards peripheral cytoplasmic compartments. Cytochemical analysis of lipid vacuole accumulations indicated attraction towards, and incorporation within, the nuclear envelope of hyperlipidemic cells. Co-localization of nuclear apoptotic 3'-DNA fragments within identified hyperlipidemic EE cells was coincident with the cytochemical and ultrastructural identification of lipid penetration through the nuclear envelope in db/db mutants. Conclusion These results are the first cytochemical indication that the metabolic disturbances in db/db mutants which

  9. Chemical inducible promoter used to obtain transgenic plants with a silent marker and organisms and cells and methods of using same for screening for mutations

    Energy Technology Data Exchange (ETDEWEB)

    Zuo, Jianru (New York, NY); Chua, Nam-Hai (Scarsdale, NY)

    2007-06-12

    Disclosed is a chemically inducible promoter for transforming plants or plant cells with genes which are regulatable by adding the plants or cells to a medium containing an inducer or by removing them from such medium. The promoter is inducible by a glucocorticoid, estrogen or inducer not endogenous to plants. Such promoters may be used with any plant genes that can promote shoot regeneration and development to induce shoot formation in the presence of a glucocorticoid, estrogen or inducer. The promoter may be used with antibiotic or herbicide resistance genes or other genes which are regulatable by the presence or absence of a given inducer. Also presented are organisms or cells comprising a gene wherein the natural promoter of the gene is disrupted and the gene is placed under the control of a transgenic inducible promoter. These organisms and cells and their progeny are useful for screening for conditional gain of function and loss of function mutations.

  10. The Effect of Dose Rate on the Frequency of Specific-Locus Mutations Induced in Mouse Spermatogonia is Restricted to Larger Lesions; a Retrospective Analysis of Historical Data

    Energy Technology Data Exchange (ETDEWEB)

    Russell, Liane B [ORNL; Hunsicker, Patricia R [ORNL

    2012-01-01

    A series of 19 large-scale germ-cell mutagenesis experiments conducted several decades ago led to the conclusion that low-LET radiation delivered to mouse spermatogonia at dose rates of 0.8 R/min and below induced only about one-third as many specific-locus mutations as did single, acute exposures at 24 R/min and above. A two-hit origin of the mutations was deemed unlikely in view of the then prevailing evidence for the small size of genetic lesions in spermatogonia. Instead, the dose-rate effect was hypothesized to be the result of a repair system that exists in spermatogonia, but not in more mature male reproductive cells. More recent genetic and molecular studies on the marker genes have identified the phenotypes associated with specific states of the mutant chromosomes, and it is now possible retrospectively to classify individual past mutations as "large lesions" or "other lesions". The mutation-frequency difference between high and low dose rates is restricted to the large lesion mutations, for which the dose-curve slopes differ by a factor exceeding 3.4. For other lesion mutations, there is essentially no difference between the slopes for protracted and acute irradiations; induced other lesions frequencies per unit dose remain similar for dose rates ranging over more than 7 orders of magnitude. For large lesions, these values rise sharply at dose rates >0.8 R/min, though they remain similar within the whole range of protracted doses, failing to provide evidence for a threshold dose rate. The downward bend at high doses that had been noted for X-ray-induced specific-locus mutations as a whole and ascribed to a positive correlation between spermatogonial death and mutation load is now found to be restricted to large lesion mutations. There is a marked difference between the mutation spectra (distributions among the seven loci) for large lesions and other lesions. Within each class, however, the spectra are similar for acute and protracted irradiation.

  11. MUTATIONS IN THE VHL GENE FRIOM POTASSIUM BROMATE-INDUCED RAT CLEAR CELL RENAL TUMORS

    Science.gov (United States)

    Potassium bromate (KBrO3) is a rat renal carcinogen and a major drinking water disinfection by-product in water disinfected with ozone. Clear cell renal tumors, the most common form of human renal epithelial neoplasm, are rare in animals but are inducible by KBrO3 in F344 rats. ...

  12. Genetic and chemical characterization of an EMS induced mutation in Cucumis melo CRTISO gene.

    Science.gov (United States)

    Galpaz, Navot; Burger, Yosi; Lavee, Tamar; Tzuri, Galil; Sherman, Amir; Melamed, Tal; Eshed, Ravit; Meir, Ayala; Portnoy, Vitaly; Bar, Einat; Shimoni-Shor, Einav; Feder, Ari; Saar, Yuval; Saar, Uzi; Baumkoler, Fabian; Lewinsohn, Efraim; Schaffer, Arthur A; Katzir, Nurit; Tadmor, Yaakov

    2013-11-15

    In order to broaden the available genetic variation of melon, we developed an ethyl methanesulfonate mutation library in an orange-flesh 'Charentais' type melon line that accumulates β-carotene. One mutagenized M2 family segregated for a novel recessive trait, a yellow-orange fruit flesh ('yofI'). HPLC analysis revealed that 'yofI' accumulates pro-lycopene (tetra-cis-lycopene) as its major fruit pigment. The altered carotenoid composition of 'yofI' is associated with a significant change of the fruit aroma since cleavage of β-carotene yields different apocarotenoids than the cleavage of pro-lycopene. Normally, pro-lycopene is further isomerized by CRTISO (carotenoid isomerase) to yield all-trans-lycopene, which is further cyclized to β-carotene in melon fruit. Cloning and sequencing of 'yofI' CRTISO identified two mRNA sequences which lead to truncated forms of CRTISO. Sequencing of the genomic CRTISO identified an A-T transversion in 'yofI' which leads to a premature STOP codon. The early carotenoid pathway genes were up regulated in yofI fruit causing accumulation of other intermediates such as phytoene and ζ-carotene. Total carotenoid levels are only slightly increased in the mutant. Mutants accumulating pro-lycopene have been reported in both tomato and watermelon fruits, however, this is the first report of a non-lycopene accumulating fruit showing this phenomenon.

  13. A single amino acid mutation in SNAP-25 induces anxiety-related behavior in mouse.

    Directory of Open Access Journals (Sweden)

    Masakazu Kataoka

    Full Text Available Synaptosomal-associated protein of 25 kDa (SNAP-25 is a presynaptic protein essential for neurotransmitter release. Previously, we demonstrate that protein kinase C (PKC phosphorylates Ser(187 of SNAP-25, and enhances neurotransmitter release by recruiting secretory vesicles near to the plasma membrane. As PKC is abundant in the brain and SNAP-25 is essential for synaptic transmission, SNAP-25 phosphorylation is likely to play a crucial role in the central nervous system. We therefore generated a mutant mouse, substituting Ser(187 of SNAP-25 with Ala using "knock-in" technology. The most striking effect of the mutation was observed in their behavior. The homozygous mutant mice froze readily in response to environmental change, and showed strong anxiety-related behavior in general activity and light and dark preference tests. In addition, the mutant mice sometimes exhibited spontaneously occurring convulsive seizures. Microdialysis measurements revealed that serotonin and dopamine release were markedly reduced in amygdala. These results clearly indicate that PKC-dependent SNAP-25 phosphorylation plays a critical role in the regulation of emotional behavior as well as the suppression of epileptic seizures, and the lack of enhancement of monoamine release is one of the possible mechanisms underlying these defects.

  14. A missense mutation in CHS1, a TIR-NB protein, induces chilling sensitivity in Arabidopsis.

    Science.gov (United States)

    Wang, Yuancong; Zhang, Yao; Wang, Zheng; Zhang, Xiaoyan; Yang, Shuhua

    2013-08-01

    Low temperature is an environmental factor that affects plant growth and development and plant-pathogen interactions. How temperature regulates plant defense responses is not well understood. In this study, we characterized chilling-sensitive mutant 1 (chs1), and functionally analyzed the role of the CHS1 gene in plant responses to chilling stress. The chs1 mutant displayed a chilling-sensitive phenotype, and also displayed defense-associated phenotypes, including extensive cell death, the accumulation of hydrogen peroxide and salicylic acid, and an increased expression of PR genes: these phenotypes indicated that the mutation in chs1 activates the defense responses under chilling stress. A map-based cloning analysis revealed that CHS1 encodes a TIR-NB-type protein. The chilling sensitivity of chs1 was fully rescued by pad4 and eds1, but not by ndr1. The overexpression of the TIR and NB domains can suppress the chs1-conferred phenotypes. Interestingly, the stability of the CHS1 protein was positively regulated by low temperatures independently of the 26S proteasome pathway. This study revealed the role of a TIR-NB-type gene in plant growth and cell death under chilling stress, and suggests that temperature modulates the stability of the TIR-NB protein in Arabidopsis.

  15. B-Myb Induces APOBEC3B Expression Leading to Somatic Mutation in Multiple Cancers

    Science.gov (United States)

    Chou, Wen-Cheng; Chen, Wei-Ting; Hsiung, Chia-Ni; Hu, Ling-Yueh; Yu, Jyh-Cherng; Hsu, Huan-Ming; Shen, Chen-Yang

    2017-01-01

    The key signature of cancer genomes is the accumulation of DNA mutations, the most abundant of which is the cytosine-to-thymine (C-to-T) transition that results from cytosine deamination. Analysis of The Cancer Genome Atlas (TCGA) database has demonstrated that this transition is caused mainly by upregulation of the cytosine deaminase APOBEC3B (A3B), but the mechanism has not been completely characterized. We found that B-Myb (encoded by MYBL2) binds the A3B promoter, causing transactivation, and this is responsible for the C-to-T transitions and DNA hypermutation in breast cancer cells. Analysis of TCGA database yielded similar results, supporting that MYBL2 and A3B are upregulated and putatively promote C-to-T transitions in multiple cancer types. Moreover, blockade of EGF receptor with afatinib attenuated B-Myb–A3B signaling, suggesting a clinically relevant means of suppressing mutagenesis. Our results suggest that B-Myb–A3B contributes to DNA damage and could be targeted by inhibiting EGF receptor. PMID:28276478

  16. Enhancement of Phenol Biodegradation by Pseudochrobactrum sp. through Ultraviolet-Induced Mutation

    Directory of Open Access Journals (Sweden)

    Zhen Mao

    2015-04-01

    Full Text Available The phenol-degrading efficiency of Pseudochrobactrum sp. was enhanced by ultraviolet (UV irradiation. First, a bacterial strain, Pseudochrobactrum sp. XF1, was isolated from the activated sludge in a coking plant. It was subjected to mutation by UV radiation for 120 s and a mutant strain with higher phenol-degrading efficiency, Pseudochrobactrum sp. XF1-UV, was selected. The mutant strain XF1-UV was capable of degrading 1800 mg/L phenol completely within 48 h and had higher tolerance to hydrogen ion concentration and temperature variation than the wild type. Haldane’s kinetic model was used to fit the exponential growth data and the following kinetic parameters were obtained: μmax = 0.092 h−1, Ks = 22.517 mg/L, and Ki = 1126.725 mg/L for XF1, whereas μmax = 0.110 h−1, Ks = 23.934 mg/L, and Ki = 1579.134 mg/L for XF1-UV. Both XF1 and XF1-UV degraded phenol through the ortho-pathway; but the phenol hydroxylase activity of XF1-UV1 was higher than that of XF1, therefore, the mutant strain biodegraded phenol faster. Taken together, our results suggest that Pseudochrobactrum sp. XF1-UV could be a promising candidate for bioremediation of phenol-containing wastewaters.

  17. Enhancement of phenol biodegradation by Pseudochrobactrum sp. through ultraviolet-induced mutation.

    Science.gov (United States)

    Mao, Zhen; Yu, Chenyang; Xin, Lingling

    2015-04-01

    The phenol-degrading efficiency of Pseudochrobactrum sp. was enhanced by ultraviolet (UV) irradiation. First, a bacterial strain, Pseudochrobactrum sp. XF1, was isolated from the activated sludge in a coking plant. It was subjected to mutation by UV radiation for 120 s and a mutant strain with higher phenol-degrading efficiency, Pseudochrobactrum sp. XF1-UV, was selected. The mutant strain XF1-UV was capable of degrading 1800 mg/L phenol completely within 48 h and had higher tolerance to hydrogen ion concentration and temperature variation than the wild type. Haldane's kinetic model was used to fit the exponential growth data and the following kinetic parameters were obtained: μmax = 0.092 h-1, Ks = 22.517 mg/L, and Ki = 1126.725 mg/L for XF1, whereas μmax = 0.110 h-1, Ks = 23.934 mg/L, and Ki = 1579.134 mg/L for XF1-UV. Both XF1 and XF1-UV degraded phenol through the ortho-pathway; but the phenol hydroxylase activity of XF1-UV1 was higher than that of XF1, therefore, the mutant strain biodegraded phenol faster. Taken together, our results suggest that Pseudochrobactrum sp. XF1-UV could be a promising candidate for bioremediation of phenol-containing wastewaters.

  18. A sucrose-rich diet induces mutations in the rat colon

    DEFF Research Database (Denmark)

    Dragsted, L.O.; Daneshvar, B.; Vogel, Ulla Birgitte

    2002-01-01

    A sucrose-rich diet has repeatedly been observed to have cocarcinogenic actions in the colon and liver of rats and to increase the number of aberrant crypt foci in rat colon. To investigate whether sucrose-rich diets might directly increase the genotoxic response in the rat colon or liver, we have...... added sucrose to the diet of Big Blue rats, a strain of Fischer rats carrying 40 copies of the lambda-phage on chromosome 4. Dietary sucrose was provided to the rats for 3 weeks at four dose levels including the background level in the purified diet [3.4% (control), 6.9%, 13.8%, or 34.5%] without...... or in blood plasma. We conclude that a sucrose-rich diet directly or indirectly increases the mutation frequency in rat colon in a dose-dependent manner and concomitantly decreases the level of background DNA adducts, without a direct effect on the expression of major DNA repair enzyme systems. We also...

  19. Ataxia telangiectasia mutated activation by transcription- and topoisomerase I-induced DNA double-strand breaks.

    Science.gov (United States)

    Sordet, Olivier; Redon, Christophe E; Guirouilh-Barbat, Josée; Smith, Susan; Solier, Stéphanie; Douarre, Céline; Conti, Chiara; Nakamura, Asako J; Das, Benu B; Nicolas, Estelle; Kohn, Kurt W; Bonner, William M; Pommier, Yves

    2009-08-01

    Ataxia telangiectasia mutated (ATM), the deficiency of which causes a severe neurodegenerative disease, is a crucial mediator for the DNA damage response (DDR). As neurons have high rates of transcription that require topoisomerase I (TOP1), we investigated whether TOP1 cleavage complexes (TOP1cc)-which are potent transcription-blocking lesions-also produce transcription-dependent DNA double-strand breaks (DSBs) with ATM activation. We show the induction of DSBs and DDR activation in post-mitotic primary neurons and lymphocytes treated with camptothecin, with the induction of nuclear DDR foci containing activated ATM, gamma-H2AX (phosphorylated histone H2AX), activated CHK2 (checkpoint kinase 2), MDC1 (mediator of DNA damage checkpoint 1) and 53BP1 (p53 binding protein 1). The DSB-ATM-DDR pathway was suppressed by inhibiting transcription and gamma-H2AX signals were reduced by RNase H1 transfection, which removes transcription-mediated R-loops. Thus, we propose that Top1cc produce transcription arrests with R-loop formation and generate DSBs that activate ATM in post-mitotic cells.

  20. Improvement of strain Penicillium sp. EZ-ZH190 for tannase production by induced mutation.

    Science.gov (United States)

    Zakipour-Molkabadi, E; Hamidi-Esfahani, Z; Sahari, M A; Azizi, M H

    2013-11-01

    In the search for an efficient producer of tannase, Penicillium sp. EZ-ZH190 was subjected to mutagenesis using heat treatment and strain EZ-ZH290 was isolated. The maximum tannase in this mutant strain was 4.32 U/mL with an incubation period of 84 h as compared to wild strain EZ-ZH190 where the incubation period was 96 h with a maximum enzyme activity of 4.33 U/mL. Also, the Penicillium sp. EZ-ZH290 tannase had a maximum activity at 40 °C and pH 5.5. Then, the spores of strain EZ-ZH290 were subjected to γ irradiation mutagenesis and strain EZ-ZH390 was isolated. Strain EZ-ZH390 exhibited higher tannase activity (7.66 U/mL) than the parent strain EZ-ZH290. It was also found that Penicillium sp. EZ-ZH390 tannase had an optimum activity at 35 °C and a broad pH profile with an optimum at pH 5.5. The tannase pH stability of Penicillium sp. EZ-ZH390 and its maximum production of tannase followed the same trend for five generations confirming the occurrence of stable mutant. This paper is shown that γ irradiation can mutate the Penicillium sp. leading to increase the tannase production.

  1. Generation of a human induced pluripotent stem cell line via CRISPR-Cas9 mediated integration of a site-specific heterozygous mutation in CHMP2B

    DEFF Research Database (Denmark)

    Zhang, Yu; Schmid, Benjamin; Nielsen, Troels Tolstrup;

    2016-01-01

    have generated an induced pluripotent stem cell (iPSC) line of a healthy individual and inserted the CHMP2B IVS5AS G-C gene mutation into one of the alleles, resulting in aberrant splicing. This human iPSC line provides an ideal model to study CHMP2B-dependent phenotypes of FTD3....

  2. Generation of induced pluripotent stem cells (iPSCs) from an Alzheimer's disease patient carrying a L150P mutation in PSEN-1

    DEFF Research Database (Denmark)

    Tubsuwan, Alisa; Pires, Carlota; Rasmussen, Mikkel A.;

    2016-01-01

    Induced pluripotent stem cells (iPSCs) were generated from skin fibroblasts isolated from a 58-year old male with a L150P mutation in the presenilin 1 (PSEN-1) gene, which is responsible for the majority of familial cases of Alzheimer's disease (AD). The iPSC swere established by co-electroporation...

  3. Generation of induced pluripotent stem cells (iPSCs) from an Alzheimer's disease patient carrying a M146I mutation in PSEN1

    DEFF Research Database (Denmark)

    Li, Tong; Pires, Carlota; Nielsen, Troels Tolstrup

    2016-01-01

    Skin fibroblasts were obtained from a 46-year-old symptomatic man carrying a M146I mutation in the presenilin 1 gene (PSEN1), responsible for causing Alzheimer's disease (AD). Induced pluripotent stem cells (iPSCs) were derived via transfection with episomal vectors carrying hOCT4, hSOX2, hKLF2, ...

  4. Induced pluripotent stem cells (iPSCs) derived from a patient with frontotemporal dementia caused by a R406W mutation in microtubule-associated protein tau (MAPT)

    DEFF Research Database (Denmark)

    Rasmussen, Mikkel A.; Hjermind, Lena E.; Hasholt, Lis F.

    2016-01-01

    Skin fibroblasts were obtained from a 59-year-old woman diagnosed with frontotemporal dementia. The disease is caused by a R406W mutation in microtubule-associated protein tau (MAPT). Induced pluripotent stem cells (iPSCs) were established by electroporation with episomal plasmids containing hOCT4...

  5. Induced pluripotent stem cells (iPSCs) derived from a patient with frontotemporal dementia caused by a P301L mutation in microtubule-associated protein tau (MAPT)

    DEFF Research Database (Denmark)

    Rasmussen, Mikkel A.; Hjermind, Lena Elisabeth; Hasholt, Lis Frydenreich

    2016-01-01

    Skin fibroblasts were obtained froma 57-year-old woman diagnosed with frontotemporal dementia. The diseaseis caused by a P301L mutation in microtubule-associated protein tau (MAPT). Induced pluripotent stem cells (iPSCs) were established by electroporation with episomal plasmids containing hOCT4, h...

  6. Generation of induced pluripotent stem cells (iPSCs) from an Alzheimer's disease patient carrying an A79V mutation in PSEN1

    DEFF Research Database (Denmark)

    Li, Tong; Pires, Carlota; Nielsen, Troels T.

    2016-01-01

    Skin fibroblasts were obtained from a 48-year-old presymptomatic woman carrying a A79V mutation in the presenilin 1 gene (PSEN1), causing Alzheimer's disease (AD). Induced pluripotent stem cell (iPSCs) were derived via transfection with episomal vectors carrying hOCT4, hSOX2, hKLF2, hL-MYC, hLIN28...

  7. Mutations of the epigenetics-modifying gene (DNMT3a, TET2, IDH1/2) at diagnosis may induce FLT3-ITD at relapse in de novo acute myeloid leukemia.

    Science.gov (United States)

    Wakita, S; Yamaguchi, H; Omori, I; Terada, K; Ueda, T; Manabe, E; Kurosawa, S; Iida, S; Ibaraki, T; Sato, Y; Todoroki, T; Hirakawa, T; Ryotokuji, T; Arai, K; Kitano, T; Mitamura, Y; Kosaka, F; Dan, K; Inokuchi, K

    2013-04-01

    Gene mutations were found in acute myeloid leukemia (AML) and their importance has been noted. To clarify the importance and stability of mutations, we examined gene mutations in paired samples at diagnosis and relapse of 34 adult AML patients. Five acquired gene mutations were detected at relapse. Of the 45 gene mutations at diagnosis, 11 of them were lost at relapse. The acquired mutations at relapse were all class I mutations as Fms-like tyrosine kinase 3 (FLT3) and rat sarcoma viral oncogene homolog (RAS) mutations. The disappeared mutations at relapse were 3 of 11 internal tandem duplications of FLT3 (FLT3-ITD) (27.3%), 3 of 3 FLT3 tyrosine kinase domain (FLT3-TKD) (100%), 3 of 13 Nucleophosmin 1 (23.1%) and 2 of 5 CCAAT/enhancer-binding protein-α (40%) mutations. However, epigenetics-modifying gene (DNMT3a, TET2 and IDH1/2) mutations had no change between diagnosis and relapse samples, and may become minimal residual disease marker. The frequency of FLT3-ITD at relapse in patients with DNMT3a mutation at diagnosis is significantly higher than those in patients without them (P=0.001). Moreover, the high frequency of FLT3-ITD at relapse is also seen in AML cases that initially present with any epigenetics-modifying gene mutations (Pgene mutations may cause genetic instability and induce FLT3-ITD, leading to resistance to therapy and relapse.

  8. Subquivers of mutation-acyclic quivers are mutation-acyclic

    CERN Document Server

    Warkentin, Matthias

    2011-01-01

    Quiver mutation plays a crucial role in the definition of cluster algebras by Fomin and Zelevinsky. It induces an equivalence relation on the set of all quivers without loops and two-cycles. A quiver is called mutation-acyclic if it is mutation-equivalent to an acyclic quiver. The aim of this note is to show that full subquivers of mutation-acyclic quivers are mutation-acyclic.

  9. Transcription-induced mutational strand bias and its effect on substitution rates in human genes.

    Science.gov (United States)

    Mugal, Carina F; von Grünberg, Hans-Hennig; Peifer, Martin

    2009-01-01

    If substitution rates are not the same on the two complementary DNA strands, a substitution is considered strand asymmetric. Such substitutional strand asymmetries are determined here for the three most frequent types of substitution on the human genome (C --> T, A --> G, and G --> T). Substitution rate differences between both strands are estimated for 4,590 human genes by aligning all repeats occurring within the introns with their ancestral consensus sequences. For 1,630 of these genes, both coding strand and noncoding strand rates could be compared with rates in gene-flanking regions. All three rates considered are found to be on average higher on the coding strand and lower on the transcribed strand in comparison to their values in the gene-flanking regions. This finding points to the simultaneous action of rate-increasing effects on the coding strand--such as increased adenine and cytosine deamination--and transcription-coupled repair as a rate-reducing effect on the transcribed strand. The common behavior of the three rates leads to strong correlations of the rate asymmetries: Whenever one rate is strand biased, the other two rates are likely to show the same bias. Furthermore, we determine all three rate asymmetries as a function of time: the A --> G and G --> T rate asymmetries are both found to be constant in time, whereas the C --> T rate asymmetry shows a pronounced time dependence, an observation that explains the difference between our results and those of an earlier work by Green et al. (2003. Transcription-associated mutational asymmetry in mammalian evolution. Nat Genet. 33:514-517.). Finally, we show that in addition to transcription also the replication process biases the substitution rates in genes.

  10. Molecular analysis of two mouse dilute locus deletion mutations: Spontaneous dilute lethal20J and radiation-induced dilute prenatal lethal Aa2 alleles

    Energy Technology Data Exchange (ETDEWEB)

    Strobel, M.C.; Seperack, P.K.; Copeland, N.G.; Jenkins, N.A. (National Cancer Institute-Frederick Cancer Research Facility, MD (USA))

    1990-02-01

    The dilute (d) coat color locus of mouse chromosome 9 has been identified by more than 200 spontaneous and mutagen-induced recessive mutations. With the advent of molecular probes for this locus, the molecular lesion associated with different dilute alleles can be recognized and precisely defined. In this study, two dilute mutations, dilute-lethal20J (dl20J) and dilute prenatal lethal Aa2, have been examined. Using a dilute locus genomic probe in Southern blot analysis, we detected unique restriction fragments in dl20J and Aa2 DNA. Subsequent analysis of these fragments showed that they represented deletion breakpoint fusion fragments. DNA sequence analysis of each mutation-associated deletion breakpoint fusion fragment suggests that both genomic deletions were generated by nonhomologous recombination events. The spontaneous dl20J mutation is caused by an interstitial deletion that removes a single coding exon of the dilute gene. The correlation between this discrete deletion and the expression of all dilute-associated phenotypes in dl20J homozygotes defines the dl20J mutation as a functional null allele of the dilute gene. The radiation-induced Aa2 allele is a multilocus deletion that, by complementation analysis, affects both the dilute locus and the proximal prenatal lethal-3 (pl-3) functional unit. Molecular analysis of the Aa2 deletion breakpoint fusion fragment has provided access to a previously undefined gene proximal to d. Initial characterization of this new gene suggests that it may represent the genetically defined pl-3 functional unit.

  11. Qualitative analysis of mouse specific-locus mutations: information on genetic organization, gene expression, and the chromosomal nature of induced lesions

    Energy Technology Data Exchange (ETDEWEB)

    Russell, L.B.

    1982-01-01

    Analysis of mouse specific-locus (SL) mutations at three loci has identified over 33 distinct complementation groups - most of which are probably overlapping deficiencies - and 13 to 14 new functional units. The complementation maps that have been generated for the d-se and c regions include numerous vital functions; however, some of the genes in these regions are non-vital. At such loci, hypomorphic mutants must represent intragenic alterations, and some viable nulls could conceivably be intragenic lesions also. Analysis of SL mutations has provided information on genetic expression. Homozygous deficiencies can be completely viable or can kill at any one of a range of developmental stages. Heterozygonus deficiencies of up to 6 cM or more in genetic length have been recovered and propagated. The time of death of homozygous and the degree of inviability of heterozygous deficiencies are related more to specific content of the missing segment than to its length. Combinations of deficiencies with x-autosome translocations that inactivate the homologous region in a mosaic fashion have shown that organismic lethals are not necessarily cell lethal. The spectrum of mutations induced depends on the nature of the mutagen and the type of germ cell exposed. Radiation of spermatogonia produces intragenic as well as null mutations. Spontaneous mutations have an admixture of types not present in populations of mutations induced in germ cells, and this raises doubts concerning the accuracy of doubling-dose calculations in genetic risk estimation. The analysis of SL mutations has yielded genetic tools for the construction of detailed gene-dosage series, cis-trans comparisons, the mapping of known genes and identification of new genes, genetic rescue of various types, and the identification and isolation of DNA sequences. (ERB)

  12. Thermodynamic analysis of cavity creating mutations in an engineered leucine zipper and energetics of glycerol-induced coiled coil stabilization.

    Science.gov (United States)

    Dürr, E; Jelesarov, I

    2000-04-18

    Protein stability in vitro can be influenced either by introduction of mutations or by changes in the chemical composition of the solvent. Recently, we have characterized the thermodynamic stability and the rate of folding of the engineered dimeric leucine zipper A(2), which has a strengthened hydrophobic core [Dürr, E., Jelesarov, I., and Bosshard, H. R. (1999) Biochemistry 38, 870-880]. Here we report on the energetic consequences of a cavity introduced by Leu/Ala substitution at the tightly packed dimeric interface and how addition of 30% glycerol affects the folding thermodynamics of A(2) and the cavity mutants. Folding could be described by a two-state transition from two unfolded monomers to a coiled coil dimer. Removal of six methylene groups by Leu/Ala substitutions destabilized the dimeric coiled coil by 25 kJ mol(-1) at pH 3.5 and 25 degrees C in aqueous buffer. Destabilization was purely entropic at around room temperature and became increasingly enthalpic at elevated temperatures. Mutations were accompanied by a decrease of the unfolding heat capacity by 0.5 kJ K(-1) mol(-1). Addition of 30% glycerol increased the free energy of folding of A(2) and the cavity mutants by 5-10 kJ mol(-1) and lowered the unfolding heat capacity by 25% for A(2) and by 50% for the Leu/Ala mutants. The origin of the stabilizing effect of glycerol varied with temperature. Stabilization of the parent leucine zipper A(2) was enthalpic with an unfavorable entropic component between 0 and 100 degrees C. In the case of cavity mutants, glycerol induced enthalpic stabilization below 50 degrees C and entropic stabilization above 50 degrees C. The effect of glycerol could not be accounted for solely by the enthalpy and entropy of transfer or protein surface from water to glycerol/water mixture. We propose that in the presence of glycerol the folded coiled coil dimer is better packed and displays less intramolecular fluctuations, leading to enhanced enthalpic interactions and to an

  13. Growth characteristics and Ha-ras mutations of cell cultures isolated from chemically induced mouse liver tumours.

    Science.gov (United States)

    Pedrick, M S; Rumsby, P C; Wright, V; Phillimore, H E; Butler, W H; Evans, J G

    1994-09-01

    Cells have been isolated from liver tumours that have arisen in control C3H/He mice, in mice given 10 micrograms diethylnitrosamine (DEN) during the neonatal period or in mice given a diet containing phenobarbitone (PB) to allow a daily intake of 85 mg/kg/day. The cells were grown to the 8 degrees subculture when their growth characteristics were investigated in monolayer culture and following suspension in soft agar and on transplantation into nude mice. In addition, DNA was isolated from the cultures and from tumours that grew in nude mice and analysed for mutations at codon 61 of the Ha-ras oncogene. All cells derived from DEN-induced hepatocellular carcinomas (HCC) demonstrated a lack of density inhibition of growth in monolayer culture, grew in soft agar and formed tumours in nude mice with an average mean latency of 29 days. Three of the seven lines showed mutations in Ha-ras: two were CAA-->AAA transversions and one showed a CAA-->CTA transversion. In contrast, cells isolated from eosinophilic nodules in mice given PB showed inhibition of growth at confluence, did not grow in soft agar and only four of eight formed tumours in nude mice with a mean average latent period of 181 days. Cells grown from HCC in mice given PB showed a lack of density inhibition of growth, however, they did not grow in soft agar nor did they form tumours in nude mice. A single spontaneous HCC from a control mouse showed a similar growth pattern to HCC cells isolated from mice given PB. Cells from a basophilic nodule, taken from a control untreated mouse grew vigorously in culture and in soft agar and formed tumours in nude mice with a latency of 6 days. None of the cells isolated from control mice or from mice given PB showed evidence of mutations at codon 61 of Ha-ras. These data confirm that there are fundamental differences in the biology of cells grown from tumours that develop in mice under different treatment regimes. These studies also demonstrate the utility of cell culture

  14. Hypokalemia-induced long QT syndrome with an underlying novel missense mutation in S4-S5 linker of KCNQ1.

    Science.gov (United States)

    Kubota, T; Shimizu, W; Kamakura, S; Horie, M

    2000-09-01

    Congenital long QT syndrome (LQTS) is caused by mutations in at least five genes coding for cardiac potassium or sodium channels that regulate the duration of ventricular action potentials. Acquired LQTS often is associated with drugs or metabolic abnormalities. A 47-year-old woman who presented with marked QT prolongation (QTc = 620 msec(1/2)) and repeated episodes of torsades de pointes associated with hypokalemia (2.6 mEq/L) was screened for mutations in LQTS genes using polymerase chain reaction/single-strand conformation polymorphism (PCR/SSCP). We identified a novel missense mutation in the intracellular linker of S4-S5 domains of KCNQ1, resulting in an amino acid substitution of cysteine for arginine at position 259 (R259C). Whole cell, patch clamp experiments were conducted on COS7 cells transfected with wild-type and/or R259C KCNQ1 with or without KCNE1. Functional analyses of the mutant KCNQ1 subunit on COS7 cells revealed its functional channels in the homozygous state, producing a significantly smaller current than the KCNQ1 channels and a less severe dominant-negative effect on I(Ks). The novel KCNQ1 mutation R259C is the molecular basis for I(Ks) dysfunction underlying an apparently sporadic case of hypokalemia-induced LQTS, consistent with a mild mutation likely to disclose the clinical manifestation of LQTS in a context of severe hypokalemia. Our findings suggest that gene carriers with such mild mutations might not be so rare as commonly expected in patients with acquired LQTS, and stress the importance of mutational analysis for detecting either "silent" forms of congenital LQTS or de novo mutations.

  15. Expression of human AID in yeast induces mutations in context similar to the context of somatic hypermutation at G-C pairs in immunoglobulin genes

    Directory of Open Access Journals (Sweden)

    Kunkel Thomas A

    2005-06-01

    Full Text Available Abstract Background Antibody genes are diversified by somatic hypermutation (SHM, gene conversion and class-switch recombination. All three processes are initiated by the activation-induced deaminase (AID. According to a DNA deamination model of SHM, AID converts cytosine to uracil in DNA sequences. The initial deamination of cytosine leads to mutation and recombination in pathways involving replication, DNA mismatch repair and possibly base excision repair. The DNA sequence context of mutation hotspots at G-C pairs during SHM is DGYW/WRCH (G-C is a hotspot position, R = A/G, Y = T/C, W = A/T, D = A/G/T. Results To investigate the mechanisms of AID-induced mutagenesis in a model system, we studied the genetic consequences of AID expression in yeast. We constructed a yeast vector with an artificially synthesized human AID gene insert using codons common to highly expressed yeast genes. We found that expression of the artificial hAIDSc gene was moderately mutagenic in a wild-type strain and highly mutagenic in an ung1 uracil-DNA glycosylase-deficient strain. A majority of mutations were at G-C pairs. In the ung1 strain, C-G to T-A transitions were found almost exclusively, while a mixture of transitions with 12% transversions was characteristic in the wild-type strain. In the ung1 strain mutations that could have originated from deamination of the transcribed stand were found more frequently. In the wild-type strain, the strand bias was reversed. DGYW/WRCH motifs were preferential sites of mutations. Conclusion The results are consistent with the hypothesis that AID-mediated deamination of DNA is a major cause of mutations at G-C base pairs in immunoglobulin genes during SHM. The sequence contexts of mutations in yeast induced by AID and those of somatic mutations at G-C pairs in immunoglobulin genes are significantly similar. This indicates that the intrinsic substrate specificity of AID itself is a primary determinant of mutational hotspots at G

  16. Translesion DNA polymerases Pol , Pol , Pol , Pol and Rev1 are not essential for repeat-induced point mutation in Neurospora crassa

    Indian Academy of Sciences (India)

    Ranjan Tamuli; C Ravindran; Durgadas P Kasbekar

    2006-12-01

    Pol , Pol , Pol , Pol and Rev1 are specialized DNA polymerases that are able to synthesize DNA across a damaged template. DNA synthesis by such translesion polymerases can be mutagenic due to the miscoding nature of most damaged nucleotides. In fact, many mutational and hypermutational processes in systems ranging from yeast to mammals have been traced to the activity of such polymerases. We show however, that the translesion polymerases are dispensable for repeat-induced point mutation (RIP) in Neurospora crassa. Additionally, we demonstrate that the upr-1 gene, which encodes the catalytic subunit of Pol , is a highly polymorphic locus in Neurospora.

