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Sample records for chromosomal proteins non-histone

  1. Non-histone chromosomal proteins. Their isolation and role in determining specificity of transcription in vitro.

    Science.gov (United States)

    Blüthmann, H; Mrozek, S; Gierer, A

    1975-10-15

    We describe a method for fractionation of chromatin components by selective dissociation with salt in buffers containing 5 M urea in combination with cromatography on hydroxyapatite at 4 degrees C. This results in two histone and four non-histone fractions which are recovered in high yield and with minimal proteolytic contamination. Template capacity measurements of the isolated chromatins and pre-saturation competition hybridization experiments support the idea that a group of non-histone proteins activate the transcription of specific DNA sequences which were not transcribed from purified DNA to the same extent. In reconstitution experiments a non-histone protein fraction, NH4, prepared from lymphocyte chromatin by hydroxyapatite chromatography is shown to cause transcription in vitro of lymphocyte-specific RNA sequences. A subfraction with a molecular weight of 30 000 comprising 40% of the NH4 fraction protein is characteristic for this tissue and not found in liver chromatin.

  2. Non-histone chromosomal proteins HMG1 and 2 enhance ligation reaction of DNA double-strand breaks.

    Science.gov (United States)

    Nagaki, S; Yamamoto, M; Yumoto, Y; Shirakawa, H; Yoshida, M; Teraoka, H

    1998-05-08

    DNA ligase IV in a complex with XRCC4 is responsible for DNA end-joining in repair of DNA double-strand breaks (DSB) and V(D)J recombination. We found that non-histone chromosomal high mobility group (HMG) proteins 1 and 2 enhanced the ligation of linearized pUC119 DNA with DNA ligase IV from rat liver nuclear extract. Intra-molecular and inter-molecular ligations of cohesive-ended and blunt-ended DNA were markedly stimulated by HMG1 and 2. Recombinant HMG2-domain A, B, and (A + B) polypeptides were similarly, but non-identically, effective for the stimulation of DSB ligation reaction. Ligation of single-strand breaks (nicks) was only slightly activated by the HMG proteins. The DNA end-binding Ku protein singly or in combination with the catalytic component of DNA-dependent protein kinase (DNA-PK) as the DNA-PK holoenzyme was ineffective for the ligation of linearized pUC119 DNA. Although the stimulatory effect of HMG1 and 2 on ligation of DSB in vitro was not specific to DNA ligase IV, these results suggest that HMG1 and 2 are involved in the final ligation step in DNA end-joining processes of DSB repair and V(D)J recombination.

  3. Epigenetic regulation: methylation of histone and non-histone proteins

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Histone methylation is believed to play important roles in epigenetic memory in various biological processes. However, questions like whether the methylation marks themselves are faithfully transmit- ted into daughter cells and through what mechanisms are currently under active investigation. Previ- ously, methylation was considered to be irreversible, but the recent discovery of histone lysine de- methylases revealed a dynamic nature of histone methylation regulation on four of the main sites of methylation on histone H3 and H4 tails (H3K4, H3K9, H3K27 and H3K36). Even so, it is still unclear whether demethylases specific for the remaining two sites, H3K79 and H4K20, exist. Furthermore, be- sides histone proteins, the lysine methylation and demethylation also occur on non-histone proteins, which are probably subjected to similar regulation as histones. This review discusses recent pro- gresses in protein lysine methylation regulation focusing on the above topics, while referring readers to a number of recent reviews for the biochemistry and biology of these enzymes.

  4. Epigenetic regulation: methylation of histone and non-histone proteins

    Institute of Scientific and Technical Information of China (English)

    LAN Fei; SHI Yang

    2009-01-01

    Histone methylation is believed to play important roles In epigenetic memory in various biological processes. However, questions like whether the methylation marks themselves are faithfully transmit-ted into daughter cells and through what mechanisms are currently under active investigation. Previ-ously, methylation was considered to be irreversible, but the recent discovery of histone lysine de-methylases revealed a dynamic nature of histone methylation regulation on four of the main sites of methylation on histone H3 and H4 tails (H3K4, H3K9, H3K27 and H3K36). Even so, it is stlll unclear whether demethylases specific for the remaining two sites, H3K79 and H4K20, exist. Furthermore, be-sides hlstone proteins, the lysine methylation and demethylation also occur on non-histone proteins,which are probably subjected to similar regulation as histones. This review discusses recent pro-gresses In protein lysine methylation regulation focusing on the above topics, while referring readers to a number of recent reviews for the biochemistry and biology of these enzymes.

  5. Protein lysine methyltransferase G9a acts on non-histone targets

    Science.gov (United States)

    Rathert, Philipp; Dhayalan, Arunkumar; Murakami, Marie; Zhang, Xing; Tamas, Raluca; Jurkowska, Renata; Komatsu, Yasuhiko; Shinkai, Yoichi; Cheng, Xiaodong; Jeltsch, Albert

    2009-01-01

    By methylation of peptide arrays, we determined the specificity profile of the protein methyltransferase G9a. We show that it mostly recognizes an Arg-Lys sequence and that its activity is inhibited by methylation of the arginine residue. Using the specificity profile, we identified new non-histone protein targets of G9a, including CDYL1, WIZ, ACINUS and G9a (automethylation), as well as peptides derived from CSB. We demonstrate potential downstream signaling pathways for methylation of non-histone proteins. PMID:18438403

  6. Identification and characterization of lysine-methylated sites on histones and non-histone proteins.

    Science.gov (United States)

    Lee, Tzong-Yi; Chang, Cheng-Wei; Lu, Cheng-Tzung; Cheng, Tzu-Hsiu; Chang, Tzu-Hao

    2014-06-01

    Protein methylation is a kind of post-translational modification (PTM), and typically takes place on lysine and arginine amino acid residues. Protein methylation is involved in many important biological processes, and most recent studies focused on lysine methylation of histones due to its critical roles in regulating transcriptional repression and activation. Histones possess highly conserved sequences and are homologous in most species. However, there is much less sequence conservation among non-histone proteins. Therefore, mechanisms for identifying lysine-methylated sites may greatly differ between histones and non-histone proteins. Nevertheless, this point of view was not considered in previous studies. Here we constructed two support vector machine (SVM) models by using lysine-methylated data from histones and non-histone proteins for predictions of lysine-methylated sites. Numerous features, such as the amino acid composition (AAC) and accessible surface area (ASA), were used in the SVM models, and the predictive performance was evaluated using five-fold cross-validations. For histones, the predictive sensitivity was 85.62% and specificity was 80.32%. For non-histone proteins, the predictive sensitivity was 69.1% and specificity was 88.72%. Results showed that our model significantly improved the predictive accuracy of histones compared to previous approaches. In addition, features of the flanking region of lysine-methylated sites on histones and non-histone proteins were also characterized and are discussed. A gene ontology functional analysis of lysine-methylated proteins and correlations of lysine-methylated sites with other PTMs in histones were also analyzed in detail. Finally, a web server, MethyK, was constructed to identify lysine-methylated sites. MethK now is available at http://csb.cse.yzu.edu.tw/MethK/.

  7. Chromosomal proteins of Arabidopsis thaliana.

    Science.gov (United States)

    Moehs, C P; McElwain, E F; Spiker, S

    1988-07-01

    In plants with large genomes, each of the classes of the histones (H1, H2A, H2B, H3 and H4) are not unique polypeptides, but rather families of closely related proteins that are called histone variants. The small genome and preponderance of single-copy DNA in Arabidopsis thaliana has led us to ask if this plant has such families of histone variants. We have thus isolated histones from Arabidopsis and analyzed them on four polyacrylamide gel electrophoretic systems: an SDS system; an acetic acid-urea system; a Triton transverse gradient system; and a two-dimensional system combining SDS and Triton-acetic acid-urea systems. This approach has allowed us to identify all four of the nucleosomal core histones in Arabidopsis and to establish the existence of a set of H2A and H2B variants. Arabidopsis has at least four H2A variants and three H2B variants of distinct molecular weights as assessed by electrophoretic mobility on SDS-polyacrylamide gels. Thus, Arabidopsis displays a diversity in these histones similar to the diversity displayed by plants with larger genomes such as wheat.The high mobility group (HMG) non-histone chromatin proteins have attracted considerable attention because of the evidence implicating them as structural proteins of transcriptionally active chromatin. We have isolated a group of non-histone chromatin proteins from Arabidopsis that meet the operational criteria to be classed as HMG proteins and that cross-react with antisera to HMG proteins of wheat.

  8. Chromosome

    Science.gov (United States)

    Chromosomes are structures found in the center (nucleus) of cells that carry long pieces of DNA. DNA ... is the building block of the human body. Chromosomes also contain proteins that help DNA exist in ...

  9. Systematic analysis of human protein complexes identifies chromosome segregation proteins.

    Science.gov (United States)

    Hutchins, James R A; Toyoda, Yusuke; Hegemann, Björn; Poser, Ina; Hériché, Jean-Karim; Sykora, Martina M; Augsburg, Martina; Hudecz, Otto; Buschhorn, Bettina A; Bulkescher, Jutta; Conrad, Christian; Comartin, David; Schleiffer, Alexander; Sarov, Mihail; Pozniakovsky, Andrei; Slabicki, Mikolaj Michal; Schloissnig, Siegfried; Steinmacher, Ines; Leuschner, Marit; Ssykor, Andrea; Lawo, Steffen; Pelletier, Laurence; Stark, Holger; Nasmyth, Kim; Ellenberg, Jan; Durbin, Richard; Buchholz, Frank; Mechtler, Karl; Hyman, Anthony A; Peters, Jan-Michael

    2010-04-30

    Chromosome segregation and cell division are essential, highly ordered processes that depend on numerous protein complexes. Results from recent RNA interference screens indicate that the identity and composition of these protein complexes is incompletely understood. Using gene tagging on bacterial artificial chromosomes, protein localization, and tandem-affinity purification-mass spectrometry, the MitoCheck consortium has analyzed about 100 human protein complexes, many of which had not or had only incompletely been characterized. This work has led to the discovery of previously unknown, evolutionarily conserved subunits of the anaphase-promoting complex and the gamma-tubulin ring complex--large complexes that are essential for spindle assembly and chromosome segregation. The approaches we describe here are generally applicable to high-throughput follow-up analyses of phenotypic screens in mammalian cells.

  10. Deacetylase inhibitors-focus on non-histone targets and effects

    Institute of Scientific and Technical Information of China (English)

    Matthias; Ocker

    2010-01-01

    Inhibitors of protein deacetylases have recently been established as a novel therapeutic principle for several human diseases,including cancer.The original notion of the mechanism of action of these compounds focused on the epigenetic control of transcriptional processes, especially of tumor suppressor genes,by interfering with the acetylation status of nuclear histone proteins,hence the name histone deacetylase inhibitors was coined.Yet,this view could not explain the high specificity for tumor cells and recent evidence now suggests that non-histone proteins represent major targets for protein deacetylase inhibitors and that the post-translational modification of the acetylome is involved in various cellular processes of differentiation,survival and cell death induction.

  11. Biological function and regulation of histone and non-histone lysine methylation in response to DNA damage

    Institute of Scientific and Technical Information of China (English)

    Yongcan Chen; Wei-Guo Zhu

    2016-01-01

    DNA damage response (DDR) signaling network is initiated to protect cells from various exogenous and endogenous damage resources.Timely and accurate regulation of DDR proteins is required for distinct DNA damage repair pathways.Post-translational modifications of histone and non-histone proteins play a vital role in the DDR factor foci formation and signaling pathway.Phosphorylation,ubiquitylation,SUMOylation,neddylation,poly(ADP-ribosyl)ation,acetylation,and methylation are all involved in the spatial-temporal regulation of DDR,among which phosphorylation and ubiquitylation are well studied.Studies in the past decade also revealed extensive roles of lysine methylation in response to DNA damage.Lysine methylation is finely regulated by plenty of lysine methyltransferases,lysine demethylases,and can be recognized by proteins with chromodomain,plant homeodomain,Tudor domain,malignant brain tumor domain,or prolinetryptophan-tryptophan-proline domain.In this review,we outline the dynamics and regulation of histone lysine methylation at canonical (H3K4,H3K9,H3K27,H3K36,H3K79,and H4K20) and non-canonical sites after DNA damage,and discuss their context-specific functions in DDR protein recruitment or extraction,chromatin environment establishment,and transcriptional regulation.We also present the emerging advances of lysine methylation in non-histone proteins during DDR.

  12. Micromechanical study of protein-DNA interactions and chromosomes

    Science.gov (United States)

    Marko, John

    I will discuss micromechanics experiments that our group has used to analyze protein-DNA interactions and chromosome organization. In single-DNA experiments we have found that a feature of protein-DNA complexes is that their dissociation rates can depend strikingly on bulk solution concentrations of other proteins and DNA segments; I will describe experiments which demonstrate this effect, which can involve tens-fold changes in off-rates with submicromolar changes in solution concentrations. Second, I will discuss experiments aimed at analyzing large-scale human chromosome structure; we isolate metaphase chromosomes, which in their native form behave as remarkably elastic networks of chromatin. Exposure to DNA-cutting restriction enzymes completely eliminates this elasticity, indicating that there is not a mechanically contiguous protein ''scaffold'' from which the chromosome gains its stability. I will show results of siRNA experiments indicating that depletion of condensin proteins leads to destabilization of chromosome mechanics, indicating condensin's role as the major chromatin ''cross-linker'' in metaphase chromosomes. Finally I will discuss similar experiments on human G1 nuclei, where we use genetic and chemical modifications to separate the contributions of the nuclear lamina and chromatin to the mechanical stiffness of the nucleus as a whole. Supported by the NSF (DMR-1206868, MCB-1022117) and the NIH (GM105847, CA193419).

  13. REVIEW ARTICLE: DNA protein interactions and bacterial chromosome architecture

    Science.gov (United States)

    Stavans, Joel; Oppenheim, Amos

    2006-12-01

    Bacteria, like eukaryotic organisms, must compact the DNA molecule comprising their genome and form a functional chromosome. Yet, bacteria do it differently. A number of factors contribute to genome compaction and organization in bacteria, including entropic effects, supercoiling and DNA-protein interactions. A gamut of new experimental techniques have allowed new advances in the investigation of these factors, and spurred much interest in the dynamic response of the chromosome to environmental cues, segregation, and architecture, during both exponential and stationary phases. We review these recent developments with emphasis on the multifaceted roles that DNA-protein interactions play.

  14. Potential Role of Meiosis Proteins in Melanoma Chromosomal Instability

    Directory of Open Access Journals (Sweden)

    Scott F. Lindsey

    2013-01-01

    Full Text Available Melanomas demonstrate chromosomal instability (CIN. In fact, CIN can be used to differentiate melanoma from benign nevi. The exact molecular mechanisms that drive CIN in melanoma have yet to be fully elucidated. Cancer/testis antigens are a unique group of germ cell proteins that are found to be primarily expressed in melanoma as compared to benign nevi. The abnormal expression of these germ cell proteins, normally expected only in the testis and ovaries, in somatic cells may lead to interference with normal cellular pathways. Germ cell proteins that may be particularly critical in CIN are meiosis proteins. Here, we review pathways unique to meiosis with a focus on how the aberrant expression of meiosis proteins in normal mitotic cells “meiomitosis” could impact chromosomal instability in melanoma and other cancers.

  15. Chromosome driven spatial patterning of proteins in bacteria.

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    Saeed Saberi

    Full Text Available The spatial patterning of proteins in bacteria plays an important role in many processes, from cell division to chemotaxis. In the asymmetrically dividing bacteria Caulobacter crescentus, a scaffolding protein, PopZ, localizes to both poles and aids the differential patterning of proteins between mother and daughter cells during division. Polar patterning of misfolded proteins in Escherichia coli has also been shown, and likely plays an important role in cellular ageing. Recent experiments on both of the above systems suggest that the presence of chromosome free regions along with protein multimerization may be a mechanism for driving the polar localization of proteins. We have developed a simple physical model for protein localization using only these two driving mechanisms. Our model reproduces all the observed patterns of PopZ and misfolded protein localization--from diffuse, unipolar, and bipolar patterns and can also account for the observed patterns in a variety of mutants. The model also suggests new experiments to further test the role of the chromosome in driving protein patterning, and whether such a mechanism is responsible for helping to drive the differentiation of the cell poles.

  16. Assignment of the protein kinase C [delta] polypeptide gene (PRKCD) to human chromosome 3 and mouse chromosome 14

    Energy Technology Data Exchange (ETDEWEB)

    Huppi, K.; Siwarski, D.; Goodnight, J.; Mischak, H. (Molecular Genetics Section Lab. of Genetics, Bethesda, MD (United States))

    1994-01-01

    The protein kinase C (pkc) enzymes are a family of serine-threonine protein kinases, each encoded by a distinct and separate gene. The chromosomal locations of human PRKCA, PRKCB, and PRKCG have previously been established. The authors now report that PRKCD, a novel member of the pkc gene family, maps to human chromosome 3. The chromosomal location of Pkcd has also been determined in the mouse by analysis of recombination frequency in an interspecific panel of back-cross mice. They find that the locus encoding pkcd resides proximal to nucleoside phosphorylase (Np-2) and Tcra on mouse chromosome 14 in a region syntenic with human 3p. 9 refs., 2 tabs.

  17. Assignment of the protein kinase C delta polypeptide gene (PRKCD) to human chromosome 3 and mouse chromosome 14.

    Science.gov (United States)

    Huppi, K; Siwarski, D; Goodnight, J; Mischak, H

    1994-01-01

    The protein kinase C (pkc) enzymes are a family of serine-threonine protein kinases, each encoded by a distinct and separate gene. The chromosomal locations of human PRKCA, PRKCB, and PRKCG have previously been established. We now report that PRKCD, a novel member of the pkc gene family, maps to human chromosome 3. The chromosomal location of Pkcd has also been determined in the mouse by analysis of recombination frequency in an interspecific panel of backcross mice. We find that the locus encoding pkcd resides proximal to nucleoside phosphorylase (Np-2) and Tcra on mouse chromosome 14 in a region syntenic with human 3p.

  18. Mitotic chromosome condensation in vertebrates

    Energy Technology Data Exchange (ETDEWEB)

    Vagnarelli, Paola, E-mail: P.Vagnarelli@ed.ac.uk

    2012-07-15

    Work from several laboratories over the past 10-15 years has revealed that, within the interphase nucleus, chromosomes are organized into spatially distinct territories [T. Cremer, C. Cremer, Chromosome territories, nuclear architecture and gene regulation in mammalian cells, Nat. Rev. Genet. 2 (2001) 292-301 and T. Cremer, M. Cremer, S. Dietzel, S. Muller, I. Solovei, S. Fakan, Chromosome territories-a functional nuclear landscape, Curr. Opin. Cell Biol. 18 (2006) 307-316]. The overall compaction level and intranuclear location varies as a function of gene density for both entire chromosomes [J.A. Croft, J.M. Bridger, S. Boyle, P. Perry, P. Teague,W.A. Bickmore, Differences in the localization and morphology of chromosomes in the human nucleus, J. Cell Biol. 145 (1999) 1119-1131] and specific chromosomal regions [N.L. Mahy, P.E. Perry, S. Gilchrist, R.A. Baldock, W.A. Bickmore, Spatial organization of active and inactive genes and noncoding DNA within chromosome territories, J. Cell Biol. 157 (2002) 579-589] (Fig. 1A, A'). In prophase, when cyclin B activity reaches a high threshold, chromosome condensation occurs followed by Nuclear Envelope Breakdown (NEB) [1]. At this point vertebrate chromosomes appear as compact structures harboring an attachment point for the spindle microtubules physically recognizable as a primary constriction where the two sister chromatids are held together. The transition from an unshaped interphase chromosome to the highly structured mitotic chromosome (compare Figs. 1A and B) has fascinated researchers for several decades now; however a definite picture of how this process is achieved and regulated is not yet in our hands and it will require more investigation to comprehend the complete process. From a biochemical point of view a vertebrate mitotic chromosomes is composed of DNA, histone proteins (60%) and non-histone proteins (40%) [6]. I will discuss below what is known to date on the contribution of these two different classes

  19. Chromosome segregation proteins of Vibrio cholerae as transcription regulators.

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    Baek, Jong Hwan; Rajagopala, Seesandra V; Chattoraj, Dhruba K

    2014-05-06

    ABSTRACT Bacterial ParA and ParB proteins are best known for their contribution to plasmid and chromosome segregation, but they may also contribute to other cell functions. In segregation, ParA interacts with ParB, which binds to parS centromere-analogous sites. In transcription, plasmid Par proteins can serve as repressors by specifically binding to their own promoters and, additionally, in the case of ParB, by spreading from a parS site to nearby promoters. Here, we have asked whether chromosomal Par proteins can likewise control transcription. Analysis of genome-wide ParB1 binding in Vibrio cholerae revealed preferential binding to the three known parS1 sites and limited spreading of ParB1 beyond the parS1 sites. Comparison of wild-type transcriptomes with those of ΔparA1, ΔparB1, and ΔparAB1 mutants revealed that two out of 20 genes (VC0067 and VC0069) covered by ParB1 spreading are repressed by both ParB1 and ParA1. A third gene (VC0076) at the outskirts of the spreading area and a few genes further away were also repressed, particularly the gene for an outer membrane protein, ompU (VC0633). Since ParA1 or ParB1 binding was not evident near VC0076 and ompU genes, the repression may require participation of additional factors. Indeed, both ParA1 and ParB1 proteins were found to interact with several V. cholerae proteins in bacterial and yeast two-hybrid screens. These studies demonstrate that chromosomal Par proteins can repress genes unlinked to parS and can do so without direct binding to the cognate promoter DNA. IMPORTANCE Directed segregation of chromosomes is essential for their maintenance in dividing cells. Many bacteria have genes (par) that were thought to be dedicated to segregation based on analogy to their roles in plasmid maintenance. It is becoming clear that chromosomal par genes are pleiotropic and that they contribute to diverse processes such as DNA replication, cell division, cell growth, and motility. One way to explain the pleiotropy

  20. Chromosomal distribution of PcG proteins during Drosophila development.

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    Nicolas Nègre

    2006-06-01

    Full Text Available Polycomb group (PcG proteins are able to maintain the memory of silent transcriptional states of homeotic genes throughout development. In Drosophila, they form multimeric complexes that bind to specific DNA regulatory elements named PcG response elements (PREs. To date, few PREs have been identified and the chromosomal distribution of PcG proteins during development is unknown. We used chromatin immunoprecipitation (ChIP with genomic tiling path microarrays to analyze the binding profile of the PcG proteins Polycomb (PC and Polyhomeotic (PH across 10 Mb of euchromatin. We also analyzed the distribution of GAGA factor (GAF, a sequence-specific DNA binding protein that is found at most previously identified PREs. Our data show that PC and PH often bind to clustered regions within large loci that encode transcription factors which play multiple roles in developmental patterning and in the regulation of cell proliferation. GAF co-localizes with PC and PH to a limited extent, suggesting that GAF is not a necessary component of chromatin at PREs. Finally, the chromosome-association profile of PC and PH changes during development, suggesting that the function of these proteins in the regulation of some of their target genes might be more dynamic than previously anticipated.

  1. Identification of Mitosis-Specific Phosphorylation in Mitotic Chromosome-Associated Proteins.

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    Ohta, Shinya; Kimura, Michiko; Takagi, Shunsuke; Toramoto, Iyo; Ishihama, Yasushi

    2016-09-01

    During mitosis, phosphorylation of chromosome-associated proteins is a key regulatory mechanism. Mass spectrometry has been successfully applied to determine the complete protein composition of mitotic chromosomes, but not to identify post-translational modifications. Here, we quantitatively compared the phosphoproteome of isolated mitotic chromosomes with that of chromosomes in nonsynchronized cells. We identified 4274 total phosphorylation sites and 350 mitosis-specific phosphorylation sites in mitotic chromosome-associated proteins. Significant mitosis-specific phosphorylation in centromere/kinetochore proteins was detected, although the chromosomal association of these proteins did not change throughout the cell cycle. This mitosis-specific phosphorylation might play a key role in regulation of mitosis. Further analysis revealed strong dependency of phosphorylation dynamics on kinase consensus patterns, thus linking the identified phosphorylation sites to known key mitotic kinases. Remarkably, chromosomal axial proteins such as non-SMC subunits of condensin, TopoIIα, and Kif4A, together with the chromosomal periphery protein Ki67 involved in the establishment of the mitotic chromosomal structure, demonstrated high phosphorylation during mitosis. These findings suggest a novel mechanism for regulation of chromosome restructuring in mitosis via protein phosphorylation. Our study generated a large quantitative database on protein phosphorylation in mitotic and nonmitotic chromosomes, thus providing insights into the dynamics of chromatin protein phosphorylation at mitosis onset.

  2. Recombinant protein expression by targeting pre-selected chromosomal loci

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    Krömer Wolfgang

    2009-12-01

    Full Text Available Abstract Background Recombinant protein expression in mammalian cells is mostly achieved by stable integration of transgenes into the chromosomal DNA of established cell lines. The chromosomal surroundings have strong influences on the expression of transgenes. The exploitation of defined loci by targeting expression constructs with different regulatory elements is an approach to design high level expression systems. Further, this allows to evaluate the impact of chromosomal surroundings on distinct vector constructs. Results We explored antibody expression upon targeting diverse expression constructs into previously tagged loci in CHO-K1 and HEK293 cells that exhibit high reporter gene expression. These loci were selected by random transfer of reporter cassettes and subsequent screening. Both, retroviral infection and plasmid transfection with eGFP or antibody expression cassettes were employed for tagging. The tagged cell clones were screened for expression and single copy integration. Cell clones producing > 20 pg/cell in 24 hours could be identified. Selected integration sites that had been flanked with heterologous recombinase target sites (FRTs were targeted by Flp recombinase mediated cassette exchange (RMCE. The results give proof of principle for consistent protein expression upon RMCE. Upon targeting antibody expression cassettes 90-100% of all resulting cell clones showed correct integration. Antibody production was found to be highly consistent within the individual cell clones as expected from their isogenic nature. However, the nature and orientation of expression control elements revealed to be critical. The impact of different promoters was examined with the tag-and-targeting approach. For each of the chosen promoters high expression sites were identified. However, each site supported the chosen promoters to a different extent, indicating that the strength of a particular promoter is dominantly defined by its chromosomal context

  3. Studies on the mitotic chromosome scaffold of Allium sativum

    Institute of Scientific and Technical Information of China (English)

    ZHAOJIAN; SHAOBOJIN; 等

    1995-01-01

    An argentophilic structure is present in the metaphase chromosomes of garlic(Allium sativum),Cytochemical studies indicate that the main component of the structure is non-histone proteins(NHPs).The results of light and electron microscopic observations reveal that the chromosme NHP scaffold is a network which is composed of fibres and granules and distributed throughout the chromosomes.In the NHP network,there are many condensed regions that are connected by redlatively looser regions.The distribution of the condensed regions varies in individual chromosomes.In some of the chromosomes the condensed regions are lognitudinally situsted in the central part of a chromatid while in others these regions appear as coillike transverse bands.At early metaphase.scaffolds of the sister chromatids of a chromosome are linked to each other in the centromeric region,meanwhile,they are connected by scafold materials along the whole length of the chromosome.At late metaphase,however,the connective scaffold materials between the two sister chromatids disappear gradually and the chromatids begin to separate from one another at their ends.but the chromatids are linked together in the centromeric region until anaphase.This connection seems to be related to the special structure of the NHP scaffold formed in the centromeric region.The morphological features and dynamic changes of the chromosome scaffold are discussed.

  4. Sir protein-independent repair of dicentric chromosomes in Saccharomyces cerevisiae.

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    McCleary, David F; Steakley, David Lee; Rine, Jasper

    2016-09-15

    Sir2 protein has been reported to be recruited to dicentric chromosomes under tension, and such chromosomes are reported to be especially vulnerable to breakage in sir2Δ mutants. We found that the loss of viability in such mutants was an indirect effect of the repression of nonhomologous end joining in Sir(-) mutants and that the apparent recruitment of Sir2 protein to chromosomes under tension was likely due to methodological weakness in early chromatin immunoprecipitation studies.

  5. Chromosomal localization of murine and human oligodendrocyte-specific protein genes

    Energy Technology Data Exchange (ETDEWEB)

    Bronstein, J.M.; Wu, S.; Korenberg, J.R. [UCLA School of Medicine, Los Angeles, CA (United States)] [and others

    1996-06-01

    Oligodendrocyte-specific protein (OSP) is a recently described protein present only in myelin of the central nervous system. Several inherited disorders of myelin are caused by mutations in myelin genes but the etiology of many remain unknown. We mapped the location of the mouse OSP gene to the proximal region of chromosome 3 using two sets of multilocus crosses and to human chromosome 3 using somatic cell hybrids. Fine mapping with fluorescence in situ hybridization placed the OSP gene at human chromosome 3q26.2-q26.3. To date, there are no known inherited neurological disorders that localize to these regions. 24 refs., 2 figs.

  6. A Quest for Missing Proteins : update 2015 on Chromosome-Centric Human Proteome Project

    NARCIS (Netherlands)

    Horvatovich, Péter; Lundberg, Emma K; Chen, Yu-Ju; Sung, Ting-Yi; He, Fuchu; Nice, Edouard C; Goode, Robert J A; Yu, Simon; Ranganathan, Shoba; Baker, Mark S; Domont, Gilberto B; Velasquez, Erika; Li, Dong; Liu, Siqi; Wang, Quanhui; He, Qing-Yu; Menon, Rajasree; Guan, Yuanfang; Corrales, Fernando Jose; Segura, Victor; Casal, José Ignacio; Pascual-Montano, Alberto; Albar, Juan Pablo; Fuentes, Manuel; Gonzalez-Gonzalez, Maria; Diez, Paula; Ibarrola, Nieves; Degano, Rosa M; Mohammed, Yassene; Borchers, Christoph H; Urbani, Andrea; Soggiu, Alessio; Yamamoto, Tadashi; Archakov, Alexander I; Ponomarenko, Elena; Lisitsa, Andrey V; Lichti, Cheryl F; Mostovenko, Ekaterina; Kroes, Roger A; Rezeli, Melinda; Vegvari, Akos; Fehniger, Thomas E; Bischoff, Rainer; Vizcaíno, Juan Antonio; Deutsch, Eric W; Lane, Lydie; Nilsson, Carol L; Marko-Varga, György; Omenn, Gilbert S; Jeong, Seul-Ki; Cho, Jin-Young; Paik, Young-Ki; Hancock, William S

    2015-01-01

    This paper summarizes the recent activities of the Chromosome-Centric Human Proteome Project (C-HPP) consortium, which develops new technologies to identify yet-to-be annotated proteins (termed "missing proteins") in biological samples that lack sufficient experimental evidence at the protein level

  7. The r1162 mob proteins can promote conjugative transfer from cryptic origins in the bacterial chromosome.

    Science.gov (United States)

    Meyer, Richard

    2009-03-01

    The mobilization proteins of the broad-host-range plasmid R1162 can initiate conjugative transfer of a plasmid from a 19-bp locus that is partially degenerate in sequence. Such loci are likely to appear by chance in the bacterial chromosome and could act as cryptic sites for transfer of chromosomal DNA when R1162 is present. The R1162-dependent transfer of chromosomal DNA, initiated from one such potential site in Pectobacterium atrosepticum, is shown here. A second active site was identified in Escherichia coli, where it is also shown that large amounts of DNA are transferred. This transfer probably reflects the combined activity of the multiple cryptic origins in the chromosome. Transfer of chromosomal DNA due to the presence of a plasmid in the cytoplasm describes a previously unrecognized potential for the exchange of bacterial DNA.

  8. Tau protein in frontotemporal dementia linked to chromosome 3 (FTD-3).

    Science.gov (United States)

    Yancopoulou, Despina; Crowther, R Anthony; Chakrabarti, Lisa; Gydesen, Susanne; Brown, Jeremy M; Spillantini, Maria Grazia

    2003-08-01

    Recent work on frontotemporal dementia (FTD) has revealed the existence of at least 3 genetically distinct groups of inherited FTD: FTDP-17, FTD and motor neuron disease linked to chromosome 9, and FTD linked to chromosome 3 (FTD-3). Tau, on chromosome 17, is the only gene where mutations have been identified and its involvement in FTD has been firmly established. The genes on chromosome 9 and chromosome 3 associated with familial forms of FTD remain to be identified. Abnormal aggregates of tau protein characterize the brain lesions of FTDP-17 patients and ubiquitin inclusions have been found in FTD with motor neuron disease linked to chromosome 9. In this study the frontal cortices of 3 FTD-3 patients from a unique Danish family were examined for characteristic neuropathological features. In these brains tau inclusions were present in neurons and some glial cells in the absence of beta-amyloid deposits. The presence of filamentous tau protein in the frontal cortex of these patients suggests a possible link between tau and the genetic defect present on chromosome 3 and associated with FTD-3, although the limited amount of tau deposits observed makes it difficult to define this as a tauopathy.

  9. Mitotic Protein CSPP1 Interacts with CENP-H Protein to Coordinate Accurate Chromosome Oscillation in Mitosis.

    Science.gov (United States)

    Zhu, Lijuan; Wang, Zhikai; Wang, Wenwen; Wang, Chunli; Hua, Shasha; Su, Zeqi; Brako, Larry; Garcia-Barrio, Minerva; Ye, Mingliang; Wei, Xuan; Zou, Hanfa; Ding, Xia; Liu, Lifang; Liu, Xing; Yao, Xuebiao

    2015-11-06

    Mitotic chromosome segregation is orchestrated by the dynamic interaction of spindle microtubules with the kinetochores. During chromosome alignment, kinetochore-bound microtubules undergo dynamic cycles between growth and shrinkage, leading to an oscillatory movement of chromosomes along the spindle axis. Although kinetochore protein CENP-H serves as a molecular control of kinetochore-microtubule dynamics, the mechanistic link between CENP-H and kinetochore microtubules (kMT) has remained less characterized. Here, we show that CSPP1 is a kinetochore protein essential for accurate chromosome movements in mitosis. CSPP1 binds to CENP-H in vitro and in vivo. Suppression of CSPP1 perturbs proper mitotic progression and compromises the satisfaction of spindle assembly checkpoint. In addition, chromosome oscillation is greatly attenuated in CSPP1-depleted cells, similar to what was observed in the CENP-H-depleted cells. Importantly, CSPP1 depletion enhances velocity of kinetochore movement, and overexpression of CSPP1 decreases the speed, suggesting that CSPP1 promotes kMT stability during cell division. Specific perturbation of CENP-H/CSPP1 interaction using a membrane-permeable competing peptide resulted in a transient mitotic arrest and chromosome segregation defect. Based on these findings, we propose that CSPP1 cooperates with CENP-H on kinetochores to serve as a novel regulator of kMT dynamics for accurate chromosome segregation.

  10. Chromosomal manipulation by site-specific recombinases and fluorescent protein-based vectors.

    Directory of Open Access Journals (Sweden)

    Munehiro Uemura

    Full Text Available Feasibility of chromosomal manipulation in mammalian cells was first reported 15 years ago. Although this technique is useful for precise understanding of gene regulation in the chromosomal context, a limited number of laboratories have used it in actual practice because of associated technical difficulties. To overcome the practical hurdles, we developed a Cre-mediated chromosomal recombination system using fluorescent proteins and various site-specific recombinases. These techniques enabled quick construction of targeting vectors, easy identification of chromosome-rearranged cells, and rearrangement leaving minimum artificial elements at junctions. Applying this system to a human cell line, we successfully recapitulated two types of pathogenic chromosomal translocations in human diseases: MYC/IgH and BCR/ABL1. By inducing recombination between two loxP sites targeted into the same chromosome, we could mark cells harboring deletion or duplication of the inter-loxP segments with different colors of fluorescence. In addition, we demonstrated that the intrachromosomal recombination frequency is inversely proportional to the distance between two recombination sites, implicating a future application of this frequency as a proximity sensor. Our method of chromosomal manipulation can be employed for particular cell types in which gene targeting is possible (e.g. embryonic stem cells. Experimental use of this system would open up new horizons in genome biology, including the establishment of cellular and animal models of diseases caused by translocations and copy-number variations.

  11. A model for the condensation of the bacterial chromosome by the partitioning protein ParB

    Science.gov (United States)

    Broedersz, Chase; Wingreen, Ned

    2013-03-01

    The molecular machinery responsible for faithful segregation of the chromosome in bacteria such as Caulobacter crescentus and Bacillus subtilis includes the ParABS a.k.a. Spo0J/Soj partitioning system. In Caulobacter, prior to division, hundreds of ParB proteins bind to the DNA near the origin of replication, and localize to one pole of the cell. Subsequently, the ParB-DNA complex is translocated to the far pole by the binding and retraction of the ParA spindle-like apparatus. Remarkably, the localization of ParB proteins to specific regions of the chromosome appears to be controlled by only a few centromeric parS binding sites. Although lateral interactions between DNA-bound ParB are likely to be important for their localization, the long-range order of ParB domains on the chromosome appears to be inconsistent with a picture in which protein-protein interactions are limited to neighboring DNA-bound proteins. We developed a coarse-grained Brownian dynamics model that allows for lateral and 3D protein-protein interactions among bound ParB proteins. Our model shows how such interactions can condense and organize the DNA spatially, and can control the localization and the long-range order of the DNA-bound proteins.