  17. Generation of a human induced pluripotent stem cell line via CRISPR-Cas9 mediated integration of a site-specific homozygous mutation in CHMP2B

    Directory of Open Access Journals (Sweden)

    Yu Zhang

    2016-07-01

    Full Text Available Frontotemporal dementia (FTD is an early onset neurodegenerative disease. Mutations in several genes cause familial FTD and one of them is charged multivesicular body protein 2B (CHMP2B on chromosome 3 (FTD3, a component of the endosomal sorting complex required for transport III (ESCRT-III. We have generated an induced pluripotent stem cell (iPSC line of a healthy individual and inserted the CHMP2B IVS5AS G-C gene mutation into both alleles, resulting in aberrant splicing. This human iPSC line provides an ideal model to study CHMP2B-dependent phenotypes of FTD3.

  18. Bystander effect-induced mutagenicity in HPRT locus of CHO cells following BNCT neutron irradiation: Characteristics of point mutations by sequence analysis

    Energy Technology Data Exchange (ETDEWEB)

    Kinashi, Yuko [Research Reactor Institute, Kyoto University, Kumatori-cho, Sennan-gun, Osaka (Japan)], E-mail: kinashi@rri.kyoto-u.ac.jp; Suzuki, Minoru; Masunaga, Shinichiro; Ono, Koji [Research Reactor Institute, Kyoto University, Kumatori-cho, Sennan-gun, Osaka (Japan)

    2009-07-15

    To investigate bystander mutagenic effects induced by alpha particles during boron neutron capture therapy (BNCT), we mixed cells that were electroporated with borocaptate sodium (BSH), which led to the accumulation of {sup 10}B inside the cells, with cells that did not contain the boron compound. BSH-containing cells were irradiated with {alpha} particles produced by the {sup 10}B(n,{alpha}){sup 7}Li reaction, whereas cells without boron were only affected by the {sup 1}H(n,{gamma}){sup 2}H and {sup 14}N(n,{rho}){sup 14}C reactions. The frequency of mutations induced in the hypoxanthine-guanine phosphoribosyltransferase (HPRT) locus was examined in Chinese hamster ovary (CHO) cells irradiated with neutrons (Kyoto University Research Reactor: 5 MW). Neutron irradiation of 1:1 mixtures of cells with and without BSH resulted in a survival fraction of 0.1, and the cells that did not contain BSH made up 99.4% of the surviving cell population. Using multiplex polymerase chain reactions (PCRs), molecular structural analysis indicated that most of the mutations induced by the bystander effect were point mutations and that the frequencies of total and partial deletions induced by the bystander effect were lower than those resulting from the {alpha} particles produced by the {sup 10}B(n,{alpha}){sup 7}Li reaction or the neutron beam from the {sup 1}H(n,{gamma}){sup 2}H and {sup 14}N(n,{rho}){sup 14}C reactions. The types of point mutations induced by the BNCT bystander effect were analyzed by cloning and sequencing methods. These mutations were comprised of 65.5% base substitutions, 27.5% deletions, and 7.0% insertions. Sequence analysis of base substitutions showed that transversions and transitions occurred in 64.7% and 35.3% of cases, respectively. G:C{yields}T:A transversion induced by 8-oxo-guanine in DNA occurred in 5.9% of base substitution mutants in the BNCT bystander group. The characteristic mutations seen in this group, induced by BNCT {alpha} particles

  19. Paroxysmal exercise-induced dyskinesia, writer's cramp, migraine with aura and absence epilepsy in twin brothers with a novel SLC2A1 missense mutation.

    Science.gov (United States)

    Urbizu, Aintzane; Cuenca-León, Ester; Raspall-Chaure, Miquel; Gratacòs, Margarida; Conill, Joan; Redecillas, Susana; Roig-Quilis, Manuel; Macaya, Alfons

    2010-08-15

    We report two monochorionic twins that progressively developed, between ages 5 and 10, a combination of episodic neurological disorders including paroxysmal exercise-induced dyskinesia, migraine without or with aura, absence seizures and writer's cramp. CSF/serum glucose ratio was moderately decreased in both patients. Mutational analysis of SLC2A1 gene identified a de novo heterozygous missense mutation in exon 4. This novel mutation has been previously showed to disrupt glucose transport in vitro. Both patients showed immediate and near-complete response to ketogenic diet. This clinical observation suggests that a high index of suspicion for GLUT1 deficiency syndrome is warranted in evaluating patients with multiple neurological paroxysmal events.

  20. Epistatic participation of REV1 and REV3 in the formation of UV-induced frameshift mutations in cell cycle-arrested yeast cells

    Energy Technology Data Exchange (ETDEWEB)

    Heidenreich, Erich [Institute of Cancer Research, Department of Medicine I, Medical University of Vienna, Borschkegasse 8a, A-1090 Vienna (Austria)]. E-mail: erich.heidenreich@meduniwien.ac.at; Eisler, Herfried [Institute of Cancer Research, Department of Medicine I, Medical University of Vienna, Borschkegasse 8a, A-1090 Vienna (Austria); Steinboeck, Ferdinand [Institute of Cancer Research, Department of Medicine I, Medical University of Vienna, Borschkegasse 8a, A-1090 Vienna (Austria)

    2006-01-29

    Mutations arising in times of cell cycle arrest may provide a selective advantage for unicellular organisms adapting to environmental changes. For multicellular organisms, however, they may pose a serious threat, in that such mutations in somatic cells contribute to carcinogenesis and ageing. The budding yeast Saccharomyces cerevisiae presents a convenient model system for studying the incidence and the mechanisms of stationary-phase mutation in a eukaryotic organism. Having studied the emergence of frameshift mutants after several days of starvation-induced cell cycle arrest, we previously reported that all (potentially error-prone) translesion synthesis (TLS) enzymes identified in S. cerevisiae did not contribute to the basal level of spontaneous stationary-phase mutations. However, we observed that an increased frequency of stationary-phase frameshift mutations, brought about by a defective nucleotide excision repair (NER) pathway or by UV irradiation, was dependent on Rev3p, the catalytic subunit of the TLS polymerase zeta (Pol {zeta}). Employing the same two conditions, we now examined the effect of deletions of the genes coding for polymerase eta (Pol {eta}) (RAD30) and Rev1p (REV1). In a NER-deficient strain background, the increased incidence of stationary-phase mutations was only moderately influenced by a lack of Pol {eta} but completely reduced to wild type level by a knockout of the REV1 gene. UV-induced stationary-phase mutations were abundant in wild type and rad30{delta} strains, but substantially reduced in a rev1{delta} as well as a rev3{delta} strain. The similarity of the rev1{delta} and the rev3{delta} phenotype and an epistatic relationship evident from experiments with a double-deficient strain suggests a participation of Rev1p and Rev3p in the same mutagenic pathway. Based on these results, we propose that the response of cell cycle-arrested cells to an excess of exo- or endogenously induced DNA damage includes a novel replication

  1. Breeding of high biomass and lipid producing Desmodesmus sp. by Ethylmethane sulfonate-induced mutation.

    Science.gov (United States)

    Zhang, Yi; He, Meilin; Zou, Shanmei; Fei, Cong; Yan, Yongquan; Zheng, Shiyan; Rajper, Aftab Ahmed; Wang, Changhai

    2016-05-01

    To improve the biomass yield and lipid productivity, two desert microalgae, Desmodesmus sp. S81 and G41 were induced mutagenesis by Ethylmethane sulfonate (EMS), and obtained two potential mutants, Desmodesmus sp. S5 and G3 from the mutagenic clones for their greatly promoted biomass and lipid production. The results showed that the biomass yield, lipid content and lipid productivity of the mutant strains S5 and G3 were 778.10mg·L(-1), 48.41% and 19.83mg·L(-1)·d(-1), 739.52mg·L(-1), 46.01%, and 17.92mg·L(-1)·d(-1), respectively, which presented the increment of 45.50%, 8.00% and 74.24%, 20.67%, 10.35% and 55.77% than those of S81 and G41. Comparing with the wild strains, the mutants showed reduced PUFAs and glycol lipids, elevated MUFAs and neutral lipids contents, which were appropriate for biodiesel production.

  2. Energetics of discrete selectivity bands and mutation-induced transitions in the calcium-sodium ion channels family

    CERN Document Server

    Kaufman, I; Tindjong, R; McClintock, P V E; Eisenberg, R S

    2013-01-01

    We use Brownian dynamics simulations to study the permeation properties of a generic electrostatic model of a biological ion channel as a function of the fixed charge Q_f at its selectivity filter. We reconcile the recently-discovered discrete calcium conduction bands M0 (Q_f=1e), M1 (3e), M2 (5e) with the set of sodium conduction bands L0 (0.5-0.7e), L1 (1.5-2e) thereby obtaining a completed pattern of conduction and selectivity bands v Q_f for the sodium-calcium channels family. An increase of Q_f leads to an increase of calcium selectivity: L0 (sodium selective, non-blocking channel) -> M0 (non-selective channel) -> L1 (sodium selective channel with divalent block) -> M1 (calcium selective channel exhibiting the anomalous mole fraction effect). We create a consistent identification scheme where the L1 band is identified with the eukaryotic (DEKA) sodium channel, and L0 (speculatively) with the bacterial NaChBac channel. The scheme created is able to account for the experimentally observed mutation-induced ...

  3. Mutation-induced quisqualic acid and ibotenic acid affinity at the metabotropic glutamate receptor subtype 4: ligand selectivity results from a synergy of several amino acid residues

    DEFF Research Database (Denmark)

    Hermit, Mette B; Greenwood, Jeremy R; Bräuner-Osborne, Hans

    2004-01-01

    resides. In this study, we have identified four non-conserved amino acid residues that are essential for differentiating mGluR1 from mGluR4. Our approach has been to increase the affinity of the classic mGluR1 agonists, quisqualic acid and ibotenic acid, at mGluR4 by making various point mutations...... that mimicked mGluR1 residues. Based on ligand docking to homology models, the non-conserved residues, Lys-74, Glu-287, Ser-313, and Lys-317, were chosen for the mutational studies and all of the mutations proved capable of partially or completely restoring the affinities of the ligands. In particular......, the mutations K74Y and K317R induced dramatic triple-order-of-magnitude increases in the affinity of ibotenic acid at mGluR4, making the affinity equivalent to that of mGluR1. Furthermore, the affinity of quisqualic acid at mGluR4 was increased to the same level as mGluR1 by the two double mutations, K74Y/K317R...

  4. An Acquired HER2 T798I Gatekeeper Mutation Induces Resistance to Neratinib in a Patient with HER2 Mutant-Driven Breast Cancer.

    Science.gov (United States)

    Hanker, Ariella B; Red Brewer, Monica; Sheehan, Jonathan H; Koch, James P; Sliwoski, Gregory R; Nagy, Rebecca; Lanman, Richard; Berger, Michael F; Hyman, David M; Solit, David B; He, Jie; Miller, Vincent; Cutler, Richard E; Lalani, Alshad S; Cross, Darren; Lovly, Christine M; Meiler, Jens; Arteaga, Carlos L

    2017-03-08

    We report a HER2T798I gatekeeper mutation in a patient with HER2L869R-mutant breast cancer with acquired resistance to neratinib. Laboratory studies suggested that HER2L869R is a neratinib-sensitive, gain-of-function mutation that upon dimerization with mutant HER3E928G, also present in the breast cancer, amplifies HER2 signaling. The patient was treated with neratinib and exhibited a sustained partial response. Upon clinical progression, HER2T798I was detected in plasma tumor cell-free DNA. Structural modeling of this acquired mutation suggested that the increased bulk of isoleucine in HER2T798I reduces neratinib binding. Neratinib blocked HER2-mediated signaling and growth in cells expressing HER2L869R but not HER2L869R/T798I. In contrast, afatinib and the osimertinib metabolite AZ5104 strongly suppressed HER2L869R/T798I-induced signaling and cell growth. Acquisition of HER2T798I upon development of resistance to neratinib in a breast cancer with an initial activating HER2 mutation suggests HER2L869R is a driver mutation. HER2T798I-mediated neratinib resistance may be overcome by other irreversible HER2 inhibitors like afatinib.

  5. Non-homologous end joining dependency of {gamma}-irradiation-induced adaptive frameshift mutation formation in cell cycle-arrested yeast cells

    Energy Technology Data Exchange (ETDEWEB)

    Heidenreich, Erich [Institute of Cancer Research, Division of Molecular Genetics, Medical University of Vienna, Borschkegasse 8a, A-1090 Vienna (Austria)]. E-mail: erich.heidenreich@meduniwien.ac.at; Eisler, Herfried [Institute of Cancer Research, Division of Molecular Genetics, Medical University of Vienna, Borschkegasse 8a, A-1090 Vienna (Austria)

    2004-11-22

    There is a strong selective pressure favoring adaptive mutations which relieve proliferation-limiting adverse living conditions. Due to their importance for evolution and pathogenesis, we are interested in the mechanisms responsible for the formation of such adaptive, gain-of-fitness mutations in stationary-phase cells. During previous studies on the occurrence of spontaneous reversions of an auxotrophy-causing frameshift allele in the yeast Saccharomyces cerevisiae, we noticed that about 50% of the adaptive reversions depended on a functional non-homologous end joining (NHEJ) pathway of DNA double-strand break (DSB) repair. Here, we show that the occasional NHEJ component Pol4, which is the yeast ortholog of mammalian DNA polymerase lambda, is not required for adaptive mutagenesis. An artificially imposed excess of DSBs by {gamma}-irradiation resulted in a dramatic increase in the incidence of adaptive, cell cycle arrest-releasing frameshift reversions. By the use of DNA ligase IV-deficient strains we detected that the majority of the {gamma}-induced adaptive mutations were also dependent on a functional NHEJ pathway. This suggests that the same mutagenic NHEJ mechanism acts on spontaneously arising as well as on ionizing radiation-induced DSBs. Inaccuracy of the NHEJ repair pathway may extensively contribute to the incidence of frameshift mutations in resting (non-dividing) eukaryotic cells, and thus act as a driving force in tumor development.

  6. Retigabine, a Kv7.2/Kv7.3-Channel Opener, Attenuates Drug-Induced Seizures in Knock-In Mice Harboring Kcnq2 Mutations.

    Science.gov (United States)

    Ihara, Yukiko; Tomonoh, Yuko; Deshimaru, Masanobu; Zhang, Bo; Uchida, Taku; Ishii, Atsushi; Hirose, Shinichi

    2016-01-01

    The hetero-tetrameric voltage-gated potassium channel Kv7.2/Kv7.3, which is encoded by KCNQ2 and KCNQ3, plays an important role in limiting network excitability in the neonatal brain. Kv7.2/Kv7.3 dysfunction resulting from KCNQ2 mutations predominantly causes self-limited or benign epilepsy in neonates, but also causes early onset epileptic encephalopathy. Retigabine (RTG), a Kv7.2/ Kv7.3-channel opener, seems to be a rational antiepileptic drug for epilepsies caused by KCNQ2 mutations. We therefore evaluated the effects of RTG on seizures in two strains of knock-in mice harboring different Kcnq2 mutations, in comparison to the effects of phenobarbital (PB), which is the first-line antiepileptic drug for seizures in neonates. The subjects were heterozygous knock-in mice (Kcnq2Y284C/+ and Kcnq2A306T/+) bearing the Y284C or A306T Kcnq2 mutation, respectively, and their wild-type (WT) littermates, at 63-100 days of age. Seizures induced by intraperitoneal injection of kainic acid (KA, 12mg/kg) were recorded using a video-electroencephalography (EEG) monitoring system. Effects of RTG on KA-induced seizures of both strains of knock-in mice were assessed using seizure scores from a modified Racine's scale and compared with those of PB. The number and total duration of spike bursts on EEG and behaviors monitored by video recording were also used to evaluate the effects of RTG and PB. Both Kcnq2Y284C/+ and Kcnq2A306T/+ mice showed significantly more KA-induced seizures than WT mice. RTG significantly attenuated KA-induced seizure activities in both Kcnq2Y284C/+ and Kcnq2A306T/+ mice, and more markedly than PB. This is the first reported evidence of RTG ameliorating KA-induced seizures in knock-in mice bearing mutations of Kcnq2, with more marked effects than those observed with PB. RTG or other Kv7.2-channel openers may be considered as first-line antiepileptic treatments for epilepsies resulting from KCNQ2 mutations.

  7. Retigabine, a Kv7.2/Kv7.3-Channel Opener, Attenuates Drug-Induced Seizures in Knock-In Mice Harboring Kcnq2 Mutations.

    Directory of Open Access Journals (Sweden)

    Yukiko Ihara

    Full Text Available The hetero-tetrameric voltage-gated potassium channel Kv7.2/Kv7.3, which is encoded by KCNQ2 and KCNQ3, plays an important role in limiting network excitability in the neonatal brain. Kv7.2/Kv7.3 dysfunction resulting from KCNQ2 mutations predominantly causes self-limited or benign epilepsy in neonates, but also causes early onset epileptic encephalopathy. Retigabine (RTG, a Kv7.2/ Kv7.3-channel opener, seems to be a rational antiepileptic drug for epilepsies caused by KCNQ2 mutations. We therefore evaluated the effects of RTG on seizures in two strains of knock-in mice harboring different Kcnq2 mutations, in comparison to the effects of phenobarbital (PB, which is the first-line antiepileptic drug for seizures in neonates. The subjects were heterozygous knock-in mice (Kcnq2Y284C/+ and Kcnq2A306T/+ bearing the Y284C or A306T Kcnq2 mutation, respectively, and their wild-type (WT littermates, at 63-100 days of age. Seizures induced by intraperitoneal injection of kainic acid (KA, 12mg/kg were recorded using a video-electroencephalography (EEG monitoring system. Effects of RTG on KA-induced seizures of both strains of knock-in mice were assessed using seizure scores from a modified Racine's scale and compared with those of PB. The number and total duration of spike bursts on EEG and behaviors monitored by video recording were also used to evaluate the effects of RTG and PB. Both Kcnq2Y284C/+ and Kcnq2A306T/+ mice showed significantly more KA-induced seizures than WT mice. RTG significantly attenuated KA-induced seizure activities in both Kcnq2Y284C/+ and Kcnq2A306T/+ mice, and more markedly than PB. This is the first reported evidence of RTG ameliorating KA-induced seizures in knock-in mice bearing mutations of Kcnq2, with more marked effects than those observed with PB. RTG or other Kv7.2-channel openers may be considered as first-line antiepileptic treatments for epilepsies resulting from KCNQ2 mutations.

  8. Somatic mutation and recombination induced with reactor thermal neutrons in Drosophila melanogaster; Mutacion y recombinacion somaticas inducidas con neutrones termicos de reactor en Drosophila melanogaster

    Energy Technology Data Exchange (ETDEWEB)

    Zambrano A, F.; Guzman R, J.; Paredes G, L.; Delfin L, A. [Instituto Nacional de Investigaciones Nucleares, A.P. 18-1027, 11801 Mexico D.F. (Mexico)

    1997-07-01

    The SMART test of Drosophila melanogaster was used to quantify the effect over the somatic mutation and recombination induced by thermal and fast neutrons at the TRIGA Mark III reactor of the ININ at the power of 300 k W for times of 30, 60 and 120 minutes with total equivalent doses respectively of 20.8, 41.6 and 83.2 Sv. A linear relation between the radiation equivalent dose and the frequency of the genetic effects such as mutation and recombination was observed. The obtained results allow to conclude that SMART is a sensitive system to the induced damage by neutrons, so this can be used for studying its biological effects. (Author)

  9. Identification and glycerol-induced correction of misfolding mutations in the X-linked mental retardation gene CASK.

    Directory of Open Access Journals (Sweden)

    Leslie E W LaConte

    Full Text Available The overwhelming amount of available genomic sequence variation information demands a streamlined approach to examine known pathogenic mutations of any given protein. Here we seek to outline a strategy to easily classify pathogenic missense mutations that cause protein misfolding and are thus good candidates for chaperone-based therapeutic strategies, using previously identified mutations in the gene CASK. We applied a battery of bioinformatics algorithms designed to predict potential impact on protein structure to five pathogenic missense mutations in the protein CASK that have been shown to underlie pathologies ranging from X-linked mental retardation to autism spectrum disorder. A successful classification of the mutations as damaging was not consistently achieved despite the known pathogenicity. In addition to the bioinformatics analyses, we performed molecular modeling and phylogenetic comparisons. Finally, we developed a simple high-throughput imaging assay to measure the misfolding propensity of the CASK mutants in situ. Our data suggests that a phylogenetic analysis may be a robust method for predicting structurally damaging mutations in CASK. Mutations in two evolutionarily invariant residues (Y728C and W919R exhibited a strong propensity to misfold and form visible aggregates in the cytosolic milieu. The remaining mutations (R28L, Y268H, and P396S showed no evidence of aggregation and maintained their interactions with known CASK binding partners liprin-α3 Mint-1, and Veli, indicating an intact structure. Intriguingly, the protein aggregation caused by the Y728C and W919R mutations was reversed by treating the cells with a chemical chaperone (glycerol, providing a possible therapeutic strategy for treating structural mutations in CASK in the future.

  10. Antagonistic effects of ethyl methanesulfonate and maleic hydrazide in inducing somatic mutations in the stamen hairs of Tradescantia clone BNL 4430

    OpenAIRE

    市川, 定夫

    1998-01-01

    Mutagenic interaction between ethyl methanesulfonate (EMS; a monofunctional alkylating agent) and maleic hydrazide (MH; a promutagen activated into a mutagen in plants highly likely by peroxidase) was studied in the stamen hairs of Tradescantia clone BNL 4430, a blue/pink heterozygote. Since EMS has been shown to act synergistically with X rays in inducing mutations, and mutagenic synergisms have also been observed between X rays and MH by exposing to X rays before MH treatments, EMS and MH w...

  11. An Alzheimer Disease-linked Rare Mutation Potentiates Netrin Receptor Uncoordinated-5C-induced Signaling That Merges with Amyloid β Precursor Protein Signaling.

    Science.gov (United States)

    Hashimoto, Yuichi; Toyama, Yuka; Kusakari, Shinya; Nawa, Mikiro; Matsuoka, Masaaki

    2016-06-03

    A missense mutation (T835M) in the uncoordinated-5C (UNC5C) netrin receptor gene increases the risk of late-onset Alzheimer disease (AD) and also the vulnerability of neurons harboring the mutation to various insults. The molecular mechanisms underlying T835M-UNC5C-induced death remain to be elucidated. In this study, we show that overexpression of wild-type UNC5C causes low-grade death, which is intensified by an AD-linked mutation T835M. An AD-linked survival factor, calmodulin-like skin protein (CLSP), and a natural ligand of UNC5C, netrin1, inhibit this death. T835M-UNC5C-induced neuronal cell death is mediated by an intracellular death-signaling cascade, consisting of death-associated protein kinase 1/protein kinase D/apoptosis signal-regulating kinase 1 (ASK1)/JNK/NADPH oxidase/caspases, which merges at ASK1 with a death-signaling cascade, mediated by amyloid β precursor protein (APP). Notably, netrin1 also binds to APP and partially inhibits the death-signaling cascade, induced by APP. These results may provide new insight into the amyloid β-independent pathomechanism of AD.

  12. An Alzheimer's Disease-Relevant Presenilin-1 Mutation Augments Amyloid-Beta-Induced Oligodendrocyte Dysfunction%An Alzheimer's Disease-Relevant Presenilin-1Mutation Augments Amyloid-Beta-Induced Oligodendrocyte Dysfunction

    Institute of Scientific and Technical Information of China (English)

    MAYA K. DESAI; BRENDAN J. GUERCIO; WADE C. NARROW; AND WILLIAM J. BOWERS

    2011-01-01

    研究表明,家族性阿尔茨海默病(FAD)患者处于无症状或临床前阶段时,脑白质即出现病理改变.此种改变在髓鞘破坏及阿尔茨海默病(AD)病理生理中的作用有待进一步研究阐明.笔者前期研究证实,三重转基因AD小鼠(人淀粉前体蛋白基因的Swedish突变,早老素-1 M146V (PS1M146V)敲入突变及tauP301L突变)表现出类似FAD患者的髓鞘破坏,Aβ1-42促进了白质病变.本研究离体实验证实,PS1M146V变异导致小鼠少突胶质前体细胞在分化过程中易出现类似Aβ1-42诱导的变化.PS1M146V的表达损伤少突胶质前体细胞的功能并影响髓鞘碱性蛋白的分布,暴露于Aβ1-42加重此影响.由PS1M146V及 Aβ1-42导致的髓鞘破坏及髓鞘碱性蛋白在亚细胞结构中的误定位可被TWS119(糖原合成激酶(GSK)-3β抑制剂)抑制,提示GSK-3β激酶活动在此病理过程中有重要作用.综上所述,本研究有助于增加对AD早期无症状阶段,由PS1M146V及 Aβ1-42导致少突胶质细胞功能异常及髓鞘损伤的机制的理解,并提供了针对少突胶质细胞预防AD相关白质病变的新的治疗靶点.%White matter pathology has been documented in the brains of familial Alzheimer's disease (FAD)-afflicted individuals during presymptomatic and preclinical stages of AD. How these defects in myelination integrity arise and what roles they may play in AD pathophysiology have yet to be fully elucidated. We previously demonstrated that triple-transgenic AD (3xTg-AD) mice, which harbor the human amyloid precursor Swedish mutation, presenilin-1 M146V (PS1M146V) knock-in mutation, and tauP301L mutation, exhibit myelin abnormalities analogous to FAD patients and that Aβ1-42 contributes to these white matter deficits. Herein, we demonstrate that the PS1M146V mutation predisposes mouse oligodendrocyte precursor (mOP) cells to Aβ1 42-induced alterations in cell differentiation in vitro. Furthermore, PS1M146V expression compromised m

  13. DNA damage-processing in E. coli: on-going protein synthesis is required for fixation of UV-induced lethality and mutation.

    Science.gov (United States)

    Burger, Amanda; Raymer, Jenny; Bockrath, R

    2002-10-01

    UV irradiation of E. coli produces photoproducts in the DNA genome. In consequence, some bacteria lose viability (colony-forming ability) or remain viable as mutant cells. However, the end-points of viability inactivation (lethality) or mutation are determined by cellular processes that act on the UV-damaged DNA. We have investigated the in vivo time course for processes that deal with cyclobutane pyrimidine dimers (CPD) which can be specifically removed by photoreactivation (PR). At different times during post-UV incubation, samples were challenged with PR and assayed for viability or mutation. We used excision-defective E. coli B/r cells and worked under yellow light to avoid background PR. During post-UV incubation (0-100min) in fully supplemented defined medium, inactivation and mutation were initially significantly reversed by PR but the extent of this reversal decreased during continued incubation defining "fixation" of lethality or mutation, respectively. In contrast, if protein synthesis was restricted during the post-UV incubation, no fixation developed. When chloramphenicol was added to inhibit protein synthesis after 30min of supplemented post-UV incubation, at a time sufficient for expression of UV-induced protein(s), fixation of lethality or mutation was still annulled (no change in the effectiveness of PR developed). Lethality fixation did progress when protein synthesis was restricted and the cells were incubated in the presence of puromycin or were either clpP or clpX defective. We discuss these and related results to suggest (1) on-going protein synthesis is required in the fixation process for lethality and mutation to sustain an effective level of a hypothetical protein sensitive to ClpXP proteolysis and (2) this protein plays a critical role in the process leading to exchange between Pol III activity and alternative polymerase activities required as each cell deals with damage in template DNA.

  14. Expression of R132H mutational IDH1 in human U87 glioblastoma cells affects the SREBP1a pathway and induces cellular proliferation.

    Science.gov (United States)

    Zhu, Jian; Cui, Gang; Chen, Ming; Xu, Qinian; Wang, Xiuyun; Zhou, Dai; Lv, Shengxiang; Fu, Linshan; Wang, Zhong; Zuo, Jianling

    2013-05-01

    Sterol regulatory element-binding protein-1a (SREBP1a) is a member of the SREBP family of transcription factors, which mainly controls homeostasis of lipids. SREBP1a can also activate the transcription of isocitrate dehydrogenase 1 (IDH1) by binding to its promoter region. IDH1 mutations, especially R132H mutation of IDH1, are a common feature of a major subset of human gliomas. There are few data available on the relationship between mutational IDH1 expression and SREBP1a pathway. In this study, we investigated cellular effects and SREBP1a pathway alterations caused by R132H mutational IDH1 expression in U87 cells. Two glioma cell lines, stably expressing mutational (U87/R132H) or wild type (U87/wt) IDH1, were established. A cell line, stably transfected with pcDNA3.1(+) (U87/vector), was generated as a control. Click-iT EdU assay, sulforhodamine B assay, and wound healing assay respectively showed that the expression of R132H induced cellular proliferation, cell growth, and cell migration. Western blot revealed that SREBP1 was increased in U87/R132H compared with that in U87/wt. Elevated SREBP1a and several its target genes, but not SREBP1c, were detected by real-time polymerase chain reaction in U87/R132H. All these findings indicated that R132H mutational IDH1 is involved in the regulation of proliferation, growth, and migration of glioma cells. These effects may partially be mediated by SREBP1a pathway.

  15. Kv3.3 channels harbouring a mutation of spinocerebellar ataxia type 13 alter excitability and induce cell death in cultured cerebellar Purkinje cells.

    Science.gov (United States)

    Irie, Tomohiko; Matsuzaki, Yasunori; Sekino, Yuko; Hirai, Hirokazu

    2014-01-01

    The cerebellum plays crucial roles in controlling sensorimotor functions. The neural output from the cerebellar cortex is transmitted solely by Purkinje cells (PCs), whose impairment causes cerebellar ataxia. Spinocerebellar ataxia type 13 (SCA13) is an autosomal dominant disease, and SCA13 patients exhibit cerebellar atrophy and cerebellar symptoms. Recent studies have shown that missense mutations in the voltage-gated K(+) channel Kv3.3 are responsible for SCA13. In the rodent brain, Kv3.3 mRNAs are expressed most strongly in PCs, suggesting that the mutations severely affect PCs in SCA13 patients. Nevertheless, how these mutations affect the function of Kv3.3 in PCs and, consequently, the morphology and neuronal excitability of PCs remains unclear. To address these questions, we used lentiviral vectors to express mutant mouse Kv3.3 (mKv3.3) channels harbouring an R424H missense mutation, which corresponds to the R423H mutation in the Kv3.3 channels of SCA13 patients, in mouse cerebellar cultures. The R424H mutant-expressing PCs showed decreased outward current density, broadened action potentials and elevated basal [Ca(2+)]i compared with PCs expressing wild-type mKv3.3 subunits or those expressing green fluorescent protein alone. Moreover, expression of R424H mutant subunits induced impaired dendrite development and cell death selectively in PCs, both of which were rescued by blocking P/Q-type Ca(2+) channels in the culture conditions. We therefore concluded that expression of R424H mutant subunits in PCs markedly affects the function of endogenous Kv3 channels, neuronal excitability and, eventually, basal [Ca(2+)]i, leading to cell death. These results suggest that PCs in SCA13 patients also exhibit similar defects in PC excitability and induced cell death, which may explain the pathology of SCA13.

  16. 紫外线致DNA突变的快速测定研究%A Fast Determination of DNA Mutation Induced by Ultraviolet Radiation

    Institute of Scientific and Technical Information of China (English)

    陆峰; 刘荔荔; 张晓芳; 吴玉田

    2001-01-01

    Electrophoresis, chromatography, immunoassay, sequencing and other time consuming approaches have been developed to determine DNA base mismatching, oxidative lesion or strand breaks. Sometimes,however, only qualitative information is enough to decide whether mutation has happened to DNA and its extent.Convolution spectrometry (CS), a new technique to discover ultrafine difference on ultraviolet (UV) absorption of different substances, is originally employed to find out any subtle mutation of DNA induced by UV radiation. Mutative DNA is compared with ego criteria based on the spectra of the former DNA, any difference is quantitatively expressed by dispersion (δ). Visible changes cannot be observed on second -derivative spectra until the mutation gets δup to 11.48%. Dimethyl sulfoxide is an intensifier of UV 254 nm induced DNA mutation and protector at 365 nm,which is simply confirmed by increasing and decreasing δ. Every convolution procedure takes less than 1 min. Convolution spectrometry provides a fast, simple, sensitive and inexpensive alternative to determine DNA mutation, and to screen anti-mutational medicines.%毛细管电泳、变性色谱、免疫吸附、DNA测序方法等已广泛用于DNA碱基错配、氧化缺失、链断裂等变化的检测,但有时如进行药物筛选时,只需定性地检测DNA是否变化或变化程度.本文采用褶合光谱法定性地检测紫外线致DNA变化程度,将突变后DNA的褶合光谱与未变异前DNA自身标准比较,并以差谱值δ量化地表示突变程度.当褶合光谱δ高达11.48%时,才能从二阶导数光谱上发现差异,表明方法的灵敏度远远高于前者.加入DMSO后,溶液在254nm照射时,δ升高,表现为DNA变异诱导剂;溶液在365 nm照射时,δ降低,表现为DNA变异保护剂.褶合光谱法快速、简便、灵敏、经济,可以作为检测DNA突变、筛选抗突变药物的一种新型方法.

  17. Efforts to accelerate domestication of winged bean (Psophocarpus tetragonolobus (L.) DC.) by means of induced mutations and tissue culture.

    NARCIS (Netherlands)

    Klu, G.Y.P.

    1996-01-01

    This thesis describes mutation breeding and tissue culture techniques developed for accelerated domestication of winged bean ( Psophocarpustetragonolobus (L.) DC.). The tissue culture techniques, which are the first steps towards genetic transformation of the crop, include: (1) direct adventitious s

  18. Transfection with extracellularly UV-damaged DNA induces human and rat cells to express a mutator phenotype towards parvovirus H-1

    Energy Technology Data Exchange (ETDEWEB)

    Dinsart, C.; Cornelis, J.J.; Klein, B.; van der Eb, A.J.; Rommelaere, J.

    1984-02-01

    Human and rat cells transfected with UV-irradiated linear double-stranded DNA from calf thymus displayed a mutator activity. This phenotype was identified by growing a lytic thermosensitive single-stranded DNA virus (parvovirus H-1) in those cells and determining viral reversion frequencies. Likewise, exogenous UV-irradiated closed circular DNAs, either double-stranded (simian virus 40) or single-stranded (phi X174), enhanced the ability of recipient cells to mutate parvovirus H-1. The magnitude of mutator activity expression increased along with the number of UV lesions present in the inoculated DNA up to a saturation level. Unirradiated DNA displayed little inducing capacity, irrespective of whether it was single or double stranded. Deprivation of a functional replication origin did not impede UV-irradiated simian virus 40 DNA from providing rat and human cells with a mutator function. Our data suggest that in mammalian cells a trans-acting mutagenic signal might be generated from UV-irradiated DNA without the necessity for damaged DNA to replicate.

  19. Sequence analysis of lacZ~- mutations induced by ion beam irradiation in double-stranded M13mp18DNA

    Institute of Scientific and Technical Information of China (English)

    杨剑波; 吴李君; 李莉; 吴家道; 余增亮; 许智宏

    1997-01-01

    While M13mpl8 double-stranded DNA was irradiated with ion beam, and transfected into E. coli JM103, a decrease of transfecting activity was discovered. The lacZ-mutation frequency at 20% survival could reach (3.6-16.8) × 104, about 2.3-10 times that of unirradiated M13DNA. Altogether, 27 lacZ~ mutants were select-ed, 10 of which were used for sequencing. 7 of the sequenced mutants show base changes in 250-bp region examined (the remaining 3 mutants probably have base changes outside the regions sequenced). 5 of the base-changed mutants contain more than one mutational base sites (some of them even have 5-6 mutational base sites in 250-bp region ex-amined) ; this dense distribution of base changes in polysites has seldom been seen in X-rays, γ-rays or UV induced DNA mutations. Our experiments also showed that the types of base changes include transitions( 50 % ), transversions (45% ) and deletion (5% ); no addition or duplication was observed. The transitions were mainly C→T and A→G; the transversion

  20. Fast capillary electrophoresis-laser induced fluorescence analysis of ligase chain reaction products: human mitochondrial DNA point mutations causing Leber's hereditary optic neuropathy.

    Science.gov (United States)

    Muth, J; Williams, P M; Williams, S J; Brown, M D; Wallace, D C; Karger, B L

    1996-12-01

    High speed capillary electrophoresis-laser-induced fluorescence (CE-LIF) has been used to separate and detect point mutations using the ligase chain reaction (LCR). The method utilizes short capillary columns (7.5 cm effective length) and fields of 400 V/cm to analyze DNA-ethidium bromide complexes using an He/Ne laser. The method was first demonstrated with a commercially available kit for LCR based on a lacI gene fragment inserted in a Bluescript II phagemid. LCR-CE-LIF was then applied to detect point mutations in human mitochondrial DNA, resulting in Leber's hereditary optic neuropathy (LHON). Three severe mutations were analyzed in which the original base is substituted by a thymidine base at positions 3460, 11778 and 14459. Appropriate primers were designed with polyT tails for length discrimination of pooled samples. Successful detection of mutated samples was achieved, with appropriate correction for small amounts of nonspecific ligated product. The method is rapid, easy to implement, and automatable.

  1. Features of a Chinese family with cerebral cavernous malformation induced by a novel CCM1 gene mutation

    Institute of Scientific and Technical Information of China (English)

    WANG Xue; LIU Xue-wu; Nora Lee; LIU Qi-ji; LI Wen-na; HAN Tao; WEI Kun-kun

    2013-01-01

    Background Familial cerebral cavernous malformations (CCMs),characterized by hemorrhagic stroke,recurrent headache and epilepsy,are congenital vascular anomalies of the central nervous system.Familial CCMs is an autosomal dominant inherited disorder and three CCM genes have been identified.We report a Chinese family with CCMs and intend to explore clinical,pathological,magnetic resonance imaging (MRI) features and pathogenic gene mutation of this family.Methods Totally 25 family members underwent brain MRI examination and clinical check.Two patients with surgical indications had surgical treatment and the specimens were subjected to histopathological and microstructural examination.In addition,polymerase chain reaction (PCR) and direct sequencing were performed with genomic DNA extracted from 25 family members' blood samples for mutation detection.Results Brain MRI identified abnormal results in seven family members.All of them had multiple intracranial lesions and four cases had skin cavernous hemangioma.T2-weighted sequence showed that the lesions were typically characterized by an area of mixed signal intensity.Gradient-echo (GRE) sequence was more sensitive to find microcavernous hemangiomas.There was a wide range in the clinical manifestations as well as the age of onset in the family.The youngest patient was an 8-year-old boy with least intracranial lesions.Histopathological and microstructural examination showed that CCMs were typically discrete multi-sublobes of berry-like lesions,with hemorrhage in various stages of illness evolution.They were formed by abnormally enlarged sinusoids and the thin basement membranes.A novel T deletion mutation in exon 14 of CCM1 gene was identified by mutation detection in the seven patients.But unaffected members and healthy controls did not carry this mutation.Conclusions The clinical manifestations were heterogenic within this family.We identified a novel mutation (c.1396delT) was the disease-causing mutation for this

  2. Nitric oxide as a carcinogen. Analysis by yeast functional assay of inactivating p53 mutations induced by nitric oxide

    Energy Technology Data Exchange (ETDEWEB)

    Murata, Jun-Ichi; Tada, Mitsuhiro; Sawamura, Yutaka; Shinohe, Yumiko; Abe, Hiroshi [Laboratory for Molecular Brain Research, Department of Neurosurgery, Hokkaido University School of Medicine, Sapporo (Japan); Iggo, Richard D. [Oncogene group, Swiss Institute for Experimental Cancer Research ISREC, Epalinges (Switzerland)

    1997-10-06

    We have used a yeast p53 functional assay to study induction of mutations in the p53 tumor suppressor gene by nitric oxide and cytosine methylation. The yeast assay identifies only biologically important p53 mutations. p53 cDNA was treated with the nitric oxide donor sydnonimine, PCR-amplified and transfected into yeast. Sydnonimine produced a significant, dose-dependent increase in C:G->A:T transversions. Many important p53 mutational hotspots are postulated to arise by deamination of methylCpG in tumors. We therefore examined nitric oxide induction of mutations in p53 cDNA methylated by PCR-mediated substitution of 5-methylcytosine for cytosine or by treatment with the SssI CpG methylase. Both methylation procedures increased the baseline mutation rate, and nitric oxide treatment produced a further increase in mutation yield. Sequence analysis showed that methylation alone led to C:G->T:A transitions, whereas nitric oxide treatment simply produced more C:G->A:T transversions. Thus the most important factor in C:G->T:A transition at CpG sites identified in this experimental system is cytosine methylation, consistent with spontaneous conversion of 5-methylcytosine to thymine by deamination

  3. Zinc finger nucleases for targeted mutagenesis and repair of the sickle-cell disease mutation: An in-silico study

    Directory of Open Access Journals (Sweden)

    Wayengera Misaki

    2012-05-01

    Full Text Available Abstract Background Sickle cell disease (or simply, SCD is an inherited hemoglobinopathy which is mostly prevalent among persons of African descent. SCD results from a monogenic (Hemoglobin, beta point-mutation (substitution of the base Adenine with Thymine at position six that leads to replacement of the amino acid glutamic acid (E with valine (V. Management of SCD within resource-poor settings is largely syndromic, since the option of cure offered by bone-marrow transplantation (BMT is risky and unaffordable by most affected individuals. Despite previous reports of repair and inhibition of the sickle beta-globin gene and messenger ribonucleic acids (mRNAs, respectively in erythrocyte precursor cells via gene-targeting using an oligomer-restriction enzyme construct and either ribozyme- or RNA-DNA chimeric oligonucleotides (or simply third strand binding, gene-therapy to treat SCD still remains largely preclinical. In the wake of the advances in target- gene- mutagenesis and repair wrought by zinc finger nuclease (ZFN technology, it was hypothesized that SCD may be cured by the same. The goal of this study thus, was constructing a database of zinc finger arrays (ZFAs and engineering ZFNs, that respectively bind and cleave within or around specific sequences in the sickle hemoglobin, beta (−βS gene. Methods and results First, using the complete 1606 genomic DNA base pair (bp sequences of the normal hemoglobin-beta (βA chain gene, and the ZiFiT-CoDA-ZFA software preset at default, 57 three-finger arrays (ZFAs that specifically bind 9 base-pair sequences within the normal hemoglobin-beta chain, were computationally assembled. Second, by serial linkage of these ZFAs to the Flavobacterium okeanokoites endonuclease Fok I― four ZFNs with unique specificity to >24 bp target-sequences at the genomic contextual positions 82, 1333, 1334, and 1413 of the βA chain-gene were constructed in-silico. Third, localizing the point-mutation of SCD at

  4. Generation of induced pluripotent stem cells (iPSCs from a Bernard–Soulier syndrome patient carrying a W71R mutation in the GPIX gene

    Directory of Open Access Journals (Sweden)

    Lourdes Lopez-Onieva

    2016-05-01

    Full Text Available We generated an induced pluripotent stem cell (iPSC line from a Bernard–Soulier Syndrome (BSS patient carrying the mutation p.Trp71Arg in the GPIX locus (BSS1-PBMC-iPS4F4. Peripheral blood mononuclear cells (PBMCs were reprogrammed using heat sensitive non-integrative Sendai viruses containing the reprogramming factors Oct3/4, SOX2, KLF4 and c-MYC. Successful silencing of the exogenous reprogramming factors was checked by RT-PCR. Characterization of BSS1-PBMC-iPS4F4 included mutation analysis of GPIX locus, Short Tandem Repeats (STR profiling, alkaline phosphatase enzymatic activity, analysis of conventional pluripotency-associated factors at mRNA and protein level and in vivo differentiation studies. BSS1-PBMC-iPS4F4 will provide a powerful tool to study BSS.

  5. Generation of induced pluripotent stem cells (iPSCs from an Alzheimer's disease patient carrying an A79V mutation in PSEN1

    Directory of Open Access Journals (Sweden)

    Tong Li

    2016-03-01

    Full Text Available Skin fibroblasts were obtained from a 48-year-old presymptomatic woman carrying a A79V mutation in the presenilin 1 gene (PSEN1, causing Alzheimer's disease (AD. Induced pluripotent stem cell (iPSCs were derived via transfection with episomal vectors carrying hOCT4, hSOX2, hKLF2, hL-MYC, hLIN28 and shTP53 genes. A79V-iPSCs were free of genomically integrated reprogramming genes, had the specific mutation but no additional genomic aberrancies, expressed the expected pluripotency markers and displayed in vitro differentiation potential to the three germ layers. The reported A79V-iPSCs line may be a useful resource for in vitro modeling of familial AD.

  6. Conjugation between quinolone-susceptible bacteria can generate mutations in the quinolone resistance-determining region, inducing quinolone resistance.

    Science.gov (United States)

    Pitondo-Silva, André; Martins, Vinicius Vicente; Silva, Carolina Fávero da; Stehling, Eliana Guedes

    2015-02-01

    Quinolones are an important group of antibacterial agents that can inhibit DNA gyrase and topoisomerase IV activity. DNA gyrase is responsible for maintaining bacteria in a negatively supercoiled state, being composed of subunits A and B. Topoisomerase IV is a homologue of DNA gyrase and consists of two subunits codified by the parC and parE genes. Mutations in gyrA and gyrB of DNA gyrase may confer resistance to quinolones, and the majority of resistant strains show mutations between positions 67 and 106 of gyrA, a region denoted the quinolone resistance-determining region (QRDR). The most frequent substitutions occur at positions 83 and 87, but little is known about the mechanisms promoting appearance of mutations in the QRDR. The present study proposes that some mutations in the QRDR could be generated as a result of the natural mechanism of conjugation between bacteria in their natural habitat. This event was observed following conjugation in vitro of two different isolates of quinolone-susceptible Pseudomonas aeruginosa, which transferred plasmids of different molecular weights to a recipient strain of Escherichia coli (HB101), also quinolone-susceptible, generating two different transconjugants that presented mutations in DNA gyrase and acquisition of resistance to all quinolones tested.

  7. Acceleration of 5-methylcytosine deamination in cyclobutane dimers by G and its implications for UV-induced C-to-T mutation hotspots.

    Science.gov (United States)

    Cannistraro, Vincent J; Taylor, John-Stephen

    2009-10-01

    Sunlight-induced C-->T mutation hotspots occur most frequently at methylated CpG sites in tumor suppressor genes and are thought to arise from translesion synthesis past deaminated cyclobutane pyrimidine dimers (CPDs). While it is known that methylation enhances CPD formation in sunlight, little is known about the effect of methylation and sequence context on the deamination of 5-methylcytosine ((m)C) and its contribution to mutagenesis at these hotspots. Using an enzymatic method, we have determined the yields and deamination rates of C and (m)C in CPDs and find that the frequency of UVB-induced CPDs correlates with the oxidation potential of the flanking bases. We also found that the deamination of T(m)C and (m)CT CPDs is about 25-fold faster when flanked by G's than by A's, C's or T's in duplex DNA and appears to involve catalysis by the O6 group of guanine. In contrast, the first deamination of either C or (m)C in AC(m)CG with a flanking G was much slower (t(1/2) >250 h) and rate limiting, while the second deamination was much faster. The observation that C(m)CG dimers deaminate very slowly but at the same time correlate with C-->T mutation hotspots suggests that their repair must be slow enough to allow sufficient time for deamination. There are, however, a greater number of single C-->T mutations than CC-->TT mutations at C(m)CG sites even though the second deamination is very fast, which could reflect faster repair of doubly deaminated dimers.

  8. Suppression of edr2-mediated powdery mildew resistance, cell death and ethylene-induced senescence by mutations in ALD1 in Arabidopsis

    Institute of Scientific and Technical Information of China (English)

    Haozhen Nie; Yingying Wu; Chunpeng Yao; Dingzhong Tang

    2011-01-01

    EDR2 is a negative regulator of the defense response and cell death in Arabidopsis. Loss-of-function of EDR2 leads to enhanced resistance to powdery mildew. To identify new components in the EDR2 signal transduction pathway, mutations that suppress edr2 resistant phenotypes were screened. Three mutants, edts5-1, edts5-2 and edts5-3 (edr (t)wo (s)uppressor 5), were identified. The EDTS5 gene was identified by map-based cloning and previously was shown to encode an aminotransferase (ALD1). Therefore we renamed these three alleles ald1-10, ald1-11 and ald1-12, respectively. Mutations in ALD1 suppressed all edr2-mediated phenotypes, including powdery mildew resistance, programmed cell death and ethylene-induced senescence. Accumulation of hydrogen peroxide in edr2 was also suppressed by ald1 mutation. The expression of defense-related genes was up-regulated in the edr2 mutant, and the up-regulation of those genes in edr2 was suppressed in the edr2/ald1 double mutant. The ald1 single mutant displayed delayed ethylene-induced senescence. In addition, ald1 mutation suppressed edr1-mediated powdery mildew resistance, but could not suppress the edr1/edr2 double-mutant phenotype. These data demonstrate that ALD1 plays important roles in edr2-mediated defense responses and senescence, and revealed a crosstalk between ethylene and salicylic acid signaling mediated by ALD1 and EDR2.

  9. Nitric oxide induces ataxia telangiectasia mutated (ATM) protein-dependent γH2AX protein formation in pancreatic β cells.

    Science.gov (United States)

    Oleson, Bryndon J; Broniowska, Katarzyna A; Schreiber, Katherine H; Tarakanova, Vera L; Corbett, John A

    2014-04-18

    In this study, the effects of cytokines on the activation of the DNA double strand break repair factors histone H2AX (H2AX) and ataxia telangiectasia mutated (ATM) were examined in pancreatic β cells. We show that cytokines stimulate H2AX phosphorylation (γH2AX formation) in rat islets and insulinoma cells in a nitric oxide- and ATM-dependent manner. In contrast to the well documented role of ATM in DNA repair, ATM does not appear to participate in the repair of nitric oxide-induced DNA damage. Instead, nitric oxide-induced γH2AX formation correlates temporally with the onset of irreversible DNA damage and the induction of apoptosis. Furthermore, inhibition of ATM attenuates cytokine-induced caspase activation. These findings show that the formation of DNA double strand breaks correlates with ATM activation, irreversible DNA damage, and ATM-dependent induction of apoptosis in cytokine-treated β cells.

  10. In utero exposure to nanosized carbon black (Printex90) does not induce tandem repeat mutations in female murine germ cells

    DEFF Research Database (Denmark)

    Boisen, Anne Mette Zenner; Shipley, Thomas; Jackson, Petra

    2013-01-01

    J mice were exposed four times during gestation by intratracheal instillation of 67μg/animal of nanosized carbon black Printex90 or vehicle (gestation days 7, 10, 15 and 18). Female offspring were raised to maturity and mated with unexposed CBA males. Expanded simple tandem repeat (ESTR) germline...... mutation rates in the resulting F2 generation were determined from full pedigrees (mother, father, offspring) of F1 female mice (178 CB-exposed and 258 control F2 offspring). ESTR mutation rates in CB-exposed F2 female offspring were not statistically different from those of F2 female control offspring....

  11. Autism-associated R451C mutation in neuroligin3 leads to activation of the unfolded protein response in a PC12 Tet-On inducible system.

    Science.gov (United States)

    Ulbrich, Lisa; Favaloro, Flores Lietta; Trobiani, Laura; Marchetti, Valentina; Patel, Vruti; Pascucci, Tiziana; Comoletti, Davide; Marciniak, Stefan J; De Jaco, Antonella

    2016-02-15

    Several forms of monogenic heritable autism spectrum disorders are associated with mutations in the neuroligin genes. The autism-linked substitution R451C in neuroligin3 induces local misfolding of its extracellular domain, causing partial retention in the ER (endoplasmic reticulum) of expressing cells. We have generated a PC12 Tet-On cell model system with inducible expression of wild-type or R451C neuroligin3 to investigate whether there is activation of the UPR (unfolded protein response) as a result of misfolded protein retention. As a positive control for protein misfolding, we also expressed the mutant G221R neuroligin3, which is known to be completely retained within the ER. Our data show that overexpression of either R451C or G221R mutant proteins leads to the activation of all three signalling branches of the UPR downstream of the stress sensors ATF6 (activating transcription factor 6), IRE1 (inositol-requiring enzyme 1) and PERK [PKR (dsRNA-dependent protein kinase)-like endoplasmic reticulum kinase]. Each branch displayed different activation profiles that partially correlated with the degree of misfolding caused by each mutation. We also show that up-regulation of BiP (immunoglobulin heavy-chain-binding protein) and CHOP [C/EBP (CCAAT/enhancer-binding protein)-homologous protein] was induced by both mutant proteins but not by wild-type neuroligin3, both in proliferative cells and cells differentiated to a neuron-like phenotype. Collectively, our data show that mutant R451C neuroligin3 activates the UPR in a novel cell model system, suggesting that this cellular response may have a role in monogenic forms of autism characterized by misfolding mutations.

  12. Curcumin inhibits growth potential by G1 cell cycle arrest and induces apoptosis in p53-mutated COLO 320DM human colon adenocarcinoma cells.

    Science.gov (United States)

    Dasiram, Jade Dhananjay; Ganesan, Ramamoorthi; Kannan, Janani; Kotteeswaran, Venkatesan; Sivalingam, Nageswaran

    2017-02-01

    Curcumin, a natural polyphenolic compound and it is isolated from the rhizome of Curcuma longa, have been reported to possess anticancer effect against stage I and II colon cancer. However, the effect of curcumin on colon cancer at Dukes' type C metastatic stage III remains still unclear. In the present study, we have investigated the anticancer effects of curcumin on p53 mutated COLO 320DM human colon adenocarcinoma cells derived from Dukes' type C metastatic stage. The cellular viability and proliferation were assessed by trypan blue exclusion assay and MTT assay, respectively. The cytotoxicity effect was examined by lactate dehydrogenase (LDH) cytotoxicity assay. Apoptosis was analyzed by DNA fragmentation analysis, Hoechst and propidium iodide double fluorescent staining and confocal microscopy analysis. Cell cycle distribution was performed by flow cytometry analysis. Here we have observed that curcumin treatment significantly inhibited the cellular viability and proliferation potential of p53 mutated COLO 320DM cells in a dose- and time-dependent manner. In addition, curcumin treatment showed no cytotoxic effects to the COLO 320DM cells. DNA fragmentation analysis, Hoechst and propidium iodide double fluorescent staining and confocal microscopy analysis revealed that curcumin treatment induced apoptosis in COLO 320DM cells. Furthermore, curcumin caused cell cycle arrest at the G1 phase, decreased the cell population in the S phase and induced apoptosis in COLO 320DM colon adenocarcinoma cells. Together, these data suggest that curcumin exerts anticancer effects and induces apoptosis in p53 mutated COLO 320DM human colon adenocarcinoma cells derived from Dukes' type C metastatic stage.

  13. Visible Light-Responsive Platinum-Containing Titania Nanoparticle-Mediated Photocatalysis Induces Nucleotide Insertion, Deletion and Substitution Mutations

    Directory of Open Access Journals (Sweden)

    Der-Shan Sun

    2016-12-01

    Full Text Available Conventional photocatalysts are primarily stimulated using ultraviolet (UV light to elicit reactive oxygen species and have wide applications in environmental and energy fields, including self-cleaning surfaces and sterilization. Because UV illumination is hazardous to humans, visible light-responsive photocatalysts (VLRPs were discovered and are now applied to increase photocatalysis. However, fundamental questions regarding the ability of VLRPs to trigger DNA mutations and the mutation types it elicits remain elusive. Here, through plasmid transformation and β-galactosidase α-complementation analyses, we observed that visible light-responsive platinum-containing titania (TiO2 nanoparticle (NP-mediated photocatalysis considerably reduces the number of Escherichia coli transformants. This suggests that such photocatalytic reactions cause DNA damage. DNA sequencing results demonstrated that the DNA damage comprises three mutation types, namely nucleotide insertion, deletion and substitution; this is the first study to report the types of mutations occurring after photocatalysis by TiO2-VLRPs. Our results may facilitate the development and appropriate use of new-generation TiO2 NPs for biomedical applications.

  14. Leber's hereditary optic neuropathy (LHON) pathogenic mutations induce mitochondrial-dependent apoptotic death in transmitochondrial cells incubated with galactose medium.

    Science.gov (United States)

    Ghelli, Anna; Zanna, Claudia; Porcelli, Anna Maria; Schapira, Anthony H V; Martinuzzi, Andrea; Carelli, Valerio; Rugolo, Michela

    2003-02-01

    Leber's hereditary optic neuropathy (LHON), a maternally inherited form of central vision loss, is associated with mitochondrial DNA pathogenic point mutations affecting different subunits of complex I. We here report that osteosarcoma-derived cytoplasmic hybrids (cybrid) cell lines harboring one of the three most frequent LHON pathogenic mutations, at positions 11778/ND4, 3460/ND1, and 14484/ND6, undergo cell death when galactose replaces glucose in the medium, contrary to control cybrids that maintain some growth capabilities. This is a well known way to produce a metabolic stress, forcing the cells to rely on the mitochondrial respiratory chain to produce ATP. We demonstrate that LHON cybrid cell death is apoptotic, showing chromatin condensation and nuclear DNA laddering. Moreover, we also document the mitochondrial involvement in the activation of the apoptotic cascade, as shown by the increased release of cytochrome c into the cytosol in LHON cybrid cells as compared with controls. Cybrids bearing the 3460/ND1 and 14484/ND6 mutations seemed more readily prone to undergo apoptosis as compared with the 11778/ND4 mutation. In conclusion, LHON cybrid cells forced by the reduced rate of glycolytic flux to utilize oxidative metabolism are sensitized to an apoptotic death through a mechanism involving mitochondria.

  15. [Effect of the female genotype on the yield of dominant lethal mutations induced by thiophosphamide in mature mouse spermia].

    Science.gov (United States)

    Korogodina, Iu V

    1980-02-01

    On crossing of thiophosphamide treated CBA males to untreated A/He, C57BL/6, C57BL/Mib and fidget females the lowest output of dominant lethal mutations was found in progeny of C57BL/Mib females. It is suggested that the ceparation of premutational lesions is most effective in egg cells of this strain.

  16. Evidence for dominant suppression of repeat-induced point mutation (RIP) in crosses with the wild-isolated Neurospora crassa strains Sugartown and Adiopodoume-7

    Indian Academy of Sciences (India)

    Felicite K. Noubissi; K. Aparna; Kevin McCluskey; Durgadas P. Kasbekar

    2001-08-01

    A convenient assay to score repeat-induced point mutation (RIP) in Neurospora employs the erg-3 locus as a mutagenesis target. Using this assay we screened 132 wild-isolated Neurospora crassa strains for ability to dominantly suppress RIP. RIP was exceptionally inefficient in crosses with the wild isolates Sugartown (P0854) and Adiopodoume-7 (P4305), thereby suggesting the presence of dominant RIP suppressors in these strains. In other experiments, we found no evidence for dominant RIP suppression by the Spore killer haplotypes Sk-2 and Sk-3.

  17. Molecular dynamics of mesophilic-like mutants of a cold-adapted enzyme: insights into distal effects induced by the mutations.

    Directory of Open Access Journals (Sweden)

    Elena Papaleo

    Full Text Available Networks and clusters of intramolecular interactions, as well as their "communication" across the three-dimensional architecture have a prominent role in determining protein stability and function. Special attention has been dedicated to their role in thermal adaptation. In the present contribution, seven previously experimentally characterized mutants of a cold-adapted α-amylase, featuring mesophilic-like behavior, have been investigated by multiple molecular dynamics simulations, essential dynamics and analyses of correlated motions and electrostatic interactions. Our data elucidate the molecular mechanisms underlying the ability of single and multiple mutations to globally modulate dynamic properties of the cold-adapted α-amylase, including both local and complex unpredictable distal effects. Our investigation also shows, in agreement with the experimental data, that the conversion of the cold-adapted enzyme in a warm-adapted variant cannot be completely achieved by the introduction of few mutations, also providing the rationale behind these effects. Moreover, pivotal residues, which are likely to mediate the effects induced by the mutations, have been identified from our analyses, as well as a group of suitable candidates for protein engineering. In fact, a subset of residues here identified (as an isoleucine, or networks of mesophilic-like salt bridges in the proximity of the catalytic site should be considered, in experimental studies, to get a more efficient modification of the features of the cold-adapted enzyme.

  18. The Connexin40A96S mutation from a patient with atrial fibrillation causes decreased atrial conduction velocities and sustained episodes of induced atrial fibrillation in mice.

    Science.gov (United States)

    Lübkemeier, Indra; Andrié, René; Lickfett, Lars; Bosen, Felicitas; Stöckigt, Florian; Dobrowolski, Radoslaw; Draffehn, Astrid M; Fregeac, Julien; Schultze, Joachim L; Bukauskas, Feliksas F; Schrickel, Jan Wilko; Willecke, Klaus

    2013-12-01

    Atrial fibrillation (AF) is the most common type of cardiac arrhythmia and a major cause of stroke. In the mammalian heart the gap junction proteins connexin40 (Cx40) and connexin43 (Cx43) are strongly expressed in the atrial myocardium mediating effective propagation of electrical impulses. Different heterozygous mutations in the coding region for Cx40 were identified in patients with AF. We have generated transgenic Cx40A96S mice harboring one of these mutations, the loss-of-function Cx40A96S mutation, as a model for atrial fibrillation. Cx40A96S mice were characterized by immunochemical and electrophysiological analyses. Significantly reduced atrial conduction velocities and strongly prolonged episodes of atrial fibrillation were found after induction in Cx40A96S mice. Analyses of the gating properties of Cx40A96S channels in cultured HeLa cells also revealed significantly lower junctional conductance and enhanced sensitivity voltage gating of Cx40A96S in comparison to Cx40 wild-type gap junctions. This is caused by reduced open probabilities of Cx40A96S gap junction channels, while single channel conductance remained the same. Similar to the corresponding patient, heterozygous Cx40A96S mice revealed normal expression levels and localization of the Cx40 protein. We conclude that heterozygous Cx40A96S mice exhibit prolonged episodes of induced atrial fibrillation and severely reduced atrial conduction velocities similar to the corresponding human patient.

  19. In silico reversal of repeat-induced point mutation (RIP identifies the origins of repeat families and uncovers obscured duplicated genes

    Directory of Open Access Journals (Sweden)

    Hane James K

    2010-11-01

    Full Text Available Abstract Background Repeat-induced point mutation (RIP is a fungal genome defence mechanism guarding against transposon invasion. RIP mutates the sequence of repeated DNA and over time renders the affected regions unrecognisable by similarity search tools such as BLAST. Results DeRIP is a new software tool developed to predict the original sequence of a RIP-mutated region prior to the occurrence of RIP. In this study, we apply deRIP to the genome of the wheat pathogen Stagonospora nodorum SN15 and predict the origin of several previously uncharacterised classes of repetitive DNA. Conclusions Five new classes of transposon repeats and four classes of endogenous gene repeats were identified after deRIP. The deRIP process is a new tool for fungal genomics that facilitates the identification and understanding of the role and origin of fungal repetitive DNA. DeRIP is open-source and is available as part of the RIPCAL suite at http://www.sourceforge.net/projects/ripcal.

  20. Fast homozygosity mapping and identification of a zebrafish ENU-induced mutation by whole-genome sequencing.

    Directory of Open Access Journals (Sweden)

    Marianne L Voz

    Full Text Available Forward genetics using zebrafish is a powerful tool for studying vertebrate development through large-scale mutagenesis. Nonetheless, the identification of the molecular lesion is still laborious and involves time-consuming genetic mapping. Here, we show that high-throughput sequencing of the whole zebrafish genome can directly locate the interval carrying the causative mutation and at the same time pinpoint the molecular lesion. The feasibility of this approach was validated by sequencing the m1045 mutant line that displays a severe hypoplasia of the exocrine pancreas. We generated 13 Gb of sequence, equivalent to an eightfold genomic coverage, from a pool of 50 mutant embryos obtained from a map-cross between the AB mutant carrier and the WIK polymorphic strain. The chromosomal region carrying the causal mutation was localized based on its unique property to display high levels of homozygosity among sequence reads as it derives exclusively from the initial AB mutated allele. We developed an algorithm identifying such a region by calculating a homozygosity score along all chromosomes. This highlighted an 8-Mb window on chromosome 5 with a score close to 1 in the m1045 mutants. The sequence analysis of all genes within this interval revealed a nonsense mutation in the snapc4 gene. Knockdown experiments confirmed the assertion that snapc4 is the gene whose mutation leads to exocrine pancreas hypoplasia. In conclusion, this study constitutes a proof-of-concept that whole-genome sequencing is a fast and effective alternative to the classical positional cloning strategies in zebrafish.

  1. Importance of genetics in fetal alcohol effects: null mutation of the nNOS gene worsens alcohol-induced cerebellar neuronal losses and behavioral deficits.

    Science.gov (United States)

    Bonthius, Daniel J; Winters, Zachary; Karacay, Bahri; Bousquet, Samantha Larimer; Bonthius, Daniel J

    2015-01-01

    The cerebellum is a major target of alcohol-induced damage in the developing brain. However, the cerebella of some children are much more seriously affected than others by prenatal alcohol exposure. As a consequence of in utero alcohol exposure, some children have substantial reductions in cerebellar volume and corresponding neurodevelopmental problems, including microencephaly, ataxia, and balance deficits, while other children who were exposed to similar alcohol quantities are spared. One factor that likely plays a key role in determining the impact of alcohol on the fetal cerebellum is genetics. However, no specific gene variant has yet been identified that worsens cerebellar function as a consequence of developmental alcohol exposure. Previous studies have revealed that mice carrying a homozygous mutation of the gene for neuronal nitric oxide synthase (nNOS-/- mice) have more severe acute alcohol-induced neuronal losses from the cerebellum than wild type mice. Therefore, the goals of this study were to determine whether alcohol induces more severe cerebellum-based behavioral deficits in nNOS-/- mice than in wild type mice and to determine whether these worsened behavior deficits are associated with worsened cerebellar neuronal losses. nNOS-/- mice and their wild type controls received alcohol (0.0, 2.2, or 4.4mg/g) daily over postnatal days 4-9. In adulthood, the mice underwent behavioral testing, followed by neuronal quantification. Alcohol caused dose-related deficits in rotarod and balance beam performance in both nNOS-/- and wild type mice. However, the alcohol-induced behavioral deficits were substantially worse in the nNOS-/- mice than in wild type. Likewise, alcohol exposure led to losses of Purkinje cells and cerebellar granule cells in mice of both genotypes, but the cell losses were more severe in the nNOS-/- mice than in wild type. Behavioral performances were correlated with neuronal number in the nNOS-/- mice, but not in wild type. Thus, homozygous

  2. Dilated cardiomyopathy mutation (R134W in mouse cardiac troponin T induces greater contractile deficits against α-myosin heavy chain than against β-myosin heavy chain

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    Sampath K Gollapudi

    2016-10-01

    Full Text Available Many studies have demonstrated that depressed myofilament Ca2+ sensitivity is common to dilated cardiomyopathy (DCM in humans. However, it remains unclear whether a single determinant — such as myofilament Ca2+ sensitivity — is sufficient to characterize all cases of DCM because the severity of disease varies widely with a given mutation. Because dynamic features dominate in the heart muscle, alterations in dynamic contractile parameters may offer better insight on the molecular mechanisms that underlie disparate effects of DCM mutations on cardiac phenotypes. Dynamic features are dominated by myofilament cooperativity that stem from different sources. One such source is the strong tropomyosin binding region in troponin T (TnT, which is known to modulate crossbridge (XB recruitment dynamics in a myosin heavy chain (MHC-dependent manner. Therefore, we hypothesized that the effects of DCM-linked mutations in TnT on contractile dynamics would be differently modulated by α- and β-MHC. After reconstitution with the mouse TnT equivalent (TnTR134W of the human DCM mutation (R131W, we measured dynamic contractile parameters in detergent-skinned cardiac muscle fiber bundles from normal (α-MHC and transgenic mice (β-MHC. TnTR134W significantly attenuated the rate constants of tension redevelopment, XB recruitment dynamics, XB distortion dynamics, and the magnitude of length-mediated XB recruitment only in α-MHC fiber bundles. TnTR134W decreased myofilament Ca2+ sensitivity to a greater extent in α-MHC (0.14 pCa units than in β-MHC fiber bundles (0.08 pCa units. Thus, our data demonstrate that TnTR134W induces a more severe DCM-like contractile phenotype against α-MHC than against β-MHC background.