  12. A new function of microtubule-associated protein tau: involvement in chromosome stability.

    Science.gov (United States)

    Rossi, Giacomina; Dalprà, Leda; Crosti, Francesca; Lissoni, Sara; Sciacca, Francesca L; Catania, Marcella; Di Fede, Giuseppe; Mangieri, Michela; Giaccone, Giorgio; Croci, Danilo; Tagliavini, Fabrizio

    2008-06-15

    Tau is a microtubule-associated protein that promotes assembly and stabilization of cytoskeleton microtubules. It is mostly expressed in neuronal and glial cells but it is also present in non-neural cells such as fibroblasts and lymphocytes. An altered tau produces cytoskeleton pathology resulting in neurodegenerative diseases such as Alzheimer's disease and tauopathies. Tau has been suggested to be a multifunctional protein, due to its localization in different cellular compartments. However its further functions are still unclear. We analyzed the distribution of tau in human skin fibroblasts showing its localization in the nucleus and along mitotic chromosomes. Then, we investigated if an altered tau, such as the P301L mutated protein associated with frontotemporal dementia, could produce nuclear pathology. We found that patients carrying the mutation consistently had several chromosome aberrations in their fibroblasts and lymphocytes: chromosome and chromatid breakages or gaps, aneuploidies, translocations, in addition to chromatin bridges and decondensed chromosomes. Our findings argue for a role of tau in chromosome stability by means of its interaction with both microtubules and chromatin.

  13. Phosphorylation regulates binding of the human papillomavirus type 8 E2 protein to host chromosomes.

    Science.gov (United States)

    Sekhar, Vandana; McBride, Alison A

    2012-09-01

    The papillomavirus E2 proteins are indispensable for the viral life cycle, and their functions are subject to tight regulation. The E2 proteins undergo posttranslational modifications that regulate their properties and roles in viral transcription, replication, and genome maintenance. During persistent infection, the E2 proteins from many papillomaviruses act as molecular bridges that tether the viral genomes to host chromosomes to retain them within the host nucleus and to partition them to daughter cells. The betapapillomavirus E2 proteins bind to pericentromeric regions of host mitotic chromosomes, including the ribosomal DNA loci. We recently reported that two residues (arginine 250 and serine 253) within the chromosome binding region of the human papillomavirus type 8 (HPV8) E2 protein are required for this binding. In this study, we show that serine 253 is phosphorylated, most likely by protein kinase A, and this modulates the interaction of the E2 protein with cellular chromatin. Furthermore, we show that this phosphorylation occurs in S phase, increases the half-life of the E2 protein, and promotes chromatin binding from S phase through mitosis.

  14. The escherichia coli chromosome replication initiator protein, DnaA

    DEFF Research Database (Denmark)

    Nyborg, Malene

    The experimental work presented in this thesis involve mutational analysis of the DNA binding domain of the DnaA protein and analysis of the A184V substitution in the ATP area of domain III and other amino acid substitutions found in the DnaA5 and DnaA4G proteins....

  15. Structure and chromosomal localization of the gene encoding the human myelin protein zero (MPZ)

    Energy Technology Data Exchange (ETDEWEB)

    Hayasaka, Kiyoshi; Himoro, Masato; Takada, Goro (Akita Univ. School of Medicine, Akita (Japan)); Wang, Yimin; Takata, Mizuho; Minoshima, Shinsei; Shimizu, Nobuyoshi; Miura, Masayuki; Uyemura, Keiichi (Keio Univ. School of Medicine, Tokyo (Japan))

    1993-09-01

    The authors describe the cloning, characterization, and chromosomal mapping of the human myelin protein zero (MPZ) gene (a structural protein of myelin and an adhesive glycoprotein of the immunoglobulin superfamily). The gene is about 7 kb long and consists of six exons corresponding of the functional domains. All exon-intron junction sequences conform to the GT/AG rule. The 5[prime]-flanking region of the gene has a TA-rich element (TATA-like box), two CAAT boxes, and a single defined transcription initiation site detected by the primer extension method. The gene for human MPZ was assigned to chromosome 1q22-q23 by spot blot hybridization of flow-sorted human chromosomes and fluorescence in situ hybridization. The localization of the MPZ gene coincides with the locus for Charcot-Marie-Tooth disease type 1B, determined by linkage analysis. 20 refs., 3 figs., 1 tab.

  16. Binding of Multiple Rap1 Proteins Stimulates Chromosome Breakage Induction during DNA Replication.

    Directory of Open Access Journals (Sweden)

    Greicy H Goto

    2015-08-01

    Full Text Available Telomeres, the ends of linear eukaryotic chromosomes, have a specialized chromatin structure that provides a stable chromosomal terminus. In budding yeast Rap1 protein binds to telomeric TG repeat and negatively regulates telomere length. Here we show that binding of multiple Rap1 proteins stimulates DNA double-stranded break (DSB induction at both telomeric and non-telomeric regions. Consistent with the role of DSB induction, Rap1 stimulates nearby recombination events in a dosage-dependent manner. Rap1 recruits Rif1 and Rif2 to telomeres, but neither Rif1 nor Rif2 is required for DSB induction. Rap1-mediated DSB induction involves replication fork progression but inactivation of checkpoint kinase Mec1 does not affect DSB induction. Rap1 tethering shortens artificially elongated telomeres in parallel with telomerase inhibition, and this telomere shortening does not require homologous recombination. These results suggest that Rap1 contributes to telomere homeostasis by promoting chromosome breakage.

  17. Nuclear actin-related protein is required for chromosome segregation in Toxoplasma gondii.

    Science.gov (United States)

    Suvorova, Elena S; Lehmann, Margaret M; Kratzer, Stella; White, Michael W

    2012-01-01

    Apicomplexa parasites use complex cell cycles to replicate that are not well understood mechanistically. We have established a robust forward genetic strategy to identify the essential components of parasite cell division. Here we describe a novel temperature sensitive Toxoplasma strain, mutant 13-20C2, which growth arrests due to a defect in mitosis. The primary phenotype is the mis-segregation of duplicated chromosomes with chromosome loss during nuclear division. This defect is conditional-lethal with respect to temperature, although relatively mild in regard to the preservation of the major microtubule organizing centers. Despite severe DNA loss many of the physical structures associated with daughter budding and the assembly of invasion structures formed and operated normally at the non-permissive temperature before completely arresting. These results suggest there are coordinating mechanisms that govern the timing of these events in the parasite cell cycle. The defect in mutant 13-20C2 was mapped by genetic complementation to Toxoplasma chromosome III and to a specific mutation in the gene encoding an ortholog of nuclear actin-related protein 4. A change in a conserved isoleucine to threonine in the helical structure of this nuclear actin related protein leads to protein instability and cellular mis-localization at the higher temperature. Given the age of this protist family, the results indicate a key role for nuclear actin-related proteins in chromosome segregation was established very early in the evolution of eukaryotes.

  18. Looping in on Ndc80 - how does a protein loop at the kinetochore control chromosome segregation?

    DEFF Research Database (Denmark)

    Nilsson, Jakob

    2012-01-01

    Segregation of chromosomes during mitosis requires the interaction of dynamic microtubules with the kinetochore, a large protein structure established on the centromere region of sister chromatids. The core microtubule-binding activity of the kinetochore resides in the KMN network, an outer...

  19. Noc protein binds to specific DNA sequences to coordinate cell division with chromosome segregation.

    Science.gov (United States)

    Wu, Ling Juan; Ishikawa, Shu; Kawai, Yoshikazu; Oshima, Taku; Ogasawara, Naotake; Errington, Jeff

    2009-07-08

    Coordination of chromosome segregation and cytokinesis is crucial for efficient cell proliferation. In Bacillus subtilis, the nucleoid occlusion protein Noc protects the chromosomes by associating with the chromosome and preventing cell division in its vicinity. Using protein localization, ChAP-on-Chip and bioinformatics, we have identified a consensus Noc-binding DNA sequence (NBS), and have shown that Noc is targeted to about 70 discrete regions scattered around the chromosome, though absent from a large region around the replication terminus. Purified Noc bound specifically to an NBS in vitro. NBSs inserted near the replication terminus bound Noc-YFP and caused a delay in cell division. An autonomous plasmid carrying an NBS array recruited Noc-YFP and conferred a severe Noc-dependent inhibition of cell division. This shows that Noc is a potent inhibitor of division, but that its activity is strictly localized by the interaction with NBS sites in vivo. We propose that Noc serves not only as a spatial regulator of cell division to protect the nucleoid, but also as a timing device with an important role in the coordination of chromosome segregation and cell division.

  20. Increased recombinant protein production owing to expanded opportunities for vector integration in high chromosome number Chinese hamster ovary cells.

    Science.gov (United States)

    Yamano, Noriko; Takahashi, Mai; Ali Haghparast, Seyed Mohammad; Onitsuka, Masayoshi; Kumamoto, Toshitaka; Frank, Jana; Omasa, Takeshi

    2016-08-01

    Chromosomal instability is a characteristic of Chinese hamster ovary (CHO) cells. Cultures of these cells gradually develop heterogeneity even if established from a single cell clone. We isolated cells containing different numbers of chromosomes from a CHO-DG44-based human granulocyte-macrophage colony stimulating factor (hGM-CSF)-producing cell line and found that high chromosome number cells showed higher hGM-CSF productivity. Therefore, we focused on the relationship between chromosome aneuploidy of CHO cells and high recombinant protein-producing cell lines. Distribution and stability of chromosomes were examined in CHO-DG44 cells, and two cell lines expressing different numbers of chromosomes were isolated from the original CHO-DG44 cell line to investigate the effect of aneuploid cells on recombinant protein production. Both cell lines were stably transfected with a vector that expresses immunoglobulin G3 (IgG3), and specific antibody production rates were compared. Cells containing more than 30 chromosomes had higher specific antibody production rates than those with normal chromosome number. Single cell analysis of enhanced green fluorescent protein (Egfp)-gene transfected cells revealed that increased GFP expression was relative to the number of gene integration sites rather than the difference in chromosome numbers or vector locations. Our results suggest that CHO cells with high numbers of chromosomes contain more sites for vector integration, a characteristic that could be advantageous in biopharmaceutical production.

  1. Evolutionary Characteristics of Missing Proteins: Insights into the Evolution of Human Chromosomes Related to Missing-Protein-Encoding Genes.

    Science.gov (United States)

    Xu, Aishi; Li, Guang; Yang, Dong; Wu, Songfeng; Ouyang, Hongsheng; Xu, Ping; He, Fuchu

    2015-12-01

    Although the "missing protein" is a temporary concept in C-HPP, the biological information for their "missing" could be an important clue in evolutionary studies. Here we classified missing-protein-encoding genes into two groups, the genes encoding PE2 proteins (with transcript evidence) and the genes encoding PE3/4 proteins (with no transcript evidence). These missing-protein-encoding genes distribute unevenly among different chromosomes, chromosomal regions, or gene clusters. In the view of evolutionary features, PE3/4 genes tend to be young, spreading at the nonhomology chromosomal regions and evolving at higher rates. Interestingly, there is a higher proportion of singletons in PE3/4 genes than the proportion of singletons in all genes (background) and OTCSGs (organ, tissue, cell type-specific genes). More importantly, most of the paralogous PE3/4 genes belong to the newly duplicated members of the paralogous gene groups, which mainly contribute to special biological functions, such as "smell perception". These functions are heavily restricted into specific type of cells, tissues, or specific developmental stages, acting as the new functional requirements that facilitated the emergence of the missing-protein-encoding genes during evolution. In addition, the criteria for the extremely special physical-chemical proteins were first set up based on the properties of PE2 proteins, and the evolutionary characteristics of those proteins were explored. Overall, the evolutionary analyses of missing-protein-encoding genes are expected to be highly instructive for proteomics and functional studies in the future.

  2. Bub3 is a spindle assembly checkpoint protein regulating chromosome segregation during mouse oocyte meiosis.

    Directory of Open Access Journals (Sweden)

    Mo Li

    Full Text Available In mitosis, the spindle assembly checkpoint (SAC prevents anaphase onset until all chromosomes have been attached to the spindle microtubules and aligned correctly at the equatorial metaphase plate. The major checkpoint proteins in mitosis consist of mitotic arrest-deficient (Mad1-3, budding uninhibited by benzimidazole (Bub1, Bub3, and monopolar spindle 1(Mps1. During meiosis, for the formation of a haploid gamete, two consecutive rounds of chromosome segregation occur with only one round of DNA replication. To pull homologous chromosomes to opposite spindle poles during meiosis I, both sister kinetochores of a homologue must face toward the same pole which is very different from mitosis and meiosis II. As a core member of checkpoint proteins, the individual role of Bub3 in mammalian oocyte meiosis is unclear. In this study, using overexpression and RNA interference (RNAi approaches, we analyzed the role of Bub3 in mouse oocyte meiosis. Our data showed that overexpressed Bub3 inhibited meiotic metaphase-anaphase transition by preventing homologous chromosome and sister chromatid segregations in meiosis I and II, respectively. Misaligned chromosomes, abnormal polar body and double polar bodies were observed in Bub3 knock-down oocytes, causing aneuploidy. Furthermore, through cold treatment combined with Bub3 overexpression, we found that overexpressed Bub3 affected the attachments of microtubules and kinetochores during metaphase-anaphase transition. We propose that as a member of SAC, Bub3 is required for regulation of both meiosis I and II, and is potentially involved in kinetochore-microtubule attachment in mammalian oocytes.

  3. Multiple DNA binding proteins contribute to timing of chromosome replication in E. coli

    DEFF Research Database (Denmark)

    Riber, Leise; Frimodt-Møller, Jakob; Charbon, Godefroid;

    2016-01-01

    Chromosome replication in Escherichia coli is initiated from a single origin, oriC. Initiation involves a number of DNA binding proteins, but only DnaA is essential and specific for the initiation process. DnaA is an AAA+ protein that binds both ATP and ADP with similar high affinities. Dna...... replication is initiated, or the time window in which all origins present in a single cell are initiated, i.e. initiation synchrony, or both. Overall, these DNA binding proteins modulate the initiation frequency from oriC by: (i) binding directly to oriC to affect DnaA binding, (ii) altering the DNA topology...... in or around oriC, (iii) altering the nucleotide bound status of DnaA by interacting with non-coding chromosomal sequences, distant from oriC, that are important for DnaA activity. Thus, although DnaA is the key protein for initiation of replication, other DNA-binding proteins act not only on ori...

  4. Chromosomal localization of a novel retinoic acid induced gene RA28 and the protein distribution of its encoded protein

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Gene RA28 is a retinoic acid induced novel gene isolated in our laboratory previously. All-trans retinoic acid (ATRA) was used to induce lung adenocarcinoma cell line GLC-82, and RA28 was obtained by subtractive hybridization. Green fluorescent protein (GFP) has emerged as a unique tool for examining introcellular phenomena in living cells. GFP possesses an intrinsic fluorescence at 488 nm that does not require other co-factors. In this report, an eukaryotic expression plasmid pEGFP-C1-RA28 was constructed and transfected with parental cell line GLC-82 to analyze protein expression and its distribution in living cells. Moreover, radiation hybrid (RH) technique was used to localize RA28 to the chromosome. The results show that gene RA28 is mapped to the chromosome 19q13.1 region, its encoded protein is distributed on cell membrane. All the results further demonstrate that GFP and RH techniques are accurate, fast, repetitive, and will be powerful methods for investigating the gene and protein localization.

  5. Chromosome movements promoted by the mitochondrial protein SPD-3 are required for homology search during Caenorhabditis elegans meiosis.

    Directory of Open Access Journals (Sweden)

    Leticia Labrador

    2013-05-01

    Full Text Available Pairing of homologous chromosomes during early meiosis is essential to prevent the formation of aneuploid gametes. Chromosome pairing includes a step of homology search followed by the stabilization of homolog interactions by the synaptonemal complex (SC. These events coincide with dramatic changes in nuclear organization and rapid chromosome movements that depend on cytoskeletal motors and are mediated by SUN-domain proteins on the nuclear envelope, but how chromosome mobility contributes to the pairing process remains poorly understood. We show that defects in the mitochondria-localizing protein SPD-3 cause a defect in homolog pairing without impairing nuclear reorganization or SC assembly, which results in promiscuous installation of the SC between non-homologous chromosomes. Preventing SC assembly in spd-3 mutants does not improve homolog pairing, demonstrating that SPD-3 is required for homology search at the start of meiosis. Pairing center regions localize to SUN-1 aggregates at meiosis onset in spd-3 mutants; and pairing-promoting proteins, including cytoskeletal motors and polo-like kinase 2, are normally recruited to the nuclear envelope. However, quantitative analysis of SUN-1 aggregate movement in spd-3 mutants demonstrates a clear reduction in mobility, although this defect is not as severe as that seen in sun-1(jf18 mutants, which also show a stronger pairing defect, suggesting a correlation between chromosome-end mobility and the efficiency of pairing. SUN-1 aggregate movement is also impaired following inhibition of mitochondrial respiration or dynein knockdown, suggesting that mitochondrial function is required for motor-driven SUN-1 movement. The reduced chromosome-end mobility of spd-3 mutants impairs coupling of SC assembly to homology recognition and causes a delay in meiotic progression mediated by HORMA-domain protein HTP-1. Our work reveals how chromosome mobility impacts the different early meiotic events that promote

  6. [The nuclear matrix proteins (mol. mass 38 and 50 kDa) are transported by chromosomes in mitosis].

    Science.gov (United States)

    Murasheva, M I; Chentsov, Iu S

    2010-01-01

    It was shown by immunofluorescence method that serum M68 and serum K43 from patients with autoimmune disease stain interphase nuclei and periphery of mitotic chromosomes of pig kidney cells. Western blotting reveals the polypeptide with mol. mass of 50 kDa in serum M68, and the polypeptide with mol. mass of 38 kDa in serum K43. In the nuclear protein matrix, the antibodies to protein with mol. mass of 38 kDa stained only nucleolar periphery, while the antibodies to the protein with mol. mass of 50 kDa stained both the nucleolar periphery and all the interphase nucleus. It shows that among all components of nuclear protein matrix (lamina, internuclear network, residual nucleoli) only nucleolar periphery contains the 38 kDa protein, while the 50 kDa protein is a part of residual nucleolar periphery and takes part in nuclear protein network formation. In the interphase cells, both proteins were in situ localized in the nuclei, but one of them with mol. mass of 50 kDa was in the form of small clearly outlined granules, while the other (38 kDa) was in the form of small bright granules against the background of diffusely stained nuclei. Both proteins were also revealed as continuous ring around nucleolar periphery. During all mitotic stages, the 50 kDa protein was seen on the chromosomal periphery as a cover, and the 38 kDa protein formed separate fragments and granules around them. After nuclear and chromosome decondensation induced by hypotonic treatment, both antibodies stain interphase nuclei in diffuse manner, but in mitotic cells they stained the surface of the swollen chromosomes. The polypeptide with mol. mass of 50 kDa maintained strong connection with chromosome periphery both in norm and under condition of decondensation induced by hypotonic treatment and at subsequent recondensation in isotonic medium. In contrast, the protein with mol. mass of 38 kDa partially lost the contact with a chromosome during recondensation appearing also in the form of granules in

  7. Cell cycle coordination and regulation of bacterial chromosome segregation dynamics by polarly localized proteins.

    Science.gov (United States)

    Schofield, Whitman B; Lim, Hoong Chuin; Jacobs-Wagner, Christine

    2010-09-15

    What regulates chromosome segregation dynamics in bacteria is largely unknown. Here, we show in Caulobacter crescentus that the polarity factor TipN regulates the directional motion and overall translocation speed of the parS/ParB partition complex by interacting with ParA at the new pole. In the absence of TipN, ParA structures can regenerate behind the partition complex, leading to stalls and back-and-forth motions of parS/ParB, reminiscent of plasmid behaviour. This extrinsic regulation of the parS/ParB/ParA system directly affects not only division site selection, but also cell growth. Other mechanisms, including the pole-organizing protein PopZ, compensate for the defect in segregation regulation in ΔtipN cells. Accordingly, synthetic lethality of PopZ and TipN is caused by severe chromosome segregation and cell division defects. Our data suggest a mechanistic framework for adapting a self-organizing oscillator to create motion suitable for chromosome segregation.

  8. Sodium arsenite induces chromosome endoreduplication and inhibits protein phosphatase activity in human fibroblasts

    Energy Technology Data Exchange (ETDEWEB)

    Rong-Nan Huang; I-Ching Ho; Ling-Hui Yih [Institute of Biomedical Sciences, Taiwan (China)] [and others

    1995-08-01

    Arsenic, strongly associated with increased risks of human cancers, is a potent clastogen in a variety of mammalian cell systems. The effect of sodium arsenite (a trivalent arsenic compound) on chromatid separation was studied in human skin fibroblasts (HFW). Human fibroblasts were arrested in S phase by the aid of serum starvation and aphidicolin blocking and then these cells were allowed to synchronously progress into G2 phase. Treatment of the G2-enriched HFW cells with sodium arsenite (0-200 {mu}M) resulted in arrest of cells in the G2 phase, interference with mitotic division, inhibition of spindle assembly, and induction of chromosome endoreduplication in their second mitosis. Sodium arsenite treatment also inhibited the activities of serine/threonine protein phosphatases and enhanced phosphorylation levels of a small heat shock protein (HSP27). These results suggest that sodium arsenite may mimic okadaic acid to induce chromosome endoreduplication through its inhibitory effect on protein phosphatase activity. 61 refs., 6 figs., 2 tabs.

  9. Resistance to β-Lactams in Neisseria ssp Due to Chromosomally Encoded Penicillin-Binding Proteins

    Directory of Open Access Journals (Sweden)

    André Zapun

    2016-09-01

    Full Text Available Neisseria meningitidis and Neisseria gonorrhoeae are human pathogens that cause a variety of life-threatening systemic and local infections, such as meningitis or gonorrhoea. The treatment of such infection is becoming more difficult due to antibiotic resistance. The focus of this review is on the mechanism of reduced susceptibility to penicillin and other β-lactams due to the modification of chromosomally encoded penicillin-binding proteins (PBP, in particular PBP2 encoded by the penA gene. The variety of penA alleles and resulting variant PBP2 enzymes is described and the important amino acid substitutions are presented and discussed in a structural context.

  10. The bacterial chromosome segregation protein Spo0J spreads along DNA from parS nucleation sites.

    Science.gov (United States)

    Murray, Heath; Ferreira, Henrique; Errington, Jeff

    2006-09-01

    Regulation of chromosome inheritance is essential to ensure proper transmission of genetic information. To accomplish accurate genome segregation, cells organize their chromosomes and actively separate them prior to cytokinesis. In Bacillus subtilis the Spo0J protein is required for accurate chromosome segregation and it regulates the developmental switch from vegetative growth to sporulation. Spo0J is a DNA-binding protein that recognizes at least eight identified parS sites located near the origin of replication. As judged by fluorescence microscopy, Spo0J forms discrete foci associated with the oriC region of the chromosome throughout the cell cycle. In an attempt to determine the mechanisms utilized by Spo0J to facilitate productive chromosome segregation, we have investigated the DNA binding activity of Spo0J. In vivo we find Spo0J associates with several kilobases of DNA flanking its specific binding sites (parS) through a parS-dependent nucleation event that promotes lateral spreading of Spo0J along the chromosome. Using purified components we find that Spo0J has the ability to coat non-specific DNA substrates. These 'Spo0J domains' provide large structures near oriC that could potentially demark, organize or localize the origin region of the chromosome.

  11. The human enamel protein gene amelogenin is expressed from both the X and the Y chromosomes

    Energy Technology Data Exchange (ETDEWEB)

    Salido, E.C. (Faculty of Medicine, La Laguna (Spain)); Yen, P.H.; Koprivnikar, K.; Shapiro, L.J. (University of California School of Medicine, Torrence (United States)); Yu, Lohchung (Lawrence Livermore National Laboratory, CA (United States))

    1992-02-01

    Amelogenins, a family of extracellular matrix proteins of the dental enamel, are transiently but abundantly expressed by ameloblasts during tooth development. In this paper the authors report the characterization of the AMGX and AMGY genes on the short arms of the human X and Y chromosomes which encode the amelogenins. Their studies on the expression of the amelogenin genes in male developing tooth buds showed that both the AMGX and AMGY genes are transcriptionally active and encode potentially functional proteins. They have isolated genomic and cDNA clones form both the AMGX and AMGY loci and have studied the sequence organization of these two genes. Reverse transcriptase (RT)PCR amplification of the 5[prime] portion of the amelogenin transcripts revealed several alternatively spliced products. This information will be useful for studying the molecular basis of X-linked amelogenesis imperfecta, for understanding the evolution and regulation of gene expression on the mammalian sex chromosomes, and for investigating the role of amelogenin genes during tooth development.

  12. Mitochondrial ribosomal protein S18-2 evokes chromosomal instability and transforms primary rat skin fibroblasts

    KAUST Repository

    Kashuba, Elena

    2015-05-12

    We have shown earlier that overexpression of the human mitochondrial ribosomal protein MRPS18-2 (S18-2) led to immortalization of primary rat embryonic fibroblasts. The derived cells expressed the embryonic stem cell markers, and cellular pathways that control cell proliferation, oxidative phosphorylation, cellular respiration, and other redox reactions were activated in the immortalized cells. Here we report that, upon overexpression of S18-2 protein, primary rat skin fibroblasts underwent cell transformation. Cells passed more than 300 population doublings, and two out of three tested clones gave rise to tumors in experimental animals. Transformed cells showed anchorage-independent growth and loss of contact inhibition; they expressed epithelial markers, such as E-cadherin and β-catenin. Transformed cells showed increased telomerase activity, disturbance of the cell cycle, and chromosomal instability. Taken together, our data suggest that S18-2 is a newly identified oncoprotein that may be involved in cancerogenesis.

  13. Quest for Missing Proteins: Update 2015 on Chromosome-Centric Human Proteome Project.

    Science.gov (United States)

    Horvatovich, Péter; Lundberg, Emma K; Chen, Yu-Ju; Sung, Ting-Yi; He, Fuchu; Nice, Edouard C; Goode, Robert J; Yu, Simon; Ranganathan, Shoba; Baker, Mark S; Domont, Gilberto B; Velasquez, Erika; Li, Dong; Liu, Siqi; Wang, Quanhui; He, Qing-Yu; Menon, Rajasree; Guan, Yuanfang; Corrales, Fernando J; Segura, Victor; Casal, J Ignacio; Pascual-Montano, Alberto; Albar, Juan P; Fuentes, Manuel; Gonzalez-Gonzalez, Maria; Diez, Paula; Ibarrola, Nieves; Degano, Rosa M; Mohammed, Yassene; Borchers, Christoph H; Urbani, Andrea; Soggiu, Alessio; Yamamoto, Tadashi; Salekdeh, Ghasem Hosseini; Archakov, Alexander; Ponomarenko, Elena; Lisitsa, Andrey; Lichti, Cheryl F; Mostovenko, Ekaterina; Kroes, Roger A; Rezeli, Melinda; Végvári, Ákos; Fehniger, Thomas E; Bischoff, Rainer; Vizcaíno, Juan Antonio; Deutsch, Eric W; Lane, Lydie; Nilsson, Carol L; Marko-Varga, György; Omenn, Gilbert S; Jeong, Seul-Ki; Lim, Jong-Sun; Paik, Young-Ki; Hancock, William S

    2015-09-04

    This paper summarizes the recent activities of the Chromosome-Centric Human Proteome Project (C-HPP) consortium, which develops new technologies to identify yet-to-be annotated proteins (termed "missing proteins") in biological samples that lack sufficient experimental evidence at the protein level for confident protein identification. The C-HPP also aims to identify new protein forms that may be caused by genetic variability, post-translational modifications, and alternative splicing. Proteogenomic data integration forms the basis of the C-HPP's activities; therefore, we have summarized some of the key approaches and their roles in the project. We present new analytical technologies that improve the chemical space and lower detection limits coupled to bioinformatics tools and some publicly available resources that can be used to improve data analysis or support the development of analytical assays. Most of this paper's content has been compiled from posters, slides, and discussions presented in the series of C-HPP workshops held during 2014. All data (posters, presentations) used are available at the C-HPP Wiki (http://c-hpp.webhosting.rug.nl/) and in the Supporting Information.

  14. Cloning, tissue expression pattern, and chromosome localization of human protein kinase Bγ gene

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Protein kinase B (PKB) is a member of the second messenger-regulated subfamily of protein kinases, and plays a key role in cell-cycle regulation, glucose uptake and promotion of cell differentiation. Evidence shows that PKB undergoes activation in some human tumors and is involved in Ras pathway, which implies that PKB can trigger a pathway to induce oncogenic transformation. A nucleotide sequence of mouse Pkb? was used as a probe to screen homolog in a human liver cDNA library. A fragment of 1998 bp containing a 1440 bp ORF encoding 479 amino acid residues was obtained. Then the 3'-terminal of this fragment was extended to 2788 bp by 'electronic walking' screening, and the extended fragment was confirmed by PCR amplification. The protein deduced by the gene had a high identity of 83% and 78% to the human PKBγ and γ, respectively, and was designated as human PKB?. Northern hybridization detected two equally expressed transcripts of 8.5 and 6.5 kb in length in all 16 human tissues tested, with the highest expression level in brain, and lower levels with variation in the other tissues. By RH mapping, the PKBγ was placed on chromosome 1q43, between markers D1S304 and D1S2693. It is a valuable clue for cloning the candidate genes related to prostate cancer; Arrhythmogenic Right Ventricular Dysplasia (ARVD); Chediak-Higashi, NK cell Deficiency (CHS); and Hypoparathyrodism with Short Stature, Mental Retardation and Seizures which have already been mapped in this chromosomal region.

  15. Thermodynamical study of interaction of histone H1 chromosomal protein and mitoxantrone anticancer drug

    Energy Technology Data Exchange (ETDEWEB)

    Jafargholizadeh, Naser [Department of Cell and Molecular Biology, School of Biology, College of Science, University of Tehran, Tehran (Iran, Islamic Republic of); Zargar, Seyed Jalal, E-mail: Zargar@khayam.ut.ac.ir [Department of Cell and Molecular Biology, School of Biology, College of Science, University of Tehran, Tehran (Iran, Islamic Republic of); Safarian, Shahrokh; Habibi-Rezaei, Mehran [Department of Cell and Molecular Biology, School of Biology, College of Science, University of Tehran, Tehran (Iran, Islamic Republic of)

    2012-06-10

    Highlights: Black-Right-Pointing-Pointer For the first time, our results show mitoxantrone anticancer drug binds to histone H1, via hydrophobic, hydrogen, van der Waals and electrostatic interactions. Black-Right-Pointing-Pointer Binding of mitoxantrone molecules to histone H1 is positive cooperative. Black-Right-Pointing-Pointer Histone H1 may be considered as a new target for mitoxantrone at the chromatin level. - Using ultraviolet spectroscopy technique, we have investigated the interaction of anticancer drug, mitoxantrone with calf thymus histone H1 chromosomal protein in 100 mM phosphate buffer, pH 7.0, at temperatures 300 and 310 K. UV spectroscopy results show interactions between mitoxantrone and histone H1 with a positive cooperative binding process which was confirmed by Scatchard plot. According to the obtained results, it is concluded that histone H1 can be considered as a target for mitoxantrone binding at the chromatin level.

  16. The SET and transposase domain protein Metnase enhances chromosome decatenation: regulation by automethylation.

    Science.gov (United States)

    Williamson, Elizabeth A; Rasila, Kanwaldeep Kaur; Corwin, Lori Kwan; Wray, Justin; Beck, Brian D; Severns, Virginia; Mobarak, Charlotte; Lee, Suk-Hee; Nickoloff, Jac A; Hromas, Robert

    2008-10-01

    Metnase is a human SET and transposase domain protein that methylates histone H3 and promotes DNA double-strand break repair. We now show that Metnase physically interacts and co-localizes with Topoisomerase IIalpha (Topo IIalpha), the key chromosome decatenating enzyme. Metnase promotes progression through decatenation and increases resistance to the Topo IIalpha inhibitors ICRF-193 and VP-16. Purified Metnase greatly enhanced Topo IIalpha decatenation of kinetoplast DNA to relaxed circular forms. Nuclear extracts containing Metnase decatenated kDNA more rapidly than those without Metnase, and neutralizing anti-sera against Metnase reversed that enhancement of decatenation. Metnase automethylates at K485, and the presence of a methyl donor blocked the enhancement of Topo IIalpha decatenation by Metnase, implying an internal regulatory inhibition. Thus, Metnase enhances Topo IIalpha decatenation, and this activity is repressed by automethylation. These results suggest that cancer cells could subvert Metnase to mediate clinically relevant resistance to Topo IIalpha inhibitors.

  17. Condensation and localization of the partitioning protein ParB on the bacterial chromosome.

    Science.gov (United States)

    Broedersz, Chase P; Wang, Xindan; Meir, Yigal; Loparo, Joseph J; Rudner, David Z; Wingreen, Ned S

    2014-06-17

    The ParABS system mediates chromosome segregation and plasmid partitioning in many bacteria. As part of the partitioning mechanism, ParB proteins form a nucleoprotein complex at parS sites. The biophysical basis underlying ParB-DNA complex formation and localization remains elusive. Specifically, it is unclear whether ParB spreads in 1D along DNA or assembles into a 3D protein-DNA complex. We show that a combination of 1D spreading bonds and a single 3D bridging bond between ParB proteins constitutes a minimal model for a condensed ParB-DNA complex. This model implies a scaling behavior for ParB-mediated silencing of parS-flanking genes, which we confirm to be satisfied by experimental data from P1 plasmids. Furthermore, this model is consistent with experiments on the effects of DNA roadblocks on ParB localization. Finally, we show experimentally that a single parS site is necessary and sufficient for ParB-DNA complex formation in vivo. Together with our model, this suggests that ParB binding to parS triggers a conformational switch in ParB that overcomes a nucleation barrier. Conceptually, the combination of spreading and bridging bonds in our model provides a surface tension ensuring the condensation of the ParB-DNA complex, with analogies to liquid-like compartments such as nucleoli in eukaryotes.

  18. Uniparental disomy of chromosome 2 resulting in lethal trifunctional protein deficiency due to homozygous alpha-subunit mutations.

    Science.gov (United States)

    Spiekerkoetter, Ute; Eeds, Angela; Yue, Zou; Haines, Jonathan; Strauss, Arnold W; Summar, Marshall

    2002-12-01

    The mitochondrial trifunctional protein (TFP) is an enzyme complex of the fatty acid beta-oxidation cycle composed of an alpha- and a beta-subunit. The two encoding genes are located in the same region on chromosome 2 (2p23). TFP deficiency due to either alpha- or beta-subunit mutations is characterized by mutational and phenotypic heterogeneity with severe, early-onset, cardiac forms and milder, later-onset, myopathic phenotypes. In two unrelated patients with lethal TFP deficiency, we delineated apparently homozygous alpha-subunit mutations that were present in heterozygous form in both mothers, but not in either biological father. We performed a microsatellite repeat analysis of both patients and their parents using seven chromosome 2-specific polymorphic DNA markers and four nonchromosome 2 markers. In both patients, two chromosome 2-specific markers demonstrated maternal isodisomy of chromosome 2. The other five chromosome 2-specific markers were noninformative in each patient. Inheritance of alleles from chromosomes 4, 5, and 7 was consistent with paternity. These results explain the apparently anomalous pattern of transmission. Six of our 12 known TFP-deficient patients with alpha-subunit mutations have disease due to homozygous changes and two of them via the mechanism of uniparental disomy (UPD) (16.7%). For very rare autosomal recessive diseases, UPD may represent a common mechanism. This study emphasizes the need to confirm mutations in parents whenever possible. TFP deficiency is another disorder that has become manifest due to isodisomy of chromosome 2. This information will impact genetic counseling for these families, reducing greatly the 25% risk normally used for recessive disorders.