  3. In situ genetic correction of the sickle cell anemia mutation in human induced pluripotent stem cells using engineered zinc finger nucleases.

    Science.gov (United States)

    Sebastiano, Vittorio; Maeder, Morgan L; Angstman, James F; Haddad, Bahareh; Khayter, Cyd; Yeo, Dana T; Goodwin, Mathew J; Hawkins, John S; Ramirez, Cherie L; Batista, Luis F Z; Artandi, Steven E; Wernig, Marius; Joung, J Keith

    2011-11-01

    The combination of induced pluripotent stem cell (iPSC) technology and targeted gene modification by homologous recombination (HR) represents a promising new approach to generate genetically corrected, patient-derived cells that could be used for autologous transplantation therapies. This strategy has several potential advantages over conventional gene therapy including eliminating the need for immunosuppression, avoiding the risk of insertional mutagenesis by therapeutic vectors, and maintaining expression of the corrected gene by endogenous control elements rather than a constitutive promoter. However, gene targeting in human pluripotent cells has remained challenging and inefficient. Recently, engineered zinc finger nucleases (ZFNs) have been shown to substantially increase HR frequencies in human iPSCs, raising the prospect of using this technology to correct disease causing mutations. Here, we describe the generation of iPSC lines from sickle cell anemia patients and in situ correction of the disease causing mutation using three ZFN pairs made by the publicly available oligomerized pool engineering method (OPEN). Gene-corrected cells retained full pluripotency and a normal karyotype following removal of reprogramming factor and drug-resistance genes. By testing various conditions, we also demonstrated that HR events in human iPSCs can occur as far as 82 bps from a ZFN-induced break. Our approach delineates a roadmap for using ZFNs made by an open-source method to achieve efficient, transgene-free correction of monogenic disease mutations in patient-derived iPSCs. Our results provide an important proof of principle that ZFNs can be used to produce gene-corrected human iPSCs that could be used for therapeutic applications.

  4. Low-Dose Actinomycin-D Induces Redistribution of Wild-Type and Mutated Nucleophosmin Followed by Cell Death in Leukemic Cells.

    Science.gov (United States)

    Brodská, Barbora; Holoubek, Aleš; Otevřelová, Petra; Kuželová, Kateřina

    2016-06-01

    Specific mutations involving C-terminal part of the nucleolar protein nucleophosmin (NPM) are associated with better outcome of acute myeloid leukemia (AML) therapy, possibly due to aberrant cytoplasmic NPM localization facilitating induction of anti-NPM immune response. Actinomycin D (actD) is known to induce nucleolar stress leading to redistribution of many nucleolar proteins, including NPM. We analyzed the distribution of both wild-type and mutated NPM (NPMmut) in human cell lines, before and after low-dose actD treatment, in living cells expressing exogenous fluorescently labeled proteins as well as using immunofluorescence staining of endogenous proteins in fixed cells. The wild-type NPM form is prevalently nucleolar in intact cells and relocalizes mainly to the nucleoplasm following actD addition. The mutated NPM form is found both in the nucleoli and in the cytoplasm of untreated cells. ActD treatment leads to a marked increase in NPMmut amount in the nucleoplasm while a mild decrease is observed in the cytoplasm. Cell death was induced by low-dose actD in all the studied leukemic cell lines with different p53 and NPM status. In cells expressing the tumor suppresor p53 (CML-T1, OCI-AML3), cell cycle arrest in G1/G0 phase was followed by p53-dependent apoptosis while in p53-null HL60 cells, transient G2/M-phase arrest was followed by cell necrosis. We conclude that although actD does not increase NPM concentration in the cytoplasm, it could improve the effect of standard chemotherapy in leukemias through more general mechanisms.

  5. Overexpression of Parkinson’s Disease-Associated Mutation LRRK2 G2019S in Mouse Forebrain Induces Behavioral Deficits and α-Synuclein Pathology

    Science.gov (United States)

    Grima, Jonathan C.; Chen, Guanxing; Swing, Debbie; Tessarollo, Lino

    2017-01-01

    Mutations in the leucine-rich repeat kinase 2 (LRRK2) gene have been identified as an unambiguous cause of late-onset, autosomal-dominant familial Parkinson’s disease (PD) and LRRK2 mutations are the strongest genetic risk factor for sporadic PD known to date. A number of transgenic mice expressing wild-type or mutant LRRK2 have been described with varying degrees of LRRK2-related abnormalities and modest pathologies. None of these studies directly addressed the role of the kinase domain in the changes observed and none of the mice present with robust features of the human disease. In an attempt to address these issues, we created a conditional LRRK2 G2019S (LRRK2 GS) mutant and a functionally negative control, LRRK2 G2019S/D1994A (LRRK2 GS/DA). Expression of LRRK2 GS or LRRK2 GS/DA was conditionally controlled using the tet-off system in which the presence of tetracycline-transactivator protein (tTA) with a CAMKIIα promoter (CAMKIIα-tTA) induced expression of TetP-LRRK2 GS or TetP-LRRK2 GS/DA in the mouse forebrain. Overexpression of LRRK2 GS in mouse forebrain induced behavioral deficits and α-synuclein pathology in a kinase-dependent manner. Similar to other genetically engineered LRRK2 GS mice, there was no significant loss of dopaminergic neurons. These mice provide an important new tool to study neurobiological changes associated with the increased kinase activity from the LRRK2 G2019S mutation, which may ultimately lead to a better understanding of not only the physiologic actions of LRRK2, but also potential pathologic actions that underlie LRRK2 GS-associated PD.

  6. Protein homeostasis disorders of key enzymes of amino acids metabolism: mutation-induced protein kinetic destabilization and new therapeutic strategies.

    Science.gov (United States)

    Pey, Angel L

    2013-12-01

    Many inborn errors of amino acids metabolism are caused by single point mutations affecting the ability of proteins to fold properly (i.e., protein homeostasis), thus leading to enzyme loss-of-function. Mutations may affect protein homeostasis by altering intrinsic physical properties of the polypeptide (folding thermodynamics, and rates of folding/unfolding/misfolding) as well as the interaction of partially folded states with elements of the protein homeostasis network (such as molecular chaperones and proteolytic machineries). Understanding these mutational effects on protein homeostasis is required to develop new therapeutic strategies aimed to target specific features of the mutant polypeptide. Here, I review recent work in three different diseases of protein homeostasis associated to inborn errors of amino acids metabolism: phenylketonuria, inherited homocystinuria and primary hyperoxaluria type I. These three different genetic disorders involve proteins operating in different cell organelles and displaying different structural complexities. Mutations often decrease protein kinetic stability of the native state (i.e., its half-life for irreversible denaturation), which can be studied using simple kinetic models amenable to biophysical and biochemical characterization. Natural ligands and pharmacological chaperones are shown to stabilize mutant enzymes, thus supporting their therapeutic application to overcome protein kinetic destabilization. The role of molecular chaperones in protein folding and misfolding is also discussed as well as their potential pharmacological modulation as promising new therapeutic approaches. Since current available treatments for these diseases are either burdening or only successful in a fraction of patients, alternative treatments must be considered covering studies from protein structure and biophysics to studies in animal models and patients.

  7. An Inducible Lentiviral Guide RNA Platform Enables the Identification of Tumor-Essential Genes and Tumor-Promoting Mutations In Vivo

    Directory of Open Access Journals (Sweden)

    Brandon J. Aubrey

    2015-03-01

    Full Text Available The CRISPR/Cas9 technology enables the introduction of genomic alterations into almost any organism; however, systems for efficient and inducible gene modification have been lacking, especially for deletion of essential genes. Here, we describe a drug-inducible small guide RNA (sgRNA vector system allowing for ubiquitous and efficient gene deletion in murine and human cells. This system mediates the efficient, temporally controlled deletion of MCL-1, both in vitro and in vivo, in human Burkitt lymphoma cell lines that require this anti-apoptotic BCL-2 protein for sustained survival and growth. Unexpectedly, repeated induction of the same sgRNA generated similar inactivating mutations in the human Mcl-1 gene due to low mutation variability exerted by the accompanying non-homologous end-joining (NHEJ process. Finally, we were able to generate hematopoietic cell compartment-restricted Trp53-knockout mice, leading to the identification of cancer-promoting mutants of this critical tumor suppressor.

  8. Normal repair of ultraviolet radiation-induced DNA damage in familial melanoma without CDKN2A or CDK4 gene mutation.

    Science.gov (United States)

    Shannon, J A; Matias, C; Luxford, C; Kefford, R F; Mann, G J

    1999-04-01

    Excessive sun exposure and family history are strong risk factors for the development of cutaneous melanoma. Inherited susceptibility to this type of skin cancer could therefore result from constitutively impaired capacity to repair ultraviolet (UV)-induced DNA lesions. While a proportion of familial melanoma kindreds exhibit germline mutations in the cell cycle regulatory gene CDKN2A (p16INK4a) or its protein target, cyclin-dependent kinase 4 (CDK4), the biochemical basis of most familial melanoma is unknown. We have examined lymphoblastoid cell lines from melanoma-affected and unaffected individuals from large hereditary melanoma kindreds which are not attributable to CDKN2A or CDK4 gene mutation. These lines were tested for sensitivity of clonogenic growth to UV radiation and for their ability to repair transfected UV-damaged plasmid templates (host cell reactivation). Two of seven affected-unaffected pairs differed in colony survival after exposure to UVB radiation; however, no significant differences were observed in the host-cell reactivation assays. These results indicate that melanoma susceptibility genes other than CDKN2A and CDK4 do not impair net capacity to repair UV-induced DNA damage.

  9. Collateral damage: Spread of repeat-induced point mutation from a duplicated DNA sequence into an adjoining single-copy gene in Neurospora crassa

    Indian Academy of Sciences (India)

    Meenal Vyas; Durgadas P Kasbekar

    2005-02-01

    Repeat-induced point mutation (RIP) is an unusual genome defense mechanism that was discovered in Neurospora crassa. RIP occurs during a sexual cross and induces numerous G : C to A : T mutations in duplicated DNA sequences and also methylates many of the remaining cytosine residues. We measured the susceptibility of the erg-3 gene, present in single copy, to the spread of RIP from duplications of adjoining sequences. Genomic segments of defined length (1, 1.5 or 2 kb) and located at defined distances (0, 0.5, 1 or 2 kb) upstream or downstream of the erg-3 open reading frame (ORF) were amplified by polymerase chain reaction (PCR), and the duplications were created by transformation of the amplified DNA. Crosses were made with the duplication strains and the frequency of erg-3 mutant progeny provided a measure of the spread of RIP from the duplicated segments into the erg-3 gene. Our results suggest that ordinarily RIP-spread does not occur. However, occasionally the mechanism that confines RIP to the duplicated segment seems to fail (frequency 0.1–0.8%) and then RIP can spread across as much as 1 kb of unduplicated DNA. Additionally, the bacterial hph gene appeared to be very susceptible to the spread of RIP-associated cytosine methylation.

  10. Benzo(a)pyrene and X-rays induce reversions of the pink-eyed unstable mutation in the retinal pigment epithelium of mice.

    Science.gov (United States)

    Bishop, A J; Kosaras, B; Sidman, R L; Schiestl, R H

    2000-12-20

    The pink-eyed unstable (p(un)) mutation is the result of a 70kb tandem duplication within the murine p gene. Homologous deletion/recombination of the locus to wild-type occurs spontaneously in embryos and results in pigmented spots in the fur and eye that persist for life. Such deletion events are also inducible by a variety of DNA damaging agents, as we have observed previously with the fur spot assay. Here, we describe the use of the retinal pigment epithelium (RPE) of the eye to detect reversion events induced with two differently acting agents. Benzo(a)pyrene (B(a)P) induces a high frequency, and X-ray exposure a more modest increase, of p(un) reversion in both the fur and the eye. The eye-spot assay requires fewer mice for significant results than the fur spot assay. Previous work had elucidated the cell proliferation pattern in the RPE and a position effect variegation phenotype in the pattern of p(un) reversions, which we have confirmed. Acute exposure to B(a)P or X-rays resulted in an increased frequency of reversion events. The majority of the spontaneous reversions lie toward the periphery of the RPE whereas induced events are found more centrally, closer to the optic nerve head. The induced distribution corresponds to the major sites of cell proliferation in the RPE at the time of exposure, and further advocates the proposal that dividing cells are at highest risk to develop deletions.

  11. Changing in lipid profile induced by the mutation of Foxn1 gene: A lipidomic analysis of Nude mice skin.

    Science.gov (United States)

    Lanzini, Justine; Dargère, Delphine; Regazzetti, Anne; Tebani, Abdellah; Laprévote, Olivier; Auzeil, Nicolas

    2015-11-01

    Nude mice carry a spontaneous mutation affecting the gene Foxn1 mainly expressed in the epidermis. This gene is involved in several skin functions, especially in the proliferation and the differentiation of keratinocytes which are key cells of epithelial barrier. The skin, a protective barrier for the body, is essentially composed of lipids. Taking into account these factors, we conducted a lipidomic study to search for any changes in lipid composition of skin possibly related to Foxn1 mutation. Lipids were extracted from skin biopsies of Nude and BALB/c mice to be analyzed by liquid chromatography coupled to a high resolution mass spectrometer (HRMS). Multivariate and univariate data analyses were carried out to compare lipid extracts. Identification was performed using HRMS data, retention time and mass spectrometry fragmentation study. These results indicate that mutation of Foxn1 leads to significant modifications in the lipidome in Nude mice skin. An increase in cholesterol sulfate, phospholipids, sphingolipids and fatty acids associated with a decrease in glycerolipids suggest that the lipidome in mice skin is regulated by the Foxn1 gene.

  12. Hepatic gene mutations induced in Big Blue rats by both the potent rat liver azo-carcinogen 6BT and its reported noncarcinogenic analogue 5BT.

    Science.gov (United States)

    Fletcher, K; Soames, A R; Tinwell, H; Lefevre, P A; Ashby, J

    1999-01-01

    The potent rat liver carcinogen 6-p-dimethylaminophenylazobenzthiazole (6BT) and its reported noncarcinogenic analogue 5-p-dimethylaminophenylazobenzthiazole (5BT; evaluated for carcinogenicity under the similar limited bioassay conditions used for 6BT) have been studied in order to seek an explanation for their different carcinogenic activities. Both compounds act as DNA-damaging agents to the rat liver, and both have now been shown to induce lacI (-) gene mutations in the liver of Big Blue(trade mark) transgenic rats. Both compounds were mutagenic following ten daily gavage doses or following administration in diet for 10 days. Neither chemical induced cell proliferation in the liver following repeat gavage administrations. In contrast, dietary administration of 6BT, and to a lesser extent of 5BT, induced hepatic cell proliferation. The carcinogen 6BT, but not the noncarcinogen 5BT, caused proliferation of oval stem cells in the livers by both routes of administration. It is possible that mutations induced in oval cells by 6BT are responsible for its potent carcinogenicity, and that the comparative absence of these cells in 5BT-treated livers may account for the carcinogenic inactivity of 5BT. Equally, the proliferation of the oval cells may reflect changes in liver homeostasis associated with the liver toxicity observed at the dose level of 6BT used (which was, nonetheless, the dose level used in the positive cancer bioassays). It is concluded that the new data presented cannot explain the differing carcinogenic activities of 5BT and 6BT, and that the reported noncarcinogen 5BT may also be carcinogenic when adequately assessed for this activity.

  13. Development of severe skeletal defects in induced SHP-2-deficient adult mice: a model of skeletal malformation in humans with SHP-2 mutations

    Directory of Open Access Journals (Sweden)

    Timothy J. Bauler

    2011-03-01

    SHP-2 (encoded by PTPN11 is a ubiquitously expressed protein tyrosine phosphatase required for signal transduction by multiple different cell surface receptors. Humans with germline SHP-2 mutations develop Noonan syndrome or LEOPARD syndrome, which are characterized by cardiovascular, neurological and skeletal abnormalities. To study how SHP-2 regulates tissue homeostasis in normal adults, we used a conditional SHP-2 mouse mutant in which loss of expression of SHP-2 was induced in multiple tissues in response to drug administration. Induced deletion of SHP-2 resulted in impaired hematopoiesis, weight loss and lethality. Most strikingly, induced SHP-2-deficient mice developed severe skeletal abnormalities, including kyphoses and scolioses of the spine. Skeletal malformations were associated with alterations in cartilage and a marked increase in trabecular bone mass. Osteoclasts were essentially absent from the bones of SHP-2-deficient mice, thus accounting for the osteopetrotic phenotype. Studies in vitro revealed that osteoclastogenesis that was stimulated by macrophage colony-stimulating factor (M-CSF and receptor activator of nuclear factor kappa B ligand (RANKL was defective in SHP-2-deficient mice. At least in part, this was explained by a requirement for SHP-2 in M-CSF-induced activation of the pro-survival protein kinase AKT in hematopoietic precursor cells. These findings illustrate an essential role for SHP-2 in skeletal growth and remodeling in adults, and reveal some of the cellular and molecular mechanisms involved. The model is predicted to be of further use in understanding how SHP-2 regulates skeletal morphogenesis, which could lead to the development of novel therapies for the treatment of skeletal malformations in human patients with SHP-2 mutations.

  14. Characterization of a novel mutation in NS1 protein of influenza A virus induced by a chemical substance for the attenuation of pathogenicity.

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    Kohei Sasaki

    Full Text Available It is generally accepted that live attenuated influenza vaccine (LAIV has the potential for use as a vaccination against flu. In this study, we demonstrated the nature of an influenza A virus (IAV mutant induced by treating the IAV with a stable furan derivative, (1R,2R-1-(5'-methylfur-3'-ylpropane-1,2,3-triol (MFPT, which had been isolated from Streptomyces sp. strain FV60 with the objective of it being an LAIV candidate. The resulting MFPT-resistant (MFPTr IAVs possessed attenuated pathogenicity in vitro and in vivo when compared with that of the parent virus (H1N1 subtype, NWS strain. Sequencing analysis revealed that a novel mutation, C490U in ns gene (P164S in NS1, was detected in all MFPTr virus clones tested. Therefore, NS1 might be a main target of MFPT, and it was suggested that the P164S mutation contributed to the attenuated pathogenicity of the mutants. Although the phosphatidylinositol 3-kinase (PI3K/Akt signaling pathway is one of the targets of NS1, the MFPTr virus suppressed the phosphorylation of Akt when compared with the wild-type (WT virus. It was suggested that this might lead to the subsequent inhibition of the cleavage of PARP-1 and caspase-3, which is important for the progression of apoptosis. At the same time, nucleoprotein (NP was found to be retained in the nuclei in MFPTr virus-infected cells while nuclear export of NP was detected in WT virus-infected cells. In addition, the expression levels of interferon-β transcripts were significantly decreased in MFPTr virus-infected cells. From these results it can be shown that the mutation, NS1P164S, might be one of the key residues to control NS1 function concerning the induction of apoptosis. In conclusion, MFPT induced favorable mutation in the ns gene for the attenuation of IAV, and therefore might provide the novel methodology for preparing LAIVs.

  15. SH3BP2 cherubism mutation potentiates TNF-α-induced osteoclastogenesis via NFATc1 and TNF-α-mediated inflammatory bone loss.

    Science.gov (United States)

    Mukai, Tomoyuki; Ishida, Shu; Ishikawa, Remi; Yoshitaka, Teruhito; Kittaka, Mizuho; Gallant, Richard; Lin, Yi-Ling; Rottapel, Robert; Brotto, Marco; Reichenberger, Ernst J; Ueki, Yasuyoshi

    2014-12-01

    Cherubism (OMIM# 118400) is a genetic disorder with excessive jawbone resorption caused by mutations in SH3 domain binding protein 2 (SH3BP2), a signaling adaptor protein. Studies on the mouse model for cherubism carrying a P416R knock-in (KI) mutation have revealed that mutant SH3BP2 enhances tumor necrosis factor (TNF)-α production and receptor activator of nuclear factor-κB ligand (RANKL)-induced osteoclast differentiation in myeloid cells. TNF-α is expressed in human cherubism lesions, which contain a large number of tartrate-resistant acid phosphatase (TRAP)-positive multinucleated cells, and TNF-α plays a critical role in inflammatory bone destruction in homozygous cherubism mice (Sh3bp2(KI/KI) ). The data suggest a pathophysiological relationship between mutant SH3BP2 and TNF-α-mediated bone loss by osteoclasts. Therefore, we investigated whether P416R mutant SH3BP2 is involved in TNF-α-mediated osteoclast formation and bone loss. Here, we show that bone marrow-derived M-CSF-dependent macrophages (BMMs) from the heterozygous cherubism mutant (Sh3bp2(KI/+) ) mice are highly responsive to TNF-α and can differentiate into osteoclasts independently of RANKL in vitro by a mechanism that involves spleen tyrosine kinase (SYK) and phospholipase Cγ2 (PLCγ2) phosphorylation, leading to increased nuclear translocation of NFATc1. The heterozygous cherubism mutation exacerbates bone loss with increased osteoclast formation in a mouse calvarial TNF-α injection model as well as in a human TNF-α transgenic mouse model (hTNFtg). SH3BP2 knockdown in RAW264.7 cells results in decreased TRAP-positive multinucleated cell formation. These findings suggest that the SH3BP2 cherubism mutation can cause jawbone destruction by promoting osteoclast formation in response to TNF-α expressed in cherubism lesions and that SH3BP2 is a key regulator for TNF-α-induced osteoclastogenesis. Inhibition of SH3BP2 expression in osteoclast progenitors could be a potential strategy for

  16. Novel ENU-Induced Mutation in Tbx6 Causes Dominant Spondylocostal Dysostosis-Like Vertebral Malformations in the Rat.

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    Koichiro Abe

    Full Text Available Congenital vertebral malformations caused by embryonic segmentation defects are relatively common in humans and domestic animals. Although reverse genetics approaches in mice have provided information on the molecular mechanisms of embryonic somite segmentation, hypothesis-driven approaches cannot adequately reflect human dysmorphology within the population. In a N-ethyl-N-nitrosourea (ENU mutagenesis project in Kyoto, the Oune mutant rat strain was isolated due to a short and kinked caudal vertebra phenotype. Skeletal staining of heterozygous rats showed partial loss of the cervical vertebrae as well as hemivertebrae and fused vertebral blocks in lumbar and sacral vertebrae. In homozygous embryos, severe displacement of the whole vertebrae was observed. The Oune locus was genetically mapped to rat chromosome 1 using 202 backcross animals and 50 genome-wide microsatellite markers. Subsequently, a miss-sense mutation in the Tbx6 gene was identified in the critical region. Although the mutation is located within the T-box domain near a predicted dimmer-interface, in vitro experiments revealed that the Tbx6 variant retains normal DNA binding ability and translational efficiency. However, the variant has decreased transcriptional activation potential in response to Notch-mediated signaling. Recently, it was reported that a dominant type of familial spondylocostal dysostosis is caused by a stoploss mutation in TBX6. Thus, we propose that partial dysfunction of Tbx6 leads to similar congenital vertebral malformations in both humans and rats. The Oune strain could be a unique animal model for dominant spondylocostal dysostosis and is useful for molecular dissection of the pathology of congenital vertebral malformations in humans.

  17. Vesicourethral reflux-induced renal failure in a patient with ICF syndrome due to a novel DNMT3B mutation.

    Science.gov (United States)

    Kutluğ, Seyhan; Ogur, Gönül; Yilmaz, Aysegül; Thijssen, Peter E; Abur, Ummet; Yildiran, Alisan

    2016-12-01

    ICF syndrome is a primary immunodeficiency disease characterized by hypo- or agammaglobulinemia, centromeric instability mainly on chromosomes 1, 9, and 16 and facial anomalies. ICF syndrome presents with frequent respiratory tract infections in infancy. A 20-month-old female patient was referred to our clinic due to frequent lower respiratory tract infections. ICF syndrome was considered because of comorbidity of hypogammaglobulinemia, facial anomalies, and neuromotor growth retardation. Metaphase chromosome analysis revealed centromeric instability on chromosomes 1, 9, and 16 and through Sanger a previously unreported homozygous missense mutation (c.1805T>C; [p.V602A]) was identified in the DNMT3B, confirming ICF1. The patient was found to have a breakdown in renal function 1 year later; the urinary system was examined and bilateral vesicoureteral reflux was found, warranting the need for dialysis in time. This report expands the mutation spectrum of ICF1 and is the first to describe bilateral vesicoureteral reflux accompanying ICF syndrome. © 2016 Wiley Periodicals, Inc.

  18. Temperature-dependent changes in neuronal dynamics in a patient with an SCN1A mutation and hyperthermia induced seizures

    Science.gov (United States)

    Peters, C.; Rosch, R. E.; Hughes, E.; Ruben, P. C.

    2016-09-01

    Dravet syndrome is the prototype of SCN1A-mutation associated epilepsies. It is characterised by prolonged seizures, typically provoked by fever. We describe the evaluation of an SCN1A mutation in a child with early-onset temperature-sensitive seizures. The patient carries a heterozygous missense variant (c3818C > T pAla1273Val) in the NaV1.1 brain sodium channel. We compared the functional effects of the variant vs. wild type NaV1.1 using patch clamp recordings from channels expressed in Chinese Hamster Ovary Cells at different temperatures (32, 37, and 40 °C). The variant channels produced a temperature-dependent destabilization of activation and fast inactivation. Implementing these empirical abnormalities in a computational model predicts a higher threshold for depolarization block in the variant, particularly at 40 °C, suggesting a failure to autoregulate at high-input states. These results reveal direct effects of abnormalities in NaV1.1 biophysical properties on neuronal dynamics. They illustrate the value of combining cellular measurements with computational models to integrate different observational scales (gene/channel to patient).

  19. Transposon-induced nuclear mutations that alter chloroplast gene expression. Annual report, September 1, 1991--August 31, 1992

    Energy Technology Data Exchange (ETDEWEB)

    Barkan, A.

    1992-12-31

    The goal of this project is to use mutant phenotypes as a guide to nuclear genes that determine the timing and localization of chloroplast development The immediate goals are to identify nuclear mutants with defects in chloroplast gene expression from maize lines harboring active Mu transposons; characterize their phenotypes to determine the precise defect in gene expression; clone several of the most interesting mutations by exploiting the transposon tag; and use the clones to further define the roles of these genes in modulating chloroplast gene expression. Three mutants were described earlier that had global defects in chloroplast gene expression. We have found that two of these mutations are allelic. Both alleles have global defects in chloroplast translation initiation, as revealed by the failure to assemble chloroplast mRNAs into polysomes. We have isolated and characterized three new mutants from Mu lines that have novel defects in chloroplast RNA metabolism. We are now ready to begin the task of cloning several of these genes, by using the Mu transposon tag.

  20. Recombination-Independent Recognition of DNA Homology for Repeat-Induced Point Mutation (RIP Is Modulated by the Underlying Nucleotide Sequence.

    Directory of Open Access Journals (Sweden)

    Eugene Gladyshev

    2016-05-01

    Full Text Available Haploid germline nuclei of many filamentous fungi have the capacity to detect homologous nucleotide sequences present on the same or different chromosomes. Once recognized, such sequences can undergo cytosine methylation or cytosine-to-thymine mutation specifically over the extent of shared homology. In Neurospora crassa this process is known as Repeat-Induced Point mutation (RIP. Previously, we showed that RIP did not require MEI-3, the only RecA homolog in Neurospora, and that it could detect homologous trinucleotides interspersed with a matching periodicity of 11 or 12 base-pairs along participating chromosomal segments. This pattern was consistent with a mechanism of homology recognition that involved direct interactions between co-aligned double-stranded (ds DNA molecules, where sequence-specific dsDNA/dsDNA contacts could be established using no more than one triplet per turn. In the present study we have further explored the DNA sequence requirements for RIP. In our previous work, interspersed homologies were always examined in the context of a relatively long adjoining region of perfect homology. Using a new repeat system lacking this strong interaction, we now show that interspersed homologies with overall sequence identity of only 36% can be efficiently detected by RIP in the absence of any perfect homology. Furthermore, in this new system, where the total amount of homology is near the critical threshold required for RIP, the nucleotide composition of participating DNA molecules is identified as an important factor. Our results specifically pinpoint the triplet 5'-GAC-3' as a particularly efficient unit of homology recognition. Finally, we present experimental evidence that the process of homology sensing can be uncoupled from the downstream mutation. Taken together, our results advance the notion that sequence information can be compared directly between double-stranded DNA molecules during RIP and, potentially, in other processes

  1. Pristimerin induces apoptosis in imatinib-resistant chronic myelogenous leukemia cells harboring T315I mutation by blocking NF-κB signaling and depleting Bcr-Abl

    Directory of Open Access Journals (Sweden)

    Cao Qi

    2010-05-01

    Full Text Available Abstract Background Chronic myelogenous leukemia (CML is characterized by the chimeric tyrosine kinase Bcr-Abl. Bcr-Abl-T315I is the notorious point mutation that causes resistance to imatinib and the second generation tyrosine kinase inhibitors, leading to poor prognosis. CML blasts have constitutive p65 (RelA NF-κB transcriptional activity, and NF-κB may be a potential target for molecular therapies in CML that may also be effective against CML cells with Bcr-Abl-T315I. Results In this report, we discovered that pristimerin, a quinonemethide triterpenoid isolated from Celastraceae and Hippocrateaceae, inhibited growth and induced apoptosis in CML cells, including the cells harboring Bcr-Abl-T315I mutation. Additionally, pristimerin inhibited the growth of imatinib-resistant Bcr-Abl-T315I xenografts in nude mice. Pristimerin blocked the TNFα-induced IκBα phosphorylation, translocation of p65, and expression of NF-κB-regulated genes. Pristimerin inhibited two steps in NF-κB signaling: TAK1→IKK and IKK→IκBα. Pristimerin potently inhibited two pairs of CML cell lines (KBM5 versus KBM5-T315I, 32D-Bcr-Abl versus 32D-Bcr-Abl-T315I and primary cells from a CML patient with acquired resistance to imatinib. The mRNA and protein levels of Bcr-Abl in imatinib-sensitive (KBM5 or imatinib-resistant (KBM5-T315I CML cells were reduced after pristimerin treatment. Further, inactivation of Bcr-Abl by imatinib pretreatment did not abrogate the TNFα-induced NF-κB activation while silencing p65 by siRNA did not affect the levels of Bcr-Abl, both results together indicating that NF-κB inactivation and Bcr-Abl inhibition may be parallel independent pathways. Conclusion To our knowledge, this is the first report to show that pristimerin is effective in vitro and in vivo against CML cells, including those with the T315I mutation. The mechanisms may involve inhibition of NF-κB and Bcr-Abl. We concluded that pristimerin could be a lead compound for

  2. Genetic analysis of colon tumors induced by a dietary carcinogen PhIP in CYP1A humanized mice: Identification of mutation of β-catenin/Ctnnb1 as the driver gene for the carcinogenesis.

    Science.gov (United States)

    Wang, Hong; Zhou, Hong; Liu, Anna; Guo, Xiangyi; Yang, Chung S

    2015-11-01

    Replacing mouse Cyp1a with human CYP1A enables the humanized CYP1A mice to mimic human metabolism of the dietary carcinogen, 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP), by N(2) -hydroxylation to a proximate carcinogen. Our previous study demonstrated that PhIP, combined with the dextrin sulfate sodium (DSS)-induced colitis, induces colon carcinogenesis in hCYP1A mice. Here, we employed whole exome sequencing and found multiple gene mutations in PhIP/DSS-induced colon tumors. Mutations in the exon 3 of Ctnnb1/β-catenin, however, were the predominant events. We further sequenced the key fragments of Apc, Ctnnb1, and Kras, because mutations of these genes in the humans are commonly found as the drivers of colorectal cancer. Mutations on either codon 32 or 34 in the exon 3 of Ctnnb1 were found in 39 out of 42 tumors, but no mutation was found in either Apc or Kras. The sequence context of codons 32 and 34 suggests that PhIP targets +3G in a TGGA motif of Ctnnb1. Since mutations that activate Wnt signal is a major driving force for human colorectal cancers, we conclude that the mutated β-catenin is the driver in PhIP/DSS-induced colon carcinogenesis. This result suggests that the colon tumors in hCYP1A mice mimic human colorectal carcinogenesis not only in the dietary etiology involving PhIP, but also in the aberrant activation of the Wnt signaling pathway as the driving force.

  3. HDAC6 Inhibitors Rescued the Defective Axonal Mitochondrial Movement in Motor Neurons Derived from the Induced Pluripotent Stem Cells of Peripheral Neuropathy Patients with HSPB1 Mutation.

    Science.gov (United States)

    Kim, Ji-Yon; Woo, So-Youn; Hong, Young Bin; Choi, Heesun; Kim, Jisoo; Choi, Hyunjung; Mook-Jung, Inhee; Ha, Nina; Kyung, Jangbeen; Koo, Soo Kyung; Jung, Sung-Chul; Choi, Byung-Ok

    2016-01-01

    The Charcot-Marie-Tooth disease 2F (CMT2F) and distal hereditary motor neuropathy 2B (dHMN2B) are caused by autosomal dominantly inherited mutations of the heat shock 27 kDa protein 1 (HSPB1) gene and there are no specific therapies available yet. Here, we assessed the potential therapeutic effect of HDAC6 inhibitors on peripheral neuropathy with HSPB1 mutation using in vitro model of motor neurons derived from induced pluripotent stem cells (iPSCs) of CMT2F and dHMN2B patients. The absolute velocity of mitochondrial movements and the percentage of moving mitochondria in axons were lower both in CMT2F-motor neurons and in dHMN2B-motor neurons than those in controls, and the severity of the defective mitochondrial movement was different between the two disease models. CMT2F-motor neurons and dHMN2B-motor neurons also showed reduced α-tubulin acetylation compared with controls. The newly developed HDAC6 inhibitors, CHEMICAL X4 and CHEMICAL X9, increased acetylation of α-tubulin and reversed axonal movement defects of mitochondria in CMT2F-motor neurons and dHMN2B-motor neurons. Our results suggest that the neurons derived from patient-specific iPSCs can be used in drug screening including HDAC6 inhibitors targeting peripheral neuropathy.