  19. SAP-like domain in nucleolar spindle associated protein mediates mitotic chromosome loading as well as interphase chromatin interaction

    Energy Technology Data Exchange (ETDEWEB)

    Verbakel, Werner, E-mail: werner.verbakel@chem.kuleuven.be [Laboratory of Biomolecular Dynamics, Katholieke Universiteit Leuven, Celestijnenlaan 200G, Bus 2403, 3001 Heverlee (Belgium); Carmeliet, Geert, E-mail: geert.carmeliet@med.kuleuven.be [Laboratory of Experimental Medicine and Endocrinology, Katholieke Universiteit Leuven, Herestraat 49, Bus 902, 3000 Leuven (Belgium); Engelborghs, Yves, E-mail: yves.engelborghs@fys.kuleuven.be [Laboratory of Biomolecular Dynamics, Katholieke Universiteit Leuven, Celestijnenlaan 200G, Bus 2403, 3001 Heverlee (Belgium)

    2011-08-12

    Highlights: {yields} The SAP-like domain in NuSAP is a functional DNA-binding domain with preference for dsDNA. {yields} This SAP-like domain is essential for chromosome loading during early mitosis. {yields} NuSAP is highly dynamic on mitotic chromatin, as evident from photobleaching experiments. {yields} The SAP-like domain also mediates NuSAP-chromatin interaction in interphase nucleoplasm. -- Abstract: Nucleolar spindle associated protein (NuSAP) is a microtubule-stabilizing protein that localizes to chromosome arms and chromosome-proximal microtubules during mitosis and to the nucleus, with enrichment in the nucleoli, during interphase. The critical function of NuSAP is underscored by the finding that its depletion in HeLa cells results in various mitotic defects. Moreover, NuSAP is found overexpressed in multiple cancers and its expression levels often correlate with the aggressiveness of cancer. Due to its localization on chromosome arms and combination of microtubule-stabilizing and DNA-binding properties, NuSAP takes a special place within the extensive group of spindle assembly factors. In this study, we identify a SAP-like domain that shows DNA binding in vitro with a preference for dsDNA. Deletion of the SAP-like domain abolishes chromosome arm binding of NuSAP during mitosis, but is not sufficient to abrogate its chromosome-proximal localization after anaphase onset. Fluorescence recovery after photobleaching experiments revealed the highly dynamic nature of this NuSAP-chromatin interaction during mitosis. In interphase cells, NuSAP also interacts with chromatin through its SAP-like domain, as evident from its enrichment on dense chromatin regions and intranuclear mobility, measured by fluorescence correlation spectroscopy. The obtained results are in agreement with a model where NuSAP dynamically stabilizes newly formed microtubules on mitotic chromosomes to enhance chromosome positioning without immobilizing these microtubules. Interphase Nu

  20. The Chromosomal Passenger Protein Birc5b Organizes Microfilaments and Germ Plasm in the Zebrafish Embryo

    Science.gov (United States)

    Nair, Sreelaja; Marlow, Florence; Abrams, Elliott; Kapp, Lee; Mullins, Mary C.; Pelegri, Francisco

    2013-01-01

    Microtubule-microfilament interactions are important for cytokinesis and subcellular localization of proteins and mRNAs. In the early zebrafish embryo, astral microtubule-microfilament interactions also facilitate a stereotypic segregation pattern of germ plasm ribonucleoparticles (GP RNPs), which is critical for their eventual selective inheritance by germ cells. The precise mechanisms and molecular mediators for both cytoskeletal interactions and GP RNPs segregation are the focus of intense research. Here, we report the molecular identification of a zebrafish maternal-effect mutation motley as Birc5b, a homolog of the mammalian Chromosomal Passenger Complex (CPC) component Survivin. The meiosis and mitosis defects in motley/birc5b mutant embryos are consistent with failed CPC function, and additional defects in astral microtubule remodeling contribute to failures in the initiation of cytokinesis furrow ingression. Unexpectedly, the motley/birc5b mutation also disrupts cortical microfilaments and GP RNP aggregation during early cell divisions. Birc5b localizes to the tips of astral microtubules along with polymerizing cortical F-actin and the GP RNPs. Mutant Birc5b co-localizes with cortical F-actin and GP RNPs, but fails to associate with astral microtubule tips, leading to disorganized microfilaments and GP RNP aggregation defects. Thus, maternal Birc5b localizes to astral microtubule tips and associates with cortical F-actin and GP RNPs, potentially linking the two cytoskeletons to mediate microtubule-microfilament reorganization and GP RNP aggregation during early embryonic cell cycles in zebrafish. In addition to the known mitotic function of CPC components, our analyses reveal a non-canonical role for an evolutionarily conserved CPC protein in microfilament reorganization and germ plasm aggregation. PMID:23637620

  1. The chromosomal passenger protein birc5b organizes microfilaments and germ plasm in the zebrafish embryo.

    Directory of Open Access Journals (Sweden)

    Sreelaja Nair

    2013-04-01

    Full Text Available Microtubule-microfilament interactions are important for cytokinesis and subcellular localization of proteins and mRNAs. In the early zebrafish embryo, astral microtubule-microfilament interactions also facilitate a stereotypic segregation pattern of germ plasm ribonucleoparticles (GP RNPs, which is critical for their eventual selective inheritance by germ cells. The precise mechanisms and molecular mediators for both cytoskeletal interactions and GP RNPs segregation are the focus of intense research. Here, we report the molecular identification of a zebrafish maternal-effect mutation motley as Birc5b, a homolog of the mammalian Chromosomal Passenger Complex (CPC component Survivin. The meiosis and mitosis defects in motley/birc5b mutant embryos are consistent with failed CPC function, and additional defects in astral microtubule remodeling contribute to failures in the initiation of cytokinesis furrow ingression. Unexpectedly, the motley/birc5b mutation also disrupts cortical microfilaments and GP RNP aggregation during early cell divisions. Birc5b localizes to the tips of astral microtubules along with polymerizing cortical F-actin and the GP RNPs. Mutant Birc5b co-localizes with cortical F-actin and GP RNPs, but fails to associate with astral microtubule tips, leading to disorganized microfilaments and GP RNP aggregation defects. Thus, maternal Birc5b localizes to astral microtubule tips and associates with cortical F-actin and GP RNPs, potentially linking the two cytoskeletons to mediate microtubule-microfilament reorganization and GP RNP aggregation during early embryonic cell cycles in zebrafish. In addition to the known mitotic function of CPC components, our analyses reveal a non-canonical role for an evolutionarily conserved CPC protein in microfilament reorganization and germ plasm aggregation.

  2. Neuroblastoma after Childhood: Prognostic Relevance of Segmental Chromosome Aberrations, ATRX Protein Status, and Immune Cell Infiltration

    Directory of Open Access Journals (Sweden)

    Ana P. Berbegall

    2014-06-01

    Full Text Available Neuroblastoma (NB is a common malignancy in children but rarely occurs during adolescence or adulthood. This subgroup is characterized by an indolent disease course, almost uniformly fatal, yet little is known about the biologic characteristics. The aim of this study was to identify differential features regarding DNA copy number alterations, α-thalassemia/mental retardation syndrome X-linked (ATRX protein expression, and the presence of tumor-associated inflammatory cells. Thirty-one NB patients older than 10 years who were included in the Spanish NB Registry were considered for the current study; seven young and middle-aged adult patients (range 18-60 years formed part of the cohort. We performed single nucleotide polymorphism arrays, immunohistochemistry for immune markers (CD4, CD8, CD20, CD11b, CD11c, and CD68, and ATRX protein expression. Assorted genetic profiles were found with a predominant presence of a segmental chromosome aberration (SCA profile. Preadolescent and adolescent NB tumors showed a higher number of SCA, including 17q gain and 11q deletion. There was also a marked infiltration of immune cells, mainly high and heterogeneous, in young and middle-aged adult tumors. ATRX negative expression was present in the tumors. The characteristics of preadolescent, adolescent, young adult, and middle-aged adult NB tumors are different, not only from childhood NB tumors but also from each other. Similar examinations of a larger number of such tumor tissues from cooperative groups should lead to a better older age–dependent tumor pattern and to innovative, individual risk-adapted therapeutic approaches for these patients.

  3. Nonsense Mutations in SMPX, Encoding a Protein Responsive to Physical Force, Result in X-Chromosomal Hearing Loss

    Science.gov (United States)

    Huebner, Antje K.; Gandia, Marta; Frommolt, Peter; Maak, Anika; Wicklein, Eva M.; Thiele, Holger; Altmüller, Janine; Wagner, Florian; Viñuela, Antonio; Aguirre, Luis A.; Moreno, Felipe; Maier, Hannes; Rau, Isabella; Gießelmann, Sebastian; Nürnberg, Gudrun; Gal, Andreas; Nürnberg, Peter; Hübner, Christian A.; del Castillo, Ignacio; Kurth, Ingo

    2011-01-01

    The fact that hereditary hearing loss is the most common sensory disorder in humans is reflected by, among other things, an extraordinary allelic and nonallelic genetic heterogeneity. X-chromosomal hearing impairment represents only a minor fraction of all cases. In a study of a Spanish family the locus for one of the X-chromosomal forms was assigned to Xp22 (DFNX4). We mapped the disease locus in the same chromosomal region in a large German pedigree with X-chromosomal nonsyndromic hearing impairment by using genome-wide linkage analysis. Males presented with postlingual hearing loss and onset at ages 3–7, whereas onset in female carriers was in the second to third decades. Targeted DNA capture with high-throughput sequencing detected a nonsense mutation in the small muscle protein, X-linked (SMPX) of affected individuals. We identified another nonsense mutation in SMPX in patients from the Spanish family who were previously analyzed to map DFNX4. SMPX encodes an 88 amino acid, cytoskeleton-associated protein that is responsive to mechanical stress. The presence of Smpx in hair cells and supporting cells of the murine cochlea indicates its role in the inner ear. The nonsense mutations detected in the two families suggest a loss-of-function mechanism underlying this form of hearing impairment. Results obtained after heterologous overexpression of SMPX proteins were compatible with this assumption. Because responsivity to physical force is a characteristic feature of the protein, we propose that long-term maintenance of mechanically stressed inner-ear cells critically depends on SMPX function. PMID:21549336

  4. Protein levels of genes encoded on chromosome 21 in fetal Down Syndrome brain (Part V): overexpression of phosphatidyl-inositol-glycan class P protein (DSCR5).

    Science.gov (United States)

    Ferrando-Miguel, R; Cheon, M S; Lubec, G

    2004-06-01

    Down Syndrome (DS, trisomy 21) is the most common genetic cause of mental retardation. The completed sequencing of genes encoded on chromosome 21 provides excellent basic information, however the molecular mechanisms leading to the phenotype of DS remain to be elucidated. Although overexpression of chromosome 21 encoded genes has been documented information at the protein expression level is mandatory as it is the proteins that carry out function. We therefore decided to evaluated expression level of seven proteins whose genes are encoded on chromosome 21: DSCR4, DSCR5, DSCR6; KIR4.2, GIRK2, KCNE1 and KCNE2 in fetal cortex brain of DS and controls at the early second trimester of pregnancy by Western blotting. beta-actin and neuron specific enolase (NSE) were used to normalise cell loss and neuronal loss. DSCR5 (PIG-P), a component of glycosylphosphatidylinositol- N-acetylglucosaminyltransferase (GPI-GnT), was overexpressed about twofold, even when levels were normalised with NSE. DSCR6 was overexpressed in addition but when normalised versus NSE, levels were comparable to controls. DSCR4 was not detectable in fetal brain. Potassium channels KIR4.2 and GIRK2 were comparable between DS and controls, whereas KCNE1 and KCNE2 were not detectable. Quantification of these proteins encoded on chromosome 21 revealed that not all gene products of the DS critical region are overexpressed in DS brain early in life, indicating that the DS phenotype cannot be simply explained by the gene dosage effect hypothesis. Overexpression of PIG-P (DSCR5) may lead to or represent impaired glycosylphosphatidylinositol- N-acetylglucosaminyltransferase mediated posttranslational modifications and subsequent anchoring of proteins to the plasma membrane.

  5. Non-SMC condensin I complex proteins control chromosome segregation and survival of proliferating cells in the zebrafish neural retina

    Directory of Open Access Journals (Sweden)

    Harris William A

    2009-07-01

    Full Text Available Abstract Background The condensation of chromosomes and correct sister chromatid segregation during cell division is an essential feature of all proliferative cells. Structural maintenance of chromosomes (SMC and non-SMC proteins form the condensin I complex and regulate chromosome condensation and segregation during mitosis. However, due to the lack of appropriate mutants, the function of the condensin I complex during vertebrate development has not been described. Results Here, we report the positional cloning and detailed characterization of retinal phenotypes of a zebrafish mutation at the cap-g locus. High resolution live imaging reveals that the progression of mitosis between prometa- to telophase is delayed and that sister chromatid segregation is impaired upon loss of CAP-G. CAP-G associates with chromosomes between prometa- and telophase of the cell cycle. Loss of the interaction partners CAP-H and CAP-D2 causes cytoplasmic mislocalization of CAP-G throughout mitosis. DNA content analysis reveals increased genomic imbalances upon loss of non-SMC condensin I subunits. Within the retina, loss of condensin I function causes increased rates of apoptosis among cells within the proliferative ciliary marginal zone (CMZ whereas postmitotic retinal cells are viable. Inhibition of p53-mediated apoptosis partially rescues cell numbers in cap-g mutant retinae and allows normal layering of retinal cell types without alleviating their aberrant nuclear sizes. Conclusion Our findings indicate that the condensin I complex is particularly important within rapidly amplifying progenitor cell populations to ensure faithful chromosome segregation. In contrast, differentiation of postmitotic retinal cells is not impaired upon polyploidization.

  6. The active gene that encodes human High Mobility Group 1 protein (HMG1) contains introns and maps to chromosome 13

    Energy Technology Data Exchange (ETDEWEB)

    Ferrari, S. [Dipartimento di Genetica e di Biologia dei Microrganismi, Milan (Italy); Finelli, P.; Rocchi, M. [Istituto di Genetica, Bari (Italy)] [and others

    1996-07-15

    The human genome contains a large number of sequences related to the cDNA for High Mobility Group 1 protein (HMG1), which so far has hampered the cloning and mapping of the active HMG1 gene. We show that the human HMG1 gene contains introns, while the HMG1-related sequences do not and most likely are retrotransposed pseudogenes. We identified eight YACs from the ICI and CEPH libraries that contain the human HMG1 gene. The HMG1 gene is similar in structure to the previously characterized murine homologue and maps to human chromosome 13 and q12, as determined by in situ hybridization. The mouse Hmg1 gene maps to the telomeric region of murine Chromosome 5, which is syntenic to the human 13q12 band. 18 refs., 3 figs.

  7. Yeast X-chromosome-associated protein 5 (Xap5) functions with H2A.Z to suppress aberrant transcripts.

    Science.gov (United States)

    Anver, Shajahan; Roguev, Assen; Zofall, Martin; Krogan, Nevan J; Grewal, Shiv I S; Harmer, Stacey L

    2014-08-01

    Chromatin regulatory proteins affect diverse developmental and environmental response pathways via their influence on nuclear processes such as the regulation of gene expression. Through a genome-wide genetic screen, we implicate a novel protein called X-chromosome-associated protein 5 (Xap5) in chromatin regulation. We show that Xap5 is a chromatin-associated protein acting in a similar manner as the histone variant H2A.Z to suppress expression of antisense and repeat element transcripts throughout the fission yeast genome. Xap5 is highly conserved across eukaryotes, and a plant homolog rescues xap5 mutant yeast. We propose that Xap5 likely functions as a chromatin regulator in diverse organisms.

  8. Cdk1 phosphorylation of the kinetochore protein Nsk1 prevents error-prone chromosome segregation.

    Science.gov (United States)

    Chen, Jun-Song; Lu, Lucy X; Ohi, Melanie D; Creamer, Kevin M; English, Chauca; Partridge, Janet F; Ohi, Ryoma; Gould, Kathleen L

    2011-11-14

    Cdk1 controls many aspects of mitotic chromosome behavior and spindle microtubule (MT) dynamics to ensure accurate chromosome segregation. In this paper, we characterize a new kinetochore substrate of fission yeast Cdk1, Nsk1, which promotes proper kinetochore-MT (k-MT) interactions and chromosome movements in a phosphoregulated manner. Cdk1 phosphorylation of Nsk1 antagonizes Nsk1 kinetochore and spindle localization during early mitosis. A nonphosphorylatable Nsk1 mutant binds prematurely to kinetochores and spindle, cementing improper k-MT attachments and leading to high rates of lagging chromosomes that missegregate. Accordingly, cells lacking nsk1 exhibit synthetic growth defects with mutations that disturb MT dynamics and/or kinetochore structure, and lack of proper phosphoregulation leads to even more severe defects. Intriguingly, Nsk1 is stabilized by binding directly to the dynein light chain Dlc1 independently of the dynein motor, and Nsk1-Dlc1 forms chainlike structures in vitro. Our findings establish new roles for Cdk1 and the Nsk1-Dlc1 complex in regulating the k-MT interface and chromosome segregation.

  9. ParA2, a Vibrio cholerae chromosome partitioning protein, forms left-handed helical filaments on DNA.

    Science.gov (United States)

    Hui, Monica P; Galkin, Vitold E; Yu, Xiong; Stasiak, Alicja Z; Stasiak, Andrzej; Waldor, Matthew K; Egelman, Edward H

    2010-03-01

    Most bacterial chromosomes contain homologs of plasmid partitioning (par) loci. These loci encode ATPases called ParA that are thought to contribute to the mechanical force required for chromosome and plasmid segregation. In Vibrio cholerae, the chromosome II (chrII) par locus is essential for chrII segregation. Here, we found that purified ParA2 had ATPase activities comparable to other ParA homologs, but, unlike many other ParA homologs, did not form high molecular weight complexes in the presence of ATP alone. Instead, formation of high molecular weight ParA2 polymers required DNA. Electron microscopy and three-dimensional reconstruction revealed that ParA2 formed bipolar helical filaments on double-stranded DNA in a sequence-independent manner. These filaments had a distinct change in pitch when ParA2 was polymerized in the presence of ATP versus in the absence of a nucleotide cofactor. Fitting a crystal structure of a ParA protein into our filament reconstruction showed how a dimer of ParA2 binds the DNA. The filaments formed with ATP are left-handed, but surprisingly these filaments exert no topological changes on the right-handed B-DNA to which they are bound. The stoichiometry of binding is one dimer for every eight base pairs, and this determines the geometry of the ParA2 filaments with 4.4 dimers per 120 A pitch left-handed turn. Our findings will be critical for understanding how ParA proteins function in plasmid and chromosome segregation.

  10. Chromosome 1p/19q status combined with expression of protein improves the diagnostic and prognostic evaluation of oligodendrogliomas

    Institute of Scientific and Technical Information of China (English)

    XIONG Ji; LIU Ying; WANG Yin; KE Rong-hu; MAO Ying; YE Zhu-rong

    2010-01-01

    Background Our previous study confirmed that oligodendrogliomas had higher frequency of chromosome 1p/19q deletion. In order to improve the diagnostic criteria and to predict the prognosis of oligodendroglioma patients, the status of chromosome 1 p/19q deletion, the methylation of O6-methylguanine-DNA methyltransferase (MGMT), and the expression of p53 protein were evaluated and investigated in relation to patients' outcomes.Methods Methylation of MGMT in 73 cases was analyzed by nested methylation-specific PCR (MSP). The levels of MGMT and p53 protein were tested with immunohistochemistry. Pearson's chi-square test and Fisher's exact test were used. Multivariate and Kaplan-Meier analysis were performed to determine patients' outcomes.Results Both oligodendrogliomas and astrocytic gliomas exhibited frequent methylation of MGMT. However, the results of MSP did not completely correspond to that of the immunohistochemical staining for MGMT. The expression of p53 protein was more frequently observed in patients without a 1 p or 19q deletion in anaplastic oligodendrogliomas (=0.032,0.025). In low-grade oligodendrogliomas, methylation of MGMT was more frequent in patients with 1 p/19q deletion than in patients with 1p/19q intact (P=0.038). Patients with oligodendrogliomas with 1p/19q loss of heterozygosity and p53-negative showed a longer progression-free survival.Conclusion Detection of chromosome 1p/19q status combined with p53 protein immunohistochemistry might be beneficial to improve the pathological diagnosis and to determine the prognosis of patients with oligodendrogliomas.

  11. Morphometric Analysis of Recognized Genes for Autism Spectrum Disorders and Obesity in Relationship to the Distribution of Protein-Coding Genes on Human Chromosomes

    Directory of Open Access Journals (Sweden)

    Austen B. McGuire

    2016-05-01

    Full Text Available Mammalian chromosomes are comprised of complex chromatin architecture with the specific assembly and configuration of each chromosome influencing gene expression and function in yet undefined ways by varying degrees of heterochromatinization that result in Giemsa (G negative euchromatic (light bands and G-positive heterochromatic (dark bands. We carried out morphometric measurements of high-resolution chromosome ideograms for the first time to characterize the total euchromatic and heterochromatic chromosome band length, distribution and localization of 20,145 known protein-coding genes, 790 recognized autism spectrum disorder (ASD genes and 365 obesity genes. The individual lengths of G-negative euchromatin and G-positive heterochromatin chromosome bands were measured in millimeters and recorded from scaled and stacked digital images of 850-band high-resolution ideograms supplied by the International Society of Chromosome Nomenclature (ISCN 2013. Our overall measurements followed established banding patterns based on chromosome size. G-negative euchromatic band regions contained 60% of protein-coding genes while the remaining 40% were distributed across the four heterochromatic dark band sub-types. ASD genes were disproportionately overrepresented in the darker heterochromatic sub-bands, while the obesity gene distribution pattern did not significantly differ from protein-coding genes. Our study supports recent trends implicating genes located in heterochromatin regions playing a role in biological processes including neurodevelopment and function, specifically genes associated with ASD.

  12. Morphometric Analysis of Recognized Genes for Autism Spectrum Disorders and Obesity in Relationship to the Distribution of Protein-Coding Genes on Human Chromosomes.

    Science.gov (United States)

    McGuire, Austen B; Rafi, Syed K; Manzardo, Ann M; Butler, Merlin G

    2016-05-05

    Mammalian chromosomes are comprised of complex chromatin architecture with the specific assembly and configuration of each chromosome influencing gene expression and function in yet undefined ways by varying degrees of heterochromatinization that result in Giemsa (G) negative euchromatic (light) bands and G-positive heterochromatic (dark) bands. We carried out morphometric measurements of high-resolution chromosome ideograms for the first time to characterize the total euchromatic and heterochromatic chromosome band length, distribution and localization of 20,145 known protein-coding genes, 790 recognized autism spectrum disorder (ASD) genes and 365 obesity genes. The individual lengths of G-negative euchromatin and G-positive heterochromatin chromosome bands were measured in millimeters and recorded from scaled and stacked digital images of 850-band high-resolution ideograms supplied by the International Society of Chromosome Nomenclature (ISCN) 2013. Our overall measurements followed established banding patterns based on chromosome size. G-negative euchromatic band regions contained 60% of protein-coding genes while the remaining 40% were distributed across the four heterochromatic dark band sub-types. ASD genes were disproportionately overrepresented in the darker heterochromatic sub-bands, while the obesity gene distribution pattern did not significantly differ from protein-coding genes. Our study supports recent trends implicating genes located in heterochromatin regions playing a role in biological processes including neurodevelopment and function, specifically genes associated with ASD.

  13. Model of a DNA-protein complex of the architectural monomeric protein MC1 from Euryarchaea.

    Directory of Open Access Journals (Sweden)

    Françoise Paquet

    Full Text Available In Archaea the two major modes of DNA packaging are wrapping by histone proteins or bending by architectural non-histone proteins. To supplement our knowledge about the binding mode of the different DNA-bending proteins observed across the three domains of life, we present here the first model of a complex in which the monomeric Methanogen Chromosomal protein 1 (MC1 from Euryarchaea binds to the concave side of a strongly bent DNA. In laboratory growth conditions MC1 is the most abundant architectural protein present in Methanosarcina thermophila CHTI55. Like most proteins that strongly bend DNA, MC1 is known to bind in the minor groove. Interaction areas for MC1 and DNA were mapped by Nuclear Magnetic Resonance (NMR data. The polarity of protein binding was determined using paramagnetic probes attached to the DNA. The first structural model of the DNA-MC1 complex we propose here was obtained by two complementary docking approaches and is in good agreement with the experimental data previously provided by electron microscopy and biochemistry. Residues essential to DNA-binding and -bending were highlighted and confirmed by site-directed mutagenesis. It was found that the Arg25 side-chain was essential to neutralize the negative charge of two phosphates that come very close in response to a dramatic curvature of the DNA.

  14. Inactivation or non-reactivation: what accounts better for the silence of sex chromosomes during mammalian male meiosis?

    Science.gov (United States)

    Page, Jesús; de la Fuente, Roberto; Manterola, Marcia; Parra, María Teresa; Viera, Alberto; Berríos, Soledad; Fernández-Donoso, Raúl; Rufas, Julio S

    2012-06-01

    During the first meiotic prophase in male mammals, sex chromosomes undergo a program of transcriptional silencing called meiotic sex chromosome inactivation (MSCI). MSCI is triggered by accumulation of proteins like BRCA1, ATR, and γH2AX on unsynapsed chromosomes, followed by local changes on the sex chromatin, including histone modifications, incorporation of specific histone variants, non-histone proteins, and RNAs. It is generally thought that MSCI represents the transition of unsynapsed chromatin from a transcriptionally active state to a repressed state. However, transcription is generally low in the whole nucleus during the early stages of the first meiotic prophase, when markers of MSCI first appear, and is then reactivated globally during pachytene. Thus, an alternative possibility is that MSCI represents the targeted maintenance and/or reinforcement of a prior repressed state, i.e., a failure to reactivate. Here, we present an analysis of the temporal and spatial appearance of transcriptional and MSCI markers, as well as chromatin modifications related to transcriptional regulation. We show that levels of RNA pol II and histone H3 acetylated at lysine 9 (H3K9ac) are low during leptotene, zygotene, and early pachytene, but increase strongly in mid-pachytene, indicating that reactivation occurs with some delay after synapsis. However, while transcription markers appear abundantly on the autosomes at mid-pachytene, they are not directed to the sex chromosomes. Interestingly, we found that chromatin modifications related to transcriptional silencing and/or MSCI, namely, histone H3 trimethylated at lysine 9 (H3K9me3), histone H3 monomethylated at lysine 4 (H3K4me1), γH2AX, SUMO1, and XMR, appear on the sex chromosomes before autosomes become reactivated. These results suggest that the onset of MSCI during late zygotene and early pachytene may prevent sex chromosome reactivation during mid-pachytene instead of promoting inactivation de novo. Additionally, we

  15. Mapping by interspecies transformation experiments of several ribosomal protein genes near the replication origin of Bacillus subtilis chromosome.

    Science.gov (United States)

    Osawa, S; Tokui, A; Saito, H

    1978-08-17

    Bacillus subtilis 168 was transformed with DNAs from B. amyloliquefaciens K or B. licheniformis IAM 11054. These two species show a considerable difference in ribosomal proteins from B. subtilis. Analyses of the transformants indicated that the genes for 16 proteins, S3, S5, S8, S12, S17, S19, BL1, BL5, BL6, BL8, BL14, BL16, BL17, BL22, BL23 and BL25 are located in the cysA-str-spc region on B. subtilis chromosome. The genes for 10 proteins, S4, S6, S13, S16, S20, BL15, BL18, BL20, BL24 and BL28 could not be found in this region in the present experiments.

  16. Dynamic interplay of ParA with the polarity protein, Scy, coordinates the growth with chromosome segregation in Streptomyces coelicolor.

    Science.gov (United States)

    Ditkowski, Bartosz; Holmes, Neil; Rydzak, Joanna; Donczew, Magdalena; Bezulska, Martyna; Ginda, Katarzyna; Kedzierski, Pawel; Zakrzewska-Czerwińska, Jolanta; Kelemen, Gabriella H; Jakimowicz, Dagmara

    2013-03-27

    Prior to bacterial cell division, the ATP-dependent polymerization of the cytoskeletal protein, ParA, positions the newly replicated origin-proximal region of the chromosome by interacting with ParB complexes assembled on parS sites located close to the origin. During the formation of unigenomic spores from multi-genomic aerial hyphae compartments of Streptomyces coelicolor, ParA is developmentally triggered to form filaments along the hyphae; this promotes the accurate and synchronized segregation of tens of chromosomes into prespore compartments. Here, we show that in addition to being a segregation protein, ParA also interacts with the polarity protein, Scy, which is a component of the tip-organizing centre that controls tip growth. Scy recruits ParA to the hyphal tips and regulates ParA polymerization. These results are supported by the phenotype of a strain with a mutant form of ParA that uncouples ParA polymerization from Scy. We suggest that the ParA-Scy interaction coordinates the transition from hyphal elongation to sporulation.

  17. Congenital diaphragmatic hernia interval on chromosome 8p23.1 characterized by genetics and protein interaction networks

    DEFF Research Database (Denmark)

    Longoni, Mauro; Hansen, Kasper Lage; Russell, Meaghan K.;

    2012-01-01

    Chromosome 8p23.1 is a common hotspot associated with major congenital malformations, including congenital diaphragmatic hernia (CDH) and cardiac defects. We present findings from high‐resolution arrays in patients who carry a loss (n = 18) or a gain (n = 1) of sub‐band 8p23.1. We confirm a region...... involved in both diaphragmatic and heart malformations. Results from a novel CNVConnect algorithm, prioritizing protein–protein interactions between products of genes in the 8p23.1 hotspot and products of previously known CDH causing genes, implicated GATA4, NEIL2, and SOX7 in diaphragmatic defects...

  18. In silico prediction of structure and functions for some proteins of male-specific region of the human Y chromosome.

    Science.gov (United States)

    Saha, Chinmoy; Polash, Ahsan Habib; Islam, Md Tariqul; Shafrin, Farhana

    2013-12-01

    Male-specific region of the human Y chromosome (MSY) comprises 95% of its length that is functionally active. This portion inherits in block from father to male offspring. Most of the genes in the MSY region are involved in male-specific function, such as sex determination and spermatogenesis; also contains genes probably involved in other cellular functions. However, a detailed characterization of numerous MSY-encoded proteins still remains to be done. In this study, 12 uncharacterized proteins of MSY were analyzed through bioinformatics tools for structural and functional characterization. Within these 12 proteins, a total of 55 domains were found, with DnaJ domain signature corresponding to be the highest (11%) followed by both FAD-dependent pyridine nucleotide reductase signature and fumarate lyase superfamily signature (9%). The 3D structures of our selected proteins were built up using homology modeling and the protein threading approaches. These predicted structures confirmed in detail the stereochemistry; indicating reasonably good quality model. Furthermore the predicted functions and the proteins with whom they interact established their biological role and their mechanism of action at molecular level. The results of these structure-functional annotations provide a comprehensive view of the proteins encoded by MSY, which sheds light on their biological functions and molecular mechanisms. The data presented in this study may assist in future prognosis of several human diseases such as Turner syndrome, gonadal sex reversal, spermatogenic failure, and gonadoblastoma.

  19. A Family of Zinc Finger Proteins Is Required forChromosome-specific Pairing and Synapsis during Meiosis in C.elegans

    Energy Technology Data Exchange (ETDEWEB)

    Phillips, Carolyn M.; Dernburg, Abby F.

    2006-06-07

    Homologous chromosome pairing and synapsis are prerequisitefor accurate chromosome segregation during meiosis. Here, we show that afamily of four related C2H2 zinc-finger proteins plays a central role inthese events in C. elegans. These proteins are encoded within a tandemgene cluster. In addition to the X-specific HIM-8 protein, threeadditional paralogs collectively mediate the behavior of the fiveautosomes. Each chromosome relies on a specific member of the family topair and synapse with its homolog. These "ZIM" proteins concentrate atspecial regions called meiotic pairing centers on the correspondingchromosomes. These sites are dispersed along the nuclear envelope duringearly meiotic prophase, suggesting a role analogous to thetelomere-mediated meiotic bouquet in other organisms. To gain insightinto the evolution of these components, wecharacterized homologs in C.briggsae and C. remanei, which revealed changes in copy number of thisgene family within the nematode lineage.

  20. Constitutive Stringent Response Restores Viability of Bacillus subtilis Lacking Structural Maintenance of Chromosome Protein.

    Directory of Open Access Journals (Sweden)

    Camille Benoist

    Full Text Available Bacillus subtilis mutants lacking the SMC-ScpAB complex are severely impaired for chromosome condensation and partitioning, DNA repair, and cells are not viable under standard laboratory conditions. We isolated suppressor mutations that restored the capacity of a smc deletion mutant (Δsmc to grow under standard conditions. These suppressor mutations reduced chromosome segregation defects and abrogated hypersensitivity to gyrase inhibitors of Δsmc. Three suppressor mutations were mapped in genes involved in tRNA aminoacylation and maturation pathways. A transcriptomic survey of isolated suppressor mutations pointed to a potential link between suppression of Δsmc and induction of the stringent response. This link was confirmed by (pppGpp quantification which indicated a constitutive induction of the stringent response in multiple suppressor strains. Furthermore, sublethal concentrations of arginine hydroxamate (RHX, a potent inducer of stringent response, restored growth of Δsmc under non permissive conditions. We showed that production of (pppGpp alone was sufficient to suppress the thermosensitivity exhibited by the Δsmc mutant. Our findings shed new light on the coordination between chromosome dynamics mediated by SMC-ScpAB and other cellular processes during rapid bacterial growth.

  1. Chromosome 6 encoded RNaseT2 protein is a cell growth regulator

    Science.gov (United States)

    Liu, Jinglan; Zhawar, Vikramjit K; Kaur, Gurpreet; Kaur, G Pal; DeRiel, Jon Kimball; Kandpal, Raj P; Athwal, Raghbir S

    2010-01-01

    Abstract We have previously shown by chromosome transfer technique that chromosome 6 alters the phenotype of a variety of tumour cells and SV40 immortalized cells. We present here the phenotypic effects of the ectopic expression of RNaseT2, a highly conserved ribonuclease encoded by chromosome 6q27, in SV40 immortalized cell lines. We contrast our findings with those reported for ovarian carcinoma cell lines and an SV40 immortalized cell line transfected with RNaseT2. Although RNaseT2 expression is elevated in normal diploid fibroblasts approaching senescence (passage 64), forced expression of the gene in immortalized cells does not cause them to senesce. A significant reduction was observed in colony forming efficiency, anchorage independence and growth rate of cells transfected with RNaseT2. The levels of transcripts involved in Akt signalling pathway, cell cycle control and pathways related to cell proliferation decreased 2–10-folds in SV40 immortalized cells in response to RNaseT2 expression. Interestingly, some immortalized cells expressed alternatively spliced transcript variants instead of the full-length RNaseT2 transcript. Our results are consistent with the conclusion that RNaseT2 is a cell growth regulator and it does not induce senescence in SV40 immortalized cell lines. PMID:19382914

  2. Molecular cloning and chromosomal localization of human genes encoding three closely related G protein-coupled receptors

    Energy Technology Data Exchange (ETDEWEB)

    Zhao-Hui Song; Bonner, T.I. [NIMH National Inst. of Health, Bethesda, MD (United States); Modi, W. [Frederick Cancer Research and Development Center, Frederick, MD (United States)

    1995-07-20

    Cosmids containing human genes for orphan G protein-coupled receptors, GPR12, GPR6, and GPR3, were isolated using their rat homologs as probes. Previous studies of the mouse and rat cDNAs have shown the receptors to be expressed primarily in brain but have failed to identify their ligands. The three receptor proteins of 334, 363, and 330 amino acids, respectively, are encoded by a single exon in each gene. Excluding the divergent sequences preceding the first transmembrane domain, they have {approximately}60% amino acid identity with each other. Flurorescence in situ hybridization of GPR12, GPR6, and GPR3 localized these three genes to human chromosomal regions 13q12, 6q21, and 1p34.3-p36.1, respectively. 9 refs., 2 figs.

  3. Linkage between stature and a region on chromosome 20 and analysis of a candidate gene, bone morphogenetic protein 2

    Energy Technology Data Exchange (ETDEWEB)

    Thompson, D.B.; Ossowski, V.; Janssen, R.C.; Knowler, W.C.; Bogardus, C. [National Inst. of Health, Phoenix, AZ (United States)

    1995-12-04

    Sib-pair linkage analysis of the quantitative trait, stature, in over 500 Pima Indians indicates that a genetic determinant of governing stature is located on chromosome 20. Analysis of 10 short tandem repeat polymorphisms localized this linkage to a 3. cM region that includes D20S98 and D20S66. Using all possible sib-pair combinations, linkage was detected to both stature (P = 0.0001) and to leg length (P = 0.001), but not to sitting height. Single-strand conformational polymorphism analysis of exon 3 of the bone morphogenetic protein 2 (BMP2) gene, a candidate gene in this region, in genomic DNA of 20 of the tallest and 20 of the shortest individuals did not show any consistent differences associated with leg length or height. Sequence analysis of the region encoding the mature protein revealed a single nucleotide substitution, a T to G transversion, not detected by single-strand conformational polymorphism (SSCP) analysis. This transversion results in a conservative amino acid substitution of glycine for valine at codon 80 of BMP2. The frequency of this allele was 0.23 in the sample. No significant differences in height were noted in persons carrying either allele. This indicates that this structural alteration in the mature BMP2 protein does not contribute to the differences in stature observed in the Pima Indians, nor is this structural change in the mature protein likely to be responsible for the linkage observed with stature on chromosome 20. 33 refs., 2 figs., 2 tabs.

  4. The HhH2/NDD domain of the Drosophila Nod chromokinesin-like protein is required for binding to chromosomes in the oocyte nucleus.

    Science.gov (United States)

    Cui, Wei; Hawley, R Scott

    2005-12-01

    Nod is a chromokinesin-like protein that plays a critical role in segregating achiasmate chromosomes during female meiosis. The C-terminal half of the Nod protein contains two putative DNA-binding domains. The first of these domains, known as the HMGN domain, consists of three tandemly repeated high-mobility group N motifs. This domain was previously shown to be both necessary and sufficient for binding of the C-terminal half of Nod to mitotic chromosomes in embryos. The second putative DNA-binding domain, denoted HhH(2)/NDD, is a helix-hairpin-helix(2)/Nod-like DNA-binding domain. Although the HhH(2)/NDD domain is not required or sufficient for chromosome binding in embryos, several well-characterized nod mutations have been mapped in this domain. To characterize the role of the HhH(2)/NDD domain in mediating Nod function, we created a series of UAS-driven transgene constructs capable of expressing either a wild-type Nod-GFP fusion protein or proteins in which the HhH(2)/NDD domain had been altered by site-directed mutagenesis. Although wild-type Nod-GFP localizes to the oocyte chromosomes and rescues the segregation defect in nod mutant oocytes, two of three proteins carrying mutants in the HhH(2)/NDD domain fail to either rescue the nod mutant phenotype or bind to oocyte chromosomes. However, these mutant proteins do bind to the polytene chromosomes in nurse-cell nuclei and enter the oocyte nucleus. Thus, even though the HhH(2)/NDD domain is not essential for chromosome binding in other cell types, it is required for chromosome binding in the oocyte. These HhH(2)/NDD mutants also block the localization of Nod to the posterior pole of stage 9-10A oocytes, a process that is thought to facilitate the interaction of Nod with the plus ends of microtubules (Cui et al. 2005). This observation suggests that the Nod HhH2/NDD domain may play other roles in addition to binding Nod to meiotic chromosomes.