  4. HDAC6 Inhibitors Rescued the Defective Axonal Mitochondrial Movement in Motor Neurons Derived from the Induced Pluripotent Stem Cells of Peripheral Neuropathy Patients with HSPB1 Mutation

    Directory of Open Access Journals (Sweden)

    Ji-Yon Kim

    2016-01-01

    Full Text Available The Charcot-Marie-Tooth disease 2F (CMT2F and distal hereditary motor neuropathy 2B (dHMN2B are caused by autosomal dominantly inherited mutations of the heat shock 27 kDa protein 1 (HSPB1 gene and there are no specific therapies available yet. Here, we assessed the potential therapeutic effect of HDAC6 inhibitors on peripheral neuropathy with HSPB1 mutation using in vitro model of motor neurons derived from induced pluripotent stem cells (iPSCs of CMT2F and dHMN2B patients. The absolute velocity of mitochondrial movements and the percentage of moving mitochondria in axons were lower both in CMT2F-motor neurons and in dHMN2B-motor neurons than those in controls, and the severity of the defective mitochondrial movement was different between the two disease models. CMT2F-motor neurons and dHMN2B-motor neurons also showed reduced α-tubulin acetylation compared with controls. The newly developed HDAC6 inhibitors, CHEMICAL X4 and CHEMICAL X9, increased acetylation of α-tubulin and reversed axonal movement defects of mitochondria in CMT2F-motor neurons and dHMN2B-motor neurons. Our results suggest that the neurons derived from patient-specific iPSCs can be used in drug screening including HDAC6 inhibitors targeting peripheral neuropathy.

  5. A factor in a wild isolated Neurospora crassa strain enables a chromosome segment duplication to suppress repeat-induced point mutation

    Indian Academy of Sciences (India)

    Mukund Ramakrishnan; T Naga Sowjanya; Kranthi B Raj; Durgadas P Kasbekar

    2011-12-01

    Repeat-induced point mutation (RIP) is a sexual stage-specific mutational process of Neurospora crassa and other fungi that alters duplicated DNA sequences. Previous studies from our laboratory showed that chromosome segment duplications (Dps) longer than ∼300 kbp can dominantly suppress RIP, presumably by titration of the RIP machinery, and that although Dps < 200 kbp did not individually suppress RIP, they could do so in homozygous and multiply heterozygous crosses, provided the sum of the duplicated DNA exceeds ∼300 kbp. Here we demonstrate suppression of RIP in a subset of progeny carrying the normally sub-threshold 154 kbp Dp(R2394) from a cross of T(R2394) to the wild isolated Carrefour Mme. Gras strain (CMG). Thus, the CMG strain contains a factor that together with Dp(R2394) produces a synthetic RIP suppressor phenotype. It is possible that the factor is a cryptic Dp that together with Dp(R2394) can exceed the size threshold for titration of the RIP machinery and thereby causes RIP suppression.

  6. Seamless modification of wild-type induced pluripotent stem cells to the natural CCR5Δ32 mutation confers resistance to HIV infection.

    Science.gov (United States)

    Ye, Lin; Wang, Jiaming; Beyer, Ashley I; Teque, Fernando; Cradick, Thomas J; Qi, Zhongxia; Chang, Judy C; Bao, Gang; Muench, Marcus O; Yu, Jingwei; Levy, Jay A; Kan, Yuet Wai

    2014-07-01

    Individuals homozygous for the C-C chemokine receptor type 5 gene with 32-bp deletions (CCR5Δ32) are resistant to HIV-1 infection. In this study, we generated induced pluripotent stem cells (iPSCs) homozygous for the naturally occurring CCR5Δ32 mutation through genome editing of wild-type iPSCs using a combination of transcription activator-like effector nucleases (TALENs) or RNA-guided clustered regularly interspaced short palindromic repeats (CRISPR)-Cas9 together with the piggyBac technology. Remarkably, TALENs or CRISPR-Cas9-mediated double-strand DNA breaks resulted in up to 100% targeting of the colonies on one allele of which biallelic targeting occurred at an average of 14% with TALENs and 33% with CRISPR. Excision of the piggyBac using transposase seamlessly reproduced exactly the naturally occurring CCR5Δ32 mutation without detectable exogenous sequences. We differentiated these modified iPSCs into monocytes/macrophages and demonstrated their resistance to HIV-1 challenge. We propose that this strategy may provide an approach toward a functional cure of HIV-1 infection.

  7. Mutations induced in Tradescantia by small doses of X-rays and neutrons - Analysis of dose-response curves.

    Science.gov (United States)

    Sparrow, A. H.; Underbrink, A. G.; Rossi, H. H.

    1972-01-01

    Dose-response curves for pink somatic mutations in Tradescantia stamen hairs were analyzed after neutron and X-ray irradiation with doses ranging from a fraction of a rad to the region of saturation. The dose-effect relation for neutrons indicates a linear dependence from 0.01 to 8 rads; between 0.25 and 5 rads, a linear dependence is indicated for X-rays also. As a consequence the relative biological effectiveness reaches a constant value (about 50) at low doses. The observations are in good agreement with the predictions of the theory of dual radiation action and support its interpretation of the effects of radiation on higher organisms. The doubling dose of X-rays was found to be nearly 1 rad.

  8. Induced pluripotent stem cells (iPSCs) derived from a patient with frontotemporal dementia caused by a P301L mutation in microtubule-associated protein tau (MAPT)

    DEFF Research Database (Denmark)

    Rasmussen, Mikkel A.; Hjermind, Lena Elisabeth; Hasholt, Lis Frydenreich;

    2016-01-01

    Skin fibroblasts were obtained froma 57-year-old woman diagnosed with frontotemporal dementia. The diseaseis caused by a P301L mutation in microtubule-associated protein tau (MAPT). Induced pluripotent stem cells (iPSCs) were established by electroporation with episomal plasmids containing hOCT4, h......SOX2, hKLF2, hL-MYC,hLIN-28 and shP53. iPSCs were free of genomically integrated reprogramming genes, contained the expected c.902C>T substitution in exon 10 of the MAPT gene, expressed the expected pluripotency markers, displayed in vitro differentiation potential to the three germ layers and had...... normal karyotype. The iPSC line may be useful for studying hereditary frontotemporal dementia and TAU pathology in vitro....

  9. Changes in membrane fatty acid composition through proton-induced fabF mutation enhancing 1-butanol tolerance in E. coli

    Science.gov (United States)

    Jeong, Haeyoung; Kim, Sun Hong; Han, Sang Soo; Kim, Myung Hee; Lee, Keun Chul

    2012-07-01

    While a rational approach based on genomic data has become the preferred method for microbial strain development, radiation-induced random mutagenesis is still a robust method for organisms such as plants whose genome or target gene information is unavailable. We previously reported on a combined approach that consists of proton irradiation and a long-term experimental evolution to enhance 1-butanol tolerance of the E. coli C strain so that it can be used as a basal strain for the production of 1-butanol, a potential biofuel along with ethanol. Genome sequencing of one randomly chosen clone (PKH5000) from the endpoint population revealed eleven mutations occurring in the coding regions, and we found that a mutation (F74C) in fabF gene encoding β-ketoacyl-ACP synthases II is associated with a twofold increase in the major unsaturated fatty acid, cis-vaccenic acid. The increase of cis-vaccenic acid by wild-type FabF, which is more active at low temperatures or in the presence of organic compounds, is considered to be a protective mechanism against cold stress. A structural analysis of the FabF protein suggests that the F74C mutation may affect the enzyme activity through a change in flexibility around the catalytic site. The expression of a plasmid that harbors mutant fabF gene in the fabF knockout strain enhanced growth in a medium containing butanol with a concomitant elevation of the cis-vaccenic acid level. Among the eight available Keio knockout strains for genes that have amino acid substitution in the PKH5000 strain, the fabF mutant showed the slowest growth in the presence of 0.7% butanol. We propose that fabF, as probably the gene most responsible for butanol tolerance in wild-type form, contributes further when converted into a F74C missense mutation, which is beneficial as it increases the level of cis-vaccenic acid.

  10. Computational modeling of allosteric communication reveals organizing principles of mutation-induced signaling in ABL and EGFR kinases.

    Directory of Open Access Journals (Sweden)

    Anshuman Dixit

    2011-10-01

    Full Text Available The emerging structural information about allosteric kinase complexes and the growing number of allosteric inhibitors call for a systematic strategy to delineate and classify mechanisms of allosteric regulation and long-range communication that control kinase activity. In this work, we have investigated mechanistic aspects of long-range communications in ABL and EGFR kinases based on the results of multiscale simulations of regulatory complexes and computational modeling of signal propagation in proteins. These approaches have been systematically employed to elucidate organizing molecular principles of allosteric signaling in the ABL and EGFR multi-domain regulatory complexes and analyze allosteric signatures of the gate-keeper cancer mutations. We have presented evidence that mechanisms of allosteric activation may have universally evolved in the ABL and EGFR regulatory complexes as a product of a functional cross-talk between the organizing αF-helix and conformationally adaptive αI-helix and αC-helix. These structural elements form a dynamic network of efficiently communicated clusters that may control the long-range interdomain coupling and allosteric activation. The results of this study have unveiled a unifying effect of the gate-keeper cancer mutations as catalysts of kinase activation, leading to the enhanced long-range communication among allosterically coupled segments and stabilization of the active kinase form. The results of this study can reconcile recent experimental studies of allosteric inhibition and long-range cooperativity between binding sites in protein kinases. The presented study offers a novel molecular insight into mechanistic aspects of allosteric kinase signaling and provides a quantitative picture of activation mechanisms in protein kinases at the atomic level.

  11. Overexpression of a Rrp1 transgene reduces the somatic mutation and recombination frequency induced by oxidative DNA damage in Drosophila melanogaster.

    Science.gov (United States)

    Szakmary, A; Huang, S M; Chang, D T; Beachy, P A; Sander, M

    1996-02-20

    Recombination repair protein 1 (Rrp1) includes a C-terminal region homologous to several DNA repair proteins, including Escherichia coli exonuclease III and human APE, that repair oxidative and alkylation damage to DNA. The nuclease activities of Rrp1 include apurinic/apyrimidinic endonuclease, 3'-phosphodiesterase, 3'-phosphatase, and 3'-exonuclease. As shown previously, the C-terminal nuclease region of Rrp1 is sufficient to repair oxidative- and alkylation-induced DNA damage in repair-deficient E. coli mutants. DNA strand-transfer and single-stranded DNA renaturation activities are associated with the unique N-terminal region of Rrp1, which suggests possible additional functions that include recombinational repair or homologous recombination. By using the Drosophila w/w+ mosaic eye system, which detects loss of heterozygosity as changes in eye pigmentation, somatic mutation and recombination frequencies were determined in transgenic flies overexpressing wild-type Rrp1 protein from a heat-shock-inducible transgene. A large decrease in mosaic clone frequency is observed when Rrp1 overexpression precedes treatment with gamma-rays, bleomycin, or paraquat. In contrast, Rrp1 overexpression does not alter the spot frequency after treatment with the alkylating agents methyl methanesulfonate or methyl nitrosourea. A reduction in mosaic clone frequency depends on the expression of the Rrp1 transgene and on the nature of the induced DNA damage. These data suggest a lesion-specific involvement of Rrp1 in the repair of oxidative DNA damage.

  12. Twenty year results on application of induced mutation in soybean (Glycine max (L.) Merr.) breeding at Agricultural Genetics Institute (AGI), Hanoi, Vietnam

    Energy Technology Data Exchange (ETDEWEB)

    Mai Quang Vinh; Phan Phai; Ngo Phuong Thinh; Tran Dinh Dong; Tran Thuy Oanh [Agricultural Genetics Institute (AGI), Hanoi (Viet Nam)

    2001-03-01

    Research on application of the induced mutation method combined with crossing in soybean breeding for 20 years (1980-2000) plays an important role in research work at AGI, (Ministry of Agriculture and Rural Development of Vietnam). 23 soybean varieties and hybrid lines (including 6 local cultivars, 14 selected and introduced varieties, 3 hybrid lines) were treated with Roentgen ray irradiation, Gamma Ray {sup 60}Co with doses 7, 10, 12, 15, 18, 20 krad, and with chemical mutagens: EI, NMU, DNMU, DES, EMS, DEU with various concentrations 0.008, 0.02, 0.04, 0.06, 0.08%. As the results, we obtained the important conclusions about the rule of induced mutation process in soybean in the natural conditions of Vietnam. 8 mutant varieties [1 National varieties (DT84) and 6 regional production varieties (DT83, DT90, DT94, DT95, DT99, AK06 (DT-55))]. Several promising varieties were selected and released for farmers to produce in the large areas that occupied 50-90% percentage of soybean cultivated areas in Vietnam. These varieties have high-yield 1.5-3.5 tons/ha, short growth duration 75-100 days, tolerance to cold and hot temperature and can be planted in 3 crops per year (Winter, Spring and Summer season) over 35-40 thousands ha/year. At present, the mutagens are being used for defect-orientated repair of some promising hybrid lines, in order to contribute new good varieties to soybean production in Vietnam. (author)

  13. Identification and characterization of adult alpha-and beta-globin genes and their genomic arrangement in Pseudosciaena crocea

    Institute of Scientific and Technical Information of China (English)

    CHU Wuying; QIAN Ronghua; WANG Lianshen; YU Xiameng; YOU Zhenqiang; YU Lian

    2006-01-01

    The α- and β-globin genes from Pseudosciaena crocea were cloned by rapid amplification of cDNA 3'-end (3'-RACE). The cDNA of the α-globin is 595 bp with the ATG start codon located at Position 37, the TAA stop codon at Position 469 and the AATAAA polyadenylation signal at Position 560, which codifies 145 amino acids. The entire open reading frame of the β-globin gene is 447 bp long, which encodes 148 amino acids. Amino acid identity of the α- globin or β-globin gene compared with those reported in other fish species, ranged from 31.9% to 76.4%. When comparing with human α- and β-globins, three important alterations in the structural regions can be noted: α39 Thr→Gln, α113 His→Tyr and β117 His→Lys. The α-globin has a unique inserted amino acid residue in the 47th position. To understand the process of globin gene duplication and identify the regulatory elements present in the intergenic and intragenic regions of globin genes, the genomic arrangement of α- and β-globin genes was investigated. The results showed that the orientation of the two genes was head-to-head relative to each other. The intergenic region between the translation initiation codons of the linked α- and β-globin genes contains classical promoter elements and the length of it is much shorter than that reported in other fish.

  14. Genomic organization and differential signature of positive selection in the alpha and beta globin gene clusters in two cetacean species.

    Science.gov (United States)

    Nery, Mariana F; Arroyo, José Ignacio; Opazo, Juan C

    2013-01-01

    The hemoglobin of jawed vertebrates is a heterotetramer protein that contains two α- and two β-chains, which are encoded by members of α- and β-globin gene families. Given the hemoglobin role in mediating an adaptive response to chronic hypoxia, it is likely that this molecule may have experienced a selective pressure during the evolution of cetaceans, which have to deal with hypoxia tolerance during prolonged diving. This selective pressure could have generated a complex history of gene turnover in these clusters and/or changes in protein structure themselves. Accordingly, we aimed to characterize the genomic organization of α- and β-globin gene clusters in two cetacean species and to detect a possible role of positive selection on them using a phylogenetic framework. Maximum likelihood and Bayesian phylogeny reconstructions revealed that both cetacean species had retained a similar complement of putatively functional genes. For the α-globin gene cluster, the killer whale presents a complement of genes composed of HBZ, HBK, and two functional copies of HBA and HBQ genes, whereas the dolphin possesses HBZ, HBK, HBA and HBQ genes, and one HBA pseudogene. For the β-globin gene cluster, both species retained a complement of four genes, two early expressed genes-HBE and HBH-and two adult expressed genes-HBD and HBB. Our natural selection analysis detected two positively selected sites in the HBB gene (56 and 62) and four in HBA (15, 21, 49, 120). Interestingly, only the genes that are expressed during the adulthood showed the signature of positive selection.

  15. Beta-globin gene cluster haplotypes and alpha-thalassemia in sickle cell disease patients from Trinidad.

    Science.gov (United States)

    Jones-Lecointe, Altheia; Smith, Erskine; Romana, Marc; Gilbert, Marie-Georges; Charles, Waveney P; Saint-Martin, Christian; Kéclard, Lisiane

    2008-01-01

    In this study, we have determined the frequency of beta(S) haplotypes in 163 sickle cell disease patients from Trinidad. The alpha(3.7) globin gene deletion status was also studied with an observed gene frequency of 0.17. Among the 283 beta(S) chromosomes analyzed, the Benin haplotype was the most prevalent (61.8%) followed by Bantu (17.3%), Senegal (8.5%), Cameroon (3.5%), and Arab-Indian (3.2%), while 5.7% of them were atypical. This beta(S) haplotypes distribution differed from those previously described in other Caribbean islands (Jamaica, Guadeloupe, and Cuba), in agreement with the known involvement of the major colonial powers (Spain, France, and Great Britain) in the slave trade in Trinidad and documented an Indian origin of the beta(S) gene.

  16. The beta-globin gene cluster haplotypes in sickle cell anemia patients from Northeast Brazil: a clinical and molecular view.

    Science.gov (United States)

    Adorno, Elisângela Vitória; Zanette, Angela; Lyra, Isa; Souza, Cyntia Cajado; Santos, Leandro Ferraz; Menezes, Joelma Figueiredo; Dupuit, Marie France; Almeida, Mari Ney Tavares; Reis, Mitermayer Galvão; Gonçalves, Marilda Souza

    2004-08-01

    The beta(S)-globin haplotypes were studied in 78 sickle cell Brazilian patients from Bahia, Northeast Brazil, that has a large population of African origin. Hemoglobin (Hb) profiles were developed by high-performance liquid chromatography (HPLC), and beta(S)-globin gene haplotypes were determined by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) techniques. We identified 44 (55.0%) patients with the CAR/Ben (Central African Republic/Benin) genotype, 16 (20.0%) Ben/Ben, 13 (16.2%) CAR/CAR and seven (8.8%) with other genotypes. Analyses of the phenotypes showed clinical differences related only to Hb F levels and blood transfusion therapy; the presence of -alpha(-3.7)-thalassemia (thal) demonstrated statistical significance when associated with hematocrit (p=0.044), MCV (p=0.0007), MCH (p=0.012) and spleen sequestration events. The haplotype diversity found in the present study can be justified by information about the origin of the slave traffic period in Bahia during the 19th century. The specific characteristics described among the Bahian sickle cell patients could be confirmed by increasing the number of patients with specific genotypes and further studies of genetic markers.

  17. Inter-ethnic polymorphism of the beta-globin gene locus control region (LCR) in sickle-cell anemia patients.

    Science.gov (United States)

    Périchon, B; Ragusa, A; Lapouméroulie, C; Romand, A; Moi, P; Ikuta, T; Labie, D; Elion, J; Krishnamoorthy, R

    1993-06-01

    Sequence polymorphisms within the 5'HS2 segment of human locus control region is described among sickle cell anemia patients. Distinct polymorphic patterns of a simple sequence repeat are observed in strong linkage disequilibrium with each of the five major beta s haplotypes. Potential functional relevance of this polymorphic region in globin gene expression is discussed.

  18. Assessing the relative stabilities of engineered hemoglobins using electrospray mass spectrometry.

    Science.gov (United States)

    Apostol, I

    1999-07-15

    An ion trap mass spectrometer equipped with an electrospray source was used to examine the relative thermodynamic stabilities of various hemoglobins with respect to both tetramer dissociation and hemin dissociation. The results demonstrated that the stability of hemoglobin molecules can be differentiated by the amount of applied collision-induced dissociation (CID) energy necessary to break up the intact tetramer into its constituent globins. The stability of the intact tetramer was affected by single mutations in the beta-globins. The stabilities of the constituent hologlobins were assessed via trap CID of selected ions. The results demonstrated the importance of the contributions of the hologlobin components to the stability of the intact tetramer. Genetic fusion of two alpha-globins, through the introduction of a single glycine residue between the C-terminus of one alpha-chain and the N-terminus of the second, significantly increased the stability of the hemoglobin pseudo-tetramer. Chemical crosslinking of the beta-globins in addition to genetic fusion of alpha-globins further stabilized the hemoglobin molecule. A dihemoglobin molecule produced by the genetic fusion of two di-alpha-globins with a flexible linker demonstrated a decreased stability relative to the corresponding monohemoglobin.

  19. Coat protein mutations in an attenuated Cucumber mosaic virus encoding mutant 2b protein that lacks RNA silencing suppressor activity induces chlorosis with photosynthesis gene repression and chloroplast abnormalities in infected tobacco plants.

    Science.gov (United States)

    Mochizuki, Tomofumi; Yamazaki, Ryota; Wada, Tomoya; Ohki, Satoshi T

    2014-05-01

    In tobacco plants, the Cucumber mosaic virus (CMV) pepo strain induces mosaic symptoms, including pale green chlorosis and malformed tissues. Here, we characterized the involvement of 2b protein and coat protein (CP) in the development of mosaic symptoms. A 2b mutant (R46C) that lacks viral suppressor of RNA silencing (VSR) activity showed an asymptomatic phenotype with low levels of virus accumulation. Tomato spotted wilt virus NSs protein did not complement the virulence of the R46C, although it did restore high-level virus accumulation. However, R46C mutants expressing mutated CP in which the amino acid P129 was mutated to A, E, C, Q, or S induced chlorosis that was associated with reduced expression of chloroplast and photosynthesis related genes (CPRGs) and abnormal chloroplasts with fewer thylakoid membranes. These results suggest that the CP of the CMV pepo strain acquires virulence by amino acid mutations, which causes CPRG repression and chloroplast abnormalities.

  20. Evaluation of AgClNPs@SBA-15/IL nanoparticle-induced oxidative stress and DNA mutation in Escherichia coli.

    Science.gov (United States)

    Karimi, Farrokh; Dabbagh, Somayyeh; Alizadeh, Sina; Rostamnia, Sadegh

    2016-08-01

    The bactericidal effects of silver nanoparticles have been demonstrated in the past years. Recently, the new antimicrobial compounds of silver nanoparticles with different formulations have been developed. In this work, AgClNPs@SBA-15/IL as a new compound of Ag nanoparticles, was synthesized and characterized by XRD, TEM, SEM, FTIR, and EDX. The antibacterial activity and the molecular mechanism effects of AgClNPs@SBA-15/IL nanoparticles (SNPs) on Escherichia coli DH5α cells were investigated by analyzing the growth inhibitory, H2O2 level, catalase activity, DNA mutation, and plasmid copy number following treatment with AgClNPs@SBA-15/IL nanoparticles. In experimental results, the minimum inhibitory concentration (MIC) was observed in 75 μg/ml and the antibacterial efficacy (ABE) in CFU analysis was estimated 95.3 %. In bacterial cells treated with 75 and 100 μg/ml, H2O2 level significantly increased and catalase activity decreased compared with control. The random amplified polymorphic DNA (RAPD) was used to evaluate the effect of AgClNPs@SBA-15/IL nanoparticles in DNA damages and mutation in E. coli genome. RADP-PCR results indicated different banding patterns including appearance or disappearance of bands and differences in their intensity. Cluster analysis of the RAPD-PCR results based on genetic similarity showed genetic difference between E. coli cells treated with AgClNPs@SBA-15/IL nanoparticles, and control and phylogenetic tree were divided to two clusters. Plasmid copy number analysis indicated that after 8 h incubation of E. coli cells with 50, 75, and 100 μg/ml AgClNPs@SBA-15/IL nanoparticles, copy number of pET21a (+) significantly decreased compared with control which indicating DNA replication inhibition by Ag nanoparticles. In conclusion, the results of this study indicated that AgClNPs@SBA-15/IL nanoparticles can be used as an effective bactericidal agent against bacterial cells.

  1. Induced point mutations in the phytoene synthase 1 gene cause differences in carotenoid content during tomato fruit ripening

    NARCIS (Netherlands)

    Gady, A.L.F.; Vriezen, W.; Wal, van de M.H.B.J.; Huang, P.; Bovy, A.G.; Visser, R.G.F.; Bachem, C.W.B.

    2012-01-01

    In tomato, carotenoids are important with regard to major breeding traits such as fruit colour and human health. The enzyme phytoene synthase (PSY1) directs metabolic flux towards carotenoid synthesis. Through TILLING (Targeting Induced Local Lesions IN Genomes), we have identified two point mutatio

  2. Growth parameter components of adaptive specificity during experimental evolution of the UVR-inducible mutator Pseudomonas cichorii 302959.

    Directory of Open Access Journals (Sweden)

    Michael R Weigand

    Full Text Available BACKGROUND: Mutagenic DNA repair (MDR transiently increases mutation rate through the activation of low-fidelity repair polymerases in response to specific, DNA-damaging environmental stress conditions such as ultraviolet radiation (UVR exposure. These repair polymerases also confer UVR tolerance, intimately linking mutability and survival in bacteria that colone habitats subject to regular UVR exposure. METHODOLOGY/PRINCIPAL FINDINGS: Here, we investigate adaptive specificity in experimental lineages of the highly UVR-mutable epiphytic plant pathogen Pseudomonas cichorii 302959. Relative fitness measurements of isolates and population samples from replicate lineages indicated that adaptive improvements emerged early in all lineages of our evolution experiment and specific increases in relative fitness correlated with distinct improvements in doubling and lag times. Adaptive improvements gained under UVR and non-UVR conditions were acquired preferentially, and differentially contributed to relative fitness under varied growth conditions. CONCLUSIONS: These results support our earlier observations that MDR activation may contribute to gains in relative fitness without impeding normal patterns of adaptive specificity in P. cichorii 302959.

  3. Analysis of UV-induced mutation spectra in Escherichia coli by DNA polymerase eta from Arabidopsis thaliana.

    Science.gov (United States)

    Santiago, María Jesús; Alejandre-Durán, Encarna; Ruiz-Rubio, Manuel

    2006-10-10

    DNA polymerase eta belongs to the Y-family of DNA polymerases, enzymes that are able to synthesize past template lesions that block replication fork progression. This polymerase accurately bypasses UV-associated cis-syn cyclobutane thymine dimers in vitro and therefore may contributes to resistance against sunlight in vivo, both ameliorating survival and decreasing the level of mutagenesis. We cloned and sequenced a cDNA from Arabidopsis thaliana which encodes a protein containing several sequence motifs characteristics of Pol eta homologues, including a highly conserved sequence reported to be present in the active site of the Y-family DNA polymerases. The gene, named AtPOLH, contains 14 exons and 13 introns and is expressed in different plant tissues. A strain from Saccharomyces cerevisiae, deficient in Pol eta activity, was transformed with a yeast expression plasmid containing the AtPOLH cDNA. The rate of survival to UV irradiation in the transformed mutant increased to similar values of the wild type yeast strain, showing that AtPOLH encodes a functional protein. In addition, when AtPOLH is expressed in Escherichia coli, a change in the mutational spectra is detected when bacteria are irradiated with UV light. This observation might indicate that AtPOLH could compete with DNA polymerase V and then bypass cyclobutane pyrimidine dimers incorporating two adenylates.

  4. Induced pluripotent stem cells (iPSCs) derived from af pre-symptomatic carrier of a R406W mutation in microtubule-associated protein tau (MAPT) causing frontotemporal dementia

    DEFF Research Database (Denmark)

    Rasmussen, Mikkel A.; Hjermind, Lena Elisabeth; Hasholt, Lis Frydenreich

    2016-01-01

    Skin fibroblasts were obtained from a 28-year-old pre-symptomatic woman carrying a R406W mutation in microtubule-associated protein tau (MAPT), known to cause frontotemporal dementia. Induced pluripotent stem cell (iPSCs) were established by electroporation with episomal plasmids containing hOCT4...

  5. SH3BP2 gain-of-function mutation exacerbates inflammation and bone loss in a murine collagen-induced arthritis model.

    Directory of Open Access Journals (Sweden)

    Tomoyuki Mukai

    Full Text Available OBJECTIVE: SH3BP2 is a signaling adapter protein which regulates immune and skeletal systems. Gain-of-function mutations in SH3BP2 cause cherubism, characterized by jawbone destruction. This study was aimed to examine the role of SH3BP2 in inflammatory bone loss using a collagen-induced arthritis (CIA model. METHODS: CIA was induced in wild-type (Sh3bp2(+/+ and heterozygous P416R SH3BP2 cherubism mutant knock-in (Sh3bp2(KI/+ mice, an SH3BP2 gain-of-function model. Severity of the arthritis was determined by assessing the paw swelling and histological analyses of the joints. Micro-CT analysis was used to determine the levels of bone loss. Inflammation and osteoclastogenesis in the joints were evaluated by quantitating the gene expression of inflammatory cytokines and osteoclast markers. Furthermore, involvement of the T- and B-cell responses was determined by draining lymph node cell culture and measurement of the serum anti-mouse type II collagen antibody levels, respectively. Finally, roles of the SH3BP2 mutation in macrophage activation and osteoclastogenesis were determined by evaluating the TNF-α production levels and osteoclast formation in bone marrow-derived M-CSF-dependent macrophage (BMM cultures. RESULTS: Sh3bp2(KI/+ mice exhibited more severe inflammation and bone loss, accompanying an increased number of osteoclasts. The mRNA levels for TNF-α and osteoclast marker genes were higher in the joints of Sh3bp2(KI/+ mice. Lymph node cell culture showed that lymphocyte proliferation and IFN-γ and IL-17 production were comparable between Sh3bp2(+/+ and Sh3bp2(KI/+ cells. Serum anti-type II collagen antibody levels were comparable between Sh3bp2(+/+ and Sh3bp2(KI/+ mice. In vitro experiments showed that TNF-α production in Sh3bp2(KI/+ BMMs is elevated compared with Sh3bp2(+/+ BMMs and that RANKL-induced osteoclastogenesis is enhanced in Sh3bp2(KI/+ BMMs associated with increased NFATc1 nuclear localization. CONCLUSION: Gain-of-function of

  6. A point mutation of PRL gene in pituitary prolactin-secreting adenoma induced by 17-b-estradiol in SD rats

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Animal model bearing pituitary prolactin-secreting adenomas (prolactinoma) induced by 17-b -estradiol (E2) in both eutopic pituitary and ectopic pituitary grafted under the renal capsule was generated.Northern blotting assay indicated that PRL mRNA level in eutopic prolactinomas was higher than that in normal pituitaries and ectopic prolactinomas (P<0.05-0.01).By polymerase chain reaction (PCR)-single-strand conformation polymorphism (SSCP) analysis and DNA sequencing,a point mutation from C to A occurring at -36 nt in proximal promoter of rat PRL (rPRL) gene was found only in eutopic prolactinomas.No base change was detected in ectopic prolactinomas.Fusion gene transfection assay in vitro exhibited increased activity of the mutant promoter derived from eutopic prolactinoma (P<0.01).These data suggested that the base change in the proximal promoter of rPRL gene may be associated with hyperexpression of rPRL gene in eutopic prolactinomas.The pathogenesis of eutopic and ectopic prolactinomas induced by E2 in SD rats may be separate.

  7. Detailed computational analysis revealed mutation V210I on PrP induced conformational conversion on β2-α2 loop and α2-α3.

    Science.gov (United States)

    Chandrasekaran, P; Rajasekaran, R

    2016-10-20

    The development of fatal transmissible spongiform encephalopathies (TSE) is associated with the conformational conversion of the normal cellular prion protein, PrP(C), into its pathogenic isoform, PrP(Sc). The present study revealed the structural consequences that induce the conversion of PrP(C)→ PrP(Sc) upon mutation V210I linked with genetic Creutzfeldt-Jakob disease (CJD) using the classical molecular dynamics (MD) approach. Similar to the experimental results, the mutant showed biased disruption in the local folding of α2 and the complete distortion of α3. In addition, substitution of bulkier Ile at position 210 induced reorientations of several residues that were the constituent of hydrophobic cores, thereby influencing α2-α3 inter-helical interactions. In addition, the β2-α2 loop was greatly altered due to the loss of π-π interactions of the residue Tyr(169) with Phe(175), Tye(163), Tyr(162), and Tyr(218), facilitating more conformational flexibility, which may be involved in the conversion of PrP(C)→ PrP(Sc). This study afforded a detailed structure and dynamic properties of the mutant, which were consistent with the experimental results, providing an insight into the molecular basis for the conversion of PrP(C)→ PrP(Sc), which could be used for the development of antiprion drugs.

  8. A gain-of-function mutation in Msl10 triggers cell death and wound-induced hyperaccumulation of jasmonic acid in Arabidopsis

    Institute of Scientific and Technical Information of China (English)

    Yan Zou; Jian-Min Zhou; Satya Chintamanani; Ping He; Hirotada Fukushige; Liping Yu; Meiyu Shao; Lihuang Zhu; David F Hildebrand; Xiaoyan Tang

    2016-01-01

    Jasmonates (JAs) are rapidly induced after wound-ing and act as key regulators for wound induced signaling pathway. However, what perceives the wound signal and how that triggers JA biosynthesis remains poorly understood. To identify components involved in Arabidopsis wound and JA signaling pathway, we screened for mutants with abnormal expression of a luciferase reporter, which is under the control of a wound-responsive promoter of an ethylene response factor (ERF) transcription factor gene, RAP2.6 (Related to APetala 2.6). The rea1 (RAP2.6 expresser in shoot apex) mutant constitutively expressed the RAP2.6-LUC reporter gene in young leaves. Along with the typical JA phenotypes including shorter petioles, loss of apical dominance, accumulation of anthocyanin pig-ments and constitutive expression of JA response gene, rea1 plants also displayed cell death and accumulated high levels of JA in response to wounding. The phenotype of rea1 mutant is caused by a gain-of-function mutation in the C-terminus of a mechanosensitive ion channel MscS-like 10 (MSL10). MSL10 is localized in the plasma membrane and is expressed predom-inantly in root tip, shoot apex and vascular tissues. These results suggest that MSL10 is involved in the wound-triggered early signal transduction pathway and possibly in regulating the positive feedback synthesis of JA.

  9. Mutations in thep16 gene in DMBA-induced pancreatic intraepithelial neoplasia and pancreatic cancer in rats

    Institute of Scientific and Technical Information of China (English)

    Zhu Zhu; Tao Liu; Fei Han; Su-Dong Zhan; Chun-You Wang

    2015-01-01

    BACKGROUND: 7, 12-dimethylbenzanthracene (DMBA)-induced pancreatic intraepithelial neoplasia (PanIN) and pancreatic cancer in rats provide a classic model for uncovering the molec-ular mechanisms underlying pancreatic cancer. However, this model has not been characterized genetically, and in particular, the major genetic alterations in the p16 gene are unknown. METHODS: Lesions of PanIN and pancreatic cancer were in-duced with DMBA implantation in 40 rats, and control pancre-atic tissue was obtained from 10 age-matched rats without ex-posure to DMBA. Pancreatic tissue was harvested three months after DMBA implantation and DNA was extracted. Homozy-gous deletions and point mutations of the p16 (exons 1 and 2) gene were detected by PCR ampliifcation and direct sequencing. RESULTS: DMBA implantation in the 40 rats induced 26 Pan-INs and 9 carcinomas. The overall frequency of p16 alterations in the pancreatic tissue of these rats was 42.86% (15/35), and the changes were point mutations, not homozygous deletions. p16 mutations were present in 30.77% (8/26) of the rats with PanIN and 77.78% (7/9) of the rats with carcinoma (P CONCLUSION: Our ifndings indicated that p16 alteration is a common event in the carcinogenesis of this model and that the mutation pattern is analogous to that of human lesions.