  5. Human-Chromatin-Related Protein Interactions Identify a Demethylase Complex Required for Chromosome Segregation

    Directory of Open Access Journals (Sweden)

    Edyta Marcon

    2014-07-01

    Full Text Available Chromatin regulation is driven by multicomponent protein complexes, which form functional modules. Deciphering the components of these modules and their interactions is central to understanding the molecular pathways these proteins are regulating, their functions, and their relation to both normal development and disease. We describe the use of affinity purifications of tagged human proteins coupled with mass spectrometry to generate a protein-protein interaction map encompassing known and predicted chromatin-related proteins. On the basis of 1,394 successful purifications of 293 proteins, we report a high-confidence (85% precision network involving 11,464 protein-protein interactions among 1,738 different human proteins, grouped into 164 often overlapping protein complexes with a particular focus on the family of JmjC-containing lysine demethylases, their partners, and their roles in chromatin remodeling. We show that RCCD1 is a partner of histone H3K36 demethylase KDM8 and demonstrate that both are important for cell-cycle-regulated transcriptional repression in centromeric regions and accurate mitotic division.

  6. Human-chromatin-related protein interactions identify a demethylase complex required for chromosome segregation.

    Science.gov (United States)

    Marcon, Edyta; Ni, Zuyao; Pu, Shuye; Turinsky, Andrei L; Trimble, Sandra Smiley; Olsen, Jonathan B; Silverman-Gavrila, Rosalind; Silverman-Gavrila, Lorelei; Phanse, Sadhna; Guo, Hongbo; Zhong, Guoqing; Guo, Xinghua; Young, Peter; Bailey, Swneke; Roudeva, Denitza; Zhao, Dorothy; Hewel, Johannes; Li, Joyce; Gräslund, Susanne; Paduch, Marcin; Kossiakoff, Anthony A; Lupien, Mathieu; Emili, Andrew; Wodak, Shoshana J; Greenblatt, Jack

    2014-07-10

    Chromatin regulation is driven by multicomponent protein complexes, which form functional modules. Deciphering the components of these modules and their interactions is central to understanding the molecular pathways these proteins are regulating, their functions, and their relation to both normal development and disease. We describe the use of affinity purifications of tagged human proteins coupled with mass spectrometry to generate a protein-protein interaction map encompassing known and predicted chromatin-related proteins. On the basis of 1,394 successful purifications of 293 proteins, we report a high-confidence (85% precision) network involving 11,464 protein-protein interactions among 1,738 different human proteins, grouped into 164 often overlapping protein complexes with a particular focus on the family of JmjC-containing lysine demethylases, their partners, and their roles in chromatin remodeling. We show that RCCD1 is a partner of histone H3K36 demethylase KDM8 and demonstrate that both are important for cell-cycle-regulated transcriptional repression in centromeric regions and accurate mitotic division.

  7. Evolution and tinkering: what do a protein kinase, a transcriptional regulator and chromosome segregation/cell division proteins have in common?

    Science.gov (United States)

    Derouiche, Abderahmane; Shi, Lei; Kalantari, Aida; Mijakovic, Ivan

    2016-02-01

    In this study, we focus on functional interactions among multi-domain proteins which share a common evolutionary origin. The examples we develop are four Bacillus subtilis proteins, which all possess an ATP-binding Walker motif: the bacterial tyrosine kinase (BY-kinase) PtkA, the chromosome segregation protein Soj (ParA), the cell division protein MinD and a transcription regulator SalA. These proteins have arisen via duplication of the ancestral ATP-binding domain, which has undergone fusions with other functional domains in the process of divergent evolution. We point out that these four proteins, despite having very different physiological roles, engage in an unusually high number of binary functional interactions. Namely, MinD attracts Soj and PtkA to the cell pole, and in addition, activates the kinase function of PtkA. SalA also activates the kinase function of PtkA, and it gets phosphorylated by PtkA as well. The consequence of this phosphorylation is the activation of SalA as a transcriptional repressor. We hypothesize that these functional interactions remain preserved during divergent evolution and represent a constraint on the process of evolutionary "tinkering", brought about by fusions of different functional domains.

  8. A novel human gene encoding a G-protein-coupled receptor (GPR15) is located on chromosome 3

    Energy Technology Data Exchange (ETDEWEB)

    Heiber, M.; Marchese, A.; O`Dowd, B.F. [Univ. of Toronto, Ontario (Canada)] [and others

    1996-03-05

    We used sequence similarities among G-protein-coupled receptor genes to discover a novel receptor gene. Using primers based on conserved regions of the opioid-related receptors, we isolated a PCR product that was used to locate the full-length coding region of a novel human receptor gene, which we have named GPR15. A comparison of the amino acid sequence of the receptor gene, which we have named GPR15. A comparison of the amino acid sequence of the receptor encoded by GPR15 with other receptors revealed that it shared sequence identity with the angiotensin II AT1 and AT2 receptors, the interleukin 8b receptor, and the orphan receptors GPR1 and AGTL1. GPR15 was mapped to human chromosome 3q11.2-q13.1. 12 refs., 2 figs.

  9. The actinobacterial signature protein ParJ (SCO1662) regulates ParA polymerization and affects chromosome segregation and cell division during Streptomyces sporulation.

    Science.gov (United States)

    Ditkowski, Bartosz; Troć, Paulina; Ginda, Katarzyna; Donczew, Magdalena; Chater, Keith F; Zakrzewska-Czerwińska, Jolanta; Jakimowicz, Dagmara

    2010-12-01

    Bacterial chromosome segregation usually involves cytoskeletal ParA proteins, ATPases which can form dynamic filaments. In aerial hyphae of the mycelial bacterium Streptomyces coelicolor, ParA filaments extend over tens of microns and are responsible for segregation of dozens of chromosomes. We have identified a novel interaction partner of S. coelicolor ParA, ParJ. ParJ negatively regulates ParA polymerization in vitro and is important for efficient chromosome segregation in sporulating aerial hyphae. ParJ-EGFP formed foci along aerial hyphae even in the absence of ParA. ParJ, which is encoded by sco1662, turned out to be one of the five actinobacterial signature proteins, and another of the five is a ParJ paralogue. We hypothesize that polar growth, which is characteristic not only of streptomycetes, but even of simple Actinobacteria, may be interlinked with ParA polymer assembly and its specific regulation by ParJ.

  10. Localization of the cellular retinoic acid binding protein (CRABP) gene relative to the acute promyelocytic leukemia-associated breakpoint on human chromosome 15

    NARCIS (Netherlands)

    A.H.M. Geurts van Kessel (Ad); H. de Leeuw (H.); E.J. Dekker (E.); J.M. Rijks (Jolianne); N. Spurr (N.); A.M. Ledbetter (Andrew M.); E. Kootwijk (E.); M.J. Vaessen (Marie-Josée)

    1991-01-01

    textabstractA human genomic fragment comprising the cellular retinoic acid binding protein (CRABP) gene was isolated. By using a panel of somatic cell hybrids, this gene could be assigned to human chromosome 15. Subsequently, a possible involvement of the CRABP gene in translocation (15;17) (q22;q11

  11. Bacterial chromosome segregation.

    Science.gov (United States)

    Possoz, Christophe; Junier, Ivan; Espeli, Olivier

    2012-01-01

    Dividing cells have mechanisms to ensure that their genomes are faithfully segregated into daughter cells. In bacteria, the description of these mechanisms has been considerably improved in the recent years. This review focuses on the different aspects of bacterial chromosome segregation that can be understood thanks to the studies performed with model organisms: Escherichia coli, Bacillus subtilis, Caulobacter crescentus and Vibrio cholerae. We describe the global positionning of the nucleoid in the cell and the specific localization and dynamics of different chromosomal loci, kinetic and biophysic aspects of chromosome segregation are presented. Finally, a presentation of the key proteins involved in the chromosome segregation is made.

  12. Mapping of two genes encoding isoforms of the actin binding protein ABP-280, a dystrophin like protein, to Xq28 and to chromosome 7.

    Science.gov (United States)

    Maestrini, E; Patrosso, C; Mancini, M; Rivella, S; Rocchi, M; Repetto, M; Villa, A; Frattini, A; Zoppè, M; Vezzoni, P

    1993-06-01

    ABP-280 is a ubiquitous actin binding protein present in the cytoskeleton of many different cell types. ABP-280 was mapped to distal Xq28, 50-60 kb downstream of the Green Colour Pigment (GCP) genes. To establish if ABP-280 may be a candidate for one of the muscle disease localized by linkage analysis to distal Xq28 we looked for alternative forms of ABP-280 mRNA. Several different ABP-280 mRNAs were indeed identified: two are X-linked and are produced by alternative splicing of a small exon of 24 nucleotides. At least one additional gene encoding a RNA more than 70% identical to ABP-280 in the 1700 bp sequenced has also been found. It was mapped to chromosome 7. While both forms of the X-linked ABP-280 are ubiquitous, the gene on chromosome 7 is highly expressed only in skeletal muscle and heart. The two genes were therefore excellent candidates for the X-linked and for the autosomal dominant form of the Emery-Dreifuss Muscular Dystrophy (EDMD) both of which have been described. So far, however we were unable to demonstrate mutations in the coding region or affecting the alternative splicing of the X-linked form of ABP-280, in several patients studied, and we think that it is quite unlikely that this is the gene responsible for EDMD.

  13. The role of high mobility group box chromosomal protein 1 expression in the differential diagnosis of hepatic actinomycosis: a case report

    Directory of Open Access Journals (Sweden)

    Wu Chuan-Xin

    2013-01-01

    Full Text Available Abstract Introduction Primary hepatic actinomycosis is a rare disease, but is important in the differential diagnosis of hepatoma in endemic areas. As high mobility group box chromosomal protein 1 plays an important role in the pathogenesis of both acute and chronic inflammatory conditions, we postulate that high mobility group box chromosomal protein 1 may have a possible pathogenic role in hepatic actinomycosis. To the best of our knowledge, our report is the first to detect an association between highly elevated high mobility group box chromosomal protein 1 expression and hepatic actinomycosis. Case presentation A 67-year-old Chinese man was admitted to our hospital with a three-month history of epigastric pain, anorexia, and subjective weight loss. Ultrasonography and computed tomography of the patient’s abdomen confirmed a hypodense mass measuring seven cm in diameter in the left lateral segment of his liver. A hepatic tumor was suspected and surgical resection was scheduled. Histopathologic examination revealed that the overall features of the hepatic tissues were consistent with hepatic actinomycosis. Whole blood and hepatic tissue samples of the patient, of patients who had hepatocellular carcinoma and of healthy donors were collected. Serum high mobility group box chromosomal protein 1 concentration in actinomycosis was 8.5ng/mL, which was higher than the hepatocellular carcinoma level of 5.2ng/mL and the normal level of Conclusion High mobility group box chromosomal protein 1 may have a potent biological effect on the pathogenesis of hepatic actinomycosis as a novel cytokine and may be a useful marker in the differential diagnosis of hepatic actinomycosis.

  14. Chromosomal rearrangements and protein globularity changes in Mycobacterium tuberculosis isolates from cerebrospinal fluid

    Directory of Open Access Journals (Sweden)

    Seow Hoon Saw

    2016-09-01

    Full Text Available Background Meningitis is a major cause of mortality in tuberculosis (TB. It is not clear what factors promote central nervous system invasion and pathology but it has been reported that certain strains of Mycobacterium tuberculosis (Mtb might have genetic traits associated with neurotropism. Methods In this study, we generated whole genome sequences of eight clinical strains of Mtb that were isolated from the cerebrospinal fluid (CSF of patients presenting with tuberculous meningitis (TBM in Malaysia, and compared them to the genomes of H37Rv and other respiratory Mtb genomes either downloaded from public databases or extracted from local sputum isolates. We aimed to find genomic features that might be distinctly different between CSF-derived and respiratory Mtb. Results Genome-wide comparisons revealed rearrangements (translocations, inversions, insertions and deletions and non-synonymous SNPs in our CSF-derived strains that were not observed in the respiratory Mtb genomes used for comparison. These rearranged segments were rich in genes for PE (proline-glutamate/PPE (proline-proline-glutamate, transcriptional and membrane proteins. Similarly, most of the ns SNPs common in CSF strains were noted in genes encoding PE/PPE proteins. Protein globularity differences were observed among mycobacteria from CSF and respiratory sources and in proteins previously reported to be associated with TB meningitis. Transcription factors and other transcription regulators featured prominently in these proteins. Homologs of proteins associated with Streptococcus pneumoniae meningitis and Neisseria meningitidis virulence were identified in neuropathogenic as well as respiratory mycobacterial spp. examined in this study. Discussion The occurrence of in silico genetic differences in CSF-derived but not respiratory Mtb suggests their possible involvement in the pathogenesis of TBM. However, overall findings in this comparative analysis support the postulation that TB

  15. RABL6A, a novel RAB-like protein, controls centrosome amplification and chromosome instability in primary fibroblasts.

    Directory of Open Access Journals (Sweden)

    Xuefeng Zhang

    Full Text Available RABL6A (RAB-like 6 isoform A is a novel protein that was originally identified based on its association with the Alternative Reading Frame (ARF tumor suppressor. ARF acts through multiple p53-dependent and p53-independent pathways to prevent cancer. How RABL6A functions, to what extent it depends on ARF and p53 activity, and its importance in normal cell biology are entirely unknown. We examined the biological consequences of RABL6A silencing in primary mouse embryo fibroblasts (MEFs that express or lack ARF, p53 or both proteins. We found that RABL6A depletion caused centrosome amplification, aneuploidy and multinucleation in MEFs regardless of ARF and p53 status. The centrosome amplification in RABL6A depleted p53-/- MEFs resulted from centrosome reduplication via Cdk2-mediated hyperphosphorylation of nucleophosmin (NPM at threonine-199. Thus, RABL6A prevents centrosome amplification through an ARF/p53-independent mechanism that restricts NPM-T199 phosphorylation. These findings demonstrate an essential role for RABL6A in centrosome regulation and maintenance of chromosome stability in non-transformed cells, key processes that ensure genomic integrity and prevent tumorigenesis.

  16. Isolation of a novel G protein-coupled receptor (GPR4) localized to chromosome 19q13.3

    Energy Technology Data Exchange (ETDEWEB)

    Mahadevan, M.S.; Baird, S.; Bailly, J.E. [Univ. of Ottawa, Ontario (Canada)] [and others

    1995-11-01

    We present the cloning and sequencing of the human gene for a novel G-protein coupled receptor (GPR4), from the critical myotonic dystrophy (DM) region on chromosome 19q13.3. The homologous porcine gene was isolated and sequenced as well. The genes of both species are intronless and contain an open reading frame encoding a protein of 362 amino acids. In human, two isoforms of GPR4 are expressed, differing in their 3{prime} untranslated region due to the use of alternate polyadenylation signals and measuring approximately 2.8 and 1.8 kb, respectively. Northern blot analysis showed that GPR4 is widely expressed, with higher levels in kidney, heart, and especially lung, where it is at least fivefold greater than in other tissues. Sequence analysis suggests that GPR4 is a peptide receptor and shares strongest homologies with purinergic receptors and receptors for angiotensin II, platelet activating factor, thrombin, and bradykinin. 25 refs., 3 figs., 1 tab.

  17. Dynamic spatial organization of multi-protein complexes controlling microbial polar organization, chromosome replication, and cytokinesis

    Energy Technology Data Exchange (ETDEWEB)

    McAdams, Harley; Shapiro, Lucille; Horowitz, Mark; Andersen, Gary; Downing, Kenneth; Earnest, Thomas; Ellisman, Mark; Gitai, Zemer; Larabell, Carolyn; Viollier, Patrick

    2012-06-18

    This project was a program to develop high-throughput methods to identify and characterize spatially localized multiprotein complexes in bacterial cells. We applied a multidisciplinary systems engineering approach to the detailed characterization of localized multi-protein structures in vivo a problem that has previously been approached on a fragmented, piecemeal basis.

  18. Marker chromosomes.

    Science.gov (United States)

    Rao, Kiran Prabhaker; Belogolovkin, Victoria

    2013-04-01

    Marker chromosomes are a morphologically heterogeneous group of structurally abnormal chromosomes that pose a significant challenge in prenatal diagnosis. Phenotypes associated with marker chromosomes are highly variable and range from normal to severely abnormal. Clinical outcomes are very difficult to predict when marker chromosomes are detected prenatally. In this review, we outline the classification, etiology, cytogenetic characterization, and clinical consequences of marker chromosomes, as well as practical approaches to prenatal diagnosis and genetic counseling.

  19. Chromosomal protein HMGN1 enhances the acetylation of lysine 14 in histone H3

    OpenAIRE

    Lim, Jae-Hwan; West, Katherine L.; Rubinstein, Yaffa; Bergel, Michael; Postnikov, Yuri V.; Bustin, Michael

    2005-01-01

    The acetylation levels of lysine residues in nucleosomes, which are determined by the opposing activities of histone acetyltransferases (HATs) and deacetylases, play an important role in regulating chromatin-related processes, including transcription. We report that HMGN1, a nucleosomal binding protein that reduces the compaction of the chromatin fiber, increases the levels of acetylation of K14 in H3. The levels of H3K14ac in Hmgn1−/− cells are lower than in Hmgn1+/+ cells. Induced expressio...

  20. Chromosome locations of genes encoding human signal transduction adapter proteins, Nck (NCK), Shc (SHC1), and Grb2 (GRB2)

    DEFF Research Database (Denmark)

    Huebner, K; Kastury, K; Druck, T;

    1994-01-01

    Abnormalities due to chromosomal aberration or point mutation in gene products of growth factor receptors or in ras gene products, which lie on the same signaling pathway, can cause disease in animals and humans. Thus, it can be important to determine chromosomal map positions of genes encoding "...

  1. The mouse salivary androgen-binding protein (ABP) gene cluster on chromosomes 7: characterization and evolutionary relationships.

    Science.gov (United States)

    Laukaitis, Christina M; Dlouhy, Stephen R; Karn, Robert C

    2003-10-01

    Mouse salivary androgen-binding protein (ABP) is a pair of dimers, composed of an alpha subunit disulfide bridged to either a beta or a gamma subunit. It has been proposed that each subunit is encoded by a distinct gene: Abpa, Abpb, and Abpg for the alpha, beta, and gamma subunits, respectively. We report here the structures and sequences of the genes that encode these three subunits. Each gene has three exons separated by two introns. Mouse salivary ABP is a member of the secretoglobin family, and we compare the structure of the three ABP subunit genes to those of 18 other mammalian secretoglobins. We map the three genes as a gene cluster located 10 cM from the centromere of Chromosome (Chr) 7 and show that Abpa is the closest of the three to the gene for glucose phosphate isomerase (GPI) and that Abpg is the closest to the centromere, with Abpb mapping between them. Abpa is oriented in the opposite direction to Abpb and Abpg, with its 5' end directed toward their 5' ends. We compare the location of these genes with other secretoglobin genes in the mouse genome and with the known locations of secretoglobin genes in the human genome and present evidence that strong positive selection has driven the divergence of the coding regions of Abpb and Abpg since the putative duplication event that created them.

  2. Telomere dysfunction and chromosome instability

    Energy Technology Data Exchange (ETDEWEB)

    Murnane, John P., E-mail: jmurnane@radonc.ucsf.edu [Department of Radiation Oncology, University of California San Francisco, 2340 Sutter Street, San Francisco, CA 94143-1331 (United States)

    2012-02-01

    The ends of chromosomes are composed of a short repeat sequence and associated proteins that together form a cap, called a telomere, that keeps the ends from appearing as double-strand breaks (DSBs) and prevents chromosome fusion. The loss of telomeric repeat sequences or deficiencies in telomeric proteins can result in chromosome fusion and lead to chromosome instability. The similarity between chromosome rearrangements resulting from telomere loss and those found in cancer cells implicates telomere loss as an important mechanism for the chromosome instability contributing to human cancer. Telomere loss in cancer cells can occur through gradual shortening due to insufficient telomerase, the protein that maintains telomeres. However, cancer cells often have a high rate of spontaneous telomere loss despite the expression of telomerase, which has been proposed to result from a combination of oncogene-mediated replication stress and a deficiency in DSB repair in telomeric regions. Chromosome fusion in mammalian cells primarily involves nonhomologous end joining (NHEJ), which is the major form of DSB repair. Chromosome fusion initiates chromosome instability involving breakage-fusion-bridge (B/F/B) cycles, in which dicentric chromosomes form bridges and break as the cell attempts to divide, repeating the process in subsequent cell cycles. Fusion between sister chromatids results in large inverted repeats on the end of the chromosome, which amplify further following additional B/F/B cycles. B/F/B cycles continue until the chromosome acquires a new telomere, most often by translocation of the end of another chromosome. The instability is not confined to a chromosome that loses its telomere, because the instability is transferred to the chromosome donating a translocation. Moreover, the amplified regions are unstable and form extrachromosomal DNA that can reintegrate at new locations. Knowledge concerning the factors promoting telomere loss and its consequences is

  3. Chromosome-specific families in Vibrio genomes

    Directory of Open Access Journals (Sweden)

    Oksana eLukjancenko

    2014-03-01

    Full Text Available We have compared chromosome-specific genes in a set of 18 finished Vibrio genomes, and, in addition, also calculated the pan- and core-genomes from a data set of more than 250 draft Vibrio genome sequences. These genomes come from 9 known species and 2 unknown species. Within the finished chromosomes, we find a core set of 1269 encoded protein families for chromosome 1, and a core of 252 encoded protein families for chromosome 2. Many of these core proteins are also found in the draft genomes (although which chromosome they are located on is unknown. Of the chromosome specific core protein families, 1169 and 153 are uniquely found in chromosomes 1 and 2, respectively. Gene ontology (GO terms for each of the protein families were determined, and the different sets for each chromosome were compared. A total of 363 different `Molecular Function` GO categories were found for chromosome 1 specific protein families, and these include several broad activities: pyridoxine 5' phosphate synthetase, glucosylceramidase, heme transport, DNA ligase, amino acid binding, and ribosomal components; in contrast, chromosome 2 specific protein families have only 66 Molecular Function GO terms and include many membrane-associated activities, such as ion channels, transmembrane transporters, and electron transport chain proteins. Thus, it appears that whilst there are many 'housekeeping systems' encoded in chromosome 1, there are far fewer core functions found in chromosome 2. However, the presence of many membrane-associated encoded proteins in chromosome 2 is surprising.

  4. [Tripartite motif-containing protein 34 (TRIM34) colocalized with micronuclei chromosome and hampers its movement to equatorial plate during the metaphase stage of mitosis].

    Science.gov (United States)

    Sun, Dakang; An, Xinye; Ji, Bing; Cheng, Yanli; Gao, Honglian; Tian, Mingming

    2016-06-01

    Objective To examine whether tripartite motif-containing protein 34 (TRIM34) is colocalized with micronuclei and investigate the influence on the movement of micronuclei chromosome in mitosis. Methods The eukaryotic expression vector TRIM34-pEGFP-N3 was constructed, identified and then transfected into HEK293T cells. With 4', 6-diamidino-2-phenylindole 2HCI (DAPI) staining, the colocalization between TRIM34 and micronuclei was observed under a fluorescence microscope. Moreover, MitoTracker(R)Deep Red was used to identify the colocalization between the complex of TRIM34-micronulei and mitochondria under a confocal microscope. Finally, the effect of TRIM34 on the movement of micronuclei chromosome in mitosis was examined. Results DNA sequencing confirmed that the vector TRIM34-pEGFP-N3 was constructed successfully. A fluorescence microscope revealed that TRIM34 could be colocalized with micronuclei in HEK293T cells transfected with TRIM34-pEGFP-N3. In the same manner, a confocal microscope distinctly showed that TRIM34 was colocalized with micronuclei similarly in appearance. However, there was no distinguished colocalization relationship between the complex of TRIM34-micronulei and mitochondria. Interestingly, the micronuclei chromosome conjugated with TRIM34 was hardly transferred to equatorial plate during the metaphase stage of mitosis. Conclusion TRIM34 is colocalized with micronuclei chromosome and hampers its movement to equatorial plate in mitosis.

  5. cDNA cloning and chromosomal mapping of a predicted coiled-coil proline-rich protein immunogenic in meningioma patients.

    Science.gov (United States)

    Heckel, D; Brass, N; Fischer, U; Blin, N; Steudel, I; Türeci, O; Fackler, O; Zang, K D; Meese, E

    1997-11-01

    There is increasing evidence that tumor expressed genes induce immune responses in cancer patients. To identify meningioma expressed antigens, we established a meningioma expression library which was screened with autologous serum. Out of 20 positive cDNA clones eight share high sequence homologies as determined by sequence analysis. These eight clones can be grouped into three classes which differ in length and which are characterized by specific sequence variations. The longest open reading frame was found to be 2412 bp encoding an immunoreactive antigen termed meningioma expressed antigen 6 (MEA6). Using five sequence specific primer pairs, somatic hybrid panel mapping revealed locations of the three classes on several human chromosomes including chromosomes 2, 3, 6, 7, 9, 13 and 14. The mapping results were confirmed by fluorescence in situ hybridization. RT-PCR showed consistent expression of all classes in several meningiomas and additional tissues using the same set of primer pairs as for chromosomal mapping. The expression data were confirmed by northern blot analysis. For the predicted amino acid sequence BLASTX revealed a homology to a human C219-reactive peptide which was previously isolated by an antibody directed against p-glycoprotein. Sequence properties of the MEA protein include an acidic activation domain, a proline-rich region and two coiled-coil domains indicating protein binding and activation functions.

  6. [Sex chromosomes and meiosis].

    Science.gov (United States)

    Guichaoua, M-R; Geoffroy-Siraudin, C; Tassistro, V; Ghalamoun-Slaimi, R; Perrin, J; Metzler-Guillemain, C

    2009-01-01

    Sex chromosome behaviour fundamentally differs between male and female meiosis. In oocyte, X chromosomes synapse giving a XX bivalent which is not recognizable in their morphology and behaviour from autosomal bivalents. In human male, X and Y chromosomes differ from one another in their morphology and their genetic content, leading to a limited pairing and preventing genetic recombination, excepted in homologous region PAR1. During pachytene stage of the first meiotic prophase, X and Y chromosomes undergo a progressive condensation and form a transcriptionally silenced peripheral XY body. The condensation of the XY bivalent during pachytene stage led us to describe four pachytene substages and to localize the pachytene checkpoint between substages 2 and 3. We also defined the pachytene index (PI=P1+P2/P1+P2+P3+P4) which is always less than 0.50 in normal meiosis. XY body undergoes decondensation at diplotene stage, but transcriptional inactivation of the two sex chromosomes or Meiotic Sex Chromosome Inactivation (MSCI) persists through to the end of spermatogenesis. Sex chromosome inactivation involves several proteins, some of them were now identified. Two isoforms of the HP1 protein, HP1beta and HP1gamma, are involved in the facultative heterochromatinization of the XY body, but the initiation of this process involves the phosphorylation of the protein H2AX by the kinase ATR whose recruitment depends on BRCA1. Extensive researches on the inactivation of the sex chromosomes during male meiosis will allow to a better understanding of some male infertilities.

  7. PprA Protein Is Involved in Chromosome Segregation via Its Physical and Functional Interaction with DNA Gyrase in Irradiated Deinococcus radiodurans Bacteria.

    Science.gov (United States)

    Devigne, Alice; Guérin, Philippe; Lisboa, Johnny; Quevillon-Cheruel, Sophie; Armengaud, Jean; Sommer, Suzanne; Bouthier de la Tour, Claire; Servant, Pascale

    2016-01-01

    PprA, a radiation-induced Deinococcus-specific protein, was previously shown to be required for cell survival and accurate chromosome segregation after exposure to ionizing radiation. Here, we used an in vivo approach to determine, by shotgun proteomics, putative PprA partners coimmunoprecipitating with PprA when cells were exposed to gamma rays. Among them, we found the two subunits of DNA gyrase and, thus, chose to focus our work on characterizing the activities of the deinococcal DNA gyrase in the presence or absence of PprA. Loss of PprA rendered cells hypersensitive to novobiocin, an inhibitor of the B subunit of DNA gyrase. We showed that treatment of bacteria with novobiocin resulted in induction of the radiation desiccation response (RDR) regulon and in defects in chromosome segregation that were aggravated by the absence of PprA. In vitro, the deinococcal DNA gyrase, like other bacterial DNA gyrases, possesses DNA negative supercoiling and decatenation activities. These two activities are inhibited in vitro by novobiocin and nalidixic acid, whereas PprA specifically stimulates the decatenation activity of DNA gyrase. Together, these results suggest that PprA plays a major role in chromosome decatenation via its interaction with the deinococcal DNA gyrase when D. radiodurans cells are recovering from exposure to ionizing radiation. IMPORTANCE D. radiodurans is one of the most radiation-resistant organisms known. This bacterium is able to cope with high levels of DNA lesions generated by exposure to extreme doses of ionizing radiation and to reconstruct a functional genome from hundreds of radiation-induced chromosomal fragments. Here, we identified partners of PprA, a radiation-induced Deinococcus-specific protein, previously shown to be required for radioresistance. Our study leads to three main findings: (i) PprA interacts with DNA gyrase after irradiation, (ii) treatment of cells with novobiocin results in defects in chromosome segregation that are

  8. Normal histone modifications on the inactive X chromosome in ICF and Rett syndrome cells: implications for methyl-CpG binding proteins

    Directory of Open Access Journals (Sweden)

    Canfield Theresa K

    2004-09-01

    Full Text Available Abstract Background In mammals, there is evidence suggesting that methyl-CpG binding proteins may play a significant role in histone modification through their association with modification complexes that can deacetylate and/or methylate nucleosomes in the proximity of methylated DNA. We examined this idea for the X chromosome by studying histone modifications on the X chromosome in normal cells and in cells from patients with ICF syndrome (Immune deficiency, Centromeric region instability, and Facial anomalies syndrome. In normal cells the inactive X has characteristic silencing type histone modification patterns and the CpG islands of genes subject to X inactivation are hypermethylated. In ICF cells, however, genes subject to X inactivation are hypomethylated on the inactive X due to mutations in the DNA methyltransferase (DNMT3B genes. Therefore, if DNA methylation is upstream of histone modification, the histones on the inactive X in ICF cells should not be modified to a silent form. In addition, we determined whether a specific methyl-CpG binding protein, MeCP2, is necessary for the inactive X histone modification pattern by studying Rett syndrome cells which are deficient in MeCP2 function. Results We show here that the inactive X in ICF cells, which appears to be hypomethylated at all CpG islands, exhibits normal histone modification patterns. In addition, in Rett cells with no functional MeCP2 methyl-CpG binding protein, the inactive X also exhibits normal histone modification patterns. Conclusions These data suggest that DNA methylation and the associated methyl-DNA binding proteins may not play a critical role in determining histone modification patterns on the mammalian inactive X chromosome at the sites analyzed.

  9. Mitotic chromosome biorientation in fission yeast is enhanced by dynein and a minus-end-directed, kinesin-like protein.

    Science.gov (United States)

    Grishchuk, Ekaterina L; Spiridonov, Ilia S; McIntosh, J Richard

    2007-06-01

    Chromosome biorientation, the attachment of sister kinetochores to sister spindle poles, is vitally important for accurate chromosome segregation. We have studied this process by following the congression of pole-proximal kinetochores and their subsequent anaphase segregation in fission yeast cells that carry deletions in any or all of this organism's minus end-directed, microtubule-dependent motors: two related kinesin 14s (Pkl1p and Klp2p) and dynein. None of these deletions abolished biorientation, but fewer chromosomes segregated normally without Pkl1p, and to a lesser degree without dynein, than in wild-type cells. In the absence of Pkl1p, which normally localizes to the spindle and its poles, the checkpoint that monitors chromosome biorientation was defective, leading to frequent precocious anaphase. Ultrastructural analysis of mutant mitotic spindles suggests that Pkl1p contributes to error-free biorientation by promoting normal spindle pole organization, whereas dynein helps to anchor a focused bundle of spindle microtubules at the pole.

  10. HURP is a Ran-importin beta-regulated protein that stabilizes kinetochore microtubules in the vicinity of chromosomes

    NARCIS (Netherlands)

    Silljé, Herman H W; Nagel, Susanna; Körner, Roman; Nigg, Erich A

    2006-01-01

    BACKGROUND: Formation of a bipolar mitotic spindle in somatic cells requires the cooperation of two assembly pathways, one based on kinetochore capture by centrosomal microtubules, the other on RanGTP-mediated microtubule organization in the vicinity of chromosomes. How RanGTP regulates kinetochore-

  11. Modeling Chromosomes

    Science.gov (United States)

    Robertson, Carol

    2016-01-01

    Learning about chromosomes is standard fare in biology classrooms today. However, students may find it difficult to understand the relationships among the "genome", "chromosomes", "genes", a "gene locus", and "alleles". In the simple activity described in this article, which follows the 5E approach…

  12. Heterogeneous nuclear ribonucleoproteins H, H', and F are members of a ubiquitously expressed subfamily of related but distinct proteins encoded by genes mapping to different chromosomes

    DEFF Research Database (Denmark)

    Honoré, B; Rasmussen, H H; Vorum, H;

    1995-01-01

    and keratinocytes. In normal human keratinocytes, the expression level of H was unaffected by treatment with several substances tested including two second messengers and seven cytokines. Likewise the expression level of F was independent of these substances, although it was strikingly down-regulated by long term...... treatment with 4 beta-phorbol 12-myristate 13-acetate, indicating that the protein kinase C signaling pathway regulates its expression. No effect of 4 beta-phorbol 12-myristate 13-acetate was observed on the expression of hnRNP H. The genes coding for hnRNPs H, H', and F were chromosome-mapped to 5q35...

  13. Higher order structure of chromosomes.

    Science.gov (United States)

    Okada, T A; Comings, D E

    1979-04-01

    Isolated Chinese hamster metaphase chromosomes were resuspended in 4 M ammonium acetate and spread on a surface of distilled water or 0.15 to 0.5 M ammonium acetate. The DNA was released in the form of a regular series of rosettes connected by interrossette DNA. The mean length of the rosette DNA was 14 micron, similar to the mean length of 10 micron for chromomere DNA of Drosophila polytene chromosomes. The mean interrosette DNA was 4.2 micron. SDS gel electrophoresis of the chromosomal nonhistone proteins showed them to be very similar to nuclear nonhistone proteins except for the presence of more actin and tubulin. Nuclear matrix proteins were present in the chromosomes and may play a role in forming the rosettes. Evidence that the rosette pattern is artifactual versus the possibility that it represents a real organizational substructure of the chromosomes is reviewed.

  14. Cloning of a conserved receptor-like protein kinase gene and its use as a functional marker for homoeologous group-2 chromosomes of the triticeae species.

    Directory of Open Access Journals (Sweden)

    Bi Qin

    Full Text Available Receptor-like kinases (RLKs play broad biological roles in plants. We report on a conserved receptor-like protein kinase (RPK gene from wheat and other Triticeae species. The TaRPK1 was isolated from the Triticum aestivum cv. Prins - Triticum timopheevii introgression line IGVI-465 carrying the powdery mildew resistance gene Pm6. The TaRPK1 was mapped to homoeologous chromosomes 2A (TaRPK1-2A, 2D (TaRPK1-2D and the Pm6-carrier chromosome 2G (TaRPK1-2G of IGVI-465. Under the tested conditions, only the TaRPK1-2G allele was actively transcribed, producing two distinct transcripts via alternative splicing. The predicted 424-amino acid protein of TaRPK1-2G contained a signal peptide, a transmembrane domain and an intracellular serine/threonine kinase domain, but lacked a typical extracellular domain. The expression of TaRPK1-2G gene was up-regulated upon the infection by Blumeria graminis f.sp. tritici (Bgt and treatment with methyl jasmonate (MeJA, but down-regulated in response to treatments of SA and ABA. Over-expression of TaRPK1-2G in the powdery mildew susceptible wheat variety Prins by a transient expression assay showed that it slightly reduced the haustorium index of the infected Bgt. These data indicated that TaRPK1-2G participated in the defense response to Bgt infection and in the JA signaling pathway. Phylogenetic analysis indicated that TaRPK1-2G was highly conserved among plant species, and the amino acid sequence similarity of TaRPK1-2G among grass species was more than 86%. Based on its conservation, the RPK gene-based STS primers were designed, and used to amplify the RPK orthologs from the homoeologous group-2 chromosomes of all the tested Triticeae species, such as chromosome 2G of T. timopheevii, 2R of Secale cereale, 2H of Hordeum vulgare, 2S of Aegilops speltoides, 2S(l of Ae. longissima, 2M(g of Ae. geniculata, 2S(p and 2U(p of Ae. peregrina. The developed STS markers serve as conserved functional markers for the

  15. Cohesin in determining chromosome architecture

    Energy Technology Data Exchange (ETDEWEB)

    Haering, Christian H., E-mail: christian.haering@embl.de [Cell Biology and Biophysics Unit, European Molecular Biology Laboratory (EMBL), Heidelberg (Germany); Jessberger, Rolf, E-mail: rolf.jessberger@tu-dresden.de [Institute of Physiological Chemistry, Dresden University of Technology, Dresden (Germany)

    2012-07-15

    Cells use ring-like structured protein complexes for various tasks in DNA dynamics. The tripartite cohesin ring is particularly suited to determine chromosome architecture, for it is large and dynamic, may acquire different forms, and is involved in several distinct nuclear processes. This review focuses on cohesin's role in structuring chromosomes during mitotic and meiotic cell divisions and during interphase.

  16. Changes in chromatin-associated proteins of virus-infected tobacco leaves

    NARCIS (Netherlands)

    Telgen, van H.J.