  10. Ligand- and mutation-induced conformational selection in the CCR5 chemokine G protein-coupled receptor.

    Science.gov (United States)

    Abrol, Ravinder; Trzaskowski, Bartosz; Goddard, William A; Nesterov, Alexandre; Olave, Ivan; Irons, Christopher

    2014-09-09

    We predicted the structural basis for pleiotropic signaling of the C-C chemokine type 5 (CCR5) G protein-coupled receptor (GPCR) by predicting the binding of several ligands to the lower-energy conformations of the CCR5 receptor and 11 mutants. For each case, we predicted the ∼ 20 most stable conformations for the receptor along with the binding sites for four anti-HIV ligands. We found that none of the ligands bind to the lowest-energy apo-receptor conformation. The three ligands with a similar pharmacophore (Maraviroc, PF-232798, and Aplaviroc) bind to a specific higher-energy receptor conformation whereas TAK-779 (with a different pharmacophore) binds to a different high-energy conformation. This result is in agreement with the very different binding-site profiles for these ligands obtained by us and others. The predicted Maraviroc binding site agrees with the recent structure of CCR5 receptor cocrystallized with Maraviroc. We performed 11 site-directed mutagenesis experiments to validate the predicted binding sites. Here, we independently predicted the lowest 10 mutant protein conformations for each of the 11 mutants and then docked the ligands to these lowest conformations. We found the predicted binding energies to be in excellent agreement with our mutagenesis experiments. These results show that, for GPCRs, each ligand can stabilize a different protein conformation, complicating the use of cocrystallized structures for ligand screening. Moreover, these results show that a single-point mutation in a GPCR can dramatically alter the available low-energy conformations, which in turn alters the binding site, potentially altering downstream signaling events. These studies validate the conformational selection paradigm for the pleiotropic function and structural plasticity of GPCRs.

  11. X射线诱发外周血淋巴细胞TCR基因突变研究%X-ray induced TCR gene mutation of peripheral blood lymphocytes

    Institute of Scientific and Technical Information of China (English)

    侯殿俊; 马娅; 刘伟; 乔建维; 卢峰; 商希梅; 李洁清; 封丽

    2009-01-01

    objective To study the TCR gene mutation in peripheral blood lymphocytes induced by X-ray exposure using cultured lymphocytes cloning method.Methods Freshly isolated peripheral lymphocytes from healthy aduh donors were irradiated with X-ray in doses ranging from 0 to 8 Gy and cultured with interleukin2 and phytohemagglutinin for 7 days.The mutant frequencies of TCR gene(TCR MF)were detected by flow cytonletry and the dose response curves were fitted.Results TCR MF increased with the dose going up.An aquadratic polynomial dose response model was fitted.Conclusions TCR gene mutation could which serve as a potential biological dosimeter.It might be applied for the estimation of biological dose in emergency exposure.%目的 用培养法研究X射线诱发的人外周血淋巴细胞TCR基因突变情况.方法 以不同剂量(0~8 Gy)的X射线照射新鲜分离的健康成人外周血淋巴细胞,植物血凝素、白细胞介素2(IL-2)协同刺激培养7 d,流式细胞术检测TCR基因突变频率(TCR MF),并拟合剂量效应关系.结果 随着照射剂量的增加,TCR基因突变频率随之上升,最佳拟合曲线为二次多项式模型.结论 TCR基因突变可作为辐射生物剂量计,用于急性辐射照射生物剂量的估算.

  12. Dengue type four viruses with E-Glu345Lys adaptive mutation from MRC-5 cells induce low viremia but elicit potent neutralizing antibodies in rhesus monkeys.

    Science.gov (United States)

    Lin, Hsiao-Han; Lee, Hsiang-Chi; Li, Xiao-Feng; Tsai, Meng-Ju; Hsiao, Hung-Ju; Peng, Jia-Guan; Sue, Shih-Che; Qin, Cheng-Feng; Wu, Suh-Chin

    2014-01-01

    Knowledge of virulence and immunogenicity is important for development of live-attenuated dengue vaccines. We previously reported that an infectious clone-derived dengue type 4 virus (DENV-4) passaged in MRC-5 cells acquired a Glu345Lys (E-E345K) substitution in the E protein domain III (E-DIII). The same cloned DENV-4 was found to yield a single E-Glu327Gly (E-E327G) mutation after passage in FRhL cells and cause the loss of immunogenicity in rhesus monkeys. Here, we used site-directed mutagenesis to generate the E-E345K and E-E327G mutants from DENV-4 and DENV-4Δ30 infectious clones and propagated in Vero or MRC-5 cells. The E-E345K mutations were consistently presented in viruses recovered from MRC-5 cells, but not Vero cells. Recombinant E-DIII proteins of E345K and E327G increased heparin binding correlated with the reduced infectivity by heparin treatment in cell cultures. Different from the E-E327G mutant viruses to lose the immunogencity in rhesus monkeys, the E-E345K mutant viruses were able to induce neutralizing antibodies in rhesus monkeys with an almost a 10-fold lower level of viremia as compared to the wild type virus. Monkeys immunized with the E-E345K mutant virus were completely protected with no detectable viremia after live virus challenges with the wild type DENV-4. These results suggest that the E-E345K mutant virus propagated in MRC-5 cells may have potential for the use in live-attenuated DENV vaccine development.

  13. Par-3 partitioning defective 3 homolog (C. elegans and androgen-induced prostate proliferative shutoff associated protein genes are mutationally inactivated in prostate cancer cells

    Directory of Open Access Journals (Sweden)

    Ivanov Igor

    2009-09-01

    Full Text Available Abstract Background Gene identification by nonsense-mediated mRNA decay inhibition (GINI has proven its usefulness in identifying mutant genes in cancer cell lines. An increase in transcription in response to NMD inhibition of a subset of genes is a major cause of false positives when genes are selected for sequencing analysis. To distinguish between mRNA accumulations caused by stress response-induced transcription and nonsense-containing mRNA stabilizations is a challenge in identifying mutant genes using GINI. Methods To identify potential tumor-suppressor genes mutated in prostate cancer cell lines, we applied a version of GINI that involves inhibition of NMD in two steps. In the first step, NMD is inhibited in duplicate tissue-culture plates. During this step, both the substrate for NMD and stress-response mRNA transcripts are accumulated in cells. In the second step, transcription is inhibited in both plates and NMD is inhibited in one plate and released in the second plate. Microarray analysis of gene-expression profiles in both plates after the second step detects only the differences in mRNA degradation but not in mRNA accumulation. Results Analyzing gene expression profile alterations in 22RV1 and LNCaP prostate cancer cells following NMD inhibition we selected candidates for sequencing analysis in both cell lines. Sequencing identified inactivating mutations in both alleles of the PARD3 and AS3 genes in the LNCaP and 22RV1 cells, respectively. Introduction of a wild-type PARD3 cDNA into the LNCaP cells resulted in a higher proliferation rate in tissue culture, a higher adhesion of LNCaP cells to the components of extracellular matrix and impaired the growth of the LNCaP cells in soft agar and in a three-dimensional cell-culture. Conclusion The mutational inactivation in a prostate cancer cell line of the PARD3 gene involved in asymmetric cell division and maintenance of cell-polarity suggests that the loss of cell-polarity contributes

  14. Romidepsin-induced HIV-1 viremia during effective antiretroviral therapy contains identical viral sequences with few deleterious mutations

    Science.gov (United States)

    Winckelmann, Anni; Barton, Kirston; Hiener, Bonnie; Schlub, Timothy E.; Shao, Wei; Rasmussen, Thomas A.; Østergaard, Lars; Søgaard, Ole S.; Tolstrup, Martin; Palmer, Sarah

    2017-01-01

    Objective: To investigate the origin of the HIV-1 viremia induced by the latency-reversing agent romidepsin. Design: Six individuals on suppressive antiretroviral therapy received romidepsin administered intravenously once weekly for 3 consecutive weeks. CD4+ T cells were obtained at baseline, following the second and third romidepsin infusion, and 10 weeks after the final romidepsin treatment. Plasma samples were collected 24 and 72 h after romidepsin infusions. Methods: Single-genome sequencing of the env and p24-RT region was used to genetically characterize the virus from proviral DNA, the transcribed cell-associated RNA and the plasma RNA pool. Results: In three of six participants with available plasma samples we identified plasma HIV-1 RNA sequences that were identical to DNA and/or cell-associated RNA sequences from peripheral blood CD4+ T cells. In two participants, plasma RNA sequences contained expansions of identical sequences, corresponding to 62 and 100% of the total sequences, respectively. Plasma HIV-1 RNA had very low amounts of defective viruses compared to cell-associated RNA (odds ratio 20.85, P < 0.001) and to DNA (odds ratio 7.07, P = 0.011) during romidepsin therapy. Conclusions: Romidepsin induced transcription from proviruses in peripheral blood cells, which contributed to viremia in patients on suppressive therapy. The intermingling of these cell-associated HIV-1 RNA with DNA sequences indicates transcription from a diverse range of proviruses, but the expansions of identical viral plasma sequences with few defects indicate that the romidepsin-induced viremia arises from intact proviruses with highly similar or identical genetic backgrounds. PMID:28272134

  15. Missense Mutations in LRP5 Associated with High Bone Mass Protect the Mouse Skeleton from Disuse- and Ovariectomy-Induced Osteopenia.

    Science.gov (United States)

    Niziolek, Paul J; Bullock, Whitney; Warman, Matthew L; Robling, Alexander G

    2015-01-01

    The low density lipoprotein receptor-related protein-5 (LRP5), a co-receptor in the Wnt signaling pathway, modulates bone mass in humans and in mice. Lrp5 knock-out mice have severely impaired responsiveness to mechanical stimulation whereas Lrp5 gain-of-function knock-in and transgenic mice have enhanced responsiveness to mechanical stimulation. Those observations highlight the importance of Lrp5 protein in bone cell mechanotransduction. It is unclear if and how high bone mass-causing (HBM) point mutations in Lrp5 alter the bone-wasting effects of mechanical disuse. To address this issue we explored the skeletal effects of mechanical disuse using two models, tail suspension and Botulinum toxin-induced muscle paralysis, in two different Lrp5 HBM knock-in mouse models. A separate experiment employing estrogen withdrawal-induced bone loss by ovariectomy was also conducted as a control. Both disuse stimuli induced significant bone loss in WT mice, but Lrp5 A214V and G171V were partially or fully protected from the bone loss that normally results from disuse. Trabecular bone parameters among HBM mice were significantly affected by disuse in both models, but these data are consistent with DEXA data showing a failure to continue growing in HBM mice, rather than a loss of pre-existing bone. Ovariectomy in Lrp5 HBM mice resulted in similar protection from catabolism as was observed for the disuse experiments. In conclusion, the Lrp5 HBM alleles offer significant protection from the resorptive effects of disuse and from estrogen withdrawal, and consequently, present a potential mechanism to mimic with pharmaceutical intervention to protect against various bone-wasting stimuli.

  16. Induced pluripotent stem cells (iPSCs) derived from a symptomatic carrier of a S305I mutation in the microtubule-associated protein tau (MAPT)-gene causing frontotemporal dementia

    DEFF Research Database (Denmark)

    Nimsanor, Natakarn; Jørring, Ida; Rasmussen, Mikkel A.

    2016-01-01

    Frontotemporal dementia with parkinsonism linked to chromosome 17q21.2 (FTDP-17) is an autosomal-dominant neurodegenerative disorder. Mutations in the gene coding the microtubule-associated protein tau (MAPT) can cause FTDP-17 but the underlying mechanisms of the disease are still unknown. Induce...... pluripotent stem cells (iPSCs) hold great promise to model FTDP-17 as such cells can be differentiated in vitro to the required neuronal cell type. Here, we report the generation of iPSCs from a 44-year-old symptomatic woman carrying a S305I mutation in the MAPT-gene....

  17. Tumor Necrosis Factor Receptor-associated Protein 1 (TRAP1) Mutation and TRAP1 Inhibitor Gamitrinib-triphenylphosphonium (G-TPP) Induce a Forkhead Box O (FOXO)-dependent Cell Protective Signal from Mitochondria.

    Science.gov (United States)

    Kim, Hyunjin; Yang, Jinsung; Kim, Min Ju; Choi, Sekyu; Chung, Ju-Ryung; Kim, Jong-Min; Yoo, Young Hyun; Chung, Jongkyeong; Koh, Hyongjong

    2016-01-22

    TRAP1 (tumor necrosis factor receptor-associated protein 1), a mitochondrial Hsp90 family chaperone, has been identified as a critical regulator of cell survival and bioenergetics in tumor cells. To discover novel signaling networks regulated by TRAP1, we generated Drosophila TRAP1 mutants. The mutants successfully developed into adults and produced fertile progeny, showing that TRAP1 is dispensable in development and reproduction. Surprisingly, mutation or knockdown of TRAP1 markedly enhanced Drosophila survival under oxidative stress. Moreover, TRAP1 mutation ameliorated mitochondrial dysfunction and dopaminergic (DA) neuron loss induced by deletion of a familial Parkinson disease gene PINK1 (Pten-induced kinase 1) in Drosophila. Gamitrinib-triphenylphosphonium, a mitochondria-targeted Hsp90 inhibitor that increases cell death in HeLa and MCF7 cells, consistently inhibited cell death induced by oxidative stress and mitochondrial dysfunction induced by PINK1 mutation in mouse embryonic fibroblast cells and DA cell models such as SH-SY5Y and SN4741 cells. Additionally, gamitrinib-triphenylphosphonium also suppressed the defective locomotive activity and DA neuron loss in Drosophila PINK1 null mutants. In further genetic analyses, we showed enhanced expression of Thor, a downstream target gene of transcription factor FOXO, in TRAP1 mutants. Furthermore, deletion of FOXO almost nullified the protective roles of TRAP1 mutation against oxidative stress and PINK1 mutation. These results strongly suggest that inhibition of the mitochondrial chaperone TRAP1 generates a retrograde cell protective signal from mitochondria to the nucleus in a FOXO-dependent manner.

  18. Tumor Necrosis Factor Receptor-associated Protein 1 (TRAP1) Mutation and TRAP1 Inhibitor Gamitrinib-triphenylphosphonium (G-TPP) Induce a Forkhead Box O (FOXO)-dependent Cell Protective Signal from Mitochondria*

    Science.gov (United States)

    Kim, Hyunjin; Yang, Jinsung; Kim, Min Ju; Choi, Sekyu; Chung, Ju-Ryung; Kim, Jong-Min; Yoo, Young Hyun; Chung, Jongkyeong; Koh, Hyongjong

    2016-01-01

    TRAP1 (tumor necrosis factor receptor-associated protein 1), a mitochondrial Hsp90 family chaperone, has been identified as a critical regulator of cell survival and bioenergetics in tumor cells. To discover novel signaling networks regulated by TRAP1, we generated Drosophila TRAP1 mutants. The mutants successfully developed into adults and produced fertile progeny, showing that TRAP1 is dispensable in development and reproduction. Surprisingly, mutation or knockdown of TRAP1 markedly enhanced Drosophila survival under oxidative stress. Moreover, TRAP1 mutation ameliorated mitochondrial dysfunction and dopaminergic (DA) neuron loss induced by deletion of a familial Parkinson disease gene PINK1 (Pten-induced kinase 1) in Drosophila. Gamitrinib-triphenylphosphonium, a mitochondria-targeted Hsp90 inhibitor that increases cell death in HeLa and MCF7 cells, consistently inhibited cell death induced by oxidative stress and mitochondrial dysfunction induced by PINK1 mutation in mouse embryonic fibroblast cells and DA cell models such as SH-SY5Y and SN4741 cells. Additionally, gamitrinib-triphenylphosphonium also suppressed the defective locomotive activity and DA neuron loss in Drosophila PINK1 null mutants. In further genetic analyses, we showed enhanced expression of Thor, a downstream target gene of transcription factor FOXO, in TRAP1 mutants. Furthermore, deletion of FOXO almost nullified the protective roles of TRAP1 mutation against oxidative stress and PINK1 mutation. These results strongly suggest that inhibition of the mitochondrial chaperone TRAP1 generates a retrograde cell protective signal from mitochondria to the nucleus in a FOXO-dependent manner. PMID:26631731

  19. Deficiency of patched 1-induced Gli1 signal transduction results in astrogenesis in Swedish mutated APP transgenic mice.

    Science.gov (United States)

    He, Ping; Staufenbiel, Matthias; Li, Rena; Shen, Yong

    2014-12-15

    Normally, sonic hedgehog (Shh) signaling induces high levels of Patched 1 (Ptc1) and its associated transcription factor Gli1 with genesis of specific neuronal progeny. But their roles in the neural stem cells (NSCs), including glial precursor cells (GPCs), of Alzheimer's disease (AD) are unclear. Here, we show that Ptc1 and Gli1 are significantly deficits in the hippocampus of an aged AD transgenic mouse mode, whereas these two molecules are highly elevated at young ages. Our similar findings in autopsied AD brains validate the discovery in AD mouse models. To examine whether Aβ peptides, which are a main component of the amyloid plaques in AD brains, affected Ptc1-Gli1 signaling, we treated GPCs with Aβ peptides, we found that high dose of Aβ1-42 but not Aβ1-40 significantly decreased Ptc1-Gli1, while Shh itself was elevated in hippocampal NSCs/GPCs. Furthermore, we found that deficits of Ptc1-Gli1 signaling induced NSCs/GPCs into asymmetric division, which results in an increase in the number of dividing cells including transit-amplifying cells and neuroblasts. These precursor cells commit to apoptosis-like death under the toxic conditions. By this way, adult neural precursor cell pool is exhausted and defective neurogenesis happens in AD brains. Our findings suggest that Ptc1-Gli1 signaling deregulation resulting abnormal loss of GPCs may contribute to a cognition decline in AD brains. The novel findings elucidate a new molecular mechanism of adult NSCs/GPCs on neurogenesis and demonstrate a regulatory role for Ptc1-Gli1 in adult neural circuit integrity of the brain.

  20. Screening for microsatellite instability identifies frequent 3'-untranslated region mutation of the RB1-inducible coiled-coil 1 gene in colon tumors.

    Directory of Open Access Journals (Sweden)

    Bogdan C Paun

    Full Text Available BACKGROUND: Coding region microsatellite instability (MSI results in loss of gene products and promotion of microsatellite-unstable (MSI-H carcinogenesis. Recent studies have indicated that MSI within 3'-untranslated regions (3'UTRs may post-transcriptionally dysregulate gene products. Within this context, we conducted a broad mutational survey of 42 short 3'UTR microsatellites (MSs in 45 MSI-H colorectal tumors and their corresponding normal colonic mucosae. METHODOLOGY/PRINCIPAL FINDINGS: In order to estimate the overall susceptibility of MSs to MSI in MSI-H tumors, the observed MSI frequency of each MS was correlated with its length, interspecies sequence conservation level, and distance from some genetic elements (i.e., stop codon, polyA signal, and microRNA binding sites. All MSs were stable in normal colonic mucosae. The MSI frequency at each MS in MSI-H tumors was independent of sequence conservation level and distance from other genetic elements. In contrast, MS length correlated significantly with MSI frequency in MSI-H tumors (r=0.86, p=7.2x10(-13. 3'UTR MSs demonstrated MSI frequencies in MSI-H tumors higher than the 99% upper limit predicted by MS length for RB1-inducible coiled-coil 1(RB1CC1, mutation frequency 68.4%, NUAK family SNF1-like kinase 1(NUAK1, 31.0%, and Rtf1, Paf1/RNA polymerase II complex component, homolog (RTF1, 25.0%. An in silico prediction of RNA structure alterations was conducted for these MSI events to gauge their likelihood of affecting post-transcriptional regulation. RB1CC1 mutant was predicted to lose a microRNA-accessible loop structure at a putative binding site for the tumor-suppressive microRNA, miR-138. In contrast, the predicted 3'UTR structural change was minimal for NUAK1- and RTF1 mutants. Notably, real-time quantitative RT-PCR analysis revealed significant RB1CC1 mRNA overexpression vs. normal colonic mucosae in MSI-H cancers manifesting RB1CC1 3'UTR MSI (9.0-fold; p = 3.6x10(-4. CONCLUSIONS: This

  1. A novel in vivo transcription assay demonstrates the presence of globin-inducing trans-acting factors in uninduced Murine Erythroleukemia cells.

    NARCIS (Netherlands)

    N. Wrighton; F.G. Grosveld (Frank)

    1988-01-01

    textabstractWe report the development of a novel in vivo transcription assay for trans-acting factors regulating the human gamma- and beta-globin genes. A cDNA coding for the human tissue-type plasminogen activator (t-PA) was inserted into the globin genes. Simian virus 40 small T-antigen splice and

  2. IDH mutations in acute myeloid leukemia.

    Science.gov (United States)

    Rakheja, Dinesh; Konoplev, Sergej; Medeiros, L Jeffrey; Chen, Weina

    2012-10-01

    Acute myeloid leukemia is a heterogeneous group of diseases. Mutations of the isocitrate dehydrogenase (IDH) genes represent a novel class of point mutations in acute myeloid leukemia. These mutations prevent oxidative decarboxylation of isocitrate to α-ketoglutarate and confer novel enzymatic activity, facilitating the reduction of α-ketoglutarate to d-2-hydroxyglutarate, a putative oncometabolite. IDH1/IDH2 mutations are heterozygous, and their combined frequency is approximately 17% in unselected acute myeloid leukemia cases, 27% in cytogenetically normal acute myeloid leukemia cases, and up to 67% in acute myeloid leukemia cases with cuplike nuclei. These mutations are largely mutually exclusive. Despite many similarities of IDH1 and IDH2 mutations, it is possible that they represent distinct molecular or clinical subgroups of acute myeloid leukemia. All known mutations involve arginine (R), in codon 132 of IDH1 or codon 140 or 172 of IDH2. IDH1(R132) and IDH2(R140) mutations are frequently accompanied by normal cytogenetics and NPM1 mutation, whereas IDH2(R172) is frequently the only mutation detected in acute myeloid leukemia. There is increasing evidence that the prognostic impact of IDH1/2 mutations varies according to the specific mutation and also depends on the context of concurrent mutations of other genes. IDH1(R132) mutation may predict poor outcome in a subset of patients with molecular low-risk acute myeloid leukemia, whereas IDH2(R172) mutations confer a poor prognosis in patients with acute myeloid leukemia. Expression of IDH1/2 mutants induces an increase in global DNA hypermethylation and inhibits TET2-induced cytosine 5-hydroxymethylation, DNA demethylation. These data suggest that IDH1/2 mutations constitute a distinct mutational class in acute myeloid leukemia, which affects the epigenetic state, an important consideration for the development of therapeutic agents.

  3. Two new hemoglobin variants: Hb Brem-sur-Mer [beta9(A6)Ser-->Tyr] and Hb Passy [alpha81(F2)Ser-->Pro (alpha2)].

    Science.gov (United States)

    Lacan, Philippe; Moreau, Mathieu; Becchi, Michel; Zanella-Cleon, Isabelle; Aubry, Martine; Louis, Jean-Jacques; Couprie, Nicole; Francina, Alain

    2005-01-01

    Two new hemoglobin (Hb) variants: Hb Brem-sur-Mer [codon 9 (TCT-->TAT); beta9(A6)Ser-->Tyr] on the first exon of the beta-globin gene and Hb Passy [codon 81 (TCC-->CCC); alpha81(F2)Ser-->Pro (alpha2)] on the second exon of the alpha2-globin gene, are described. The two variants were characterized by DNA sequencing and mass spectrometry (MS). Hematological abnormalities: microcytosis and hypochromia were found only in the carrier of Hb Passy. In the absence of an association with an alpha-thalassemic deletion or mutation, the mutation 81(F2)Pro could induce a possible alpha-thalassemia (thal).

  4. Characteristics of commercially recommending sesame mutant cultivars through induced mutations by different sources of radiation and chemical in the Republic of Korea

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Churl Whan [National Crop Experiment Station, Sodundong Suwon (Korea)

    2001-03-01

    The sesame acreage in Korea has grown 2.5 times in the last two decades as the result of recommending sesame mutant cultivars and polyethylene mulch technique newly developed since 1978. The mutation was induced by X-ray irradiation at 200 Gy yielding a variety named 'Ahnsankkae' known for early ripeness, white color of seed coat, tolerance for diseases. 'Suwon 128' is a dwarf mutant bred through sodium azide and known for strong lodging resistance, dense and lower first capsule set and dense planting adaptability toward mechanized culture against typhoon. Seven mutant recommending cultivars of sesame are compared with respect to their qualitative and quantitative characteristics based on passport data regarding different mutagen sources of radiations and chemicals published by Committee New Recommending Cultivars on the Crops. Breeding sources are summarized: 5 out of 7 sources are through radiation (X-rays, {gamma}-rays, and neutrons) and the rest 2 through chemicals. Their growth characteristics such as flowering date, maturing date, plant height, length-capsule bearing stem, disease and lodging resistance, oil content, and yield ability are also presented. (S. Ohno)

  5. A Prospective Treatment Option for Lysosomal Storage Diseases: CRISPR/Cas9 Gene Editing Technology for Mutation Correction in Induced Pluripotent Stem Cells

    Directory of Open Access Journals (Sweden)

    Chloe L. Christensen

    2017-02-01

    Full Text Available Ease of design, relatively low cost and a multitude of gene-altering capabilities have all led to the adoption of the sophisticated and yet simple gene editing system: clustered regularly interspaced short palindromic repeats/CRISPR-associated protein 9 (CRISPR/Cas9. The CRISPR/Cas9 system holds promise for the correction of deleterious mutations by taking advantage of the homology directed repair pathway and by supplying a correction template to the affected patient’s cells. Currently, this technique is being applied in vitro in human-induced pluripotent stem cells (iPSCs to correct a variety of severe genetic diseases, but has not as of yet been used in iPSCs derived from patients affected with a lysosomal storage disease (LSD. If adopted into clinical practice, corrected iPSCs derived from cells that originate from the patient themselves could be used for therapeutic amelioration of LSD symptoms without the risks associated with allogeneic stem cell transplantation. CRISPR/Cas9 editing in a patient’s cells would overcome the costly, lifelong process associated with currently available treatment methods, including enzyme replacement and substrate reduction therapies. In this review, the overall utility of the CRISPR/Cas9 gene editing technique for treatment of genetic diseases, the potential for the treatment of LSDs and methods currently employed to increase the efficiency of this re-engineered biological system will be discussed.

  6. Deep vein thrombosis, ecythyma gangrenosum and heparin-induced thrombocytopenia occurring in a man with a heterozygous Factor V Leiden mutation

    Directory of Open Access Journals (Sweden)

    Mariya Apostolova

    2012-11-01

    Full Text Available Skin necrosis and limb gangrene are occasional thrombotic manifestations of anticoagulation therapy. We report a man heterozygous for the Factor V Leiden (FVL mutation, and with a history of recurrent deep venous thrombosis, who initially presented with a necrotic skin lesion of the right flank while on warfarin therapy with a therapeutic international normalized ratio. Warfarin was discontinued and he received intravenous heparin. Thereafter he developed thrombocytopenia and pedal erythema and was diagnosed with heparin-induced thrombocytopenia (HIT. Heparin was replaced with argatroban. He ultimately underwent bilateral below-knee amputations for the thrombotic complications of the HIT. The initial necrotic lesion healed with antibiotics and wound care. Pathologic examination of multiple biopsy specimens revealed two separate lesions. One was necrotic tissue infiltrated with methicillin resistant Staphylococcus aureus having features of ecthyma gangrenosum. The second showed thrombotic changes consistent with HIT. The case illustrates the differential diagnosis of skin necrosis and limb gangrene in patients on warfarin and heparin, and also the clinical complexities that can occur in a FVL heterozygote.

  7. Derivation, Characterization, and Neural Differentiation of Integration-Free Induced Pluripotent Stem Cell Lines from Parkinson's Disease Patients Carrying SNCA, LRRK2, PARK2, and GBA Mutations

    DEFF Research Database (Denmark)

    Momcilovic, Olga; Sivapatham, Renuka; Oron, Tal Ronnen;

    2016-01-01

    We report generation of induced pluripotent stem cell (iPSC) lines from ten Parkinson's disease (PD) patients carrying SNCA, PARK2, LRRK2, and GBA mutations, and one age-matched control. After validation of pluripotency, long-term genome stability, and integration-free reprogramming, eight of the...... not be sufficient to determine the cause or mechanism of the disease, and highlights the need to use more focused strategies for large-scale data analysis....... of these lines (one of each SNCA, LRRK2 and GBA, four PARK2 lines, and the control) were differentiated into neural stem cells (NSC) and subsequently to dopaminergic cultures. We did not observe significant differences in the timeline of neural induction and NSC derivation between the patient and control line......, nor amongst the patient lines, although we report considerable variability in the efficiency of dopaminergic differentiation among patient lines. We performed whole genome expression analyses of the lines at each stage of differentiation (fibroblast, iPSC, NSC, and dopaminergic culture) in an attempt...

  8. A Dominant Allele of Arabidopsis Pectin-Binding Wall-Associated Kinase Induces a Stress Response Suppressed by MPK6 but Not MPK3 Mutations

    Institute of Scientific and Technical Information of China (English)

    Bruce D.Kohorn; Susan L.Kohorn; Tanya Todorova; Gillian Baptiste; Kevin Stansky; Meghan McCullough

    2012-01-01

    The plant cell wall is composed of a matrix of cellulose fibers,flexible pectin polymers,and an array of assorted carbohydrates and proteins.The receptor-like Wall-Associated Kinases(WAKs)of Arabidopsis bind pectin in the wall,and are necessary both for cell expansion during development and for a response to pathogens and wounding.Mitogen Activated Protein Kinases(MPKs)form a major signaling link between cell surface receptors and both transcriptional and enzyme regulation in eukaryotes,and Arabidopsis MPK6 and MPK3 indeed have important roles in development and the response to stress and pathogens.A dominant allele of WAK2 requires kinase activity and activates a stress response that includes an increased ROS accumulation and the up-regulation of numerous genes involved in pathogen resistance,wounding,and cell wall biogenesis.This dominant allele requires a functional pectin binding and kinase domain,indicating that it is engaged in a WAK signaling pathway.A null mutant of the major plasma membrane ROS-producing enzyme complex,rbohd/f does not suppress the WAK2cTAP-induced phenotype.A mpk6,but not a mpk3,null allele is able to suppress the effects of this dominant WAK2 mutation,thus distinguishing MPK3 and MPK6,whose activity previously was thought to be redundant.Pectin activation of gene expression is abated in a wak2-null,but is tempered by the WAK-dominant allele that induces elevated basal stress-related transcript levels.The results suggest a mechanism in which changes to the cell wall can lead to a large change in cellular responses and help to explain how pathogens and wounding can have general effects on growth.

  9. Mutagenesis in Caenorhabditis elegans. II. A spectrum of mutational events induced with 1500 r of gamma-radiation

    Energy Technology Data Exchange (ETDEWEB)

    Rosenbluth, R.E.; Cuddeford, C.; Baillie, D.L.

    1985-03-01

    The authors previously established a gamma-ray dose-response curve for recessive lethal events (lethals) captured over the eT1 balancer. In this paper they analyze the nature of lethal events produced, with a frequency of 0.04 per eT1 region, at a dose of 1500 r. To do so, they developed a protocol that, in the absence of cytogenetics, allows balanced lethals to be analyzed for associated chromosomal rearrangements. A set of 35 lethal strains was chosen for the analysis. Although the dosage was relatively low, a large number of multiple-break events were observed. The fraction of lethals associated with rearrangements was found to be 0.76. Currently most X- and gamma-ray dosages used for mutagenesis in C. elegans are 6000-8000 r. From the data it was conservatively estimated that 43% of rearrangements induced with 8000 r would be accompanied by additional chromosome breaks in the genome. With 1500 r the value was 5%. The 35 lethals studied were derived from 875 screened F1's. Among these lethals there were (1) at least two unc-36 duplications, (2) at least four translocations, (3) at least six deficiencies of chromosome V (these delete about 90% of the unc-60 to unc-42 region) and (4) several unanalyzed rearrangements. Thus, it is possible to recover desired rearrangements at reasonable rates with a dose of only 1500 r. The authors suggest that the levels of ionizing radiation employed in most published C. elegans studies are excessive and efforts should be made to use reduced levels in the future.

  10. Gene mutations in hepatocellular adenomas

    DEFF Research Database (Denmark)

    Raft, Marie B; Jørgensen, Ernö N; Vainer, Ben

    2015-01-01

    is associated with bi-allelic mutations in the TCF1 gene and morphologically has marked steatosis. β-catenin activating HCA has increased activity of the Wnt/β-catenin pathway and is associated with possible malignant transformation. Inflammatory HCA is characterized by an oncogene-induced inflammation due....... This review offers an overview of the reported gene mutations associated with hepatocellular adenomas together with a discussion of the diagnostic and prognostic value....

  11. High hydrophobic amino acid exposure is responsible of the neurotoxic effects induced by E200K or D202N disease-related mutations of the human prion protein.

    Science.gov (United States)

    Corsaro, Alessandro; Thellung, Stefano; Bucciarelli, Tonino; Scotti, Luca; Chiovitti, Katia; Villa, Valentina; D'Arrigo, Cristina; Aceto, Antonio; Florio, Tullio

    2011-03-01

    Mutations in prion protein are thought to be causative of inherited prion diseases favoring the spontaneous conversion of the normal prion protein into the scrapie-like pathological prion protein. We previously reported that, by controlled thermal denaturation, human prion protein fragment 90-231 acquires neurotoxic properties when transformed in a β-rich conformation, resembling the scrapie-like conformation. In this study we generated prion protein fragment 90-231 bearing mutations identified in familial prion diseases (D202N and E200K), to analyze their role in the induction of a neurotoxic conformation. Prion protein fragment 90-231(wild type) and the D202N mutant were not toxic in native conformation but induced cell death only after thermal denaturation. Conversely, prion protein fragment 90-231(E200K) was highly toxic in its native structure, suggesting that E200K mutation per se favors the acquisition of a peptide neurotoxic conformation. To identify the structural determinants of prion protein fragment 90-231 toxicity, we show that while the wild type peptide is structured in α-helix, hPrP90-231 E200K is spontaneously refolded in a β-structured conformer characterized by increased proteinase K resistance and propensity to generate fibrils. However, the most significant difference induced by E200K mutation in prion protein fragment 90-231 structure in native conformation we observed, was an increase in the exposure of hydrophobic amino-acids on protein surface that was detected in wild type and D202N proteins only after thermal denaturation. In conclusion, we propose that increased hydrophobicity is one of the main determinants of toxicity induced by different mutations in prion protein-derived peptides.

  12. Lack of UV-induced respiration shutoff in a recF strain of Escherichia coli: temperature conditional suppression at 30 degrees C by the sfrA mutation.

    Science.gov (United States)

    Swenson, P A; Norton, I L

    1986-05-01

    A mutation in the recF gene of Escherichia coli results in a radiation-sensitive strain. The RecF pathway and the RecBC pathway account for nearly all of the conjugative recombination occurring in E. coli. recBC cells are radiation-sensitive and carry only out a small amount of recombination but these deficiencies are suppressed by an sbcB as recombination is shunted to the RecF pathway. A recBC sbcB recF strain is very radiation-sensitive and is devoid of recombination ability. These deficiencies are suppressed by the srfA mutation; srfA is a recA allele. UV-induced respiration shutoff is a recA+, lexA+ and recBC+ dependent. We report in this paper that respiration does not shutoff in a recF strain at 37 and 30 degrees C. an srfA mutation suppresses this lack of respiration shutoff effect in a recF srfA mutant at 30 degrees C but not at 37 degrees C; no suppression by this mutation occurs at either temperature in a recF recBC sbcB strain. An srfA strain also does not shut off its respiration at 37 degrees C and shows a temperature conditional UV-induced respiration shutoff response at 30 degrees C. The srfA mutation is thought to cause an altered RecA protein to be produced and we suggest that at 37 degrees This altered protein is temperature sensitive. We conclude from the results in this paper that the recF gene product is required for UV-induced respiration shutoff and that the RecA protein plays a special role in the induction process.

  13. Liver tumors induced in B6C3F{sub 1} mice by benz[a]anthracene and two of its halogenated derivatives contain K-RAS oncogene mutations

    Energy Technology Data Exchange (ETDEWEB)

    Xia, O.; Yi, P.; Zhan, D. [and others

    1997-10-01

    Polycyclic aromatic hydrocarbons (PAHs) and halogenated PAHs are genotoxic environmental contaminants. We previously examined the tumorigenicity of benz[a]anthracene (BA), 7-Cl-BA, and 7-Br-BA in the neonatal mouse tumorigenicity bioassay. Male B6C3F{sub 1} mice were administered i.p. injections at a total dose of 400 nmol per mouse on 1, 8, and 15 days after birth. BA, 7-Cl-BA, and 7-Br-BA induced hepatocellular adenoma in 67, 92, and 96% of the mice, respectively, and induced hepatocellular carcinoma in 15, 100 and 83% of the mice, respectively. In the present study, mRNA was isolated from each of the liver tumors induced by the three compounds, reversed-transcribed to cDNA, and portions of the K- and H-ras oncogene coding sequences were amplified and analyzed for DNA sequence alterations. 92% (11/12) of BA-induced, 79% (19/24) of 7-Cl-BA-induced and 86% (19/22) of 7-Br-BA-induced liver tumors had activated ras protooncogenes. In contrast to the general finding of H-ras mutations in B6C3F{sub 1} mouse liver tumors, all the mutations were at the first base of K-ras codon 13, resulting in a pattern of GGC{yields}CGC. No other ras oncogene mutations were detected. Our results clearly demonstrate that these chemicals induce a unique type of ras (K-ras) oncogene activation in the liver tumors of B6C3F{sub 1} mice.

  14. Habitat induced mutational effects and fatty acid profile changes in bottom dweller Cirrhinus mrigala inhabitant of river Chenab

    Directory of Open Access Journals (Sweden)

    Hussain, B.

    2015-06-01

    Full Text Available Fish from the river Chenab were analyzed for DNA damage by the Comet and Micronucleus assays. The fatty acid profile was determined by gas chromatography using a Flame Ionization Detector. Atomic absorption spectrophotometry showed significant (p p Cirrhinus mrigala of 37.29±2.51%, 34.96±2.53% and 38.80±2.42% in the comet tail, in the tail moment of 23.48±3.90, 19.78±4.26 and 14.30±1.82, in the olive moment of 16.22±2.04, 13.83±1.96 10.99±0.90, respectively, from three experimental sites. The micronucleus assay showed a high frequency of single micronucleus induction of 44.80±3.73, double induction of 06.20±0.97 and nuclear abnormalities of 09.60±1.72, as calculated in a thousand cells. C8:0, C12:0, C20:0, C16:1(n-7, C16:1(n-9, C20:1(n-9, C18:2(n-6, C18:4(n-3, C20:5(n-3, C22:4(n-6 fatty acids were found missing in the fish with a higher intensity of DNA damage but were found in optimal amounts both in farmed and wild fish from non polluted habitats. A highly significant (p Los daños en el ADN de los peces del río Chenab se analizaron mediante la técnica del “ensayo del cometa” y el ensayo de micronúcleos. El perfil de ácidos grasos se determinó mediante cromatografía de gases con detector de ionización de llama. La espectrofotometría de absorción atómica mostró diferencias significativas (p p p < 0,01 también en ácidos saturados, ácidos grasos insaturados, daño del ADN y hábitat. El presente estudio reveló que la intensidad de la contaminación del hábitat aún en la más baja no sólo induce daño en el ADN, sino también en la composición de los ácidos grasos de la serie omega y de los ácidos grasos insaturados, para los que se prefiere ingerir pescado a otros animales.

  15. A large deletion/insertion-induced frameshift mutation of the androgen receptor gene in a family with a familial complete androgen insensitivity syndrome.

    Science.gov (United States)

    Cong, Peikuan; Ye, Yinghui; Wang, Yue; Lu, Lingping; Yong, Jing; Yu, Ping; Joseph, Kimani Kagunda; Jin, Fan; Qi, Ming

    2012-06-01

    Androgen insensitivity syndrome (AIS) is an X-linked recessive genetic disorder with a normal 46, XY karyotype caused by abnormality of the androgen receptor (AR) gene. One Chinese family consisting of the proband and 5 other members with complete androgen insensitivity syndrome (CAIS) was investigated. Mutation analysis by DNA sequencing on all 8 exons and flanking intron regions of the AR gene revealed a unique large deletion/insertion mutation in the family. A 287 bp deletion and 77 bp insertion (c.933_1219delins77) mutation at codon 312 resulted in a frameshift which caused a premature stop (p.Phe312Aspfs*7) of polypeptide formation. The proband's mother and grandmother were heterozygous for the mutant allele. The proband's father, uncle and grandfather have the normal allele. From the pedigree constructed from mutational analysis of the family, it is revealed that the probably pathogenic mutation comes from the maternal side.

  16. Discovery of candidate disease genes in ENU-induced mouse mutants by large-scale sequencing, including a splice-site mutation in nucleoredoxin.

    Directory of Open Access Journals (Sweden)

    Melissa K Boles

    2009-12-01

    Full Text Available An accurate and precisely annotated genome assembly is a fundamental requirement for functional genomic analysis. Here, the complete DNA sequence and gene annotation of mouse Chromosome 11 was used to test the efficacy of large-scale sequencing for mutation identification. We re-sequenced the 14,000 annotated exons and boundaries from over 900 genes in 41 recessive mutant mouse lines that were isolated in an N-ethyl-N-nitrosourea (ENU mutation screen targeted to mouse Chromosome 11. Fifty-nine sequence variants were identified in 55 genes from 31 mutant lines. 39% of the lesions lie in coding sequences and create primarily missense mutations. The other 61% lie in noncoding regions, many of them in highly conserved sequences. A lesion in the perinatal lethal line l11Jus13 alters a consensus splice site of nucleoredoxin (Nxn, inserting 10 amino acids into the resulting protein. We conclude that point mutations can be accurately and sensitively recovered by large-scale sequencing, and that conserved noncoding regions should be included for disease mutation identification. Only seven of the candidate genes we report have been previously targeted by mutation in mice or rats, showing that despite ongoing efforts to functionally annotate genes in the mammalian genome, an enormous gap remains between phenotype and function. Our data show that the classical positional mapping approach of disease mutation identification can be extended to large target regions using high-throughput sequencing.

  17. The optimal mutagen dosage to induce point-mutations in Synechocystis sp. PCC6803 and its application to promote temperature tolerance.

    Directory of Open Access Journals (Sweden)

    Ulrich M Tillich

    Full Text Available Random mutagenesis is a useful tool to genetically modify organisms for various purposes, such as adaptation to cultivation conditions, the induction of tolerances, or increased yield of valuable substances. This is especially attractive for systems where it is not obvious which genes require modifications. Random mutagenesis has been extensively used to modify crop plants, but even with the renewed interest in microalgae and cyanobacteria for biofuel applications, there is relatively limited current research available on the application of random mutagenesis for these organisms, especially for cyanobacteria. In the presented work we characterized the lethality and rate of non-lethal point mutations for ultraviolet radiation and methyl methanesulphonate on the model cyanobacteria Synechocystis sp. PCC6803. Based on these results an optimal dosage of 10-50 J/m(2 for UV and either 0.1 or 1 v% for MMS was determined. A Synechocystis wildtype culture was then mutagenized and selected for increased temperature tolerance in vivo. During the second round of mutagenesis the viability of the culture was monitored on a cell by cell level from the treatment of the cells up to the growth at an increased temperature. After four distinct rounds of treatment (two with each mutagen the temperature tolerance of the strain was effectively raised by about 2°C. Coupled with an appropriate in vivo screening, the described methods should be applicable to induce a variety of desirable characteristics in various strains. Coupling random mutagenesis with high-throughput screening methods would additionally allow to select for important characteristics for biofuel production, which do not yield a higher fitness and can not be selected for in vivo, such as fatty acid concentration. In a combined approach with full genome sequencing random mutagenesis could be used to determine suitable target-genes for more focused methods.

  18. The optimal mutagen dosage to induce point-mutations in Synechocystis sp. PCC6803 and its application to promote temperature tolerance.

    Science.gov (United States)

    Tillich, Ulrich M; Lehmann, Sandra; Schulze, Katja; Dühring, Ulf; Frohme, Marcus

    2012-01-01

    Random mutagenesis is a useful tool to genetically modify organisms for various purposes, such as adaptation to cultivation conditions, the induction of tolerances, or increased yield of valuable substances. This is especially attractive for systems where it is not obvious which genes require modifications. Random mutagenesis has been extensively used to modify crop plants, but even with the renewed interest in microalgae and cyanobacteria for biofuel applications, there is relatively limited current research available on the application of random mutagenesis for these organisms, especially for cyanobacteria. In the presented work we characterized the lethality and rate of non-lethal point mutations for ultraviolet radiation and methyl methanesulphonate on the model cyanobacteria Synechocystis sp. PCC6803. Based on these results an optimal dosage of 10-50 J/m(2) for UV and either 0.1 or 1 v% for MMS was determined. A Synechocystis wildtype culture was then mutagenized and selected for increased temperature tolerance in vivo. During the second round of mutagenesis the viability of the culture was monitored on a cell by cell level from the treatment of the cells up to the growth at an increased temperature. After four distinct rounds of treatment (two with each mutagen) the temperature tolerance of the strain was effectively raised by about 2°C. Coupled with an appropriate in vivo screening, the described methods should be applicable to induce a variety of desirable characteristics in various strains. Coupling random mutagenesis with high-throughput screening methods would additionally allow to select for important characteristics for biofuel production, which do not yield a higher fitness and can not be selected for in vivo, such as fatty acid concentration. In a combined approach with full genome sequencing random mutagenesis could be used to determine suitable target-genes for more focused methods.

  19. Exploring the selectivity of auto-inducer complex with LuxR using molecular docking, mutational studies and molecular dynamics simulations

    Science.gov (United States)

    Rajamanikandan, Sundaraj; Srinivasan, Pappu

    2017-03-01

    Bacteria communicate with one another using extracellular signaling molecules called auto-inducers (AHLs), a process termed as quorum sensing. The quorum sensing process allows bacteria to regulate various physiological activities. In this regard, quorum sensing master regulator LuxR from Vibrio harveyi represents an attractive therapeutic target for the development of novel anti-quorum sensing agents. Eventhough the binding of AHL complex with LuxR is evidenced in earlier reports, but their mode of binding is not clearly determined. Therefore, in the present work, molecular docking, in silico mutational studies, molecular dynamics simulations and free energy calculations were performed to understand the selectivity of AHL into the binding site of LuxR. The results revealed that Asn133 and Gln137 residues play a crucial role in recognizing AHL more effectively into the binding site of LuxR with good binding free energy. In addition to that, the carbonyl group presents in the lactone ring and amide group of AHL plays a vital role in the formation of hydrogen bond interactions with the protein. Further, structure based virtual screening was performed using ChemBridge database to screen potent lead molecules against LuxR. 4-benzyl-2-pyrrolidinone and N-[2(1-cyclohexen-1-yl) enthyl]-N'(2-ethoxyphenyl) were selected based on dock score, binding affinity and mode of interactions with the receptor. Furthermore, binding free energy, density functional theory and ADME prediction were performed to rank the lead molecules. Thus, the identified lead molecules can be used for the development of anti-quorum sensing drugs.

  20. Mutation induction by ion beams in plants

    Energy Technology Data Exchange (ETDEWEB)

    Tanaka, Atsushi [Japan Atomic Energy Research Inst., Takasaki, Gunma (Japan). Takasaki Radiation Chemistry Research Establishment

    2001-03-01

    The effect of ion beams such as C, He, and Ne ions was investigated on the mutation induction in plants with the expectation that ion beams of high linear energy transfer (LET) can frequently produce large DNA alternation such as inversion, translocation and large deletion rather than point mutation. Mutation frequency was investigated using Arabidopsis visible phenotype loci and was 8 to 33 fold higher for 220 MeV carbon ions than for electrons. Mutation spectrum was investigated on the flower color of chrysanthemum cv to find that flower mutants induced by ion beams show complex and stripe types rather than single color. Polymerase chain reaction analysis was performed to investigate DNA alteration of mutations. In conclusion, the characteristics of ion beams for the mutation induction are 1) high frequency, 2) broad mutation spectrum, and 3) novel mutants. (S. Ohno)

  1. Recent Advances of Repeat-induced Point Mutation (RIP) of DNA Sequence in Fungi%真菌中 DNA 重复序列诱导点突变的研究进展

    Institute of Scientific and Technical Information of China (English)

    冯凤鹃; 曲志才; 田李; 王转斌

    2014-01-01

    Repeat -induced point mutations ( RIP) was discovered in Neurospora crassa in 1987 by Selker. RIP searches for sequence duplications in haploid nuclei of premeiotic tissue and then litters them with numerous C to T mutations.T+A rich fragments so that the G-C pairs in duplications can be mutated to A -T.In addition, RIP’ s sequences , which are concentrated in centromeric regions , and are predominantly relics of transposons , are left methylated .Mobile transposable elements are among the primary drivers of the evolution of eukaryotic genomes . For fungi , repeat-induced point mutation ( RIP) silencing minimizes deleterious effects of transposons by mutating multicopy DNA during meiosis .To explore the impact of RIP-mutated transposons is conducive to generate evolu-tionary inferences for phylogenetic and population genetic analyses .The paper has reviewed the mechanism of RIP and the progress of RIP in fungi .%1987年,由Selker等在粗糙脉孢菌中首次发现重复序列诱导点突变( repeat-induced point mu-tation,RIP)。在重复序列诱导点突变过程中,搜寻前减数分裂组织单倍体核中DNA的重复序列,然后发生众多的碱基C到T的突变,产生富碱基T+A片段,从而使重复序列中的G-C碱基对发生转换突变成为A-T碱基对。此外,发生RIP的序列多集中在着丝粒区域,主要是转座子甲基化后的遗迹。移动转座子是真核生物基因组进化的主要驱动力。对于真菌,重复序列诱导点突变( RIP)在减数分裂过程中通过突变多拷贝DNA,能最大限度地减少转座子的影响,因此对RIP的研究在一定程度上能有助于了解基因组进化的真谛。综述了重复序列诱导点突变的产生机制,以及真菌中重复序列诱导点突变的研究进展。

  2. Rapid screening for glucose-6-phosphate dehydrogenase deficiency and haemoglobin polymorphisms in Africa by a simple high-throughput SSOP-ELISA method

    DEFF Research Database (Denmark)

    Enevold, Anders; Vestergaard, Lasse S; Lusingu, John

    2005-01-01

    BACKGROUND: Mutations in the haemoglobin beta-globin (HbB) and glucose-6-phosphate dehydrogenase (G6PD) genes cause widespread human genetic disorders such as sickle cell diseases and G6PD deficiency. In sub-Saharan Africa, a few predominant polymorphic variants of each gene account for a majority...

  3. A transgenic mouse model of sickle cell disorder.

    NARCIS (Netherlands)

    D.R. Greaves (David); P.J. Fraser (Peter); M.A. Vidal; M.J. Hedges; D. Ropers; L. Luzzatto; F.G. Grosveld (Frank)

    1990-01-01

    textabstractA single base-pair mutation (beta s) in codon 6 of the human beta-globin gene, causing a single amino-acid substitution, is the cause of sickle cell anaemia. The mutant haemoglobin molecule, HbS, polymerizes when deoxygenated and causes deformation of the erythrocytes to a characteristic

  4. Generation of a high-titer retroviral vector capable of expressing high levels of the human β-globin gene

    NARCIS (Netherlands)

    M. Sadelain (Michel); C.H.J. Wang (Jason); M. Antoniou (Michael); F.G. Grosveld (Frank); R.C. Mulligan

    1995-01-01

    textabstractRetrovirus-mediated gene transfer into hematopoietic cells may provide a means of treating both inherited and acquired diseases involving hematopoietic cells. Implementation of this approach for disorders resulting from mutations affecting the beta-globin gene (e.g., beta-thalassemia and

  5. 两个携带线粒体12S rRNA 1494C>T突变的耳聋家系的遗传学特征%Characterization of two Chinese families with aminoglycoside-induced and nonsyndromic hearing loss both carrying a mitochondrial 12S rRNA 1494C>T mutation

    Institute of Scientific and Technical Information of China (English)

    龚莎莎; 管敏鑫; 陈波蓓; 彭光华; 郑静; 张婷; 郑斌娇; 方芳; 张初琴; 吕建新

    2012-01-01

    Objective To evaluate the effect of mitochondrial DNA(mtDNA) secondary mutations,haplotypes,GJB2 gene mutations on phenotype of 1494C > T mutation,and to study the molecular pathogenic mechanism of maternally transmitted aminoglycoside-induced and nonsyndromic hearing loss.Methods Two Chinese Han pedigrees of maternally transmitted aminoglycoside induced and nonsyndromic hearing loss were collected.The two probands and their family members underwent clinical,genetic and molecular evaluations including audiological examinations and mutational analysis of mitochondrial genome and GJB2 gene.Results Clinical evaluation revealed wide range of severity,age-at-onset and audiometric configuration of hearing impairment in matrilineal relatives in both families,for which the penetrance of hearing loss was respectively 42.9 % and 28.6% when aminoglycoside-induced deafness was included.When the effect of aminoglycosides was excluded,the penetrances of hearing loss were 14.3% and 14.3%.Sequence analysis of mitochondrial genomes identified a known 12S rRNA 1494C>T mutation,in addition with distinct sets of mtDNA polymorphisms belonging to Eastern Asian haplogroups C4a1a and B4b1c,respectively.Conclusion Mitochondrial 12S rRNA 1494C>T mutation probably underlie the deafness in both families.Lack of significant mutation in the GJB2 gene ruled out involvement of GJB2 in the phenotypic expression.However,aminoglycosides and other nuclear modifier genes may still modify the phenotype of the 1494C>T mutation in these families.The B4b1c is a newly identified haplogroup in aminoglycoside-induced and nonsyndromic hearing loss family carrying the 1494C>T mutation.The 1494C>T mutation seems to have occurred sporadically through evolution.

  6. UV Breeding by Induced Mutation of Mucor Protease Strain from Sufu%腐乳毛霉蛋白酶菌株紫外线诱变育种

    Institute of Scientific and Technical Information of China (English)

    刘芳; 曹新志; 方春玉; 梁秋菊

    2009-01-01

    Objective:Breeding of Mucor protease strain with high enzyme activity and good high-temperaturre for fermentation experiments or production of sufu.Method: Mucor protease strains were picked out from sufu,its original strain was induced mutation by UV and fostered by temperature control,breeding of excellent mutant strain.Result:One high enzyme vitality and excellent high-temperature mutant strain named SCLG-mucor 16 was selected,the strain can strongly grow at 32℃.Its HE is 1.39,protease vitality is 180.375u/g,which was enhanced by 7.8% and 51.4% more than the original strain respectively.Conclusion: The excellent mutant strain was used for fermentation experiments or production of sufu, it has a certain using value in shortening the fermentation time,enhancing the quality of sufu and extending the season of production.%目的:选育酶活力高、耐热性好的毛霉蛋白酶菌株,用于腐乳发酵实验或生产.方法:从腐乳中分离毛霉蛋白酶菌株.对其出发菌株进行紫外线诱变,并经控温培养,选育优良变株.结果:获得一株酶活力高、耐热性强的优良变株SCIG-毛霉16.该菌株在32℃条件下,生长茂盛,其HE值为1.39、蛋白酶活力为180.375μ/g,分别较出发菌株高出7.8%和51.4%.结论:将此优良变株用于腐乳发酵实验或生产,在缩短发酵时间,提升腐乳质量,延长生产季节等方面具有一定的应用价值.

  7. A GNAS mutation found in pancreatic intraductal papillary mucinous neoplasms induces drastic alterations of gene expression profiles with upregulation of mucin genes.

    Directory of Open Access Journals (Sweden)

    Hirotake Komatsu

    Full Text Available GNAS, a gene encoding G protein stimulating α subunit, is frequently mutated in intraductal papillary mucinous neoplasms (IPMNs, which are indolent and slow-growing pancreatic tumors that secrete abundant mucin. The GNAS mutation is not observed in conventional ductal adenocarcinomas of the pancreas. To determine the functional significance of the GNAS mutation in pancreatic ductal lineage cells, we examined in vitro phenotypes of cells of pancreatic ductal lineage, HPDE, PK-8, PCI-35, and MIA PaCa-2, with exogenous expression of either wild-type or mutated (R201H GNAS. We found that exogenous GNAS upregulated intracellular cyclic adenine monophosphate (cAMP, particularly in mutated GNAS transfectants, and upregulated expression of MUC2 and MUC5AC in HPDE and PK-8 cells. By contrast, exogenous GNAS inhibited expression of mucin genes in PCI-35 and MIA PaCa-2 cells, despite upregulation of cAMP. We examined global gene expression profiles of some of the cells transfected with exogenous mutated GNAS (PK-8, PCI-35, and MIA PaCa-2, and found that PK-8 cells exhibited drastic alterations of the gene expression profile, which contrasted with modest alterations in PCI-35 and MIA PaCa-2 cells. To identify a cause of these different effects of exogenous mutated GNAS on phenotypes of the cells, we examined effects of interactions of the signaling pathways of G protein-coupled receptor (GPCR, mitogen-activated protein kinase (MAPK, and phosphatidylinositol 3-kinase (PI3K on expression of mucin genes. The MAPK and PI3K pathways significantly influenced the expression of mucin genes. Exogenous GNAS did not promote cell growth but suppressed it in some of the cells. In conclusion, mutated GNAS found in IPMNs may extensively alter gene expression profiles, including expression of mucin genes, through the interaction with MAPK and PI3K pathways in pancreatic ductal cells; these changes may determine the characteristic phenotype of IPMN. PK-8 cells expressing

  8. CF Mutation Panel

    Science.gov (United States)

    ... Testing; Cystic Fibrosis Transmembrane Conductance Regulator Mutation Analysis; CFTR Mutation Analysis Formal name: Cystic Fibrosis Gene Mutation ... an elevated immunoreactive trypsinogen (IRT) or positive sweat chloride test , to confirm the diagnosis of cystic fibrosis. ...

  9. Generation of a human induced pluripotent stem cell (iPSC line from a patient carrying a P33T mutation in the PDX1 gene

    Directory of Open Access Journals (Sweden)

    Xianming Wang

    2016-09-01

    Full Text Available Homozygous loss-of-function mutations in the gene coding for the homeobox transcription factor PDX1 leads to pancreatic agenesis, whereas certain heterozygous point mutations are associated with Maturity-Onset Diabetes of the Young 4 (MODY4 and Type 2 Diabetes Mellitus (T2DM. To understand the pathomechanism of MODY4 and T2DM, we have generated iPSCs from a woman with a P33T heterozygous mutation in the transactivation domain of PDX1. The resulting PDX1 P33T iPSCs generated by episomal reprogramming are integration-free, have a normal karyotype and are pluripotent in vitro and in vivo. Taken together, this iPSC line will be useful to study diabetes pathomechanisms.

  10. Simultaneous measurement of benzo[a]pyrene-induced Pig-a and lacZ mutations, micronuclei and DNA adducts in Muta™ Mouse.

    Science.gov (United States)

    Lemieux, Christine L; Douglas, George R; Gingerich, John; Phonethepswath, Souk; Torous, Dorothea K; Dertinger, Stephen D; Phillips, David H; Arlt, Volker M; White, Paul A

    2011-12-01

    In this study we compared the response of the Pig-a gene mutation assay to that of the lacZ transgenic rodent mutation assay, and demonstrated that multiple endpoints can be measured in a 28-day repeat dose study. Muta™Mouse were dosed daily for 28 days with benzo[a]pyrene (BaP; 0, 25, 50 and 75 mg/kg body weight/day) by oral gavage. Micronucleus (MN) frequency was determined in reticulocytes (RETs) 48 hr following the last dose. 72 h following the last dose, mice were euthanized, and tissues (glandular stomach, small intestine, bone marrow and liver) were collected for lacZ mutation and DNA adduct analysis, and blood was evaluated for Pig-a mutants. BaP-derived DNA adducts were detected in all tissues examined and significant dose-dependent increases in mutant Pig-a phenotypes (i.e., RET(CD24-) and RBC (CD24-)) and lacZ mutants were observed. We estimate that mutagenic efficiency (i.e., rate of conversion of adducts into mutations) was much lower for Pig-a compared to lacZ, and speculate that this difference is likely explained by differences in repair capacity between the gene targets, and differences in the cell populations sampled for Pig-a versus lacZ. The BaP doubling doses for both gene targets, however, were comparable, suggesting that similar mechanisms are involved in the accumulation of gene mutations. Significant dose-related increases in % MN were also observed; however, the doubling dose was considerably higher for this endpoint. The similarity in dose response kinetics of Pig-a and lacZ provides further evidence for the mutational origin of glycosylphosphatidylinositol (GPI)-anchor deficiencies detected in the Pig-a assay.

  11. A rare CYP 21 mutation (p.E431K) induced deactivation of CYP 21A2 and resulted in congenital adrenal hyperplasia.

    Science.gov (United States)

    Kawashima, Yuki; Usui, Takeshi; Fujimoto, Masanobu; Miyahara, Naoki; Nishimura, Rei; Hanaki, Keiichi; Kanzaki, Susumu

    2015-01-01

    Congenital adrenal hyperplasia (CAH) due to 21-hydroxylase deficiency is caused by mutations in the CYP21A2 gene. The residual enzyme activity is strongly associated with the phenotype. We describe a rare case of CAH with a rare CYP21A2 mutation. The patient was a one-year-old Japanese boy. At 16 days old, he was referred to our hospital because of elevated serum 17-OH-progesterone (17-OHP) levels in neonatal screening. The compound heterozygous mutations (IVS2-13 A/C>G, and p.E431K) in CYP21A2 were identified at 2 months old, and we diagnosed non-classical CAH, since he did not have significant physical signs (pigmentation and salt-wasting). However, his body weight decreased, and his serum 17-OHP level (99.5 ng/mL) was elevated at 3 months old. Steroid replacement therapy was started at 3 months old. Our patient's clinical course resembled simple virilizing (SV) CAH, but classification was difficult because the patient showed increased renin activity indicating an aldosterone deficiency, and late onset of symptoms. While the IVS 2-13 A/C>G mutation is common in the classical form of CAH, p.E431K is a rare point mutation. Functional analysis revealed that the residual enzyme activity of p.E431L was 5.08±2.55% for 17-OHP and 4.12±2.37% for progesterone, which is consistent with SV CAH. p.E431 is localized in the L-helix near the heme-binding site. The mutation might interfere with heme binding, leading to deactivation of CYP21A2. This report showed that CYP21A2 p.E431 has an important effect on enzyme activity.

  12. Molecular identification of collagen 17a1 as a major genetic modifier of laminin gamma 2 mutation-induced junctional epidermolysis bullosa in mice.

    Directory of Open Access Journals (Sweden)

    Thomas J Sproule

    2014-02-01

    Full Text Available Epidermolysis Bullosa (EB encompasses a spectrum of mechanobullous disorders caused by rare mutations that result in structural weakening of the skin and mucous membranes. While gene mutated and types of mutations present are broadly predictive of the range of disease to be expected, a remarkable amount of phenotypic variability remains unaccounted for in all but the most deleterious cases. This unexplained variance raises the possibility of genetic modifier effects. We tested this hypothesis using a mouse model that recapitulates a non-Herlitz form of junctional EB (JEB owing to the hypomorphic jeb allele of laminin gamma 2 (Lamc2. By varying normally asymptomatic background genetics, we document the potent impact of genetic modifiers on the strength of dermal-epidermal adhesion and on the clinical severity of JEB in the context of the Lamc2(jeb mutation. Through an unbiased genetic approach involving a combination of QTL mapping and positional cloning, we demonstrate that Col17a1 is a strong genetic modifier of the non-Herlitz JEB that develops in Lamc2(jeb mice. This modifier is defined by variations in 1-3 neighboring amino acids in the non-collagenous 4 domain of the collagen XVII protein. These allelic variants alter the strength of dermal-epidermal adhesion in the context of the Lamc2(jeb mutation and, consequentially, broadly impact the clinical severity of JEB. Overall the results provide an explanation for how normally innocuous allelic variants can act epistatically with a disease causing mutation to impact the severity of a rare, heritable mechanobullous disorder.

  13. Molecular identification of collagen 17a1 as a major genetic modifier of laminin gamma 2 mutation-induced junctional epidermolysis bullosa in mice.

    Science.gov (United States)

    Sproule, Thomas J; Bubier, Jason A; Grandi, Fiorella C; Sun, Victor Z; Philip, Vivek M; McPhee, Caroline G; Adkins, Elisabeth B; Sundberg, John P; Roopenian, Derry C

    2014-02-01

    Epidermolysis Bullosa (EB) encompasses a spectrum of mechanobullous disorders caused by rare mutations that result in structural weakening of the skin and mucous membranes. While gene mutated and types of mutations present are broadly predictive of the range of disease to be expected, a remarkable amount of phenotypic variability remains unaccounted for in all but the most deleterious cases. This unexplained variance raises the possibility of genetic modifier effects. We tested this hypothesis using a mouse model that recapitulates a non-Herlitz form of junctional EB (JEB) owing to the hypomorphic jeb allele of laminin gamma 2 (Lamc2). By varying normally asymptomatic background genetics, we document the potent impact of genetic modifiers on the strength of dermal-epidermal adhesion and on the clinical severity of JEB in the context of the Lamc2(jeb) mutation. Through an unbiased genetic approach involving a combination of QTL mapping and positional cloning, we demonstrate that Col17a1 is a strong genetic modifier of the non-Herlitz JEB that develops in Lamc2(jeb) mice. This modifier is defined by variations in 1-3 neighboring amino acids in the non-collagenous 4 domain of the collagen XVII protein. These allelic variants alter the strength of dermal-epidermal adhesion in the context of the Lamc2(jeb) mutation and, consequentially, broadly impact the clinical severity of JEB. Overall the results provide an explanation for how normally innocuous allelic variants can act epistatically with a disease causing mutation to impact the severity of a rare, heritable mechanobullous disorder.

  14. Structural Insight for Roles of DR5 Death Domain Mutations on Oligomerization of DR5 Death Domain-FADD Complex in the Death-Inducing Signaling Complex Formation: A Computational Study.

    Science.gov (United States)

    Yang, Hongyi; Song, Yuhua

    2016-04-01

    Death receptor 5 (DR5)-induced apoptosis that prioritizes the death of tumor cells has been proposed as one of the promising cancer therapies. In this process, oligomerized DR5 death domain (DD) binding to Fas-associated death domain (FADD) leads to FADD activating caspase-8, which marks the formation of the death-inducing signaling complex (DISC) that initiates apoptosis. DR5 DD mutations found in cancer cells have been suggested to play an important pathological role, the mechanism through which those mutants prevent the DR5-activated DISC formation is not clear yet. This study sought to provide structural and molecular insight for the roles of four selected DR5 DD mutations (E355K, E367K, K415N, and L363F) in the oligomerization of DR5 DD-FADD complex during the DISC formation. Results from the molecular dynamics simulations show that the simulated mutants induce conformational, dynamical motions and interactions changes in the DR5 DD-FADD tetramer complex, including changes in a protein's backbone flexibility, less exposure of FADD DED's caspase-8 binding site, reduced H-bonding and hydrophobic contacts at the DR5 DD-FADD DD binding, altered distribution of the electrostatic potentials and correlated motions of residues, and reduced binding affinity of DR5 DD binding to FADD. This study provides structural and molecular insight for the influence of DR5 DD mutations on oligomerization of DR5 DD-FADD complex, which is expected to foster understanding of the DR5 DD mutants' resistance mechanism against DR5-activated DISC formation.

  15. Generation of a human induced pluripotent stem cell line via CRISPR-Cas9 mediated integration of a site-specific homozygous mutation in CHMP2B

    DEFF Research Database (Denmark)

    Zhang, Yu; Schmid, Benjamin; Nielsen, Troels T

    2016-01-01

    Frontotemporal dementia (FTD) is an early onset neurodegenerative disease. Mutations in several genes cause familial FTD and one of them is charged multivesicular body protein 2B (CHMP2B) on chromosome 3 (FTD3), a component of the endosomal sorting complex required for transport III (ESCRT-III). ...

  16. Generation of a human induced pluripotent stem cell line via CRISPR-Cas9 mediated integration of a site-specific heterozygous mutation in CHMP2B

    DEFF Research Database (Denmark)

    Zhang, Yu; Schmid, Benjamin; Nielsen, Troels Tolstrup

    2016-01-01

    Frontotemporal dementia (FTD) is an early onset neurodegenerative disease. Mutations in several genes cause familial FTD and one of them is charged multivesicular body protein 2B (CHMP2B) on chromosome 3 (FTD3), a component of the endosomal sorting complex required for transport III (ESCRT-III). ...