    1985-01-01

    Symptoms of viral infections in plants often resemble disturbances in growth and development. Therefore, symptoms appear to result from an interference of the virus with the regulation of growth and development of the host plant. Particularly the non-histone chromatin- associated proteins are consid

  17. Interactions between HMG proteins and the core sequence of DNaseI hypersensitive site 2 in the locus control region (LCR) of the human β-like globin gene cluster

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    HMG proteins are abundant chromosomal non-histone proteins. It has been suggested that the HMG proteins may play an important role in the structure and function of chromatin. In the present study, the binding of HMG proteins (HMG1/2 and HMG14/17) to the core DNA sequence of DNaseI hypersensitive site 2 (HS2core DNA sequence, -10681--10970 bp) in the locus control region (LCR) of the human b-like globin gene cluster has been examined by using both the in vitro nucleosome reconstitution and the gel mobility shift assays. Here we show that HMG1/2 can bind to the naked HS2core DNA sequence, however, HMG14/17 cannot. Using the in vitro nucleosome reconstitution we demonstrate that HMG14/17 can bind to the HS2core DNA sequence which is assembled into nucleosomes with the core histone octamer transferred from chicken erythrocytes. In contrast, HMG1/2 cannot bind to the nucleosomes reconstituted in vitro with the HS2core DNA sequence. These results indicate that the binding patterns between HMG proteins and the HS2core DNA sequence which exists in different states (the naked DNA or the in vitro reconstituted nucleosomal DNA) are quite different. We speculate that HMG proteins might play a critical role in the regulation of the human β-like globin gene's expression.

  18. Interactions between HMG proteins and the core sequence of DNaseI hypersensitive site 2 in the locus control region (LCR) of the human b-like globin gene cluster

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    HMG proteins are abundant chromosomal non-histone proteins. It has been suggested that the HMG proteins may play an important role in the structure and function of chromatin. In the present study, the binding of HMG proteins (HMG1/2 and HMG14/17) to the core DNA sequence of DNaseI hypersensitive site 2 (HS2core DNA sequence, -10681--10970 bp) in the locus control region (LCR) of the human b-like globin gene cluster has been examined by using both the in vitro nucleosome reconstitution and the gel mobility shift assays. Here we show that HMG1/2 can bind to the naked HS2core DNA sequence, however, HMG14/17 cannot. Using the in vitro nucleosome reconstitution we demonstrate that HMG14/17 can bind to the HS2core DNA sequence which is assembled into nucleosomes with the core histone octamer transferred from chicken erythrocytes. In contrast, HMG1/2 cannot bind to the nucleosomes reconstituted in vitro with the HS2core DNA sequence. These results indicate that the binding patterns between HMG proteins and the HS2core DNA sequence which exists in different states (the naked DNA or the in vitro reconstituted nucleosomal DNA) are quite different. We speculate that HMG proteins might play a critical role in the regulation of the human b-like globin gene's expression.

  19. Localization of the outer membrane protein OmpA2 in Caulobacter crescentus depends on the position of the gene in the chromosome.

    Science.gov (United States)

    Ginez, Luis David; Osorio, Aurora; Poggio, Sebastian

    2014-08-01

    The outer membrane of Gram-negative bacteria is an essential structure involved in nutrient uptake, protection against harmful substances, and cell growth. Different proteins keep the outer membrane from blebbing out by simultaneously interacting with it and with the cell wall. These proteins have been mainly studied in enterobacteria, where OmpA and the Braun and Pal lipoproteins stabilize the outer membrane. Some degree of functional redundancy exists between these proteins, since none of them is essential but the absence of two of them results in a severe phenotype. Caulobacter crescentus has a different strategy to maintain its outer membrane, since it lacks the Braun lipoprotein and Pal is essential. In this work, we characterized OmpA2, an OmpA-like protein, in this bacterium. Our results showed that this protein is required for normal stalk growth and that it plays a minor role in the stability of the outer membrane. An OmpA2 fluorescent fusion protein showed that the concentration of this protein decreases from the stalk to the new pole. This localization pattern is important for its function, and it depends on the position of the gene locus in the chromosome and, as a consequence, in the cell. This result suggests that little diffusion occurs from the moment that the gene is transcribed until the mature protein attaches to the cell wall in the periplasm. This mechanism reveals the integration of different levels of information from protein function down to genome arrangement that allows the cell to self-organize.

  20. A separable domain of the p150 subunit of human chromatin assembly factor-1 promotes protein and chromosome associations with nucleoli.

    Science.gov (United States)

    Smith, Corey L; Matheson, Timothy D; Trombly, Daniel J; Sun, Xiaoming; Campeau, Eric; Han, Xuemei; Yates, John R; Kaufman, Paul D

    2014-09-15

    Chromatin assembly factor-1 (CAF-1) is a three-subunit protein complex conserved throughout eukaryotes that deposits histones during DNA synthesis. Here we present a novel role for the human p150 subunit in regulating nucleolar macromolecular interactions. Acute depletion of p150 causes redistribution of multiple nucleolar proteins and reduces nucleolar association with several repetitive element-containing loci. Of note, a point mutation in a SUMO-interacting motif (SIM) within p150 abolishes nucleolar associations, whereas PCNA or HP1 interaction sites within p150 are not required for these interactions. In addition, acute depletion of SUMO-2 or the SUMO E2 ligase Ubc9 reduces α-satellite DNA association with nucleoli. The nucleolar functions of p150 are separable from its interactions with the other subunits of the CAF-1 complex because an N-terminal fragment of p150 (p150N) that cannot interact with other CAF-1 subunits is sufficient for maintaining nucleolar chromosome and protein associations. Therefore these data define novel functions for a separable domain of the p150 protein, regulating protein and DNA interactions at the nucleolus.

  1. An N-terminally truncated envelope protein encoded by a human endogenous retrovirus W locus on chromosome Xq22.3

    Directory of Open Access Journals (Sweden)

    Roebke Christina

    2010-08-01

    Full Text Available Abstract Background We previously showed that the envelope (env sequence of a human endogenous retrovirus (HERV-W locus on chromosome Xq22.3 is transcribed in human peripheral blood mononuclear cells. The env open reading frame (ORF of this locus is interrupted by a premature stop at codon 39, but otherwise harbors a long ORF for an N-terminally truncated 475 amino acid Env protein, starting at an in-frame ATG at codon 68. We set out to characterize the protein encoded by that ORF. Results Transient expression of the 475 amino acid Xq22.3 HERV-W env ORF produced an N-terminally truncated HERV-W Env protein, as detected by the monoclonal anti-HERV-W Env antibodies 6A2B2 and 13H5A5. Remarkably, reversion of the stop at codon 39 in Xq22.3 HERV-W env reconstituted a full-length HERV-W Xq22.3 Env protein. Similar to the full-length HERV-W Env protein Syncytin-1, reconstituted full-length Xq22.3 HERV-W Env is glycosylated, forms oligomers, and is expressed at the cell surface. In contrast, Xq22.3 HERV-W Env is unglycosylated, does not form oligomers, and is located intracellularly, probably due to lack of a signal peptide. Finally, we reconfirm by immunohistochemistry that monoclonal antibody 6A2B2 detects an antigen expressed in placenta and multiple sclerosis brain lesions. Conclusions A partially defective HERV-W env gene located on chromosome Xq22.3, which we propose to designate ERVWE2, has retained coding capacity and can produce ex vivo an N-terminally truncated Env protein, named N-Trenv. Detection of an antigen by 6A2B2 in placenta and multiple sclerosis lesions opens the possibility that N-Trenv could be expressed in vivo. More generally, our findings are compatible with the idea that defective HERV elements may be capable of producing incomplete HERV proteins that, speculatively, may exert functions in human physiology or pathology.

  2. Pedigree with frontotemporal lobar degeneration – motor neuron disease and Tar DNA binding protein-43 positive neuropathology: genetic linkage to chromosome 9

    Directory of Open Access Journals (Sweden)

    Loy Clement T

    2008-08-01

    Full Text Available Abstract Background Frontotemporal lobar degeneration (FTLD represents a clinically, pathologically and genetically heterogenous neurodegenerative disorder, often complicated by neurological signs such as motor neuron-related limb weakness, spasticity and paralysis, parkinsonism and gait disturbances. Linkage to chromosome 9p had been reported for pedigrees with the neurodegenerative disorder, frontotemporal lobar degeneration (FTLD and motor neuron disease (MND. The objective in this study is to identify the genetic locus in a multi-generational Australian family with FTLD-MND. Methods Clinical review and standard neuropathological analysis of brain sections from affected pedigree members. Genome-wide scan using microsatellite markers and single nucleotide polymorphism fine mapping. Examination of candidate genes by direct DNA sequencing. Results Neuropathological examination revealed cytoplasmic deposition of the TDP-43 protein in three affected individuals. Moreover, we identify a family member with clinical Alzheimer's disease, and FTLD-Ubiquitin neuropathology. Genetic linkage and haplotype analyses, defined a critical region between markers D9S169 and D9S1845 on chromosome 9p21. Screening of all candidate genes within this region did not reveal any novel genetic alterations that co-segregate with disease haplotype, suggesting that one individual carrying a meiotic recombination may represent a phenocopy. Re-analysis of linkage data using the new affection status revealed a maximal two-point LOD score of 3.24 and a multipoint LOD score of 3.41 at marker D9S1817. This provides the highest reported LOD scores from a single FTLD-MND pedigree. Conclusion Our reported increase in the minimal disease region should inform other researchers that the chromosome 9 locus may be more telomeric than predicted by published recombination boundaries. Moreover, the existence of a family member with clinical Alzheimer's disease, and who shares the disease

  3. Interactions between HMG proteins and the core sequence of DNaseI hypersensitive site 2 in the locus control region (LCR) of the human β-Mike globin gene cluster

    Institute of Scientific and Technical Information of China (English)

    赵晖; 张树冰; 蒋俶; 钱若兰

    2000-01-01

    HMG proteins are abundant chromosomal non-histone proteins. It has been suggested that the HMG proteins may play an important role in the structure and function of chromatin. In the present study, the binding of HMG proteins (HMG1/2 and HMG14/17) to the core DNA sequence of DNasel hypersensitive site 2 (HS2core DNA sequence, -10681-10970 bp) in the locus control region (LCR) of the human β-like globin gene cluster has been examined by using both the in vitro nucleosome reconstitution and the gel mobility shift assays. Here we show that HMG1/2 can bind to the naked HS2core DNA sequence, however, HMG 14/17 cannot. Using the in vitro nucleosome reconstitution we demonstrate that HMG14/17 can bind to the HS2core DNA sequence which is assembled into nucleosomes with the core histone octamer transferred from chicken erythrocytes. In contrast, HMG 1/2 cannot bind to the nucleosomes reconstituted in vitro with the HS2core DNA sequence. These results indicate that the binding patterns between HMG proteins and t

  4. Structural Basis for Dimer Formation of Human Condensin Structural Maintenance of Chromosome Proteins and Its Implications for Single-stranded DNA Recognition.

    Science.gov (United States)

    Uchiyama, Susumu; Kawahara, Kazuki; Hosokawa, Yuki; Fukakusa, Shunsuke; Oki, Hiroya; Nakamura, Shota; Kojima, Yukiko; Noda, Masanori; Takino, Rie; Miyahara, Yuya; Maruno, Takahiro; Kobayashi, Yuji; Ohkubo, Tadayasu; Fukui, Kiichi

    2015-12-01

    Eukaryotic structural maintenance of chromosome proteins (SMC) are major components of cohesin and condensins that regulate chromosome structure and dynamics during cell cycle. We here determine the crystal structure of human condensin SMC hinge heterodimer with ~30 residues of coiled coils. The structure, in conjunction with the hydrogen exchange mass spectrometry analyses, revealed the structural basis for the specific heterodimer formation of eukaryotic SMC and that the coiled coils from two different hinges protrude in the same direction, providing a unique binding surface conducive for binding to single-stranded DNA. The characteristic hydrogen exchange profiles of peptides constituted regions especially across the hinge-hinge dimerization interface, further suggesting the structural alterations upon single-stranded DNA binding and the presence of a half-opened state of hinge heterodimer. This structural change potentially relates to the DNA loading mechanism of SMC, in which the hinge domain functions as an entrance gate as previously proposed for cohesin. Our results, however, indicated that this is not the case for condensins based on the fact that the coiled coils are still interacting with each other, even when DNA binding induces structural changes in the hinge region, suggesting the functional differences of SMC hinge domain between condensins and cohesin in DNA recognition.

  5. Accurate Chromosome Segregation at First Meiotic Division Requires AGO4, a Protein Involved in RNA-Dependent DNA Methylation in Arabidopsis thaliana.

    Science.gov (United States)

    Oliver, Cecilia; Santos, Juan Luis; Pradillo, Mónica

    2016-10-01

    The RNA-directed DNA methylation (RdDM) pathway is important for the transcriptional repression of transposable elements and for heterochromatin formation. Small RNAs are key players in this process by regulating both DNA and histone methylation. Taking into account that methylation underlies gene silencing and that there are genes with meiosis-specific expression profiles, we have wondered whether genes involved in RdDM could play a role during this specialized cell division. To address this issue, we have characterized meiosis progression in pollen mother cells from Arabidopsis thaliana mutant plants defective for several proteins related to RdDM. The most relevant results were obtained for ago4-1 In this mutant, meiocytes display a slight reduction in chiasma frequency, alterations in chromatin conformation around centromeric regions, lagging chromosomes at anaphase I, and defects in spindle organization. These abnormalities lead to the formation of polyads instead of tetrads at the end of meiosis, and might be responsible for the fertility defects observed in this mutant. Findings reported here highlight an involvement of AGO4 during meiosis by ensuring accurate chromosome segregation at anaphase I.

  6. Synthetic chromosomes.

    Science.gov (United States)

    Schindler, Daniel; Waldminghaus, Torsten

    2015-11-01

    What a living organism looks like and how it works and what are its components-all this is encoded on DNA, the genetic blueprint. Consequently, the way to change an organism is to change its genetic information. Since the first pieces of recombinant DNA have been used to transform cells in the 1970s, this approach has been enormously extended. Bigger and bigger parts of the genetic information have been exchanged or added over the years. Now we are at a point where the construction of entire chromosomes becomes a reachable goal and first examples appear. This development leads to fundamental new questions, for example, about what is possible and desirable to build or what construction rules one needs to follow when building synthetic chromosomes. Here we review the recent progress in the field, discuss current challenges and speculate on the appearance of future synthetic chromosomes.

  7. Lactococcus garvieae carries a chromosomally encoded pentapeptide repeat protein that confers reduced susceptibility to quinolones in Escherichia coli producing a cytotoxic effect.

    Science.gov (United States)

    Gibello, Alicia; Díaz de Alba, Paula; Blanco, M Mar; Machuca, Jesus; Cutuli, M Teresa; Rodríguez-Martínez, José Manuel

    2014-09-01

    This study characterises a chromosomal gene of Lactococcus garvieae encoding a pentapeptide repeat protein designated as LgaQnr. This gene has been implicated in reduced susceptibility to quinolones in this bacterium, which is of relevance to both veterinary and human medicine. All of the L. garvieae isolates analysed were positive for the lgaqnr gene. The expression of lgaqnr in Escherichia coli reduced the susceptibility to quinolones, producing an adverse effect. The reduced susceptibility to ciprofloxacin was 16-fold in E. coli ATCC 25922 and 32-fold in E. coli DH10B, compared to the control strains. The minimum inhibitory concentration of nalidixic acid was also increased 4 or 5-fold. The effect of the expression of lgaqnr in E. coli was investigated by electron microscopy and was observed to affect the structure of the cell and the inner membrane of the recombinant cells.

  8. Molecular cloning of a highly conserved mouse and human integral membrane protein (Itm1) and genetic mapping to mouse chromosome 9

    Energy Technology Data Exchange (ETDEWEB)

    Hong, Guizhu; Tylzanowski, P. [Univ. of Antwerp (Belgium); Deleersnijder, W. [N.V. Innogenetics, Ghent (Belgium)] [and others

    1996-02-01

    We have isolated and characterized a novel cDNA coding for a highly hydrophobic protein (B5) from a fetal mouse mandibular condyle cDNA library. The full-length mouse B5 cDNA is 3095 nucleotides long and contains a potential open reading frame coding for a protein of 705 amino acids with a calculated molecular weight of 80.5 kDa. The B5 mRNA is differentially polyadenylated, with the most abundant transcript having a length of 2.7 kb. The human homolog of B5 was isolated from a cDNA testis library. The predicted amino acid sequence of the human B5 is 98.5% identical to that of mouse. The most striking feature of the B5 protein is the presence of numerous (10-14) potential transmembrane domains, characteristic of an integral membrane protein. Similarity searches in public databanks reveal that B5 is 58% similar to the T12A2.2 gene of Caenorhabditis elegans and 60% similar to the STT3 gene of Saccharomyces cerevisiae. Futhermore, the report of an EST sequence (Accession No. Z13858) related to the human B5, but identical to the STT3 gene, indicates that B5 belongs to a larger gene family coding for novel putative transmembrane proteins. This family exhibits a remarkable degree of conservation in different species. The gene for B5, designated Itm1 (Integral membrane protein 1), is located on mouse chromosome 9. 28 refs., 4 figs.

  9. Building bridges within the bacterial chromosome.

    Science.gov (United States)

    Song, Dan; Loparo, Joseph J

    2015-03-01

    All organisms must dramatically compact their genomes to accommodate DNA within the cell. Bacteria use a set of DNA-binding proteins with low sequence specificity called nucleoid-associated proteins (NAPs) to assist in chromosome condensation and organization. By bending or bridging DNA, NAPs also facilitate chromosome segregation and regulate gene expression. Over the past decade, emerging single-molecule and chromosome conformation capture techniques have investigated the molecular mechanisms by which NAPs remodel and organize the bacterial chromosome. In this review we describe how such approaches reveal the biochemical mechanisms of three NAPs that are believed to facilitate DNA bridging: histone-like nucleoid structuring protein (H-NS), ParB, and structural maintenance of chromosomes (SMC). These three proteins form qualitatively different DNA bridges, leading to varied effects on transcription and chromosome segregation.

  10. Bacterial chromosome organization and segregation.

    Science.gov (United States)

    Badrinarayanan, Anjana; Le, Tung B K; Laub, Michael T

    2015-01-01

    If fully stretched out, a typical bacterial chromosome would be nearly 1 mm long, approximately 1,000 times the length of a cell. Not only must cells massively compact their genetic material, but they must also organize their DNA in a manner that is compatible with a range of cellular processes, including DNA replication, DNA repair, homologous recombination, and horizontal gene transfer. Recent work, driven in part by technological advances, has begun to reveal the general principles of chromosome organization in bacteria. Here, drawing on studies of many different organisms, we review the emerging picture of how bacterial chromosomes are structured at multiple length scales, highlighting the functions of various DNA-binding proteins and the impact of physical forces. Additionally, we discuss the spatial dynamics of chromosomes, particularly during their segregation to daughter cells. Although there has been tremendous progress, we also highlight gaps that remain in understanding chromosome organization and segregation.

  11. Silica nanoparticles induce multinucleation through activation of PI3K/Akt/GSK-3β pathway and downregulation of chromosomal passenger proteins in L-02 cells

    Science.gov (United States)

    Geng, Weijia; Li, Yang; Yu, Yongbo; Yu, Yang; Duan, Junchao; Jiang, Lizhen; Li, Qiuling; Sun, Zhiwei

    2016-04-01

    Silica nanoparticles (SNPs) are applicable in various fields due to their unique physicochemical characteristics. However, concerns over their potential adverse effects have been raised. In our previous studies, we reported that SNPs could induce abnormal high incidence of multinucleation. The aim of this study is to further investigate the mechanisms of multinucleation induced by SNPs (68 nm) in human normal liver L-02 cells (L-02 cells). In order to determine the cytotoxicity of SNPs, MTT assay was performed, and the cell viability was decreased in a dose-dependent manner. The intracellular reactive oxygen species (ROS) detected by flow cytometry and multinucleation observed by Giemsa stain showed that ROS generation and rate of multinucleated cells increased after SNPs exposure. N-acetyl-cysteine (NAC), a glutathione precursor against SNP-induced toxicity, was used as a ROS inhibitor to elucidate the relationship between ROS and multinucleation. The presence of NAC resulted in inhibition of both ROS generation and rate of multinucleation. Moreover, Western blot analysis showed that the protein levels of Cdc20, Aurora B, and Survivin were down-regulated, and the PI3K/Akt/GSK-3β pathway was activated by SNPs. In conclusion, our findings strongly suggested that multinucleation induced by SNPs was related to PI3K/Akt/GSK-3β signal pathway activation and downregulation of G2/M phase-related protein and chromosomal passenger proteins.

  12. Sex chromosome rearrangements in Polyphaga beetles.

    Science.gov (United States)

    Dutrillaux, A M; Dutrillaux, B

    2009-01-01

    The presence of a parachute sex chromosome bivalent (Xyp) at metaphase I of male meiosis is a well-known characteristic of Coleoptera, present in almost all families of this order and assumed to represent their ancestral sex chromosome formula. Sex chromosomes appear to be manifold more frequently involved in inter-chromosomal rearrangements than the average of the nine autosomal pairs usually forming their karyotype. This leads to various formulae such as neo-sex, multiple sex and perhaps unique sex chromosomes. These rearrangements alter the intimate association between sex chromosomes and nucleolar proteins, which are usual components of the Xyp. Different situations, selected in a series of 125 mitotic and meiotic cytogenetic studies of Polyphaga beetle species, are reported and discussed, with the aim to improve our knowledge on the mechanisms of sex chromosome rearrangements, the relationships with nucleoli and the consequences on dosage compensation and chromosome segregation.

  13. Chromosome Analysis

    Science.gov (United States)

    1998-01-01

    Perceptive Scientific Instruments, Inc., provides the foundation for the Powergene line of chromosome analysis and molecular genetic instrumentation. This product employs image processing technology from NASA's Jet Propulsion Laboratory and image enhancement techniques from Johnson Space Center. Originally developed to send pictures back to earth from space probes, digital imaging techniques have been developed and refined for use in a variety of medical applications, including diagnosis of disease.

  14. Assignment of the human gene for pregnancy-associated plasma protein A (PAPPA) to 9q33.1 by fluorescence in situ hybridization to mitotic and meiotic chromosomes

    DEFF Research Database (Denmark)

    Silahtaroglu, A N; Tümer, Z; Kristensen, Torsten;

    1993-01-01

    Low levels of pregnancy-associated plasma protein A (PAPPA) during the first trimester has been suggested as a biochemical indicator of pregnancies with aneuploid fetuses. Furthermore, the complete absence of PAPPA in pregnancies associated with Cornelia de Lange syndrome (CL) has suggested a cau...... a causal connection between PAPPA and the development of CL. We have assigned the locus for PAPPA to chromosome region 9q33.1 on mitotic and meiotic chromosomes by fluorescence in situ hybridization, using a 3.7-kb partial PAPPA cDNA probe...

  15. Entropy as the driver of chromosome segregation.

    Science.gov (United States)

    Jun, Suckjoon; Wright, Andrew

    2010-08-01

    We present a new physical biology approach to understanding the relationship between the organization and segregation of bacterial chromosomes. We posit that replicated Escherichia coli daughter strands will spontaneously demix as a result of entropic forces, despite their strong confinement within the cell; in other words, we propose that entropy can act as a primordial physical force which drives chromosome segregation under the right physical conditions. Furthermore, proteins implicated in the regulation of chromosome structure and segregation may in fact function primarily in supporting such an entropy-driven segregation mechanism by regulating the physical state of chromosomes. We conclude that bacterial chromosome segregation is best understood in terms of spontaneous demixing of daughter strands. Our concept may also have important implications for chromosome segregation in eukaryotes, in which spindle-dependent chromosome movement follows an extended period of sister chromatid demixing and compaction.

  16. Generation of a Stable Transgenic Swine Model Expressing a Porcine Histone 2B-eGFP Fusion Protein for Cell Tracking and Chromosome Dynamics Studies

    Science.gov (United States)

    Simpson, Sean; Collins, Bruce; Sommer, Jeff; Petters, Robert M.; Caballero, Ignacio; Platt, Jeff L.

    2017-01-01

    Transgenic pigs have become an attractive research model in the field of translational research, regenerative medicine, and stem cell therapy due to their anatomic, genetic and physiological similarities with humans. The development of fluorescent proteins as molecular tags has allowed investigators to track cell migration and engraftment levels after transplantation. Here we describe the development of two transgenic pig models via SCNT expressing a fusion protein composed of eGFP and porcine Histone 2B (pH2B). This fusion protein is targeted to the nucleosomes resulting a nuclear/chromatin eGFP signal. The first model (I) was generated via random insertion of pH2B-eGFP driven by the CAG promoter (chicken beta actin promoter and rabbit Globin poly A; pCAG-pH2B-eGFP) and protected by human interferon-β matrix attachment regions (MARs). Despite the consistent, high, and ubiquitous expression of the fusion protein pH2B-eGFP in all tissues analyzed, two independently generated Model I transgenic lines developed neurodegenerative symptoms including Wallerian degeneration between 3–5 months of age, requiring euthanasia. A second transgenic model (II) was developed via CRISPR-Cas9 mediated homology-directed repair (HDR) of IRES-pH2B-eGFP into the endogenous β-actin (ACTB) locus. Model II transgenic animals showed ubiquitous expression of pH2B-eGFP on all tissues analyzed. Unlike the pCAG-pH2B-eGFP/MAR line, all Model II animals were healthy and multiple pregnancies have been established with progeny showing the expected Mendelian ratio for the transmission of the pH2B-eGFP. Expression of pH2B-eGFP was used to examine the timing of the maternal to zygotic transition after IVF, and to examine chromosome segregation of SCNT embryos. To our knowledge this is the first viable transgenic pig model with chromatin-associated eGFP allowing both cell tracking and the study of chromatin dynamics in a large animal model. PMID:28081156

  17. Deciphering evolutionary strata on plant sex chromosomes and fungal mating-type chromosomes through compositional segmentation.

    Science.gov (United States)

    Pandey, Ravi S; Azad, Rajeev K

    2016-03-01

    Sex chromosomes have evolved from a pair of homologous autosomes which differentiated into sex determination systems, such as XY or ZW system, as a consequence of successive recombination suppression between the gametologous chromosomes. Identifying the regions of recombination suppression, namely, the "evolutionary strata", is central to understanding the history and dynamics of sex chromosome evolution. Evolution of sex chromosomes as a consequence of serial recombination suppressions is well-studied for mammals and birds, but not for plants, although 48 dioecious plants have already been reported. Only two plants Silene latifolia and papaya have been studied until now for the presence of evolutionary strata on their X chromosomes, made possible by the sequencing of sex-linked genes on both the X and Y chromosomes, which is a requirement of all current methods that determine stratum structure based on the comparison of gametologous sex chromosomes. To circumvent this limitation and detect strata even if only the sequence of sex chromosome in the homogametic sex (i.e. X or Z chromosome) is available, we have developed an integrated segmentation and clustering method. In application to gene sequences on the papaya X chromosome and protein-coding sequences on the S. latifolia X chromosome, our method could decipher all known evolutionary strata, as reported by previous studies. Our method, after validating on known strata on the papaya and S. latifolia X chromosome, was applied to the chromosome 19 of Populus trichocarpa, an incipient sex chromosome, deciphering two, yet unknown, evolutionary strata. In addition, we applied this approach to the recently sequenced sex chromosome V of the brown alga Ectocarpus sp. that has a haploid sex determination system (UV system) recovering the sex determining and pseudoautosomal regions, and then to the mating-type chromosomes of an anther-smut fungus Microbotryum lychnidis-dioicae predicting five strata in the non

  18. Chromosomal localization of mitochondrial transcription factor A (TCF6), single-stranded DNA-binding protein (SSBP), and endonuclease G (ENDOG), three human housekeeping genes involving in mitochondrial biogenesis

    Energy Technology Data Exchange (ETDEWEB)

    Tiranti, V.; Rossi, G.; DiDonato, S. [Istituto Nazionale Neurologico, Carlo Besta (Italy)] [and others

    1995-01-20

    By using a PCR-based screening of a somatic cell hybrid panel and FISH, we have assigned the loci of mitochondrial single-stranded DNA-binding protein (SSBP), mitochondrial transcription factor A (TCF6), and mitochondrial endonuclease G (ENDOG) genes to human chromosomes 7q34, 10q21, and 9q34.1, respectively. The products of these three genes are involved in fundamental aspects of mitochondrial biogenesis, such as replication and transcription of the mitochondrial genome. The chromosomal localization of these genes is important to testing whether the corresponding proteins may play a role in the etiopathogenesis of human disorders associated with qualitative or quantitative abnormalities of mitochondrial DNA. 20 refs., 1 fig., 2 tabs.

  19. Global analysis of lysine acetylation suggests the involvement of protein acetylation in diverse biological processes in rice (Oryza sativa.

    Directory of Open Access Journals (Sweden)

    Babi Ramesh Reddy Nallamilli

    Full Text Available Lysine acetylation is a reversible, dynamic protein modification regulated by lysine acetyltransferases and deacetylases. Recent advances in high-throughput proteomics have greatly contributed to the success of global analysis of lysine acetylation. A large number of proteins of diverse biological functions have been shown to be acetylated in several reports in human cells, E.coli, and dicot plants. However, the extent of lysine acetylation in non-histone proteins remains largely unknown in monocots, particularly in the cereal crops. Here we report the mass spectrometric examination of lysine acetylation in rice (Oryza sativa. We identified 60 lysine acetylated sites on 44 proteins of diverse biological functions. Immunoblot studies further validated the presence of a large number of acetylated non-histone proteins. Examination of the amino acid composition revealed substantial amino acid bias around the acetylation sites and the amino acid preference is conserved among different organisms. Gene ontology analysis demonstrates that lysine acetylation occurs in diverse cytoplasmic, chloroplast and mitochondrial proteins in addition to the histone modifications. Our results suggest that lysine acetylation might constitute a regulatory mechanism for many proteins, including both histones and non-histone proteins of diverse biological functions.

  20. GSK-3 inhibitors induce chromosome instability

    Directory of Open Access Journals (Sweden)

    Staples Oliver D

    2007-08-01

    Full Text Available Abstract Background Several mechanisms operate during mitosis to ensure accurate chromosome segregation. However, during tumour evolution these mechanisms go awry resulting in chromosome instability. While several lines of evidence suggest that mutations in adenomatous polyposis coli (APC may promote chromosome instability, at least in colon cancer, the underlying mechanisms remain unclear. Here, we turn our attention to GSK-3 – a protein kinase, which in concert with APC, targets β-catenin for proteolysis – and ask whether GSK-3 is required for accurate chromosome segregation. Results To probe the role of GSK-3 in mitosis, we inhibited GSK-3 kinase activity in cells using a panel of small molecule inhibitors, including SB-415286, AR-A014418, 1-Azakenpaullone and CHIR99021. Analysis of synchronised HeLa cells shows that GSK-3 inhibitors do not prevent G1/S progression or cell division. They do, however, significantly delay mitotic exit, largely because inhibitor-treated cells have difficulty aligning all their chromosomes. Although bipolar spindles form and the majority of chromosomes biorient, one or more chromosomes often remain mono-oriented near the spindle poles. Despite a prolonged mitotic delay, anaphase frequently initiates without the last chromosome aligning, resulting in chromosome non-disjunction. To rule out the possibility of "off-target" effects, we also used RNA interference to selectively repress GSK-3β. Cells deficient for GSK-3β exhibit a similar chromosome alignment defect, with chromosomes clustered near the spindle poles. GSK-3β repression also results in cells accumulating micronuclei, a hallmark of chromosome missegregation. Conclusion Thus, not only do our observations indicate a role for GSK-3 in accurate chromosome segregation, but they also raise the possibility that, if used as therapeutic agents, GSK-3 inhibitors may induce unwanted side effects by inducing chromosome instability.

  1. Stable expression of human H1-histamine-receptor cDNA in Chinese hamster ovary cells. Pharmacological characterisation of the protein, tissue distribution of messenger RNA and chromosomal localisation of the gene.

    Science.gov (United States)

    Moguilevsky, N; Varsalona, F; Noyer, M; Gillard, M; Guillaume, J P; Garcia, L; Szpirer, C; Szpirer, J; Bollen, A

    1994-09-01

    A cDNA clone for the histamine H1 receptor was isolated from a human lung cDNA library; it encoded a protein of 487 amino acids which showed characteristic features of G-protein-coupled receptors. The percentages of identity of the deduced amino acid sequence with bovine, rat and guinea pig H1 histamine receptors were 82.6%, 79.4% and 73.3%, respectively, whereas these percentages decreased to 74.6%, 66% and 56.7% for the amino acid sequence of the third intracellular loop. The human H1-receptor cDNA was transfected into Chinese hamster ovary cells (CHO) via an eukaryotic expression vector; the receptor protein present on cell membranes specifically bound [3H]mepyramine with a Kd of 3.7 nM. The binding was displaced by H1-histamine-receptor antagonists and histamine. Northern blot analysis indicated the presence of two histamine H1 receptor mRNAs of 3.5 kb and 4.1 kb in various human tissues and an additional mRNA of 4.8 kb restricted to the human brain. Finally, by means of somatic cell hybrids segregating either human or rat chromosomes, the gene for histamine H1 receptor was found to reside on human chromosome 3 and rat chromosome 4.

  2. Genome architecture: domain organization of interphase chromosomes.

    Science.gov (United States)

    Bickmore, Wendy A; van Steensel, Bas

    2013-03-14

    The architecture of interphase chromosomes is important for the regulation of gene expression and genome maintenance. Chromosomes are linearly segmented into hundreds of domains with different protein compositions. Furthermore, the spatial organization of chromosomes is nonrandom and is characterized by many local and long-range contacts among genes and other sequence elements. A variety of genome-wide mapping techniques have made it possible to chart these properties at high resolution. Combined with microscopy and computational modeling, the results begin to yield a more coherent picture that integrates linear and three-dimensional (3D) views of chromosome organization in relation to gene regulation and other nuclear functions.

  3. Sequence analysis of a 13.4 kbp fragment from the left arm of chromosome XV reveals a malate dehydrogenase gene, a putative Ser/Thr protein kinase, the ribosomal L25 gene and four new open reading frames.

    Science.gov (United States)

    Casamayor, A; Khalid, H; Balcells, L; Aldea, M; Casas, C; Herrero, E; Ariño, J

    1996-09-01

    A 13421 bp fragment located near the left telomere of chromosome XV (cosmid pEOA461) has been sequenced. Seven non-overlapping open reading frames (ORFs) encoding polypeptides longer than 100 residues have been found (AOB859, AOC184, AOE375, AOX142i, AOE423, AOA476 and AOE433). An additional ORF (AOE131) is found within AOA476. Three of them (AOC184, AOA476 and AOE433) show no remarkable identity with proteins deposited in the data banks. ORF AOB859 is quite similar to a hypothetical yeast protein of similar size located in chromosome VI, particularly within the C-terminal half. AOE375 encodes a new member of the glycogen synthase kinase-3 subfamily of Ser/Thr protein kinases. AOX142i is the gene encoding the previously described ribosomal protein L25. AOE423 codes for a protein virtually identical to the MDH2 malate dehydrogenase isozyme. However, our DNA sequence shows a single one-base insertion upstream of the reported initiating codon. This would produce a larger ORF by extending 46 residues the N-terminus of the protein. The existence of this insertion has been confirmed in three different yeast strains, including FY1679.