  17. Successful liver transplantation in a patient with splanchnic vein thrombosis and pulmonary embolism due to polycythemia vera with Jak2v617f mutation and heparin-induced thrombocytopenia.

    Science.gov (United States)

    Biagioni, Emanuela; Pedrazzi, Paola; Marietta, Marco; Di Benedetto, Fabrizio; Villa, Erica; Luppi, Mario; Girardis, Massimo

    2013-10-01

    Heparin-induced thrombocytopenia (HIT) is a rare complication of heparin treatment resulting in a severe acquired thrombophilic condition with an associated mortality of about 10 %. We report the first case of successful urgent liver transplantation (LT) in a patient with end-stage liver disease due to a Budd-Chiari syndrome, portal vein thrombosis and pulmonary embolism due to acquired thrombophilia associated to polycythemia vera carrying JAK2V617F gene mutation and HIT in the acute phase. Lepirudin was used to provide anticoagulation in the LT perioperative period that was performed without haemorrhagic and thrombotic complications despite the donor received heparin during liver explantation.

  18. A mutation in the cytosolic O-acetylserine (thiol lyase induces a genome-dependent early leaf death phenotype in Arabidopsis

    Directory of Open Access Journals (Sweden)

    Schippers Jos HM

    2010-04-01

    Full Text Available Abstract Background Cysteine is a component in organic compounds including glutathione that have been implicated in the adaptation of plants to stresses. O-acetylserine (thiol lyase (OAS-TL catalyses the final step of cysteine biosynthesis. OAS-TL enzyme isoforms are localised in the cytoplasm, the plastids and mitochondria but the contribution of individual OAS-TL isoforms to plant sulphur metabolism has not yet been fully clarified. Results The seedling lethal phenotype of the Arabidopsis onset of leaf death3-1 (old3-1 mutant is due to a point mutation in the OAS-A1 gene, encoding the cytosolic OAS-TL. The mutation causes a single amino acid substitution from Gly162 to Glu162, abolishing old3-1 OAS-TL activity in vitro. The old3-1 mutation segregates as a monogenic semi-dominant trait when backcrossed to its wild type accession Landsberg erecta (Ler-0 and the Di-2 accession. Consistent with its semi-dominant behaviour, wild type Ler-0 plants transformed with the mutated old3-1 gene, displayed the early leaf death phenotype. However, the old3-1 mutation segregates in an 11:4:1 (wild type: semi-dominant: mutant ratio when backcrossed to the Colombia-0 and Wassilewskija accessions. Thus, the early leaf death phenotype depends on two semi-dominant loci. The second locus that determines the old3-1 early leaf death phenotype is referred to as odd-ler (for old3 determinant in the Ler accession and is located on chromosome 3. The early leaf death phenotype is temperature dependent and is associated with increased expression of defence-response and oxidative-stress marker genes. Independent of the presence of the odd-ler gene, OAS-A1 is involved in maintaining sulphur and thiol levels and is required for resistance against cadmium stress. Conclusions The cytosolic OAS-TL is involved in maintaining organic sulphur levels. The old3-1 mutation causes genome-dependent and independent phenotypes and uncovers a novel function for the mutated OAS-TL in cell

  19. MT-CYB mutations in hypertrophic cardiomyopathy

    DEFF Research Database (Denmark)

    Hagen, Christian M; Aidt, Frederik H; Havndrup, Ole

    2013-01-01

    Mitochondrial dysfunction is a characteristic of heart failure. Mutations in mitochondrial DNA, particularly in MT-CYB coding for cytochrome B in complex III (CIII), have been associated with isolated hypertrophic cardiomyopathy (HCM). We hypothesized that MT-CYB mutations might play an important...... and m.15482T>C; p.S246P were identified. Modeling showed that the p.C93Y mutation leads to disruption of the tertiary structure of Cytb by helix displacement, interfering with protein-heme interaction. The p.S246P mutation induces a diproline structure, which alters local secondary structure and induces...... of HCM patients. We propose that further patients with HCM should be examined for mutations in MT-CYB in order to clarify the role of these variants....

  20. The I4895T mutation in the type 1 ryanodine receptor induces fiber-type specific alterations in skeletal muscle that mimic premature aging.

    Science.gov (United States)

    Boncompagni, Simona; Loy, Ryan E; Dirksen, Robert T; Franzini-Armstrong, Clara

    2010-12-01

    The I4898T (IT) mutation in type 1 ryanodine receptor (RyR1), the Ca(2+) release channel of the sarcoplasmic reticulum (SR) is linked to a form of central core disease (CCD) in humans and results in a nonleaky channel and excitation-contraction uncoupling. We characterized age-dependent and fiber-type-dependent alterations in muscle ultrastructure, as well as the magnitude and spatiotemporal properties of evoked Ca(2+) release in heterozygous Ryr1(I4895T/WT) (IT/+) knock-in mice on a mixed genetic background. The results indicate a classical but mild CCD phenotype that includes muscle weakness and the presence of mitochondrial-deficient areas in type I fibers. Electrically evoked Ca(2+) release is significantly reduced in single flexor digitorum brevis (FDB) fibers from young and old IT/+ mice. Structural changes are strongly fiber-type specific, affecting type I and IIB/IIX fibers in very distinct ways, and sparing type IIA fibers. Ultrastructural alterations in our IT/+ mice are also present in wild type, but at a lower frequency and older ages, suggesting that the disease mutation on the mixed background promotes an acceleration of normal age-dependent changes. The observed functional and structural alterations and their similarity to age-associated changes are entirely consistent with the known properties of the mutated channel, which result in reduced calcium release as is also observed in normal aging muscle. In strong contrast to these observations, a subset of patients with the analogous human heterozygous mutation and IT/+ mice on an inbred 129S2/SvPasCrl background exhibit a more severe disease phenotype, which is not directly consistent with the mutated channel properties.

  1. 扩展的简单串联重复位点诱发突变在遗传毒理学的应用进展%Expanded simple tandem repeat loci induced mutation in genetic toxicology and its progress

    Institute of Scientific and Technical Information of China (English)

    梁春柳; 姚朗; 张天宝

    2011-01-01

    Expanded simple tandem repeats (ESTRs) are unstable tandem repetitive DNA loci , which are applied largely in induced mutation of germline, because of the high spontaneous mutation rate. So far,three types of repeat sequences have been found. They are named a small satellite, microsatellite and ESTRs, respectively. While pedigree and single-molecule PCR are used to monitor changes in repeat sequences . However, the mutation mechanisms of these repeat sequences are exactly unknown till now. So, in this paper reviewed, the similar and differences of three different repeatitive loci, the advantages and disadvantages of the two methods , as well as the mutation mechanism were focused.%扩展的简单串联重复(ESTRs)序列是基因组DNA上高不稳定的一类重复序列.由于其自发突变和诱发突变率高,因而在生殖细胞诱发突变中的研究中得到广泛的应用.随着研究的深入,目前发现有3类重复序列——小卫星、微卫星和ESTRs,主要通过系谱法和单分子PCR法来研究这些重复序列的变化.但迄今为止,这些重复序列的突变机制还不明确.本文主要综述了目前国内外对这3种重复序列的异同、ESTRs突变研究方法的优缺点以及突变机制.

  2. A preclinical approach for gene therapy of beta-thalassemia.

    Science.gov (United States)

    Breda, Laura; Kleinert, Dorothy A; Casu, Carla; Casula, Laura; Cartegni, Luca; Fibach, Eitan; Mancini, Irene; Giardina, Patricia J; Gambari, Roberto; Rivella, Stefano

    2010-08-01

    Lentiviral-mediated beta-globin gene transfer successfully treated beta-thalassemic mice. Based on this result, clinical trials were initiated. To date, however, no study has investigated the efficacy of gene therapy in relation to the nature of the different beta-globin mutations found in patients. Most mutations can be classified as beta(0) or beta(+), based on the amount of beta-globin protein produced. Therefore, we propose that a screening in vitro is necessary to verify the efficacy of gene transfer prior to treatment of individual patients. We used a two-phase liquid culture system to expand and differentiate erythroid progenitor cells (ErPCs) transduced with lentiviral vectors. We propose the use of this system to test the efficiency of lentiviral vectors carrying the human beta-globin gene, to correct the phenotype of ErPCs from patients preparing for gene therapy. This new approach might have profound implications for designing gene therapy and for understanding the genotype/phenotype variability observed in Cooley's anemia patients.

  3. PTEN/PIK3CA genes are frequently mutated in spontaneous and medroxyprogesterone acetate-accelerated 7,12-dimethylbenz(a)anthracene-induced mammary tumours of tree shrews.

    Science.gov (United States)

    Xia, Hou-Jun; He, Bao-Li; Wang, Chun-Yan; Zhang, Hai-Lin; Ge, Guang-Zhe; Zhang, Yuan-Xu; Lv, Long-Bao; Jiao, Jian-Lin; Chen, Ceshi

    2014-12-01

    Tree shrew has increasingly become an attractive experimental animal model for human diseases, particularly for breast cancer due to spontaneous breast tumours and their close relationship to primates and by extension to humans. However, neither normal mammary glands nor breast tumours have been well characterised in the Chinese tree shrew (Tupaia belangeri chinensis). In this study, normal mammary glands from four different developmental stages and 18 spontaneous breast tumours were analysed. Haematoxylin and eosin (H&E) staining and immunohistochemistry (IHC) showed that normal mammary gland morphology and structures of tree shrews were quite similar to those found in humans. Spontaneous breast tumours of tree shrews were identified as being intraductal papilloma, papillary carcinoma, and invasive ductal carcinoma with or without lung metastasis. To further analyse breast cancer tumours among tree shrews, 40 3-4 month-old female tree shrews were orally administrated 20 mg 7,12-dimethylbenz(a)anthracene (DMBA) or peanut oil thrice, and then, 15 of these DMBA administrated tree shrews were implanted with medroxyprogesterone acetate (MPA) pellets. DMBA was shown to induce breast tumours (12%) while the addition of MPA increased the tumour incidence (50%). Of these, three induced breast tumours were intraductal papillary carcinomas and one was invasive ductal carcinoma (IDC). The PTEN/PIK3CA (phosphatase and tensin homologue/phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic subunit alpha), but not TP53 and GATA3, genes are frequently mutated in breast tumours, and the PTEN/PIK3CA gene mutation status correlated with the expression of pAKT in tree shrew breast tumours. These results suggest that tree shrews may be a promising animal model for a subset of human breast cancers with PTEN/PIK3CA gene mutations.

  4. Relationship between UV-induced mutant p53 patches and skin tumours, analysed by mutation spectra and by induction kinetics in various DNA-repair-deficient mice.

    Science.gov (United States)

    Rebel, Heggert; Kram, Nicolien; Westerman, Anja; Banus, Sander; van Kranen, Henk J; de Gruijl, Frank R

    2005-12-01

    Clusters of p53 immunopositive epidermal keratinocytes (so-called p53 patches, clones or foci) are found in sun or ultraviolet (UV) light-exposed skin. We investigated to what extent these p53 patches are genuine precursors of skin carcinomas in chronically irradiated hairless (SKH1) mice. The mutation spectra of exons 5-8 of the p53 gene of laser-micro-dissected mutant p53 patches and carcinomas were therefore compared. The mutations we found were mainly UV-signature mutations (C-->T and CC-->TT at dipyrimidine sites) located at known hotspots. No significant differences were found between both spectra, indicating that all p53 patches harbour mutations with which they could progress to carcinomas. To examine whether these p53 patches can be used as tumour risk indicators, we made an extensive comparison of the induction kinetics of these patches and carcinomas in genetically modified mice with various defects in nucleotide excision repair (NER), i.e. xeroderma pigmentosum A (Xpa), Xpc and Cockayne syndrome B (Csb) and wild-type mice. In this aforementioned order, the mouse strains developed both p53 patches and carcinomas in the course of daily exposure to 40 J/m(2) UV. Hence, the order in which the NER-deficient mice developed patches was predictive of the order in which they developed tumours. The induction kinetics of the patches in Xpc-deficient mice differed notably from the others: there was a stationary phase (days 13-41) where the numbers were limited to 5-10 patches per mouse before an explosive increase which ran parallel to the other groups. The chance that a p53 patch progresses to carcinoma is relatively small (estimated at 1 out of 8300-40,000/individual when the first tumour appears), but our results are strongly indicative of a causal relationship between p53 patches and carcinomas.

  5. Dilated Cardiomyopathy Mutation (R134W) in Mouse Cardiac Troponin T Induces Greater Contractile Deficits against α-Myosin Heavy Chain than against β-Myosin Heavy Chain

    OpenAIRE

    Gollapudi, Sampath K.; Murali Chandra

    2016-01-01

    Many studies have demonstrated that depressed myofilament Ca2+ sensitivity is common to dilated cardiomyopathy (DCM) in humans. However, it remains unclear whether a single determinant — such as myofilament Ca2+ sensitivity — is sufficient to characterize all cases of DCM because the severity of disease varies widely with a given mutation. Because dynamic features dominate in the heart muscle, alterations in dynamic contractile parameters may offer better insight on the molecular mechanisms...

  6. Deep vein thrombosis, ecythyma gangrenosum and heparin-induced thrombocytopenia occurring in a man with a heterozygous Factor V Leiden mutation

    OpenAIRE

    Mariya Apostolova; Baoying Weng; Pote, Harry H.; Harold Ashcraft; Curtis Goldblatt; Paul V. Woolley

    2012-01-01

    Skin necrosis and limb gangrene are occasional thrombotic manifestations of anticoagulation therapy. We report a man heterozygous for the Factor V Leiden (FVL) mutation, and with a history of recurrent deep venous thrombosis, who initially presented with a necrotic skin lesion of the right flank while on warfarin therapy with a therapeutic international normalized ratio. Warfarin was discontinued and he received intravenous heparin. Thereafter he developed thrombocytopenia and pedal erythema ...

  7. Mutation G805R in the transmembrane domain of the LDL receptor gene causes familial hypercholesterolemia by inducing ectodomain cleavage of the LDL receptor in the endoplasmic reticulum

    Directory of Open Access Journals (Sweden)

    Thea Bismo Strøm

    2014-01-01

    Full Text Available More than 1700 mutations in the low density lipoprotein receptor (LDLR gene have been found to cause familial hypercholesterolemia (FH. These are commonly divided into five classes based upon their effects on the structure and function of the LDLR. However, little is known about the mechanism by which mutations in the transmembrane domain of the LDLR gene cause FH. We have studied how the transmembrane mutation G805R affects the function of the LDLR. Based upon Western blot analyses of transfected HepG2 cells, mutation G805R reduced the amounts of the 120 kDa precursor LDLR in the endoplasmic reticulum. This led to reduced amounts of the mature 160 kDa LDLR at the cell surface. However, significant amounts of a secreted 140 kDa G805R-LDLR ectodomain fragment was observed in the culture media. Treatment of the cells with the metalloproteinase inhibitor batimastat largely restored the amounts of the 120 and 160 kDa forms in cell lysates, and prevented secretion of the 140 kDa ectodomain fragment. Together, these data indicate that a metalloproteinase cleaved the ectodomain of the 120 kDa precursor G805R-LDLR in the endoplasmic reticulum. It was the presence of the polar Arg805 and not the lack of Gly805 which led to ectodomain cleavage. Arg805 also prevented γ-secretase cleavage within the transmembrane domain. It is conceivable that introducing a charged residue within the hydrophobic membrane lipid bilayer, results in less efficient incorporation of the 120 kDa G805R-LDLR in the endoplasmic reticulum membrane and makes it a substrate for metalloproteinase cleavage.

  8. Ethyl methane sulfonate induced mutations in M2 generation and physiological variations in M1 generation of peppers (Capsicum annuum L.

    Directory of Open Access Journals (Sweden)

    Mohamed Hamed Arisha

    2015-06-01

    Full Text Available This study was conducted to enhance genetic variability in peppers (Capsicum annuum, cv B12 using ethyl methansulphonate (EMS. Exposure to an EMS concentration of 0.6%, v/v for 12 hours was used to mutagenize 2000 seeds for the first generation (M1. It was observed that the growth behaviors including plant height, flowering date and number of seeds per first fruit were different in the M1 generation than in wild type plants. In addition one phenotypic mutation (leaf shape and plant architecture was observed during the M1 generation. During the seedling stage in the M2 generation, the observed changes were in the form of slow growth or chlorophyll defect (e.g., albino, pale green and yellow seedlings. At maturity, there were three kinds of phenotypic mutations observed in three different families of the mutant population. The first observed change was a plant with yellow leaf color, and the leaves of this mutant plant contained 62.19% less chlorophyll a and 64.06% less chlorophyll b as compared to the wild-type. The second mutation resulted in one dwarf plant with a very short stature (6 cm, compact internodes and the leaves and stem were rough and thick. The third type of mutation occurred in four plants and resulted in the leaves of these plants being very thick and longer than those of wild type plants. Furthermore, anatomical observations of the leaf blade section of this mutant plant type contained more xylem and collenchyma tissue in the leaf midrib of the mutant plant than wild type. In addition, its leaf blade contained thicker palisade and spongy tissue than the wild type.

  9. A novel insertion-induced frameshift mutation of the SLC26A4 gene in a Korean family with Pendred syndrome.

    Science.gov (United States)

    Sagong, Borum; Seok, Jun Ho; Kwon, Tae-Jun; Kim, Un-Kyung; Lee, Sang-Heun; Lee, Kyu-Yup

    2012-10-15

    Pendred syndrome (PS) is an autosomal recessive disorder characterized by congenital bilateral sensorineural hearing loss, goiter, and incomplete iodide organification. Patients with PS also have structural anomalies of the inner ear such as enlarged vestibular aqueducts (EVA) and Mondini's malformation. The goiter, which is a major clinical manifestation of PS, usually develops around adolescence. PS is caused by biallelic mutations of the SLC26A4 gene, while nonsyndromic bilateral EVA is associated with zero or one SLC26A4 mutant allele. We report here a Korean family including a young female with PS who had goiter and progressive, fluctuating sensorineural hearing loss that could be partially recovered by oral steroid treatment. Genetic investigation revealed compound heterozygous mutations for p.R677AfsX11, a novel frameshift mutation, and p.H723R in the SLC26A4 gene. Our findings provide detailed information regarding the distribution of mutant alleles for PS and may serve as a foundation for studies to comprehend the genetic portion of syndromic hearing loss.

  10. Identification of IFN-alpha Induced Envelope Mutations of Hepatitis C Virus In Vitro Associated with Increased Viral Fitness and Interferon Resistance

    DEFF Research Database (Denmark)

    Serre, Stéphanie B N; Krarup, Henrik B; Bukh, Jens

    2013-01-01

    with acquisition of putative escape mutations in HCV structural and nonstructural proteins. Reverse genetic studies showed that primarily amino acid changes I348T in 1a(H77) E1 and F345V/V414A in 3a(S52) E1/E2 increased viral fitness. Single-cycle assays revealed that I348T and F345V/V414A enhanced viral entry...... is limited. Experimental studies were hampered by lack of HCV culture systems. Using genotype (strain) 1a(H77) and 3a(S52) Core-NS2 JFH1-based recombinants, we aimed at identifying viral correlates of IFN-α resistance in vitro. Long-term culture with IFN-α2b in Huh7.5 cells resulted in viral spread...... and release, respectively. In assays allowing viral spread, these mutations conferred a level of IFN-α resistance exceeding the observed fitness effect. The identified mutations acted in a subtype-specific manner but were not found in genotype 1a and 3a patients, who failed IFN-α therapy. Studies with HCV...

  11. 45例少见β地中海贫血患者β球蛋白基因序列分析%Study on rate gene mutation of β -thalassemia

    Institute of Scientific and Technical Information of China (English)

    宋春林; 赖金甜; 范菊花; 郭晓玲; 陈淑芬

    2010-01-01

    目的 研究佛山地区稀有β地中海贫血基因突变.方法 对来佛山妇幼保健院产前检查的8400例患者进行血细胞和血红蛋白电泳常规筛查,对其中3600例血象异常怀疑β地中海贫血的患者行反向点杂交检测常见的17种突变,确诊1260例,然后对未发现常见突变的45例可疑患者扩增β球蛋白基因送公司直接基因测序.结果 发现了15例稀有β地中海贫血,其中nt-90(C→T)、CD6(GAG→AAG)突变各2例,IVS-I-116(T→G)、IVS-I-128(T→G)、IVS-I-130(G→C)突变各1例,CD113(GTG→GAG)突变8例.结论 针对未发现常见17种β地中海贫血基因突变的可疑患者采用β球蛋白基因直接基因测序鉴定可以发现稀有突变,并为患者更好地提供产前基因诊断服务.%Objective To detect the rare gene mutation of β-thalassemia in Foshan area. Methods Basic erythrocyte hematologic parameters were performed through auto cell counter Sysmex XT2000i in routine for all 8400 patients who came to Foshan Maternal and Children's Hospital for prenatal screen. And Hb electrophoresis were carried out through auto analyzer Helena Spire 3000. Then identified the commonest known 17 types beta thalassemia mutations by reverse dot blot hybridization for the 3600 patients whose erythrocyte parameters were associated with hypochromia or whose electrophoresis results had elevated HbA2 or HbF or abnormal band. 1260 cases were identified as beta thalassemia. For the 45 doubtful patients who were not found the commonest known 17 types beta thalassemia mutations, direct DNA sequencing of the entire β-globin gene was performed. Results There were 45 patients were associate with hypochromia and had elevated HbA2 or HbF or abnormal band who were not found the commonest 17 types beta thalassemia mutations by reverse dot blot hybridization. After sequencing the entire beta globin gene, 15 rare beta thalassemia gene mutations were found, of which 2 cases were nt-90 (C→T), 2 cases were

  12. Mutation analysis of beta thalassemia gene in Guangxi Zhuang Autonomous Region%广西壮族自治区β-地中海贫血基因突变分析

    Institute of Scientific and Technical Information of China (English)

    张强; 范歆; 何升; 唐燕青; 陈秋丽; 郑陈光

    2014-01-01

    770 suspected patients,including 10 891 patients with beta thalassemia,49 patients were homozygous,10 718 patients were heterozygote,and 124 patients were compound heterozygous.After beta globin gene sequencing test,14 regular mutations in people of south China and 7 rare types mutations were detected,the detection rate of rare type of beta thalassemia was 17.949% (7/39).Conclusions Mutation spectrum of beta thalassemia in Guangxi is complex.Gene diagnosis of rare type thalassemia needs to be done in patients with phenotypes of thalassemia and negative of regular gene diagnosis,in order to reduce misdiagnosis,and improve accuracy of clinical diagnosis.

  13. Mitochondrial DNA Mutations Associated with Aminoglycoside Ototoxicity

    Institute of Scientific and Technical Information of China (English)

    GUAN Min-Xin

    2006-01-01

    The mitochondrial 12S rRNA has been shown to be the hot spot for mutations associated with both aminoglycoside-induced and non-syndromic hearing loss. Of all the mutations, the homoplasmic A1555G and C1494T mutations at a highly conserved decoding region in the 12S rRNA have been associated with aminoglycoside-induced and non-syndromic hearing loss in many families worldwide. The A1555G or C1494T mutation is expected to form novel 1494C-G1555 or 1494U-A1555 base-pair at the highly conserved A-site of 12S rRNA. These transitions make the secondary structure of this RNA more closely resemble the corresponding region of bacterial 16S rRNA. Thus, the new U - A or G-C pair in 12S rRNA created by the C1494T or A1555G transition facilitates the binding of aminoglycosides, thereby accounting for the fact that the exposure to aminoglycosides can induce or worsen hearing loss in individuals carrying these mutations. Furthermore, the growth defect and impairment of mitochondrial translation were observed in cell lines carrying the A1555G or C1494T mutation in the presence of high concentration of aminoglycosides. In addition, nuclear modifier genes and mitochondrial haplotypes modulate the phenotypic manifestation of the A1555G and C1494T mutations. These observations provide the direct genetic and biochemical evidences that the A1555G or C1494T mutation is a pathogenic mtDNA mutation associated with aminoglycoside-induced and nonsyndromic hearing loss. Therefore, these data have been providing valuable information and technology to predict which individuals are at risk for ototoxicity, to improve the safety of aminoglycoside antibiotic therapy, and eventually to decrease the incidence of deafness.

  14. Acrylamide-induced carcinogenicity in mouse lung involves mutagenicity: cII gene mutations in the lung of big blue mice exposed to acrylamide and glycidamide for up to 4 weeks.

    Science.gov (United States)

    Manjanatha, Mugimane G; Guo, Li-Wu; Shelton, Sharon D; Doerge, Daniel R

    2015-06-01

    Potential health risks for humans from exposure to acrylamide (AA) and its epoxide metabolite glycidamide (GA) have garnered much attention lately because substantial amounts of AA are present in a variety of fried and baked starchy foods. AA is tumorigenic in rodents, and a large number of in vitro and in vivo studies indicate that AA is genotoxic. A recent cancer bioassay on AA demonstrated that the lung was one of the target organs for tumor induction in mice; however, the mutagenicity of AA in this tissue is unclear. Therefore, to investigate whether or not gene mutation is involved in the etiology of AA- or GA-induced mouse lung carcinogenicity, we screened for cII mutant frequency (MF) in lungs from male and female Big Blue (BB) mice administered 0, 1.4, and 7.0 mM AA or GA in drinking water for up to 4 weeks (19-111 mg/kg bw/days). Both doses of AA and GA produced significant increases in cII MFs, with the high doses producing responses 2.7-5.6-fold higher than the corresponding controls (P ≤ 0.05; control MFs = 17.2 ± 2.2 and 15.8 ± 3.5 × 10(-6) in males and females, respectively). Molecular analysis of the mutants from high doses indicated that AA and GA produced similar mutation spectra and that these spectra were significantly different from the spectra in control mice (P ≤ 0.01). The predominant types of mutations in the lung cII gene from AA- and GA-treated mice were A:T → T:A, and G:C → C:G transversions, and -1/+1 frameshifts at a homopolymeric run of Gs. The MFs and types of mutations induced by AA and GA in the lung are consistent with AA exerting its genotoxicity via metabolism to GA. These results suggest that AA is a mutagenic carcinogen in mouse lungs and therefore further studies on its potential health risk to humans are warranted. Environ. Mol. Mutagen. 56:446-456, 2015. © 2015 Wiley Periodicals, Inc.

  15. Molecular mechanism of R-bicalutamide switching from androgen receptor antagonist to agonist induced by amino acid mutations using molecular dynamics simulations and free energy calculation

    Science.gov (United States)

    Liu, Hongli; Han, Rui; Li, Jiazhong; Liu, Huanxiang; Zheng, Lifang

    2016-12-01

    R-bicalutamide, a first generation antiandrogen, was used to treat prostate cancer for decades. Although it is very effective at the beginning, resistance appears after 2-3 years of treatment. Mutation of androgen receptor (AR) is considered a main reason for drug resistance. It is reported that AR W741C, W741L, W741C_T877A, T877A, F876L, F876L_T877A and L701H mutations can convert R-bicalutamide from AR antagonist to agonist, but the switching mechanisms are not clear. In this study, molecular dynamics simulations and molecular mechanics generalized Born surface area (MM-GBSA) calculations were performed to analyze the interaction mechanisms between R-bicalutamide and wild type/mutant ARs. The results indicate that helix H12, which lies on the top of AR LBD like a cover, plays a vital role in R-bicalutamide binding. When interacting with AR, the B-ring of R-bicalutamide pushes H12 aside, distorting the coactivator binding site (AF2) resulting in the inactivation of transcription. Several residue mutations appear to enlarge the distance between the B-ring of R-bicalutamide and H12, reducing steric clash, which is conducive to a closed H12 conformation, leading to the formation of the coactivator binding site AF2 and increased transcription. Hydrogen bond and per-residue free energy decomposition analyses are also investigated to explore the interacting mechanisms, and M895 is found to be a key residue in the antagonist mechanism. The obtained molecular mechanisms will aid rational screening and design of novel AR antagonists, even to mutant AR.

  16. UVA activation of N-dialkylnitrosamines releasing nitric oxide, producing strand breaks as well as oxidative damages in DNA, and inducing mutations in the Ames test

    Energy Technology Data Exchange (ETDEWEB)

    Arimoto-Kobayashi, Sakae, E-mail: arimoto@cc.okayama-u.ac.jp [Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, 1-1-1 Tsushima, Okayama 700-8530 (Japan); Sano, Kayoko; Machida, Masaki; Kaji, Keiko; Yakushi, Keiko [Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, 1-1-1 Tsushima, Okayama 700-8530 (Japan)

    2010-09-10

    We investigated the photo-mutagenicity and photo-genotoxicity of N-dialkylnitrosamines and its mechanisms of UVA activation. With simultaneous irradiation of UVA, photo-mutagenicity of seven N-dialkylnitrosamines was observed in Ames bacteria (Salmonella typhimurium TA1535) in the absence of metabolic activation. Mutagenicity of pre-irradiated N-dialkylnitrosamines was also observed with S. typhimurium hisG46, TA100, TA102 and YG7108 in the absence of metabolic activation. UVA-mediated mutation with N-nitrosodimethylamine (NDMA) and N-nitrosodiethylamine (NDEA) decreased by adding either the NO or OH radical scavenger. When superhelical DNA was irradiated with N-dialkylnitrosamines, nicked circular DNA appeared. Ten N-dialkylnitrosamines examined produced strand breaks in the treated DNA in the presence of UVA. The level of single-strand breaks in {phi}X174 DNA mediated by N-nitrosomorpholine (NMOR) and UVA decreased by adding either a radical scavenger or superoxide dismutase. When calf thymus DNA was treated with N-dialkylnitrosamines (NDMA, NDEA, NMOR, N-nitrosopyrrolidine (NPYR) and N-nitrosopiperidine (NPIP)) and UVA, the ratio of 8-oxodG/dG in the DNA increased. Action spectra were obtained to determine if nitrosamine acts as a sensitizer of UVA. Both mutation frequency and NO formation were highest at the absorption maximum of nitrosamines, approximately 340 nm. The plots of NO formation and mutation frequency align with the absorption curve of NPYR, NMOR and NDMA. A significant linear correlation between the optical density of N-dialkynitrosamines at 340 nm and NO formation in each irradiated solution was revealed by ANOVA. We would like to propose the hypothesis that the N-nitroso moiety of N-dialkylnitrosamines absorbs UVA photons, UVA-photolysis of N-dialkylnitrosamines brings release of nitric oxide, and subsequent production of alkyl radical cations and active oxygen species follow as secondary events, which cause DNA strand breaks, oxidative and

  17. The I4895T Mutation in the Type 1 Ryanodine Receptor Induces Fiber-Type Specific Alterations in Skeletal Muscle that Mimic Premature Aging

    OpenAIRE

    2010-01-01

    The I4898T (IT) mutation in type 1 ryanodine receptor (RyR1), the Ca2+ release channel of the sarcoplasmic reticulum (SR) is linked to a form of central core disease (CCD) in humans and results in a non leaky channel and excitation-contraction uncoupling. We characterized age- and fiber type-dependent alterations in muscle ultrastructure, as well as the magnitude and spatiotemporal properties of evoked Ca2+ release in heterozygous Ryr1I4895T/WT (IT/+) knock-in mice on a mixed genetic backgrou...

  18. Transgenic Animal Mutation Assays

    Institute of Scientific and Technical Information of China (English)

    Tao Chen; Ph.D.D.A.B.T.

    2005-01-01

    @@ The novel transgenic mouse and rat mutation assays have provided a tool for analyzing in vivo mutation in any tissue, thus permitting the direct comparison of cancer incidence with mutant frequency.

  19. Modelling mutational landscapes of human cancers in vitro

    Science.gov (United States)

    Olivier, Magali; Weninger, Annette; Ardin, Maude; Huskova, Hana; Castells, Xavier; Vallée, Maxime P.; McKay, James; Nedelko, Tatiana; Muehlbauer, Karl-Rudolf; Marusawa, Hiroyuki; Alexander, John; Hazelwood, Lee; Byrnes, Graham; Hollstein, Monica; Zavadil, Jiri

    2014-03-01

    Experimental models that recapitulate mutational landscapes of human cancers are needed to decipher the rapidly expanding data on human somatic mutations. We demonstrate that mutation patterns in immortalised cell lines derived from primary murine embryonic fibroblasts (MEFs) exposed in vitro to carcinogens recapitulate key features of mutational signatures observed in human cancers. In experiments with several cancer-causing agents we obtained high genome-wide concordance between human tumour mutation data and in vitro data with respect to predominant substitution types, strand bias and sequence context. Moreover, we found signature mutations in well-studied human cancer driver genes. To explore endogenous mutagenesis, we used MEFs ectopically expressing activation-induced cytidine deaminase (AID) and observed an excess of AID signature mutations in immortalised cell lines compared to their non-transgenic counterparts. MEF immortalisation is thus a simple and powerful strategy for modelling cancer mutation landscapes that facilitates the interpretation of human tumour genome-wide sequencing data.

  20. Ubiquitin Ligase Cbl-b Is Involved in Icotinib (BPI-2009H-Induced Apoptosis and G1 Phase Arrest of EGFR Mutation-Positive Non-Small-Cell Lung Cancer

    Directory of Open Access Journals (Sweden)

    Xiaodong Mu

    2013-01-01

    Full Text Available Epidermal growth factor receptor (EGFR is one of the most promising targets for non-small-cell lung cancer (NSCLC. Icotinib, a highly selective EGFR tyrosine kinase inhibitor (EGFR-TKI, has shown promising clinical efficacy and safety in patients with NSCLC. The exact molecular mechanism of icotinib remains unclear. In this study, we first investigated the antiproliferative effect of icotinib on NSCLC cells. Icotinib significantly inhibited proliferation of the EGFR-mutated lung cancer HCC827 cells. The IC50 values at 48 and 72 h were 0.67 and 0.07 μM, respectively. Flow cytometric analysis showed that icotinib caused the G1 phase arrest and increased the rate of apoptosis in HCC827 cells. The levels of cyclin D1 and cyclin A2 were decreased. The apoptotic process was associated with activation of caspase-3, -8, and poly(ADP-ribose polymerase (PARP. Further study revealed that icotinib inhibited phosphorylation of EGFR, Akt, and extracellular signal-regulated kinase. In addition, icotinib upregulated ubiquitin ligase Cbl-b expression. These observations suggest that icotinib-induced upregulation of Cbl-b is responsible, at least in part, for the antitumor effect of icotinib via the inhibition of phosphoinositide 3-kinase (PI3K/Akt and mitogen-activated protein kinase pathways in EGFR-mutated NSCLC cells.