  4. Inherited variants in the inner centromere protein (INCENP) gene of the chromosomal passenger complex contribute to the susceptibility of ER-negative breast cancer

    NARCIS (Netherlands)

    M. Kabisch (Maria); J.L. Bermejo (Justo Lorenzo); T. Dun̈nebier (Thomas); S. Ying (Shibo); K. Michailidou (Kyriaki); M.K. Bolla (Manjeet); Q. Wang (Qing); J. Dennis (Joe); M. Shah (Mitul); B. Perkins (Barbara); K. Czene (Kamila); H. Darabi (Hatef); M. Eriksson (Mikael); S.E. Bojesen (Stig); B.G. Nordestgaard (Børge); S.F. Nielsen (Sune); H. Flyger (Henrik); D. Lambrechts (Diether); P. Neven (Patrick); S.T.H. Peeters (Stephanie); C. Weltens (Caroline); F.J. Couch (Fergus); J.E. Olson (Janet); X. Wang (Xianshu); K. Purrington (Kristen); J. Chang-Claude (Jenny); A. Rudolph (Anja); P. Seibold (Petra); D. Flesch-Janys (Dieter); J. Peto (Julian); I. dos Santos Silva (Isabel); N. Johnson (Nichola); O. Fletcher (Olivia); H. Nevanlinna (Heli); T.A. Muranen (Taru); K. Aittomäki (Kristiina); C. Blomqvist (Carl); M.K. Schmidt (Marjanka); A. Broeks (Annegien); S. Cornelissen (Sten); F.B.L. Hogervorst (Frans); J. Li (Jingmei); J.S. Brand (Judith S.); M.K. Humphreys (Manjeet); P. Guénel (Pascal); T. Truong (Thérèse); F. Menegaux (Florence); M. Sanchez (Marie); B. Burwinkel (Barbara); F. Marme (Federick); R. Yang (Rongxi); P. Bugert (Peter); A. González-Neira (Anna); J. Benítez (Javier); M.P. Zamora (Pilar); J.I. Arias Pérez (José Ignacio); A. Cox (Angela); S.S. Cross (Simon); M.W.R. Reed (Malcolm); I.L. Andrulis (Irene); J.A. Knight (Julia); G. Glendon (Gord); S. Tchatchou (Sandrine); E.J. Sawyer (Elinor); I.P. Tomlinson (Ian); M. Kerin (Michael); N. Miller (Nicola); C.A. Haiman (Christopher); F.R. Schumacher (Fredrick); B.E. Henderson (Brian); L. Le Marchand (Loic); A. Lindblom (Annika); S. Margolin (Sara); M.J. Hooning (Maartje); A. Hollestelle (Antoinette); M. Kriege (Mieke); L.B. Koppert (Linetta); J. Hopper (John); M.C. Southey (Melissa); H. Tsimiklis (Helen); C. Apicella (Carmel); S. Slettedahl (Seth); A.E. Toland (Amanda); C. Vachon (Celine); D. Yannoukakos (Drakoulis); G.G. Giles (Graham); R.L. Milne (Roger); C.A. McLean (Catriona Ann); P.A. Fasching (Peter); M. Ruebner (Matthias); A.B. Ekici (Arif); M.W. Beckmann (Matthias); H. Brenner (Hermann); A.K. Dieffenbach (Aida Karina); V. Arndt (Volker); C. Stegmaier (Christa); A. Ashworth (Alan); N. Orr (Nick); M. Schoemaker (Minouk); A.J. Swerdlow (Anthony ); M. García-Closas (Montserrat); J.D. Figueroa (Jonine); S.J. Chanock (Stephen); J. Lissowska (Jolanta); M.S. Goldberg (Mark); F. Labrèche (France); M. Dumont (Martine); R. Winqvist (Robert); K. Pykäs (Katri); A. Jukkola-Vuorinen (Arja); M. Grip (Mervi); H. Brauch (Hiltrud); T. Brüning (Thomas); Y-D. Ko (Yon-Dschun); P. Radice (Paolo); P. Peterlongo (Paolo); G. Scuvera (Giulietta); S. Fortuzzi (S.); N.V. Bogdanova (Natalia); T. Dörk (Thilo); A. Mannermaa (Arto); V. Kataja (Vesa); V-M. Kosma (Veli-Matti); J.M. Hartikainen (J.); P. Devilee (Peter); R.A.M. Tollenaar (Robert A.M.); C.M. Seynaeve (Caroline); C.J. van Asperen (Christi); A. Jakubowska (Anna); J. Lubinski (Jan); K. Jaworska-Bieniek (Katarzyna); K. Durda (Katarzyna); W. Zheng (Wei); M. Shrubsole (Martha); Q. Cai (Qiuyin); D. Torres (Diana); H. Anton-Culver (Hoda); V. Kristensen (Vessela); F. Bacot (Francois); D.C. Tessier (Daniel C.); D. Vincent (Daniel); C. Luccarini (Craig); C. Baynes (Caroline); S. Ahmed (Shahana); M. Maranian (Melanie); J. Simard (Jacques); G. Chenevix-Trench (Georgia); P. Hall (Per); P.D.P. Pharoah (Paul); A.M. Dunning (Alison); D.F. Easton (Douglas); U. Hamann (Ute)

    2014-01-01

    textabstractThe chromosomal passenger complex (CPC) plays a pivotal role in the regulation of cell division. Therefore, inherited CPC variability could influence tumor development. The present candidate gene approach investigates the relationship between single nucleotide polymorphisms (SNPs) in gen

  5. Inherited variants in the inner centromere protein (INCENP) gene of the chromosomal passenger complex contribute to the susceptibility of ER-negative breast cancer

    DEFF Research Database (Denmark)

    Kabisch, Maria; Lorenzo Bermejo, Justo; Dünnebier, Thomas

    2015-01-01

    The chromosomal passenger complex (CPC) plays a pivotal role in the regulation of cell division. Therefore, inherited CPC variability could influence tumor development. The present candidate gene approach investigates the relationship between single nucleotide polymorphisms (SNPs) in genes encodi...

  6. Mechanisms of Chromosome Congression during Mitosis

    Science.gov (United States)

    Maiato, Helder; Gomes, Ana Margarida; Sousa, Filipe; Barisic, Marin

    2017-01-01

    Chromosome congression during prometaphase culminates with the establishment of a metaphase plate, a hallmark of mitosis in metazoans. Classical views resulting from more than 100 years of research on this topic have attempted to explain chromosome congression based on the balance between opposing pulling and/or pushing forces that reach an equilibrium near the spindle equator. However, in mammalian cells, chromosome bi-orientation and force balance at kinetochores are not required for chromosome congression, whereas the mechanisms of chromosome congression are not necessarily involved in the maintenance of chromosome alignment after congression. Thus, chromosome congression and maintenance of alignment are determined by different principles. Moreover, it is now clear that not all chromosomes use the same mechanism for congressing to the spindle equator. Those chromosomes that are favorably positioned between both poles when the nuclear envelope breaks down use the so-called “direct congression” pathway in which chromosomes align after bi-orientation and the establishment of end-on kinetochore-microtubule attachments. This favors the balanced action of kinetochore pulling forces and polar ejection forces along chromosome arms that drive chromosome oscillatory movements during and after congression. The other pathway, which we call “peripheral congression”, is independent of end-on kinetochore microtubule-attachments and relies on the dominant and coordinated action of the kinetochore motors Dynein and Centromere Protein E (CENP-E) that mediate the lateral transport of peripheral chromosomes along microtubules, first towards the poles and subsequently towards the equator. How the opposite polarities of kinetochore motors are regulated in space and time to drive congression of peripheral chromosomes only now starts to be understood. This appears to be regulated by position-dependent phosphorylation of both Dynein and CENP-E and by spindle microtubule

  7. Mechanisms of Chromosome Congression during Mitosis

    Directory of Open Access Journals (Sweden)

    Helder Maiato

    2017-02-01

    Full Text Available Chromosome congression during prometaphase culminates with the establishment of a metaphase plate, a hallmark of mitosis in metazoans. Classical views resulting from more than 100 years of research on this topic have attempted to explain chromosome congression based on the balance between opposing pulling and/or pushing forces that reach an equilibrium near the spindle equator. However, in mammalian cells, chromosome bi-orientation and force balance at kinetochores are not required for chromosome congression, whereas the mechanisms of chromosome congression are not necessarily involved in the maintenance of chromosome alignment after congression. Thus, chromosome congression and maintenance of alignment are determined by different principles. Moreover, it is now clear that not all chromosomes use the same mechanism for congressing to the spindle equator. Those chromosomes that are favorably positioned between both poles when the nuclear envelope breaks down use the so-called “direct congression” pathway in which chromosomes align after bi-orientation and the establishment of end-on kinetochore-microtubule attachments. This favors the balanced action of kinetochore pulling forces and polar ejection forces along chromosome arms that drive chromosome oscillatory movements during and after congression. The other pathway, which we call “peripheral congression”, is independent of end-on kinetochore microtubule-attachments and relies on the dominant and coordinated action of the kinetochore motors Dynein and Centromere Protein E (CENP-E that mediate the lateral transport of peripheral chromosomes along microtubules, first towards the poles and subsequently towards the equator. How the opposite polarities of kinetochore motors are regulated in space and time to drive congression of peripheral chromosomes only now starts to be understood. This appears to be regulated by position-dependent phosphorylation of both Dynein and CENP-E and by spindle

  8. The implication and potential applications of high-mobility group box 1 protein in breast cancer.

    Science.gov (United States)

    Sohun, Moonindranath; Shen, Huiling

    2016-06-01

    High-mobility group box 1 protein (HMGB1) is a highly conserved, non-histone and ubiquitous chromosomal protein found enriched in active chromatin forming part of the high mobility group family of proteins and is encoded by the HMGB1 gene (13q12) in human beings. It has various intranuclear and extracellular functions. It plays an important role in the pathogenesis of many diseases including cancer. In 2012, there was approximately 1.67 million new breast cancer cases diagnosed which makes it the second most frequent cancer in the world after lung cancer (25% of all cancers) and the commonest cancer among women. Both pre-clinical and clinical studies have suggested that HMGB1 might be a useful target in the management of breast cancer. This review summarises the structure and functions of HMGB1 and its dual role in carcinogenesis both as a pro-tumorigenic and anti-tumorigenic factor. It also sums up evidence from in vitro and in vivo studies using breast cancer cell lines and samples which demonstrate its influence in radiotherapy, chemotherapy and hormonal therapy in breast cancer. It may have particular importance in HER2 positive and metastatic breast cancer. It might pave the way for new breast cancer treatments through development of novel drugs, use of microRNAs (miRNAs), targeting breast cancer stem cells (CSCs) and breast cancer immunotherapy. It may also play a role in determining breast cancer prognosis. Thus HMGB1 may open up novel avenues in breast cancer management.

  9. SMC complexes in bacterial chromosome condensation and segregation.

    Science.gov (United States)

    Strunnikov, Alexander V

    2006-03-01

    Bacterial chromosomes segregate via a partition apparatus that employs a score of specialized proteins. The SMC complexes play a crucial role in the chromosome partitioning process by organizing bacterial chromosomes through their ATP-dependent chromatin-compacting activity. Recent progress in the composition of these complexes and elucidation of their structural and enzymatic properties has advanced our comprehension of chromosome condensation and segregation mechanics in bacteria.

  10. SMC complexes in bacterial chromosome condensation and segregation

    OpenAIRE

    Strunnikov, Alexander V.

    2005-01-01

    Bacterial chromosomes segregate via a partition apparatus that employs a score of specialized proteins. The SMC complexes play a crucial role in the chromosome partitioning process by organizing bacterial chromosomes through their ATP-dependent chromatin-compacting activity. Recent progress in the composition of these complexes and elucidation of their structural and enzymatic properties has advanced our comprehension of chromosome condensation and segregation mechanics in bacteria.

  11. Undetected sex chromosome aneuploidy by chromosomal microarray.

    Science.gov (United States)

    Markus-Bustani, Keren; Yaron, Yuval; Goldstein, Myriam; Orr-Urtreger, Avi; Ben-Shachar, Shay

    2012-11-01

    We report on a case of a female fetus found to be mosaic for Turner syndrome (45,X) and trisomy X (47,XXX). Chromosomal microarray analysis (CMA) failed to detect the aneuploidy because of a normal average dosage of the X chromosome. This case represents an unusual instance in which CMA may not detect chromosomal aberrations. Such a possibility should be taken into consideration in similar cases where CMA is used in a clinical setting.

  12. Dissecting the genetic basis for the effect of rice chalkiness, amylose content, protein content, and rapid viscosity analyzer profile characteristics on the eating quality of cooked rice using the chromosome segment substitution line population across eight environments.

    Science.gov (United States)

    Liu, Xiaolu; Wan, Xiangyuan; Ma, Xiaodong; Wan, Jianmin

    2011-01-01

    Quantitative trait locus (QTL) mapping and stability analysis were carried out for 16 rice (Oryza sativa L.) quality traits across eight environments, by using a set of chromosome segment substitution lines with 'Asominori' as genetic background. The 16 quality traits include percentage of grain with chalkiness (PGWC), area of chalky endosperm (ACE), amylose content (AC), protein content (PC), peak viscosity, hot paste viscosity, cool paste viscosity, breakdown viscosity (BDV), setback viscosity (SBV), consistency viscosity, cooked-rice luster (LT), scent, tenderness (TD), viscosity, elasticity, and the integrated values of organleptic evaluation (IVOE). A total of 132 additive effect QTLs are detected for the 16 quality straits in the eight environments. Among these QTLs, 56 loci were detected repeatedly in at least three environments. Interestingly, several QTL clusters were observed for multiple quality traits. Especially, one QTL cluster near the G1149 marker on chromosome 8 includes nine QTLs: qPGWC-8, qACE-8, qAC-8, qPC-8a, qBDV-8a, qSBV-8b, qLT-8a, qTD-8a, and qIVOE-8a, which control PGWC, ACE, AC, PC, BDV, SBV, LT, TD, and IVOE, respectively. Moreover, this QTL cluster shows high stability and repeatability in all eight environments. In addition, one QTL cluster was located near the C2340 marker on chromosome 1 and another was detected near the XNpb67 marker on chromosome 2; each cluster contained five loci. Near the C563 marker on chromosome 3, one QTL cluster with four loci was found. Also, there were nine QTL clusters that each had two or three loci; however, their repeatability in different environments was relatively lower, and the genetic contribution rate was relatively smaller. Considering the correlations among all of the 16 quality traits with QTL cluster distributions, we can conclude that the stable and major QTL cluster on chromosome 8 is the main genetic basis for the effect of rice chalkiness, AC, PC, and rapid viscosity analyzer profile

  13. Chromosomal localization and molecular marker development of the lipopolysaccharide and beta-1,3-glucan binding protein gene in the Zhikong scallop Chlamys farreri (Jones et Preston (Pectinoida, Pectinidae

    Directory of Open Access Journals (Sweden)

    Pin Huan

    2010-01-01

    Full Text Available Zhikong scallop Chlamys farreri (Jones et Preston is an economically important species in China. Understanding its immune system would be of great help in controlling diseases. In the present study, an important immunity-related gene, the Lipopolysaccharide and Beta-1,3-glucan Binding Protein (LGBP gene, was located on C. farreri chromosomes by mapping several lgbp-containing BAC clones through fluorescence in situ hybridization (FISH. Through the localization of various BAC clones, it was shown that only one locus of this gene existed in the genome of C. farreri, and that this was located on the long arm of a pair of homologous chromosomes. Molecular markers, consisting of eight single nucleotide polymorphism (SNPs markers and one insertion-deletion (indel, were developed from the LGBP gene. Indel marker testing in an F1 family revealed slightly distorted segregation (p = 0.0472. These markers can be used to map the LGBP gene to the linkage map and assign the linkage group to the corresponding chromosome. Segregation distortion of the indel marker indicated genes with deleterious alleles might exist in the surrounding region of the LGBP gene.

  14. Silencing expression of the catalytic subunit of DNA-dependent protein kinase by small interfering RNA sensitizes human cells for radiation-induced chromosome damage, cell killing, and mutation

    Science.gov (United States)

    Peng, Yuanlin; Zhang, Qinming; Nagasawa, Hatsumi; Okayasu, Ryuichi; Liber, Howard L.; Bedford, Joel S.

    2002-01-01

    Targeted gene silencing in mammalian cells by RNA interference (RNAi) using small interfering RNAs (siRNAs) was recently described by Elbashir et al. (S. M. Elbashir et al., Nature (Lond.), 411: 494-498, 2001). We have used this methodology in several human cell strains to reduce expression of the Prkdc (DNA-PKcs) gene coding for the catalytic subunit of the DNA-dependent protein kinase (DNA-PKcs) that is involved in the nonhomologous end joining of DNA double-strand breaks. We have also demonstrated a radiosensitization for several phenotypic endpoints of radiation damage. In low-passage normal human fibroblasts, siRNA knock-down of DNA-PKcs resulted in a reduced capacity for restitution of radiation-induced interphase chromosome breaks as measured by premature chromosome condensation, an increased yield of acentric chromosome fragments at the first postirradiation mitosis, and an increased radiosensitivity for cell killing. For three strains of related human lymphoblasts, DNA-PKcs-targeted siRNA transfection resulted in little or no increase in radiosensitivity with respect to cell killing, a 1.5-fold decrease in induced mutant yield in TK6- and p53-null NH32 cells, but about a 2-fold increase in induced mutant yield in p53-mutant WTK1 cells at both the hypoxanthine quanine phosphoribosyl transferase (hprt) and the thymidine kinase loci.

  15. Chromosome Disorder Outreach

    Science.gov (United States)

    ... BLOG Join Us Donate You are not alone. Chromosome Disorder Outreach, Inc. is a non-profit organization, ... Support For all those diagnosed with any rare chromosome disorder. Since 1992, CDO has supported the parents ...

  16. Shaping mitotic chromosomes: From classical concepts to molecular mechanisms.

    Science.gov (United States)

    Kschonsak, Marc; Haering, Christian H

    2015-07-01

    How eukaryotic genomes are packaged into compact cylindrical chromosomes in preparation for cell divisions has remained one of the major unsolved questions of cell biology. Novel approaches to study the topology of DNA helices inside the nuclei of intact cells, paired with computational modeling and precise biomechanical measurements of isolated chromosomes, have advanced our understanding of mitotic chromosome architecture. In this Review Essay, we discuss - in light of these recent insights - the role of chromatin architecture and the functions and possible mechanisms of SMC protein complexes and other molecular machines in the formation of mitotic chromosomes. Based on the information available, we propose a stepwise model of mitotic chromosome condensation that envisions the sequential generation of intra-chromosomal linkages by condensin complexes in the context of cohesin-mediated inter-chromosomal linkages, assisted by topoisomerase II. The described scenario results in rod-shaped metaphase chromosomes ready for their segregation to the cell poles.

  17. Selective interactions between vertebrate polycomb homologs and the SUV39H1 histone lysine methyltransferase suggest that histone H3-K9 methylation contributes to chromosomal targeting of Polycomb group proteins.

    Science.gov (United States)

    Sewalt, Richard G A B; Lachner, Monika; Vargas, Mark; Hamer, Karien M; den Blaauwen, Jan L; Hendrix, Thijs; Melcher, Martin; Schweizer, Dieter; Jenuwein, Thomas; Otte, Arie P

    2002-08-01

    Polycomb group (PcG) proteins form multimeric chromatin-associated protein complexes that are involved in heritable repression of gene activity. Two distinct human PcG complexes have been characterized. The EED/EZH2 PcG complex utilizes histone deacetylation to repress gene activity. The HPC/HPH PcG complex contains the HPH, RING1, BMI1, and HPC proteins. Here we show that vertebrate Polycomb homologs HPC2 and XPc2, but not M33/MPc1, interact with the histone lysine methyltransferase (HMTase) SUV39H1 both in vitro and in vivo. We further find that overexpression of SUV39H1 induces selective nuclear relocalization of HPC/HPH PcG proteins but not of the EED/EZH2 PcG proteins. This SUV39H1-dependent relocalization concentrates the HPC/HPH PcG proteins to the large pericentromeric heterochromatin domains (1q12) on human chromosome 1. Within these PcG domains we observe increased H3-K9 methylation. Finally, we show that H3-K9 HMTase activity is associated with endogenous HPC2. Our findings suggest a role for the SUV39H1 HMTase and histone H3-K9 methylation in the targeting of human HPC/HPH PcG proteins to modified chromatin structures.

  18. Chromosome painting in plants.

    NARCIS (Netherlands)

    Schubert, I.; Fransz, P.F.; Fuchs, J.; Jong, de J.H.

    2001-01-01

    The current 'state-of-art' as to chromosome painting in plants is reviewed. We define different situations described as painting so far: i) Genomic in situ hybridisation (GISH) with total genomic DNA to distinguish alien chromosomes on the basis of divergent dispersed repeats, ii) 'Chromosomal in si

  19. ZEBRAFISH CHROMOSOME-BANDING

    NARCIS (Netherlands)

    PIJNACKER, LP; FERWERDA, MA

    1995-01-01

    Banding techniques were carried out on metaphase chromosomes of zebrafish (Danio rerio) embryos. The karyotypes with the longest chromosomes consist of 12 metacentrics, 26 submetacentrics, and 12 subtelocentrics (2n = 50). All centromeres are C-band positive. Eight chromosomes have a pericentric C-b

  20. Condensin-Based Chromosome Organization from Bacteria to Vertebrates.

    Science.gov (United States)

    Hirano, Tatsuya

    2016-02-25

    Condensins are large protein complexes that play a central role in chromosome organization and segregation in the three domains of life. They display highly characteristic, rod-shaped structures with SMC (structural maintenance of chromosomes) ATPases as their core subunits and organize large-scale chromosome structure through active mechanisms. Most eukaryotic species have two distinct condensin complexes whose balanced usage is adapted flexibly to different organisms and cell types. Studies of bacterial condensins provide deep insights into the fundamental mechanisms of chromosome segregation. This Review surveys both conserved features and rich variations of condensin-based chromosome organization and discusses their evolutionary implications.

  1. Tumor suppressor protein DAB2IP participates in chromosomal stability maintenance through activating spindle assembly checkpoint and stabilizing kinetochore-microtubule attachments

    Science.gov (United States)

    Yu, Lan; Shang, Zeng-Fu; Abdisalaam, Salim; Lee, Kyung-Jong; Gupta, Arun; Hsieh, Jer-Tsong; Asaithamby, Aroumougame; Chen, Benjamin P.C.; Saha, Debabrata

    2016-01-01

    Defects in kinetochore-microtubule (KT-MT) attachment and the spindle assembly checkpoint (SAC) during cell division are strongly associated with chromosomal instability (CIN). CIN has been linked to carcinogenesis, metastasis, poor prognosis and resistance to cancer therapy. We previously reported that the DAB2IP is a tumor suppressor, and that loss of DAB2IP is often detected in advanced prostate cancer (PCa) and is indicative of poor prognosis. Here, we report that the loss of DAB2IP results in impaired KT-MT attachment, compromised SAC and aberrant chromosomal segregation. We discovered that DAB2IP directly interacts with Plk1 and its loss inhibits Plk1 kinase activity, thereby impairing Plk1-mediated BubR1 phosphorylation. Loss of DAB2IP decreases the localization of BubR1 at the kinetochore during mitosis progression. In addition, the reconstitution of DAB2IP enhances the sensitivity of PCa cells to microtubule stabilizing drugs (paclitaxel, docetaxel) and Plk1 inhibitor (BI2536). Our findings demonstrate a novel function of DAB2IP in the maintenance of KT-MT structure and SAC regulation during mitosis which is essential for chromosomal stability. PMID:27568005

  2. Entropy as the driver of chromosome segregation

    OpenAIRE

    Jun, Suckjoon; Wright, Andrew

    2010-01-01

    We present a new physical biology approach to understanding the relationship between the organization and segregation of bacterial chromosomes. We posit that replicated Escherichia coli daughter strands will spontaneously demix as a result of entropic forces, despite their strong confinement within the cell; in other words, we propose that entropy can act as a primordial physical force which drives chromosome segregation under the right physical conditions. Furthermore, proteins implicated in...

  3. Analysis of phage Mu DNA transposition by whole-genome Escherichia coli tiling arrays reveals a complex relationship to distribution of target selection protein B, transcription and chromosome architectural elements

    Indian Academy of Sciences (India)

    Jun Ge; Zheng Lou; Hong Cui; Lei Shang; Rasika M Harshey

    2011-09-01

    Of all known transposable elements, phage Mu exhibits the highest transposition efficiency and the lowest target specificity. In vitro, MuB protein is responsible for target choice. In this work, we provide a comprehensive assessment of the genome-wide distribution of MuB and its relationship to Mu target selection using high-resolution Escherichia coli tiling DNA arrays. We have also assessed how MuB binding and Mu transposition are influenced by chromosome-organizing elements such as AT-rich DNA signatures, or the binding of the nucleoid-associated protein Fis, or processes such as transcription. The results confirm and extend previous biochemical and lower resolution in vivo data. Despite the generally random nature of Mu transposition and MuB binding, there were hot and cold insertion sites and MuB binding sites in the genome, and differences between the hottest and coldest sites were large. The new data also suggest that MuB distribution and subsequent Mu integration is responsive to DNA sequences that contribute to the structural organization of the chromosome.

  4. Interchange of the active and silent S-layer protein genes of Lactobacillus acidophilus by inversion of the chromosomal sip segment

    NARCIS (Netherlands)

    Boot, H.J.; Kolen, C.P.A.M.; Pouwels, P.H.

    1996-01-01

    The most-dominant surface-exposed protein in many bacterial species is the S-protein. This protein crystallises into a regular monolayer on the outside surface of the bacteria: the S-layer. Lactobacillus acidophilus harbours two S-protein-encoding genes, slpA and slpB, only one of which (slpA) is ex

  5. Drug-induced premature chromosome condensation (PCC) protocols: cytogenetic approaches in mitotic chromosome and interphase chromatin.

    Science.gov (United States)

    Gotoh, Eisuke

    2015-01-01

    Chromosome analysis is a fundamental technique which is used in wide areas of cytogenetic study including karyotyping species, hereditary diseases diagnosis, or chromosome biology study. Chromosomes are usually prepared from mitotic cells arrested by colcemid block protocol. However, obtaining mitotic chromosomes is often hampered under several circumstances. As a result, cytogenetic analysis will be sometimes difficult or even impossible in such cases. Premature chromosome condensation (PCC) (see Note 1) is an alternative method that has proved to be a unique and useful way in chromosome analysis. Former, PCC has been achieved following cell fusion method (cell-fusion PCC) mediated either by fusogenic viruses (e.g., Sendai virus) or cell fusion chemicals (e.g., polyethylene glycol), but the cell fusion PCC has several drawbacks. The novel drug-induced PCC using protein phosphatase inhibitors was introduced about 20 years ago. This method is much simpler and easier even than the conventional mitotic chromosome preparation protocol use with colcemid block and furthermore obtained PCC index (equivalent to mitotic index for metaphase chromosome) is usually much higher than colcemid block method. Moreover, this method allows the interphase chromatin to be condensed to visualize like mitotic chromosomes. Therefore drug-induced PCC has opened the way for chromosome analysis not only in metaphase chromosomes but also in interphase chromatin. The drug-induced PCC has thus proven the usefulness in cytogenetics and other cell biology fields. For this second edition version, updated modifications/changes are supplemented in Subheadings 2, 3, and 4, and a new section describing the application of PCC in chromosome science fields is added with citation of updated references.

  6. ScII类似蛋白是洋葱根端细胞核、染色体和染色体骨架的组成成分%ScⅡ-like Protein is Localized in the Nuclei, Chromosomes and Chromosome Scaffolds of Allium cepa

    Institute of Scientific and Technical Information of China (English)

    王岩; 邢苗; 阎石

    2000-01-01

    The nuclei were isolated from the root meristematic cells of Allium cepa and the nuclear matrices were prepared. A 135kD polypeptide, which is equivalent to Sc Ⅱ in molecular weight, was revealed in the nuclei by SDS-PAGE and was then demonstrated to be an Sc Ⅱ-like protein by Western blot with an anti-chicken Sc antiserum. Neither the 135kD polypeptide nor the positive labelling of the anti-Sc antiserum was found in the nuclear matrices. The immuno-fluorescence tests showed that the nuclei labelled with the anti-Sc Ⅱ antiserum emanated strong, specific fluorescence, while the fluorescence of the nuclear matrices was too weak to be detected. The results of immunoelectron microscopy indicated that a large number of the gold particles were concentrated in the condensed chromatin of the nuclei, but very few gold particles were distributed in cytoplasm and nucleoplasm. These results strongly suggested that an Sc Ⅱ like protein is a component of the nuclei of A. cepa and is mainly located in the condensed chromatin regions, but the nuclear matrices contain no or very little amount of that protein. By means of immunofluorescence and immunoelectron microscopy, the chromosomes and chromosomal scaffolds of A. cepa labelled with the anti-chicken Sc Ⅱ antiserum were observed to send off specific fluorescence and have many gold particles representing the presence of the Sc Ⅱ-like protein distributed among them. The significance of the Sc Ⅱ-like protein as a novel component in the nuclei, chromosomes and chromosome scaffolds of higher plants is discussed.%采用机械破碎和蔗糖梯度离心方法从洋葱根端分生组织中分离出细胞核并制备出核骨架。细胞核SDS-PAGE谱带中135kD处有一多肽,免疫印迹实验结果表明,该多肽可被抗鸡Sc Ⅱ抗体标记,核骨架中没有此多肽。经抗Sc Ⅱ抗体和FITC偶联的二抗标记后,细胞核发出代表Sc Ⅱ的特异性荧光,而核骨架中无荧光发出。经抗Sc

  7. Chromosomal instability in meningiomas.

    Science.gov (United States)

    van Tilborg, Angela A G; Al Allak, Bushra; Velthuizen, Sandra C J M; de Vries, Annie; Kros, Johan M; Avezaat, Cees J J; de Klein, Annelies; Beverloo, H Berna; Zwarthoff, Ellen C

    2005-04-01

    Approximately 60% of sporadic meningiomas are caused by inactivation of the NF2 tumor suppressor gene on chromosome 22. No causative gene is known for the remaining 40%. Cytogenetic analysis shows that meningiomas caused by inactivation of the NF2 gene can be divided into tumors that show monosomy 22 as the sole abnormality and tumors with a more complex karyotype. Meningiomas not caused by the NF2 gene usually have a diploid karyotype. Here we report that, besides the clonal chromosomal aberrations, the chromosome numbers in many meningiomas varied from one metaphase spread to the other, a feature that is indicative of chromosomal instability. Unexpectedly and regardless of genotype, a subgroup of tumors was observed with an average number of 44.9 chromosomes and little variation in the number of chromosomes per metaphase spread. In addition, a second subgroup was recognized with a hyperdiploid number of chromosomes (average 48.5) and considerable variation in numbers per metaphase. However, this numerical instability resulted in a clonal karyotype with chromosomal gains and losses in addition to loss of chromosome 22 only in meningiomas caused by inactivation of the NF2 gene. In cultured cells of all tumor groups, bi- and multinucleated cells were seen, as well as anaphase bridges, residual chromatid strings, multiple spindle poles, and unseparated chromatids, suggesting defects in the mitotic apparatus or kinetochore. Thus, we conclude that even a benign and slow-growing tumor like a meningioma displays chromosomal instability.

  8. In situ hybridization to somatic chromosomes in Drosophila.

    Science.gov (United States)

    Dernburg, Abby F

    2011-09-01

    In situ hybridization was originally developed as a technique for visualizing and physically mapping specific sequences on Drosophila melanogaster polytene chromosomes. Hybridization techniques can also be used to localize sequences on smaller, diploid chromosomes, such as condensed mitotic chromosomes. Variations of the method also allow the hybridization of probes to chromosomes within intact cells and tissues, rather than to chromosomes isolated from their cellular context and flattened on slides. This article presents methods for hybridizing fluorescent probes to chromosomes in whole-mount Drosophila tissues. These methods allow the investigation of nuclear organization even at stages where chromosomes are decondensed (as in interphase) or, for other reasons, cannot be discriminated in the light microscope. Consequently, they are useful for addressing a variety of cell biological questions. In addition to enhancing our understanding of somatic chromosome organization, this experimental approach has also revealed interactions among meiotic chromosomes in Drosophila females, which spend much of meiosis in a compact ball called the karyosome. Fluorescent in situ hybridization (FISH) methods can also be used to karyotype individual nuclei using chromosome-specific markers. With appropriate fixation conditions, hybridization to chromosomal DNA can be performed in conjunction with immunostaining, allowing the colocalization of cellular or chromosomal proteins.

  9. Systematic yeast synthetic lethal and synthetic dosage lethal screens identify genes required for chromosome segregation

    OpenAIRE

    Measday, Vivien; Baetz, Kristin; Guzzo, Julie; Yuen, Karen; Kwok, Teresa; Sheikh, Bilal; Ding, Huiming; Ueta, Ryo; Hoac, Trinh; Cheng, Benjamin; Pot, Isabelle; Tong, Amy; Yamaguchi-Iwai, Yuko; Boone, Charles; Hieter, Phil

    2005-01-01

    Accurate chromosome segregation requires the execution and coordination of many processes during mitosis, including DNA replication, sister chromatid cohesion, and attachment of chromosomes to spindle microtubules via the kinetochore complex. Additional pathways are likely involved because faithful chromosome segregation also requires proteins that are not physically associated with the chromosome. Using kinetochore mutants as a starting point, we have identified genes with roles in chromosom...

  10. Survivin mediates targeting of the chromosomal passenger complex to the centromere and midbody

    NARCIS (Netherlands)

    Vader, G; Kauw, JJW; Medema, RH; Lens, SMA

    2006-01-01

    The chromosomal passenger complex (CPC) coordinates chromosomal and cytoskeletal events of mitosis. The enzymatic core of this complex (Aurora-B) is guided through the mitotic cell by its companion chromosomal passenger proteins, inner centromere protein (INCENP), Survivin and Borealin/Dasra-B, ther

  11. Analysis of plant meiotic chromosomes by chromosome painting.

    Science.gov (United States)

    Lysak, Martin A; Mandáková, Terezie

    2013-01-01

    Chromosome painting (CP) refers to visualization of large chromosome regions, entire chromosome arms, or entire chromosomes via fluorescence in situ hybridization (FISH). For CP in plants, contigs of chromosome-specific bacterial artificial chromosomes (BAC) from the target species or from a closely related species (comparative chromosome painting, CCP) are typically applied as painting probes. Extended pachytene chromosomes provide the highest resolution of CP in plants. CP enables identification and tracing of particular chromosome regions and/or entire chromosomes throughout all meiotic stages as well as corresponding chromosome territories in premeiotic interphase nuclei. Meiotic pairing and structural chromosome rearrangements (typically inversions and translocations) can be identified by CP. Here, we describe step-by-step protocols of CP and CCP in plant species including chromosome preparation, BAC DNA labeling, and multicolor FISH.

  12. [Dosage compensation mechanism of X chromosome].

    Science.gov (United States)

    Wang, Yan-Yun; Chen, Mei; Li, Bin

    2012-08-01

    Dosage compensation mechanism is crucial for the balance expression of X chromosome genes, which ensures the protein or enzyme encoded by the X chromosome to be equal or almost equal expression amounts between males and females. However, different organisms have evolved distinct dosage compensation strategies, and so far three kinds of dosage compensation strategies among organisms have been reported. The first strategy is that the single male X chromosome expression is doubly activated; the second one is to inactivate one female X chromosome by leaving both sexes with one active allele; and the third one is to reduce the expression to half activity in both X chromosomes of the female. The study of dosage compensation will be useful to reveal the mechanism of regulation of X-linked genes as well as the evolution and the differentiation progress of the sex chromosome, and it can also contribute to illustrate mutation and distortion of sex chromosome. Therefore, this paper briefly reviewed and discussed the progresses and prospects of the important mechanism of dosage compensation.

  13. Chromosomal localization of heat shock protein 70 (HSP70) gene in Zhikong scallop Chlamys farreri using BAC-FISH%栉孔扇贝热休克蛋白70(HSP70)基因的BAC-FISH定位

    Institute of Scientific and Technical Information of China (English)

    郇聘; 张晓军; 李富花; 张洋; 赵翠; 刘保忠; 相建海

    2009-01-01

    Zhikong scallop (Chlamys farreri) is one of key species in the marine aquaculture of China. Till present, the disease control is the main issue and many subjects were focused on disease- resistance and stress-related genes. Heat shock protein 70 (HSP70) shows diverse functions in the anti-stress reaction and pathogen-resistance reaction. However, the studies on HSP70 in C. farreri were mainly on a sequence analysis and expression profile, there is no result about the gene localization of HSP70. In this study, with the support of a BAC DNA library of C. farreri, a HSP70-eontaining BAC clone, CFB 123C08, was mapped to the long arms of a pair of homologous chromosomes of C. farreri using BAC-FISH. This study would facilitate further studies on the HSP70 of C. farreri. And as the first attempt of chromosomal mapping of low-copy genes in C. farreri, this study would promote the researches on the chromosome identification of C farreri.%利用BAC-FISH技术,将包含HSP70基因的BAC克隆定位到栉孔扇贝的一对同源染色体的长臂上.HSP70基因的染色体定位将对深入研究该基因的结构及功能并将其应用于生产实践提供基础支持.同时,本研究是首次对栉孔扇贝低拷贝基因进行染色体定位的实践,其结果将为栉孔扇贝的染色体的深入研究以及染色体鉴别等工作提供必要的参考.

  14. The Precarious Prokaryotic Chromosome

    OpenAIRE

    Kuzminov, Andrei

    2014-01-01

    Evolutionary selection for optimal genome preservation, replication, and expression should yield similar chromosome organizations in any type of cells. And yet, the chromosome organization is surprisingly different between eukaryotes and prokaryotes. The nuclear versus cytoplasmic accommodation of genetic material accounts for the distinct eukaryotic and prokaryotic modes of genome evolution, but it falls short of explaining the differences in the chromosome organization. I propose that the t...

  15. Mechanisms for chromosome segregation.

    Science.gov (United States)

    Bouet, Jean-Yves; Stouf, Mathieu; Lebailly, Elise; Cornet, François

    2014-12-01

    Bacteria face the problem of segregating their gigantic chromosomes without a segregation period restricted in time and space, as Eukaryotes do. Segregation thus involves multiple activities, general or specific of a chromosome region and differentially controlled. Recent advances show that these various mechanisms conform to a “pair and release” rule, which appears as a general rule in DNA segregation. We describe the latest advances in segregation of bacterial chromosomes with emphasis on the different pair and release mechanisms.

  16. Chromosome oscillations in mitosis

    Science.gov (United States)

    Campas, Otger

    2008-03-01

    Successful cell division necessitates a tight regulation of chromosome movement via the activity of molecular motors. Many of the key players at the origin of the forces generating the motion have been identified, but their spatial and temporal organization remains elusive. In animal cells, chromosomes periodically switch between phases of movement towards and away from the pole. This characteristic oscillatory behaviour cannot be explained by the current models of chromosome positioning and congression. We perform a self-contained theoretical analysis in which the motion of mono-oriented chromosomes results from the competition between the activity of the kinetochore and chromokinesin motors on the chromosome arms. Our analysis, consistent with the available experimental data, proposes that the interplay between the aster-like morphology of the spindle and the collective kinetics of molecular motors is at the origin of chromosome oscillations, positioning and congression. It provides a natural explanation for the so-called chromosome directional instability and for the mechanism by which chromosomes sense their position in space. In addition, we estimate the in vivo velocity of chromokinesins at vanishing load and propose new experiments to assess the mechanism at the origin of chromosome movement in cell division.

  17. Mapping of the receptor protein-tyrosine kinase 10 to human chromosome 1q21-q23 and mouse chromosome 1H1-5 by fluorescence in situ hybridization

    Energy Technology Data Exchange (ETDEWEB)

    Edelhoff, S.; Disteche, C.M. [Univ. of Washington School of Medicine, Seattle, WA (United States); Lai, C. [Scripps Research Inst., LaJolla, CA (United States)

    1995-01-01

    Receptor protein-tyrosine kinases (PTKs) play a critical role in the transduction of signals important to cell growth, differentiation, and survival. Mutations affecting the expression of receptor PTK genes have been associated with a number of vertebrate and invertebrate developmental abnormalities, and the aberrant regulation of tyrosine phosphorylation is implicated in a variety of neoplasias. One estimate suggests that approximately 100 receptor PTK genes exist in the mammalian genome, about half of which have been identified. The tyro-10 receptor protein-tyrosine kinase, first identified in a PCR-based survey for novel tyrosine kinases in the rat nervous system, defines a new subfamily of PTKs. It exhibits a catalytic domain most closely related to those found in the trk PTK receptor subfamily, which transduces signals for nerve growth factor and the related molecules brain-derived neurotrophic factor (BDNF), neurotrophin-3, and neurotrophin-4 (NT-3 and NT-4). Trk and the related PTK receptors trkB and trkC play a critical role in the neurotrophin-dependent survival of subsets of sensory and motor neurons. The predicted tyro-10 extracellular region is, however, distinct from that of the trk subfamily and is unique except for a domain shared with the blood coagulation factors V and VIII, thought to be involved in phospholipid binding. Although tyro-10 RNA is most abundant in heart and skeletal muscle in the adult rat, it is expressed in a wide variety of tissues, including the developing and mature brain. Tyro-10 appears identical to the murine TKT sequence reported by Karn et al. and exhibits a high degree of similarity with the CaK, DDR, and Nep PTKs. A ligand for tyro-10 has not yet been identified. 10 refs., 1 fig.

  18. Chromosome replication and segregation in bacteria.

    Science.gov (United States)

    Reyes-Lamothe, Rodrigo; Nicolas, Emilien; Sherratt, David J

    2012-01-01

    In dividing cells, chromosome duplication once per generation must be coordinated with faithful segregation of newly replicated chromosomes and with cell growth and division. Many of the mechanistic details of bacterial replication elongation are well established. However, an understanding of the complexities of how replication initiation is controlled and coordinated with other cellular processes is emerging only slowly. In contrast to eukaryotes, in which replication and segregation are separate in time, the segregation of most newly replicated bacterial genetic loci occurs sequentially soon after replication. We compare the strategies used by chromosomes and plasmids to ensure their accurate duplication and segregation and discuss how these processes are coordinated spatially and temporally with growth and cell division. We also describe what is known about the three conserved families of ATP-binding proteins that contribute to chromosome segregation and discuss their inter-relationships in a range of disparate bacteria.

  19. Fetal chromosome analysis: screening for chromosome disease?

    DEFF Research Database (Denmark)

    Philip, J; Tabor, Ann; Bang, J

    1983-01-01

    The aim of the study was to investigate the rationale of the current indications for fetal chromosome analysis. 5372 women had 5423 amniocentesis performed, this group constituting a consecutive sample at the chromosome laboratory, Rigshospitalet, Copenhagen from March 1973 to September 1980 (Group...... to women having amniocentesis, although considered not to have any increased risk of fetal chromosome abnormality (1390 pregnancies, group B). They were also compared with 750 consecutive pregnancies in women 25-34 years of age, in whom all heritable diseases were excluded (group C). The risk of unbalanced...... with women without elevated risk. Spontaneous abortion rate and prematurity rate did not differ from rates expected without amniocentesis. It is concluded that current indications may be characterized as a mixture of evident high risk factors and factors with only a minor influence on risk. Indications...

  20. Tracking of chromosome dynamics in live Streptococcus pneumoniae reveals that transcription promotes chromosome segregation.

    Science.gov (United States)

    Kjos, Morten; Veening, Jan-Willem

    2014-03-01

    Chromosome segregation is an essential part of the bacterial cell cycle but is poorly characterized in oval-shaped streptococci. Using time-lapse fluorescence microscopy and total internal reflection fluorescence microscopy, we have tracked the dynamics of chromosome segregation in live cells of the human pathogen Streptococcus pneumoniae. Our observations show that the chromosome segregation process last for two-thirds of the total cell cycle; the origin region segregates rapidly in the early stages of the cell cycle while nucleoid segregation finishes just before cell division. Previously we have demonstrated that the DNA-binding protein ParB and the condensin SMC promote efficient chromosome segregation, likely by an active mechanism. We now show that in the absence of SMC, cell division can occur over the unsegregated chromosomes. However, neither smc nor parB are essential in S. pneumoniae, suggesting the importance of additional mechanisms. Here we have identified the process of transcription as one of these mechanisms important for chromosome segregation in S. pneumoniae. Transcription inhibitors rifampicin and streptolydigin as well as mutants affected in transcription elongation cause chromosome segregation defects. Together, our results highlight the importance of passive (or indirect) processes such as transcription for chromosome segregation in oval-shaped bacteria.

  1. XYY chromosome anomaly and schizophrenia.

    Science.gov (United States)

    Rajagopalan, M; MacBeth, R; Varma, S L

    1998-02-07

    Sex chromosome anomalies have been associated with psychoses, and most of the evidence is linked to the presence of an additional X chromosome. We report a patient with XYY chromosome anomaly who developed schizophrenia.

  2. The DNA sequence of a 7941 bp fragment of the left arm of chromosome VII of Saccharomyces cerevisiae contains four open reading frames including the multicopy suppressor gene of the pop2 mutation and a putative serine/threonine protein kinase gene.

    Science.gov (United States)

    Coglievina, M; Bertani, I; Klima, R; Zaccaria, P; Bruschi, C V

    1995-06-30

    We report the sequence of a 7941 bp DNA fragment from the left arm of chromosome VII of Saccharomyces cerevisiae which contains four open reading frames (ORFs) of greater than 100 amino acid residues. ORF biC834 shows 100% bp identity with the recently identified multicopy suppressor gene of the pop2 mutation (MPT5); its deduced protein product carries an eight-repeat domain region, homologous to that found in the hypothetical regulatory YGL023 protein of S. cerevisiae and the Pumilio protein of Drosophila. ORF biE560 protein exhibits patterns typical of serine/threonine protein kinases, with which it shares high degrees of homology.

  3. Chromosome painting reveals asynaptic full alignment of homologs and HIM-8-dependent remodeling of X chromosome territories during Caenorhabditis elegans meiosis.

    Directory of Open Access Journals (Sweden)

    Kentaro Nabeshima

    2011-08-01

    Full Text Available During early meiotic prophase, a nucleus-wide reorganization leads to sorting of chromosomes into homologous pairs and to establishing associations between homologous chromosomes along their entire lengths. Here, we investigate global features of chromosome organization during this process, using a chromosome painting method in whole-mount Caenorhabditis elegans gonads that enables visualization of whole chromosomes along their entire lengths in the context of preserved 3D nuclear architecture. First, we show that neither spatial proximity of premeiotic chromosome territories nor chromosome-specific timing is a major factor driving homolog pairing. Second, we show that synaptonemal complex-independent associations can support full lengthwise juxtaposition of homologous chromosomes. Third, we reveal a prominent elongation of chromosome territories during meiotic prophase that initiates prior to homolog association and alignment. Mutant analysis indicates that chromosome movement mediated by association of chromosome pairing centers (PCs with mobile patches of the nuclear envelope (NE-spanning SUN-1/ZYG-12 protein complexes is not the primary driver of territory elongation. Moreover, we identify new roles for the X chromosome PC (X-PC and X-PC binding protein HIM-8 in promoting elongation of X chromosome territories, separable from their role(s in mediating local stabilization of pairing and association of X chromosomes with mobile SUN-1/ZYG-12 patches. Further, we present evidence that HIM-8 functions both at and outside of PCs to mediate chromosome territory elongation. These and other data support a model in which synapsis-independent elongation of chromosome territories, driven by PC binding proteins, enables lengthwise juxtaposition of chromosomes, thereby facilitating assessment of their suitability as potential pairing partners.

  4. Histone-DNA contacts in structure/function relationships of nucleosomes as revealed by crosslinking

    Energy Technology Data Exchange (ETDEWEB)

    Usachenko, S.I. [Univ. of California, Davis, CA (United States); Bradbury, E.M. [Los Alamos National Lab., NM (United States). Life Science Div.]|[Univ. of California, Davis, CA (United States)

    1998-12-31

    The magnitude of the problem of understanding the structure/function relationships of eukaryotic chromosomes can be appreciated from the fact that the human diploid genome contains more than 2 meters of DNA packaged into 46 chromosomes, each at metaphase being several microns in length. Each chromatid of a chromosome contains a single DNA molecule several centimeters in length. In addition to the DNA, chromosomes contain an equal weight of histones and an equal weight of non-histone chromosomal proteins. These histones are the major chromosomal structural proteins. The non-histone chromosomal proteins are involved in the DNA processes of transcription and replication, in chromosome organization and in nuclear architecture. Polytene chromosomes with their bands and interbands and puffs of active genetic loci provide visual evidence for long range order as do the bands and interbands of mammalian metaphase chromosomes. The gentle removal of histones and all but the most tightly bound 2--3% of non-histone proteins from metaphase chromosomes revealed by electron microscopy a residual protein scaffold constraining a halo of DNA loops extending out from the scaffold.

  5. Chromosomes in the flow to simplify genome analysis.

    Science.gov (United States)

    Doležel, Jaroslav; Vrána, Jan; Safář, Jan; Bartoš, Jan; Kubaláková, Marie; Simková, Hana

    2012-08-01

    Nuclear genomes of human, animals, and plants are organized into subunits called chromosomes. When isolated into aqueous suspension, mitotic chromosomes can be classified using flow cytometry according to light scatter and fluorescence parameters. Chromosomes of interest can be purified by flow sorting if they can be resolved from other chromosomes in a karyotype. The analysis and sorting are carried out at rates of 10(2)-10(4) chromosomes per second, and for complex genomes such as wheat the flow sorting technology has been ground-breaking in reducing genome complexity for genome sequencing. The high sample rate provides an attractive approach for karyotype analysis (flow karyotyping) and the purification of chromosomes in large numbers. In characterizing the chromosome complement of an organism, the high number that can be studied using flow cytometry allows for a statistically accurate analysis. Chromosome sorting plays a particularly important role in the analysis of nuclear genome structure and the analysis of particular and aberrant chromosomes. Other attractive but not well-explored features include the analysis of chromosomal proteins, chromosome ultrastructure, and high-resolution mapping using FISH. Recent results demonstrate that chromosome flow sorting can be coupled seamlessly with DNA array and next-generation sequencing technologies for high-throughput analyses. The main advantages are targeting the analysis to a genome region of interest and a significant reduction in sample complexity. As flow sorters can also sort single copies of chromosomes, shotgun sequencing DNA amplified from them enables the production of haplotype-resolved genome sequences. This review explains the principles of flow cytometric chromosome analysis and sorting (flow cytogenetics), discusses the major uses of this technology in genome analysis, and outlines future directions.

  6. Chromosomes of Protists: The crucible of evolution.

    Science.gov (United States)

    Soyer-Gobillard, Marie-Odile; Dolan, Michael F

    2015-12-01

    As early as 1925, the great protozoologist Edouard Chatton classified microorganisms into two categories, the prokaryotic and the eukaryotic microbes, based on light microscopical observation of their nuclear organization. Now, by means of transmission electron microscopy, we know that prokaryotic microbes are characterized by the absence of nuclear envelope surrounding the bacterial chromosome, which is more or less condensed and whose chromatin is deprived of histone proteins but presents specific basic proteins. Eukaryotic microbes, the protists, have nuclei surrounded by a nuclear envelope and have chromosomes more or less condensed, with chromatin-containing histone proteins organized into nucleosomes. The extraordinary diversity of mitotic systems presented by the 36 phyla of protists (according to Margulis et al., Handbook of Protoctista, 1990) is in contrast to the relative homogeneity of their chromosome structure and chromatin components. Dinoflagellates are the exception to this pattern. The phylum is composed of around 2000 species, and characterized by unique features including their nucleus (dinokaryon), dinomitosis, chromosome organization and chromatin composition. Although their DNA synthesis is typically eukaryotic, dinoflagellates are the only eukaryotes in which the chromatin, organized into quasi-permanently condensed chromosomes, is in some species devoid of histones and nucleosomes. In these cases, their chromatin contains specific DNA-binding basic proteins. The permanent compaction of their chromosomes throughout the cell cycle raises the question of the modalities of their division and their transcription. Successful in vitro reconstitution of nucleosomes using dinoflagellate DNA and heterologous corn histones raises questions about dinoflagellate evolution and phylogeny. [Int Microbiol 18(4):209-216 (2015)].

  7. Sequential cloning of chromosomes

    Science.gov (United States)

    Lacks, S.A.

    1995-07-18

    A method for sequential cloning of chromosomal DNA of a target organism is disclosed. A first DNA segment homologous to the chromosomal DNA to be sequentially cloned is isolated. The first segment has a first restriction enzyme site on either side. A first vector product is formed by ligating the homologous segment into a suitably designed vector. The first vector product is circularly integrated into the target organism`s chromosomal DNA. The resulting integrated chromosomal DNA segment includes the homologous DNA segment at either end of the integrated vector segment. The integrated chromosomal DNA is cleaved with a second restriction enzyme and ligated to form a vector-containing plasmid, which is replicated in a host organism. The replicated plasmid is then cleaved with the first restriction enzyme. Next, a DNA segment containing the vector and a segment of DNA homologous to a distal portion of the previously isolated DNA segment is isolated. This segment is then ligated to form a plasmid which is replicated within a suitable host. This plasmid is then circularly integrated into the target chromosomal DNA. The chromosomal DNA containing the circularly integrated vector is treated with a third, retrorestriction (class IIS) enzyme. The cleaved DNA is ligated to give a plasmid that is used to transform a host permissive for replication of its vector. The sequential cloning process continues by repeated cycles of circular integration and excision. The excision is carried out alternately with the second and third enzymes. 9 figs.

  8. Chromosomal mosaicism goes global

    Directory of Open Access Journals (Sweden)

    Yurov Yuri B

    2008-11-01

    Full Text Available Intercellular differences of chromosomal content in the same individual are defined as chromosomal mosaicism (alias intercellular or somatic genomic variations or, in a number of publications, mosaic aneuploidy. It has long been suggested that this phenomenon poorly contributes both to intercellular (interindividual diversity and to human disease. However, our views have recently become to change due to a series of communications demonstrated a higher incidence of chromosomal mosaicism in diseased individuals (major psychiatric disorders and autoimmune diseases as well as depicted chromosomal mosaicism contribution to genetic diversity, the central nervous system development, and aging. The later has been produced by significant achievements in the field of molecular cytogenetics. Recently, Molecular Cytogenetics has published an article by Maj Hulten and colleagues that has provided evidences for chromosomal mosaicism to underlie formation of germline aneuploidy in human female gametes using trisomy 21 (Down syndrome as a model. Since meiotic aneuploidy is suggested to be the leading genetic cause of human prenatal mortality and postnatal morbidity, these data together with previous findings define chromosomal mosaicism not as a casual finding during cytogenetic analyses but as a more significant biological phenomenon than previously recognized. Finally, the significance of chromosomal mosaicism can be drawn from the fact, that this phenomenon is involved in genetic diversity, normal and abnormal prenatal development, human diseases, aging, and meiotic aneuploidy, the intrinsic cause of which remains, as yet, unknown.

  9. A separable domain of the p150 subunit of human chromatin assembly factor-1 promotes protein and chromosome associations with nucleoli

    OpenAIRE

    2014-01-01

    Chromatin assembly factor-1 (CAF-1) is a three-subunit protein complex conserved throughout eukaryotes that deposits histones during DNA synthesis. Here we present a novel role for the human p150 subunit in regulating nucleolar macromolecular interactions. Acute depletion of p150 causes redistribution of multiple nucleolar proteins and reduces nucleolar association with several repetitive element–containing loci. Of note, a point mutation in a SUMO-interacting motif (SIM) within p150 abolishe...

  10. Female meiotic sex chromosome inactivation in chicken.

    Science.gov (United States)

    Schoenmakers, Sam; Wassenaar, Evelyne; Hoogerbrugge, Jos W; Laven, Joop S E; Grootegoed, J Anton; Baarends, Willy M

    2009-05-01

    During meiotic prophase in male mammals, the heterologous X and Y chromosomes remain largely unsynapsed, and meiotic sex chromosome inactivation (MSCI) leads to formation of the transcriptionally silenced XY body. In birds, the heterogametic sex is female, carrying Z and W chromosomes (ZW), whereas males have the homogametic ZZ constitution. During chicken oogenesis, the heterologous ZW pair reaches a state of complete heterologous synapsis, and this might enable maintenance of transcription of Z- and W chromosomal genes during meiotic prophase. Herein, we show that the ZW pair is transiently silenced, from early pachytene to early diplotene using immunocytochemistry and gene expression analyses. We propose that ZW inactivation is most likely achieved via spreading of heterochromatin from the W on the Z chromosome. Also, persistent meiotic DNA double-strand breaks (DSBs) may contribute to silencing of Z. Surprisingly, gammaH2AX, a marker of DSBs, and also the earliest histone modification that is associated with XY body formation in mammalian and marsupial spermatocytes, does not cover the ZW during the synapsed stage. However, when the ZW pair starts to desynapse, a second wave of gammaH2AX accumulates on the unsynapsed regions of Z, which also show a reappearance of the DSB repair protein RAD51. This indicates that repair of meiotic DSBs on the heterologous part of Z is postponed until late pachytene/diplotene, possibly to avoid recombination with regions on the heterologously synapsed W chromosome. Two days after entering diplotene, the Z looses gammaH2AX and shows reactivation. This is the first report of meiotic sex chromosome inactivation in a species with female heterogamety, providing evidence that this mechanism is not specific to spermatogenesis. It also indicates the presence of an evolutionary force that drives meiotic sex chromosome inactivation independent of the final achievement of synapsis.

  11. Female meiotic sex chromosome inactivation in chicken.

    Directory of Open Access Journals (Sweden)

    Sam Schoenmakers

    2009-05-01

    Full Text Available During meiotic prophase in male mammals, the heterologous X and Y chromosomes remain largely unsynapsed, and meiotic sex chromosome inactivation (MSCI leads to formation of the transcriptionally silenced XY body. In birds, the heterogametic sex is female, carrying Z and W chromosomes (ZW, whereas males have the homogametic ZZ constitution. During chicken oogenesis, the heterologous ZW pair reaches a state of complete heterologous synapsis, and this might enable maintenance of transcription of Z- and W chromosomal genes during meiotic prophase. Herein, we show that the ZW pair is transiently silenced, from early pachytene to early diplotene using immunocytochemistry and gene expression analyses. We propose that ZW inactivation is most likely achieved via spreading of heterochromatin from the W on the Z chromosome. Also, persistent meiotic DNA double-strand breaks (DSBs may contribute to silencing of Z. Surprisingly, gammaH2AX, a marker of DSBs, and also the earliest histone modification that is associated with XY body formation in mammalian and marsupial spermatocytes, does not cover the ZW during the synapsed stage. However, when the ZW pair starts to desynapse, a second wave of gammaH2AX accumulates on the unsynapsed regions of Z, which also show a reappearance of the DSB repair protein RAD51. This indicates that repair of meiotic DSBs on the heterologous part of Z is postponed until late pachytene/diplotene, possibly to avoid recombination with regions on the heterologously synapsed W chromosome. Two days after entering diplotene, the Z looses gammaH2AX and shows reactivation. This is the first report of meiotic sex chromosome inactivation in a species with female heterogamety, providing evidence that this mechanism is not specific to spermatogenesis. It also indicates the presence of an evolutionary force that drives meiotic sex chromosome inactivation independent of the final achievement of synapsis.

  12. CHROMOSOMES OF AMERICAN MARSUPIALS.

    Science.gov (United States)

    BIGGERS, J D; FRITZ, H I; HARE, W C; MCFEELY, R A

    1965-06-18

    Studies of the chromosomes of four American marsupials demonstrated that Caluromys derbianus and Marmosa mexicana have a diploid number of 14 chromosomes, and that Philander opossum and Didelphis marsupialis have a diploid number of 22. The karyotypes of C. derbianus and M. mexicana are similar, whereas those of P. opossum and D. marsupialis are dissimilar. If the 14-chromosome karyotype represents a reduction from a primitive number of 22, these observations suggest that the change has occurred independently in the American and Australasian forms.

  13. Combination of Multiple Spectral Libraries Improves the Current Search Methods Used to Identify Missing Proteins in the Chromosome-Centric Human Proteome Project.

    Science.gov (United States)

    Cho, Jin-Young; Lee, Hyoung-Joo; Jeong, Seul-Ki; Kim, Kwang-Youl; Kwon, Kyung-Hoon; Yoo, Jong Shin; Omenn, Gilbert S; Baker, Mark S; Hancock, William S; Paik, Young-Ki

    2015-12-01

    Approximately 2.9 billion long base-pair human reference genome sequences are known to encode some 20 000 representative proteins. However, 3000 proteins, that is, ~15% of all proteins, have no or very weak proteomic evidence and are still missing. Missing proteins may be present in rare samples in very low abundance or be only temporarily expressed, causing problems in their detection and protein profiling. In particular, some technical limitations cause missing proteins to remain unassigned. For example, current mass spectrometry techniques have high limits and error rates for the detection of complex biological samples. An insufficient proteome coverage in a reference sequence database and spectral library also raises major issues. Thus, the development of a better strategy that results in greater sensitivity and accuracy in the search for missing proteins is necessary. To this end, we used a new strategy, which combines a reference spectral library search and a simulated spectral library search, to identify missing proteins. We built the human iRefSPL, which contains the original human reference spectral library and additional peptide sequence-spectrum match entries from other species. We also constructed the human simSPL, which contains the simulated spectra of 173 907 human tryptic peptides determined by MassAnalyzer (version 2.3.1). To prove the enhanced analytical performance of the combination of the human iRefSPL and simSPL methods for the identification of missing proteins, we attempted to reanalyze the placental tissue data set (PXD000754). The data from each experiment were analyzed using PeptideProphet, and the results were combined using iProphet. For the quality control, we applied the class-specific false-discovery rate filtering method. All of the results were filtered at a false-discovery rate of libraries, iRefSPL and simSPL, were designed to ensure no overlap of the proteome coverage. They were shown to be complementary to spectral library

  14. Chromosomal polymorphism in the Sporothrix schenckii complex.

    Science.gov (United States)

    Sasaki, Alexandre A; Fernandes, Geisa F; Rodrigues, Anderson M; Lima, Fábio M; Marini, Marjorie M; Dos S Feitosa, Luciano; de Melo Teixeira, Marcus; Felipe, Maria Sueli Soares; da Silveira, José Franco; de Camargo, Zoilo P

    2014-01-01

    Sporotrichosis is a polymorphic disease caused by a complex of thermodimorphic fungi including S. brasiliensis, S. schenckii sensu stricto (s. str.), S. globosa and S. luriei. Humans and animals can acquire the disease through traumatic inoculation of propagules into the subcutaneous tissue. Despite the importance of sporotrichosis as a disease that can take epidemic proportions there are just a few studies dealing with genetic polymorphisms and genomic architecture of these pathogens. The main objective of this study was to investigate chromosomal polymorphisms and genomic organization among different isolates in the S. schenckii complex. We used pulsed field gel electrophoresis (PFGE) to separate chromosomal fragments of isolated DNA, followed by probe hybridization. Nine loci (β-tubulin, calmodulin, catalase, chitin synthase 1, Internal Transcribed Spacer, Pho85 cyclin-dependent kinase, protein kinase C Ss-2, G protein α subunit and topoisomerase II) were mapped onto chromosomal bands of Brazilian isolates of S. schenckii s. str. and S. brasiliensis. Our results revealed the presence of intra and interspecies polymorphisms in chromosome number and size. The gene hybridization analysis showed that closely related species in phylogenetic analysis had similar genetic organizations, mostly due to identification of synteny groups in chromosomal bands of similar sizes. Our results bring new insights into the genetic diversity and genome organization among pathogenic species in the Sporothrix schenckii complex.

  15. Roles of the Y chromosome genes in human cancers

    Directory of Open Access Journals (Sweden)

    Tatsuo Kido

    2015-06-01

    Full Text Available Male and female differ genetically by their respective sex chromosome composition, that is, XY as male and XX as female. Although both X and Y chromosomes evolved from the same ancestor pair of autosomes, the Y chromosome harbors male-specific genes, which play pivotal roles in male sex determination, germ cell differentiation, and masculinization of various tissues. Deletions or translocation of the sex-determining gene, SRY, from the Y chromosome causes disorders of sex development (previously termed as an intersex condition with dysgenic gonads. Failure of gonadal development results not only in infertility, but also in increased risks of germ cell tumor (GCT, such as gonadoblastoma and various types of testicular GCT. Recent studies demonstrate that either loss of Y chromosome or ectopic expression of Y chromosome genes is closely associated with various male-biased diseases, including selected somatic cancers. These observations suggest that the Y-linked genes are involved in male health and diseases in more frequently than expected. Although only a small number of protein-coding genes are present in the male-specific region of Y chromosome, the impacts of Y chromosome genes on human diseases are still largely unknown, due to lack of in vivo models and differences between the Y chromosomes of human and rodents. In this review, we highlight the involvement of selected Y chromosome genes in cancer development in men.

  16. Chromosomal abnormalities and autism

    Directory of Open Access Journals (Sweden)

    Farida El-Baz

    2016-01-01

    Conclusion: Chromosomal abnormalities were not detected in the studied autistic children, and so the relation between the genetics and autism still needs further work up with different study methods and techniques.

  17. The Inner Centromere Protein (INCENP) Coil Is a Single α-Helix (SAH) Domain That Binds Directly to Microtubules and Is Important for Chromosome Passenger Complex (CPC) Localization and Function in Mitosis.

    Science.gov (United States)

    Samejima, Kumiko; Platani, Melpomeni; Wolny, Marcin; Ogawa, Hiromi; Vargiu, Giulia; Knight, Peter J; Peckham, Michelle; Earnshaw, William C

    2015-08-28

    The chromosome passenger complex (CPC) is a master regulator of mitosis. Inner centromere protein (INCENP) acts as a scaffold regulating CPC localization and activity. During early mitosis, the N-terminal region of INCENP forms a three-helix bundle with Survivin and Borealin, directing the CPC to the inner centromere where it plays essential roles in chromosome alignment and the spindle assembly checkpoint. The C-terminal IN box region of INCENP is responsible for binding and activating Aurora B kinase. The central region of INCENP has been proposed to comprise a coiled coil domain acting as a spacer between the N- and C-terminal domains that is involved in microtubule binding and regulation of the spindle checkpoint. Here we show that the central region (213 residues) of chicken INCENP is not a coiled coil but a ∼ 32-nm-long single α-helix (SAH) domain. The N-terminal half of this domain directly binds to microtubules in vitro. By analogy with previous studies of myosin 10, our data suggest that the INCENP SAH might stretch up to ∼ 80 nm under physiological forces. Thus, the INCENP SAH could act as a flexible "dog leash," allowing Aurora B to phosphorylate dynamic substrates localized in the outer kinetochore while at the same time being stably anchored to the heterochromatin of the inner centromere. Furthermore, by achieving this flexibility via an SAH domain, the CPC avoids a need for dimerization (required for coiled coil formation), which would greatly complicate regulation of the proximity-induced trans-phosphorylation that is critical for Aurora B activation.

  18. Inherited variants in the inner centromere protein (INCENP) gene of the chromosomal passenger complex contribute to the susceptibility of ER-negative breast cancer

    Science.gov (United States)

    Kabisch, Maria; Lorenzo Bermejo, Justo; Dünnebier, Thomas; Ying, Shibo; Michailidou, Kyriaki; Bolla, Manjeet K.; Wang, Qin; Dennis, Joe; Shah, Mitul; Perkins, Barbara J.; Czene, Kamila; Darabi, Hatef; Eriksson, Mikael; Bojesen, Stig E.; Nordestgaard, Børge G.; Nielsen, Sune F.; Flyger, Henrik; Lambrechts, Diether; Neven, Patrick; Peeters, Stephanie; Weltens, Caroline; Couch, Fergus J.; Olson, Janet E.; Wang, Xianshu; Purrington, Kristen; Chang-Claude, Jenny; Rudolph, Anja; Seibold, Petra; Flesch-Janys, Dieter; Peto, Julian; dos-Santos-Silva, Isabel; Johnson, Nichola; Fletcher, Olivia; Nevanlinna, Heli; Muranen, Taru A.; Aittomäki, Kristiina; Blomqvist, Carl; Schmidt, Marjanka K.; Broeks, Annegien; Cornelissen, Sten; Hogervorst, Frans B.L.; Li, Jingmei; Brand, Judith S.; Humphreys, Keith; Guénel, Pascal; Truong, Thérèse; Menegaux, Florence; Sanchez, Marie; Burwinkel, Barbara; Marmé, Frederik; Yang, Rongxi; Bugert, Peter; González-Neira, Anna; Benitez, Javier; Pilar Zamora, M.; Arias Perez, Jose I.; Cox, Angela; Cross, Simon S.; Reed, Malcolm W.R.; Andrulis, Irene L.; Knight, Julia A.; Glendon, Gord; Tchatchou, Sandrine; Sawyer, Elinor J.; Tomlinson, Ian; Kerin, Michael J.; Miller, Nicola; Haiman, Christopher A.; Schumacher, Fredrick; Henderson, Brian E.; Le Marchand, Loic; Lindblom, Annika; Margolin, Sara; Hooning, Maartje J.; Hollestelle, Antoinette; Kriege, Mieke; Koppert, Linetta B.; Hopper, John L.; Southey, Melissa C.; Tsimiklis, Helen; Apicella, Carmel; Slettedahl, Seth; Toland, Amanda E.; Vachon, Celine; Yannoukakos, Drakoulis; Giles, Graham G.; Milne, Roger L.; McLean, Catriona; Fasching, Peter A.; Ruebner, Matthias; Ekici, Arif B.; Beckmann, Matthias W.; Brenner, Hermann; Dieffenbach, Aida K.; Arndt, Volker; Stegmaier, Christa; Ashworth, Alan; Orr, Nicholas; Schoemaker, Minouk J.; Swerdlow, Anthony; García-Closas, Montserrat; Figueroa, Jonine; Chanock, Stephen J.; Lissowska, Jolanta; Goldberg, Mark S.; Labrèche, France; Dumont, Martine; Winqvist, Robert; Pylkäs, Katri; Jukkola-Vuorinen, Arja; Grip, Mervi; Brauch, Hiltrud; Brüning, Thomas; Ko, Yon-Dschun; Radice, Paolo; Peterlongo, Paolo; Scuvera, Giulietta; Fortuzzi, Stefano; Bogdanova, Natalia; Dörk, Thilo; Mannermaa, Arto; Kataja, Vesa; Kosma, Veli-Matti; Hartikainen, Jaana M.; Devilee, Peter; Tollenaar, Robert A.E.M.; Seynaeve, Caroline; Van Asperen, Christi J.; Jakubowska, Anna; Lubinski, Jan; Jaworska-Bieniek, Katarzyna; Durda, Katarzyna; Zheng, Wei; Shrubsole, Martha J.; Cai, Qiuyin; Torres, Diana; Anton-Culver, Hoda; Kristensen, Vessela; Bacot, François; Tessier, Daniel C.; Vincent, Daniel; Luccarini, Craig; Baynes, Caroline; Ahmed, Shahana; Maranian, Mel; Simard, Jacques; Chenevix-Trench, Georgia; Hall, Per; Pharoah, Paul D.P.; Dunning, Alison M.; Easton, Douglas F.; Hamann, Ute

    2015-01-01

    The chromosomal passenger complex (CPC) plays a pivotal role in the regulation of cell division. Therefore, inherited CPC variability could influence tumor development. The present candidate gene approach investigates the relationship between single nucleotide polymorphisms (SNPs) in genes encoding key CPC components and breast cancer risk. Fifteen SNPs in four CPC genes (INCENP, AURKB, BIRC5 and CDCA8) were genotyped in 88 911 European women from 39 case-control studies of the Breast Cancer Association Consortium. Possible associations were investigated in fixed-effects meta-analyses. The synonymous SNP rs1675126 in exon 7 of INCENP was associated with overall breast cancer risk [per A allele odds ratio (OR) 0.95, 95% confidence interval (CI) 0.92–0.98, P = 0.007] and particularly with estrogen receptor (ER)-negative breast tumors (per A allele OR 0.89, 95% CI 0.83–0.95, P = 0.0005). SNPs not directly genotyped were imputed based on 1000 Genomes. The SNPs rs1047739 in the 3ʹ untranslated region and rs144045115 downstream of INCENP showed the strongest association signals for overall (per T allele OR 1.03, 95% CI 1.00–1.06, P = 0.0009) and ER-negative breast cancer risk (per A allele OR 1.06, 95% CI 1.02–1.10, P = 0.0002). Two genotyped SNPs in BIRC5 were associated with familial breast cancer risk (top SNP rs2071214: per G allele OR 1.12, 95% CI 1.04–1.21, P = 0.002). The data suggest that INCENP in the CPC pathway contributes to ER-negative breast cancer susceptibility in the European population. In spite of a modest contribution of CPC-inherited variants to the total burden of sporadic and familial breast cancer, their potential as novel targets for breast cancer treatment should be further investigated. PMID:25586992

  19. Chromosome doubling method

    Science.gov (United States)

    Kato, Akio

    2006-11-14

    The invention provides methods for chromosome doubling in plants. The technique overcomes the low yields of doubled progeny associated with the use of prior techniques for doubling chromosomes in plants such as grasses. The technique can be used in large scale applications and has been demonstrated to be highly effective in maize. Following treatment in accordance with the invention, plants remain amenable to self fertilization, thereby allowing the efficient isolation of doubled progeny plants.

  20. Activation of X Chromosome Inactivation

    NARCIS (Netherlands)

    C.M. Maduro (Cheryl)

    2016-01-01

    markdownabstractIn mammals, males are the heterogametic sex having an X chromosome and a Y chromosome whereas females have two X chromosomes. Despite originating from an ancient homologous autosomal pair, the X and Y chromosome now differ greatly in size and gene content after ~180 MY of evolution.

  1. The Philadelphia chromosome in leukemogenesis

    Institute of Scientific and Technical Information of China (English)

    ZhiJieKang; JinSongYan; QuentinLiu; YuFeiLiu; LingZhiXu; ZiJieLong; DanHuang; YaYang; BingLiu; JiuXingFeng; YuJiaPan

    2016-01-01

    The truncated chromosome 22 that results from the reciprocal translocation t(9;22)(q34;q11) is known as the Phila‑delphia chromosome (Ph) and is a hallmark of chronic myeloid leukemia (CML). In leukemia cells, Ph not only impairs the physiological signaling pathways but also disrupts genomic stability. This aberrant fusion gene encodes the breakpoint cluster region‑proto‑oncogene tyrosine‑protein kinase (BCR‑ABL1) oncogenic protein with persistently enhanced tyrosine kinase activity. The kinase activity is responsible for maintaining proliferation, inhibiting differentia‑tion, and conferring resistance to cell death. During the progression of CML from the chronic phase to the accelerated phase and then to the blast phase, the expression patterns of different BCR‑ABL1 transcripts vary. Each BCR‑ABL1 transcript is present in a distinct leukemia phenotype, which predicts both response to therapy and clinical outcome. Besides CML, the Ph is found in acute lymphoblastic leukemia, acute myeloid leukemia, and mixed‑phenotype acute leukemia. Here, we provide an overview of the clinical presentation and cellular biology of different phenotypes of Ph‑positive leukemia and highlight key ifndings regarding leukemogenesis.

  2. CHROMOSOME SEGREGATION: NOVEL INSIGHTS INTO THE MECHANISM AND REGULATION

    Directory of Open Access Journals (Sweden)

    Miroslava Pozgajova

    2013-02-01

    Full Text Available A crucial feature of every healthy living organism is accurate segregation of chromosomes. Errors in this process may lead to aneuploidy, which is responsible for diverse genetic defects and diseases such as Down syndrome, miscarriages, cancer and others. Although, chromosome segregation has been studied intensively in the past, the exact mechanism of accurate chromosome segregation still remains unclear. Identification and characterization of proteins and protein complexes involved in this process is essential for understanding of processes that lead to chromosome missegregation. Basic molecular mechanism share common principles in animals, humans, plants and unicellular organisms; it is therefore possible to study these mechanisms in simple model organisms such as yeasts. The fission yeast Schizosaccharomyces pombe is an excellent model organism to study the function and regulation of chromosome segregation in both mitosis and meiosis.

  3. Proteomic analysis of human metaphase chromosomes reveals Topoisomerase II alpha as an Aurora B substrate

    DEFF Research Database (Denmark)

    Morrison, Ciaran; Henzing, Alexander J; Jensen, Ole Nørregaard;

    2002-01-01

    The essential Aurora B kinase is a chromosomal passenger protein that is required for mitotic chromosome alignment and segregation. Aurora B function is dependent on the chromosome passenger, INCENP. INCENP, in turn, requires sister chromatid cohesion for its appropriate behaviour. Relatively few...

  4. Localization of the human stress responsive MAP kinase-like CSAIDs binding protein (CSBP) gene to chromosome 6p21.3/21.2

    Energy Technology Data Exchange (ETDEWEB)

    McDonnell, P.C.; Young, P.R.; DiLella, A.G. [SmithKline Beecham Pharmaceuticals, King of Prussia, PA (United States)] [and others

    1995-09-01

    The proinflammatory cytokines interleukin 1 (IL-1) and tumor necrosis factor (TNF) play a pivotal role in the initiation of inflammatory responses. Soluble protein antagonists of IL-1 and TNF, such as IL-1ra, sTNFR-Fc fusion, and monoclonal antibodies to TNF have proven to be effective at blocking acute and chronic responses in a number of animal models of inflammatory diseases such as rheumatoid arthritis, septic shock, and inflammatory bowel disease. Consequently, there has been considerable interest in discovering compounds that could inhibit the production of these cytokines and might therefore become treatments. Recently, a structurally related series of pyridinyl imidazoles was found to block IL-1 and TNF production from LPS-stimulated human monocytes and to ameliorate inflammatory diseases significantly in vivo, leading to their being named CSAIDs (cytokine suppressive anti-inflammatory drugs). The protein target of these compounds, termed CSBP (CSAID binding protein), was discovered to be a new member of the MAP kinase family of serine-threonine protein kinases whose kinase activity is activated by LPS in human monocytes. Independently, the same kinase, or its rodent homologues, was found to respond also to chemical, thermal, and osmotic stress and IL-1 treatment. Inhibition of this kinase correlated with reduction in inflammatory cytokine production from LPS-activated monocytes. 15 refs., 1 fig.

  5. Vibrio chromosomes share common history

    Directory of Open Access Journals (Sweden)

    Gevers Dirk

    2010-05-01

    Full Text Available Abstract Background While most gamma proteobacteria have a single circular chromosome, Vibrionales have two circular chromosomes. Horizontal gene transfer is common among Vibrios, and in light of this genetic mobility, it is an open question to what extent the two chromosomes themselves share a common history since their formation. Results Single copy genes from each chromosome (142 genes from chromosome I and 42 genes from chromosome II were identified from 19 sequenced Vibrionales genomes and their phylogenetic comparison suggests consistent phylogenies for each chromosome. Additionally, study of the gene organization and phylogeny of the respective origins of replication confirmed the shared history. Conclusions Thus, while elements within the chromosomes may have experienced significant genetic mobility, the backbones share a common history. This allows conclusions based on multilocus sequence analysis (MLSA for one chromosome to be applied equally to both chromosomes.

  6. Telomere dysfunction and chromosome structure modulate the contribution of individual chromosomes in abnormal nuclear morphologies

    Energy Technology Data Exchange (ETDEWEB)

    Pampalona, J.; Soler, D.; Genesca, A. [Department of Cell Biology, Physiology and Immunology, Universitat Autonoma de Barcelona, Bellaterra E-08193 (Spain); Tusell, L., E-mail: laura.tusell@uab.es [Department of Cell Biology, Physiology and Immunology, Universitat Autonoma de Barcelona, Bellaterra E-08193 (Spain)

    2010-01-05

    The cytokinesis-block micronucleus assay has emerged as a biomarker of chromosome damage relevant to cancer. Although it was initially developed to measure micronuclei, it is also useful for measuring nucleoplasmic bridges and nuclear buds. Abnormal nuclear morphologies are frequently observed in malignant tissues and short-term tumour cell cultures. Changes in chromosome structure and number resulting from chromosome instability are important factors in oncogenesis. Telomeres have become key players in the initiation of chromosome instability related to carcinogenesis by means of breakage-fusion-bridge cycles. To better understand the connection between telomere dysfunction and the appearance of abnormal nuclear morphologies, we have characterised the presence of micronuclei, nucleoplasmic bridges and nuclear buds in human mammary primary epithelial cells. These cells can proliferate beyond the Hayflick limit by spontaneously losing expression of the p16{sup INK4a} protein. Progressive telomere shortening leads to the loss of the capping function, and the appearance of end-to-end chromosome fusions that can enter into breakage-fusion-bridge cycles generating massive chromosomal instability. In human mammary epithelial cells, different types of abnormal nuclear morphologies were observed, however only nucleoplasmatic bridges and buds increased significantly with population doublings. Fluorescent in situ hybridisation using centromeric and painting specific probes for chromosomes with eroded telomeres has revealed that these chromosomes are preferentially included in the different types of abnormal nuclear morphologies observed, thus reflecting their common origin. Accordingly, real-time imaging of cell divisions enabled us to determine that anaphase bridge resolution was mainly through chromatin breakage and the formation of symmetric buds in daughter nuclei. Few micronuclei emerged in this cell system thus validating the scoring of nucleoplasmic bridges and

  7. Abnormal sex chromosome constitution and longitudinal growth: serum levels of insulin-like growth factor (IGF)-I, IGF binding protein-3, luteinizing hormone, and testosterone in 109 males with 47,XXY, 47,XYY, or sex-determining region of the Y chromosome (SRY)-positive 46,XX karyotypes

    DEFF Research Database (Denmark)

    Aksglaede, L.; Skakkebaek, N.E.; Juul, A.

    2008-01-01

    CONTEXT: Growth is a highly complex process regulated by the interaction between sex steroids and the GH IGF-axis. However, other factors such as sex chromosome-related genes play independent roles. AIM: The aim of the study was to evaluate the role of abnormal chromosome constitution for longitu...

  8. Can molecular cell biology explain chromosome motions?

    Directory of Open Access Journals (Sweden)

    Gagliardi L

    2011-05-01

    Full Text Available Abstract Background Mitotic chromosome motions have recently been correlated with electrostatic forces, but a lingering "molecular cell biology" paradigm persists, proposing binding and release proteins or molecular geometries for force generation. Results Pole-facing kinetochore plates manifest positive charges and interact with negatively charged microtubule ends providing the motive force for poleward chromosome motions by classical electrostatics. This conceptual scheme explains dynamic tracking/coupling of kinetochores to microtubules and the simultaneous depolymerization of kinetochore microtubules as poleward force is generated. Conclusion We question here why cells would prefer complex molecular mechanisms to move chromosomes when direct electrostatic interactions between known bound charge distributions can accomplish the same task much more simply.

  9. The complete sequence of human chromosome 5

    Energy Technology Data Exchange (ETDEWEB)

    Schmutz, Jeremy; Martin, Joel; Terry, Astrid; Couronne, Olivier; Grimwood, Jane; Lowry, State; Gordon, Laurie A.; Scott, Duncan; Xie, Gary; Huang, Wayne; Hellsten, Uffe; Tran-Gyamfi, Mary; She, Xinwei; Prabhakar, Shyam; Aerts, Andrea; Altherr, Michael; Bajorek, Eva; Black, Stacey; Branscomb, Elbert; Caoile, Chenier; Challacombe, Jean F.; Chan, Yee Man; Denys, Mirian; Detter, Chris; Escobar, Julio; Flowers, Dave; Fotopulos, Dea; Glavina, Tijana; Gomez, Maria; Gonzales, Eidelyn; Goodstenin, David; Grigoriev, Igor; Groza, Matthew; Hammon, Nancy; Hawkins, Trevor; Haydu, Lauren; Israni, Sanjay; Jett, Jamie; Kadner, Kristen; Kimbal, Heather; Kobayashi, Arthur; Lopez, Frederick; Lou, Yunian; Martinez, Diego; Medina, Catherine; Morgan, Jenna; Nandkeshwar, Richard; Noonan, James P.; Pitluck, Sam; Pollard, Martin; Predki, Paul; Priest, James; Ramirez, Lucia; Rash, Sam; Retterer, James; Rodriguez, Alex; Rogers, Stephanie; Salamov, Asaf; Salazar, Angelica; Thayer, Nina; Tice, Hope; Tsai, Ming; Ustaszewska, Anna; Vo, Nu; Wheeler, Jeremy; Wu, Kevin; Yang, Joan; Dickson, Mark; Cheng, Jan-Fang; Eichler, Evan E.; Olsen, Anne; Pennacchio, Len A.; Rokhsar, Daniel S.; Richardson, Paul; Lucas, Susan M.; Myers, Richard M.; Rubin, Edward M.

    2004-04-15

    Chromosome 5 is one of the largest human chromosomes yet has one of the lowest gene densities. This is partially explained by numerous gene-poor regions that display a remarkable degree of noncoding and syntenic conservation with non-mammalian vertebrates, suggesting they are functionally constrained. In total, we compiled 177.7 million base pairs of highly accurate finished sequence containing 923 manually curated protein-encoding genes including the protocadherin and interleukin gene families and the first complete versions of each of the large chromosome 5 specific internal duplications. These duplications are very recent evolutionary events and play a likely mechanistic role, since deletions of these regions are the cause of debilitating disorders including spinal muscular atrophy (SMA).

  10. Protein

    Science.gov (United States)

    ... Food Service Resources Additional Resources About FAQ Contact Protein Protein is found throughout the body—in muscle, ... the heart and respiratory system, and death. All Protein Isn’t Alike Protein is built from building ...

  11. "Chromosome": a knowledge-based system for the chromosome classification.

    Science.gov (United States)

    Ramstein, G; Bernadet, M

    1993-01-01

    Chromosome, a knowledge-based analysis system has been designed for the classification of human chromosomes. Its aim is to perform an optimal classification by driving a tool box containing the procedures of image processing, pattern recognition and classification. This paper presents the general architecture of Chromosome, based on a multiagent system generator. The image processing tool box is described from the met aphasic enhancement to the fine classification. Emphasis is then put on the knowledge base intended for the chromosome recognition. The global classification process is also presented, showing how Chromosome proceeds to classify a given chromosome. Finally, we discuss further extensions of the system for the karyotype building.

  12. Genetic control of wheat quality: interactions between chromosomal regions determining protein content and composition, dough rheology, and sponge and dough baking properties.

    Science.gov (United States)

    Mann, Gulay; Diffey, Simon; Cullis, Brian; Azanza, Fermin; Martin, David; Kelly, Alison; McIntyre, Lynne; Schmidt, Adele; Ma, Wujun; Nath, Zena; Kutty, Ibrahim; Leyne, P Emmett; Rampling, Lynette; Quail, Ken J; Morell, Matthew K

    2009-05-01

    While the genetic control of wheat processing characteristics such as dough rheology is well understood, limited information is available concerning the genetic control of baking parameters, particularly sponge and dough (S&D) baking. In this study, a quantitative trait loci (QTL) analysis was performed using a population of doubled haploid lines derived from a cross between Australian cultivars Kukri x Janz grown at sites across different Australian wheat production zones (Queensland in 2001 and 2002 and Southern and Northern New South Wales in 2003) in order to examine the genetic control of protein content, protein expression, dough rheology and sponge and dough baking performance. The study highlighted the inconsistent genetic control of protein content across the test sites, with only two loci (3A and 7A) showing QTL at three of the five sites. Dough rheology QTL were highly consistent across the 5 sites, with major effects associated with the Glu-B1 and Glu-D1 loci. The Glu-D1 5 + 10 allele had consistent effects on S&D properties across sites; however, there was no evidence for a positive effect of the high dough strength Glu-B1-al allele at Glu-B1. A second locus on 5D had positive effects on S&D baking at three of five sites. This study demonstrated that dough rheology measurements were poor predictors of S&D quality. In the absence of robust predictive tests, high heritability values for S&D demonstrate that direct selection is the current best option for achieving genetic gain in this product category.

  13. Evolution and survival on eutherian sex chromosomes.

    Directory of Open Access Journals (Sweden)

    Melissa A Wilson

    2009-07-01

    Full Text Available Since the two eutherian sex chromosomes diverged from an ancestral autosomal pair, the X has remained relatively gene-rich, while the Y has lost most of its genes through the accumulation of deleterious mutations in nonrecombining regions. Presently, it is unclear what is distinctive about genes that remain on the Y chromosome, when the sex chromosomes acquired their unique evolutionary rates, and whether X-Y gene divergence paralleled that of paralogs located on autosomes. To tackle these questions, here we juxtaposed the evolution of X and Y homologous genes (gametologs in eutherian mammals with their autosomal orthologs in marsupial and monotreme mammals. We discovered that genes on the X and Y acquired distinct evolutionary rates immediately following the suppression of recombination between the two sex chromosomes. The Y-linked genes evolved at higher rates, while the X-linked genes maintained the lower evolutionary rates of the ancestral autosomal genes. These distinct rates have been maintained throughout the evolution of X and Y. Specifically, in humans, most X gametologs and, curiously, also most Y gametologs evolved under stronger purifying selection than similarly aged autosomal paralogs. Finally, after evaluating the current experimental data from the literature, we concluded that unique mRNA/protein expression patterns and functions acquired by Y (versus X gametologs likely contributed to their retention. Our results also suggest that either the boundary between sex chromosome strata 3 and 4 should be shifted or that stratum 3 should be divided into two strata.

  14. Holocentric chromosomes: convergent evolution, meiotic adaptations, and genomic analysis.

    Science.gov (United States)

    Melters, Daniël P; Paliulis, Leocadia V; Korf, Ian F; Chan, Simon W L

    2012-07-01

    In most eukaryotes, the kinetochore protein complex assembles at a single locus termed the centromere to attach chromosomes to spindle microtubules. Holocentric chromosomes have the unusual property of attaching to spindle microtubules along their entire length. Our mechanistic understanding of holocentric chromosome function is derived largely from studies in the nematode Caenorhabditis elegans, but holocentric chromosomes are found over a broad range of animal and plant species. In this review, we describe how holocentricity may be identified through cytological and molecular methods. By surveying the diversity of organisms with holocentric chromosomes, we estimate that the trait has arisen at least 13 independent times (four times in plants and at least nine times in animals). Holocentric chromosomes have inherent problems in meiosis because bivalents can attach to spindles in a random fashion. Interestingly, there are several solutions that have evolved to allow accurate meiotic segregation of holocentric chromosomes. Lastly, we describe how extensive genome sequencing and experiments in nonmodel organisms may allow holocentric chromosomes to shed light on general principles of chromosome segregation.

  15. Caulobacter chromosome segregation is an ordered multistep process.

    Science.gov (United States)

    Shebelut, Conrad W; Guberman, Jonathan M; van Teeffelen, Sven; Yakhnina, Anastasiya A; Gitai, Zemer

    2010-08-10

    Despite its fundamental nature, bacterial chromosome segregation remains poorly understood. Viewing segregation as a single process caused multiple proposed mechanisms to appear in conflict and failed to explain how asymmetrically dividing bacteria break symmetry to move only one of their chromosomes. Here, we demonstrate that the ParA ATPase extends from one cell pole and pulls the chromosome by retracting upon association with the ParB DNA-binding protein. Surprisingly, ParA disruption has a specific effect on chromosome segregation that only perturbs the latter stages of this process. Using quantitative high-resolution imaging, we demonstrate that this specificity results from the multistep nature of chromosome translocation. We propose that Caulobacter chromosome segregation follows an ordered pathway of events with distinct functions and mechanisms. Initiation releases polar tethering of the origin of replication, distinction spatially differentiates the two chromosomes, and commitment irreversibly translocates the distal centromeric locus. Thus, much as eukaryotic mitosis involves a sequence of distinct subprocesses, Caulobacter cells also segregate their chromosomes through an orchestrated series of steps. We discuss how the multistep view of bacterial chromosome segregation can help to explain and reconcile outstanding puzzles and frame future investigation.

  16. Evolutionary interaction between W/Y chromosome and transposable elements.

    Science.gov (United States)

    Śliwińska, Ewa B; Martyka, Rafał; Tryjanowski, Piotr

    2016-06-01

    The W/Y chromosome is unique among chromosomes as it does not recombine in its mature form. The main side effect of cessation of recombination is evolutionary instability and degeneration of the W/Y chromosome, or frequent W/Y chromosome turnovers. Another important feature of W/Y chromosome degeneration is transposable element (TEs) accumulation. Transposon accumulation has been confirmed for all W/Y chromosomes that have been sequenced so far. Models of W/Y chromosome instability include the assemblage of deleterious mutations in protein coding genes, but do not include the influence of transposable elements that are accumulated gradually in the non-recombining genome. The multiple roles of genomic TEs, and the interactions between retrotransposons and genome defense proteins are currently being studied intensively. Small RNAs originating from retrotransposon transcripts appear to be, in some cases, the only mediators of W/Y chromosome function. Based on the review of the most recent publications, we present knowledge on W/Y evolution in relation to retrotransposable element accumulation.

  17. Chromosome numbers in Bromeliaceae

    Directory of Open Access Journals (Sweden)

    Cotias-de-Oliveira Ana Lúcia Pires

    2000-01-01

    Full Text Available The present study reports chromosome numbers of 17 species of Bromeliaceae, belonging to the genera Encholirium, Bromelia, Orthophytum, Hohenbergia, Billbergia, Neoglaziovia, Aechmea, Cryptanthus and Ananas. Most species present 2n = 50, however, Bromelia laciniosa, Orthophytum burle-marxii and O. maracasense are polyploids with 2n = 150, 2n = 100 and 2n = 150, respectively, while for Cryptanthus bahianus, 2n = 34 + 1-4B. B chromosomes were observed in Bromelia plumieri and Hohenbergia aff. utriculosa. The chromosome number of all species was determined for the first time, except for Billbergia chlorosticta and Cryptanthus bahianus. Our data supports the hypothesis of a basic number of x = 25 for the Bromeliaceae family and decreasing aneuploidy in the genus Cryptanthus.

  18. Those amazing dinoflagellate chromosomes

    Institute of Scientific and Technical Information of China (English)

    PETER J RIZZO

    2003-01-01

    Dinoflagellates are a very large and diverse group of eukaryotic algae that play a major role in aquatic food webs of both fresh water and marine habitats. Moreover, the toxic members of this group pose a health threat in the form of red tides. Finally, dinoflagellates are of great evolutionary importance,because of their taxonomic position, and their unusual chromosome structure and composition. While the cytoplasm of dinoflagellates is typically eukaryotic, the nucleus is unique when compared to the nucleus of other eukaryotes. More specifically, while the chromosomes of all other eukaryotes contain histones,dinoflagellate chromosomes lack histones completely. There are no known exceptions to this observation: all dinoflagellates lack histones, and all other eukaryotes contain histones. Nevertheless, dinoflagellates remain a relatively unstudied group of eukaryotes.

  19. Chromosomal redistribution of male-biased genes in mammalian evolution with two bursts of gene gain on the X chromosome.

    Science.gov (United States)

    Zhang, Yong E; Vibranovski, Maria D; Landback, Patrick; Marais, Gabriel A B; Long, Manyuan

    2010-10-05

    Mammalian X chromosomes evolved under various mechanisms including sexual antagonism, the faster-X process, and meiotic sex chromosome inactivation (MSCI). These forces may contribute to nonrandom chromosomal distribution of sex-biased genes. In order to understand the evolution of gene content on the X chromosome and autosome under these forces, we dated human and mouse protein-coding genes and miRNA genes on the vertebrate phylogenetic tree. We found that the X chromosome recently acquired a burst of young male-biased genes, which is consistent with fixation of recessive male-beneficial alleles by sexual antagonism. For genes originating earlier, however, this pattern diminishes and finally reverses with an overrepresentation of the oldest male-biased genes on autosomes. MSCI contributes to this dynamic since it silences X-linked old genes but not X-linked young genes. This demasculinization process seems to be associated with feminization of the X chromosome with more X-linked old genes expressed in ovaries. Moreover, we detected another burst of gene originations after the split of eutherian mammals and opossum, and these genes were quickly incorporated into transcriptional networks of multiple tissues. Preexisting X-linked genes also show significantly higher protein-level evolution during this period compared to autosomal genes, suggesting positive selection accompanied the early evolution of mammalian X chromosomes. These two findings cast new light on the evolutionary history of the mammalian X chromosome in terms of gene gain, sequence, and expressional evolution.

  20. Chromosomal redistribution of male-biased genes in mammalian evolution with two bursts of gene gain on the X chromosome.

    Directory of Open Access Journals (Sweden)

    Yong E Zhang

    Full Text Available Mammalian X chromosomes evolved under various mechanisms including sexual antagonism, the faster-X process, and meiotic sex chromosome inactivation (MSCI. These forces may contribute to nonrandom chromosomal distribution of sex-biased genes. In order to understand the evolution of gene content on the X chromosome and autosome under these forces, we dated human and mouse protein-coding genes and miRNA genes on the vertebrate phylogenetic tree. We found that the X chromosome recently acquired a burst of young male-biased genes, which is consistent with fixation of recessive male-beneficial alleles by sexual antagonism. For genes originating earlier, however, this pattern diminishes and finally reverses with an overrepresentation of the oldest male-biased genes on autosomes. MSCI contributes to this dynamic since it silences X-linked old genes but not X-linked young genes. This demasculinization process seems to be associated with feminization of the X chromosome with more X-linked old genes expressed in ovaries. Moreover, we detected another burst of gene originations after the split of eutherian mammals and opossum, and these genes were quickly incorporated into transcriptional networks of multiple tissues. Preexisting X-linked genes also show significantly higher protein-level evolution during this period compared to autosomal genes, suggesting positive selection accompanied the early evolution of mammalian X chromosomes. These two findings cast new light on the evolutionary history of the mammalian X chromosome in terms of gene gain, sequence, and expressional evolution.

  1. Sequencing the mouse Y chromosome reveals convergent gene acquisition and amplification on both sex chromosomes.

    Science.gov (United States)

    Soh, Y Q Shirleen; Alföldi, Jessica; Pyntikova, Tatyana; Brown, Laura G; Graves, Tina; Minx, Patrick J; Fulton, Robert S; Kremitzki, Colin; Koutseva, Natalia; Mueller, Jacob L; Rozen, Steve; Hughes, Jennifer F; Owens, Elaine; Womack, James E; Murphy, William J; Cao, Qing; de Jong, Pieter; Warren, Wesley C; Wilson, Richard K; Skaletsky, Helen; Page, David C

    2014-11-06

    We sequenced the MSY (male-specific region of the Y chromosome) of the C57BL/6J strain of the laboratory mouse Mus musculus. In contrast to theories that Y chromosomes are heterochromatic and gene poor, the mouse MSY is 99.9% euchromatic and contains about 700 protein-coding genes. Only 2% of the MSY derives from the ancestral autosomes that gave rise to the mammalian sex chromosomes. Instead, all but 45 of the MSY's genes belong to three acquired, massively amplified gene families that have no homologs on primate MSYs but do have acquired, amplified homologs on the mouse X chromosome. The complete mouse MSY sequence brings to light dramatic forces in sex chromosome evolution: lineage-specific convergent acquisition and amplification of X-Y gene families, possibly fueled by antagonism between acquired X-Y homologs. The mouse MSY sequence presents opportunities for experimental studies of a sex-specific chromosome in its entirety, in a genetically tractable model organism.

  2. Integrative bacterial artificial chromosomes for DNA integration into the Bacillus subtilis chromosome.

    Science.gov (United States)

    Juhas, Mario; Ajioka, James W

    2016-06-01

    Bacillus subtilis is a well-characterized model bacterium frequently used for a number of biotechnology and synthetic biology applications. Novel strategies combining the advantages of B. subtilis with the DNA assembly and editing tools of Escherichia coli are crucial for B. subtilis engineering efforts. We combined Gibson Assembly and λ red recombineering in E. coli with RecA-mediated homologous recombination in B. subtilis for bacterial artificial chromosome-mediated DNA integration into the well-characterized amyE target locus of the B. subtilis chromosome. The engineered integrative bacterial artificial chromosome iBAC(cav) can accept any DNA fragment for integration into B. subtilis chromosome and allows rapid selection of transformants by B. subtilis-specific antibiotic resistance and the yellow fluorescent protein (mVenus) expression. We used the developed iBAC(cav)-mediated system to integrate 10kb DNA fragment from E. coli K12 MG1655 into B. subtilis chromosome. iBAC(cav)-mediated chromosomal integration approach will facilitate rational design of synthetic biology applications in B. subtilis.

  3. Human ring chromosomes and small supernumerary marker chromosomes-do they have telomeres?

    Science.gov (United States)

    Guilherme, Roberta Santos; Klein, Elisabeth; Venner, Claudia; Hamid, Ahmed B; Bhatt, Samarth; Melaragno, Maria Isabel; Volleth, Marianne; Polityko, Anna; Kulpanovich, Anna; Kosyakova, Nadezda; Liehr, Thomas

    2012-10-01

    Ring chromosomes and small supernumerary marker chromosomes (sSMC) are enigmatic types of derivative chromosomes, in which the telomeres are thought to play a crucial role in their formation and stabilization. Considering that there are only a few studies that evaluate the presence of telomeric sequences in ring chromosomes and on sSMC, here, we analyzed 14 ring chromosomes and 29 sSMC for the presence of telomeric sequences through fluorescence in situ hybridization (FISH). The results showed that ring chromosomes can actually fall into two groups: the ones with or without telomeres. Additionally, telomeric signals were detectable at both ends of centric and neocentric sSMC with inverted duplication shape, as well as in complex sSMC. Apart from that, generally both ring- and centric minute-shaped sSMC did not present telomeric sequences neither detectable by FISH nor by a second protein-directed immunohistochemical approach. However, the fact that telomeres are absent does not automatically mean that the sSMC has a ring shape, as often deduced in the previous literature. Overall, the results obtained by FISH studies directed against telomeres need to be checked carefully by other approaches.

  4. The 172 kb prkA-addAB region from 83° to 97° of the Bacillus subtilis chromosome contains several dysfunctional genes, the glyB marker, many genes encoding transporter proteins, and the ubiquitous hit gene

    NARCIS (Netherlands)

    Noback, Michiel A.; Holsappel, Siger; Kiewiet, Rense; Terpstra, Peter; Wambutt, Rolf; Wedler, Holger; Venema, Gerard; Bron, Sierd

    1998-01-01

    A 171812 bp nucleotide sequence between prkA and addAB (83° to 97°) on the genetic map of the Bacillus subtilis 168 chromosome was determined and analysed. An accurate physical/genetic map of this previously poorly described chromosomal region was constructed. One hundred and seventy open reading fr

  5. The 172 kb prkA-addAB region from 83 degrees to 97 degrees of the Bacillus subtilis chromosome contains several dysfunctional genes, the glyB marker, many genes encoding transporter proteins, and the ubiquitous hit gene

    NARCIS (Netherlands)

    Noback, MA; Holsappel, S; Kiewiet, R; Terpstra, P; Wambutt, R; Wedler, H; Venema, G; Bron, S

    1998-01-01

    A 171812 bp nucleotide sequence between prkA and addAB (83 degrees to 97 degrees) on the genetic map of the Bacillus subtilis 168 chromosome was determined and analysed. An accurate physical/genetic map of this previously poorly described chromosomal region was constructed. One hundred and seventy o

  6. The gene for human gap junction protein connexin37 (GJA4) maps to chromosome 1p35.1, in the vicinity of D1S195

    Energy Technology Data Exchange (ETDEWEB)

    Van Camp, G.; Coucke, P.; Willems, P.J. [Univ. of Antwerp (Belgium)] [and others

    1995-11-20

    Gap junctions are plasma membrane structures containing channels that allow the exchange of small molecules between cells. Each hemichannel is an oligomer of six subunit proteins called connexins. The formation of intercellular channels is possible through interaction with connexins in the plasma membrane of adjacent cells. Gapjunction channels allow the passage of different molecules up to 1 kDa, such as ions, many second messengers, and small metabolites. Connexins are numbered according to their molecular mass in kilodaltons, calculated from the gene sequences. They are found in the vast majority of cell types and facilitate intercellular communication between cells. Connexins are encoded by a family of homologous genes with highly conserved extracellular and transmembrane domains, whereas the cytoplasmic regions are specific for each subtype. All connexin genes described up to now contain no introns in the coding region. 17 refs., 1 fig.

  7. Chromosomal rearrangements in cattle and pigs revealed by chromosome microdissection and chromosome painting

    Directory of Open Access Journals (Sweden)

    Yerle Martine

    2003-11-01

    Full Text Available Abstract A pericentric inversion of chromosome 4 in a boar, as well as a case of (2q-;5p+ translocation mosaicism in a bull were analysed by chromosome painting using probes generated by conventional microdissection. For the porcine inversion, probes specific for p arms and q arms were produced and hybridised simultaneously on metaphases of a heterozygote carrier. In the case of the bovine translocation, two whole chromosome probes (chromosome 5, and derived chromosome 5 were elaborated and hybridised independently on chromosomal preparations of the bull who was a carrier of the mosaic translocation. The impossibility of differentiating chromosomes 2 and der(2 from other chromosomes of the metaphases did not allow the production of painting probes for these chromosomes. For all experiments, the quality of painting was comparable to that usually observed with probes obtained from flow-sorted chromosomes. The results obtained allowed confirmation of the interpretations proposed with G-banding karyotype analyses. In the bovine case, however, the reciprocity of the translocation could not be proven. The results presented in this paper show the usefulness of the microdissection technique for characterising chromosomal rearrangements in species for which commercial probes are not available. They also confirmed that the main limiting factor of the technique is the quality of the chromosomal preparations, which does not allow the identification of target chromosomes or chromosome fragments in all cases.

  8. Cbx2 stably associates with mitotic chromosomes via a PRC2- or PRC1-independent mechanism and is needed for recruiting PRC1 complex to mitotic chromosomes.

    Science.gov (United States)

    Zhen, Chao Yu; Duc, Huy Nguyen; Kokotovic, Marko; Phiel, Christopher J; Ren, Xiaojun

    2014-11-15

    Polycomb group (PcG) proteins are epigenetic transcriptional factors that repress key developmental regulators and maintain cellular identity through mitosis via a poorly understood mechanism. Using quantitative live-cell imaging in mouse ES cells and tumor cells, we demonstrate that, although Polycomb repressive complex (PRC) 1 proteins (Cbx-family proteins, Ring1b, Mel18, and Phc1) exhibit variable capacities of association with mitotic chromosomes, Cbx2 overwhelmingly binds to mitotic chromosomes. The recruitment of Cbx2 to mitotic chromosomes is independent of PRC1 or PRC2, and Cbx2 is needed to recruit PRC1 complex to mitotic chromosomes. Quantitative fluorescence recovery after photobleaching analysis indicates that PRC1 proteins rapidly exchange at interphasic chromatin. On entry into mitosis, Cbx2, Ring1b, Mel18, and Phc1 proteins become immobilized at mitotic chromosomes, whereas other Cbx-family proteins dynamically bind to mitotic chromosomes. Depletion of PRC1 or PRC2 protein has no effect on the immobilization of Cbx2 on mitotic chromosomes. We find that the N-terminus of Cbx2 is needed for its recruitment to mitotic chromosomes, whereas the C-terminus is required for its immobilization. Thus these results provide fundamental insights into the molecular mechanisms of epigenetic inheritance.

  9. Chromosomal rearrangement interferes with meiotic X chromosome inactivation

    OpenAIRE

    Homolka, David; Ivanek, Robert; Capkova, Jana; Jansa, Petr; Forejt, Jiri

    2007-01-01

    Heterozygosity for certain mouse and human chromosomal rearrangements is characterized by the incomplete meiotic synapsis of rearranged chromosomes, by their colocalization with the XY body in primary spermatocytes, and by male-limited sterility. Previously, we argued that such X–autosomal associations could interfere with meiotic sex chromosome inactivation. Recently, supporting evidence has reported modifications of histones in rearranged chromosomes by a process called the meiotic silencin...

  10. DNA Repair Defects and Chromosomal Aberrations

    Science.gov (United States)

    Hada, Megumi; George, K. A.; Huff, J. L.; Pluth, J. M.; Cucinotta, F. A.

    2009-01-01

    Yields of chromosome aberrations were assessed in cells deficient in DNA doublestrand break (DSB) repair, after exposure to acute or to low-dose-rate (0.018 Gy/hr) gamma rays or acute high LET iron nuclei. We studied several cell lines including fibroblasts deficient in ATM (ataxia telangiectasia mutated; product of the gene that is mutated in ataxia telangiectasia patients) or NBS (nibrin; product of the gene mutated in the Nijmegen breakage syndrome), and gliomablastoma cells that are proficient or lacking in DNA-dependent protein kinase (DNA-PK) activity. Chromosomes were analyzed using the fluorescence in situ hybridization (FISH) chromosome painting method in cells at the first division post irradiation, and chromosome aberrations were identified as either simple exchanges (translocations and dicentrics) or complex exchanges (involving >2 breaks in 2 or more chromosomes). Gamma irradiation induced greater yields of both simple and complex exchanges in the DSB repair-defective cells than in the normal cells. The quadratic dose-response terms for both simple and complex chromosome exchanges were significantly higher for the ATM- and NBS-deficient lines than for normal fibroblasts. However, in the NBS cells the linear dose-response term was significantly higher only for simple exchanges. The large increases in the quadratic dose-response terms in these repair-defective cell lines points the importance of the functions of ATM and NBS in chromatin modifications to facilitate correct DSB repair and minimize the formation of aberrations. The differences found between ATM- and NBS-deficient cells at low doses suggest that important questions should with regard to applying observations of radiation sensitivity at high dose to low-dose exposures. For aberrations induced by iron nuclei, regression models preferred purely linear dose responses for simple exchanges and quadratic dose responses for complex exchanges. Relative biological effectiveness (RBE) factors of all of

  11. Ki-67 acts as a biological surfactant to disperse mitotic chromosomes.

    Science.gov (United States)

    Cuylen, Sara; Blaukopf, Claudia; Politi, Antonio Z; Müller-Reichert, Thomas; Neumann, Beate; Poser, Ina; Ellenberg, Jan; Hyman, Anthony A; Gerlich, Daniel W

    2016-07-14

    Eukaryotic genomes are partitioned into chromosomes that form compact and spatially well-separated mechanical bodies during mitosis. This enables chromosomes to move independently of each other for segregation of precisely one copy of the genome to each of the nascent daughter cells. Despite insights into the spatial organization of mitotic chromosomes and the discovery of proteins at the chromosome surface, the molecular and biophysical bases of mitotic chromosome structural individuality have remained unclear. Here we report that the proliferation marker protein Ki-67 (encoded by the MKI67 gene), a component of the mitotic chromosome periphery, prevents chromosomes from collapsing into a single chromatin mass after nuclear envelope disassembly, thus enabling independent chromosome motility and efficient interactions with the mitotic spindle. The chromosome separation function of human Ki-67 is not confined within a specific protein domain, but correlates with size and net charge of truncation mutants that apparently lack secondary structure. This suggests that Ki-67 forms a steric and electrostatic charge barrier, similar to surface-active agents (surfactants) that disperse particles or phase-separated liquid droplets in solvents. Fluorescence correlation spectroscopy showed a high surface density of Ki-67 and dual-colour labelling of both protein termini revealed an extended molecular conformation, indicating brush-like arrangements that are characteristic of polymeric surfactants. Our study thus elucidates a biomechanical role of the mitotic chromosome periphery in mammalian cells and suggests that natural proteins can function as surfactants in intracellular compartmentalization.

  12. Electochemical detection of chromosome translocation

    DEFF Research Database (Denmark)

    Kwasny, Dorota; Dimaki, Maria; Silahtaroglu, Asli;

    2014-01-01

    Cytogenetics is a study of the cell structure with a main focus on chromosomes content and their structure. Chromosome abnormalities, such as translocations may cause various genetic disorders and heametological malignancies. Chromosome translocations are structural rearrangements of two...... chromosomes that results in formation of derivative chromosomes with a mixed DNA sequence. The method currently used for their detection is Fluorescent In Situ Hybridization, which requires a use of expensive, fluorescently labeled probes that target the derivative chromosomes. We present here a double...... hybridization approach developed for label-free detection of the chromosome translocations. For specific translocation detection it is necessary to determine that the two DNA sequences forming a derivative chromosome are connected, which is achieved by two subsequent hybridization steps. The electrochemical...

  13. Chromosome Variations And Human Behavior

    Science.gov (United States)

    Soudek, D.

    1974-01-01

    Article focused on the science of cytogenetics, which studied the transmission of the units of heredity called chromosomes, and considered the advantage of proper diagnosis of genetic diseases, treated on the chromosomal level. (Author/RK)

  14. Ring chromosome 13

    DEFF Research Database (Denmark)

    Brandt, C A; Hertz, Jens Michael; Petersen, M B;

    1992-01-01

    A stillborn male child with anencephaly and multiple malformations was found to have the karyotype 46,XY,r(13) (p11q21.1). The breakpoint at 13q21.1, determined by high resolution banding, is the most proximal breakpoint ever reported in patients with ring chromosome 13. In situ hybridisation...

  15. Chromosomes, cancer and radiosensitivity

    Energy Technology Data Exchange (ETDEWEB)

    Samouhos, E.

    1983-08-01

    Some specific chromosomal abnormalities are associated with certain cancers. The earliest description of such a specific association is the one of the Philadelphia chromosome and myelogenous leukemia (1960). Other congenital karyotype abnormalities are associated with specific cancers. Examples of these are Down's syndrome with leukemia and Klinefelter's syndrome with male breast cancer. Genetic diseases of increased chromosome breakage, or of defective chromosome repair, are associated with greatly increased cancer incidence. Three such diseases have been recognized: 1) Fanconi's anemia, associated with leukemias and lymphomas, 2) Bloom's syndrome, associated with acute leukemias and lymphosarcoma, and 3) ataxia telangiectasia, associated with Hodgkin's disease, leukemia, and lymphosarcomas. Ten percent of individuals with ataxia telangiectasia will develop one of these neoplasms. Individuals with certain of these syndromes display an unusually high radiosensitivity. Radiation therapy for cancers has been fatal in patients who received as low as 3000 rad. This remarkable radiosensitivity has been quantitated in cell cultures from such cases. Evidence suggests that the apparent sensitivity may reflect subnormal ability to repair radiation damage. The rapid proliferation of information in this field stems from the interdigitation of many disciplines and specialties, including cytogenetics, cell biology, molecular biology, epidemiology, radiobiology, and several others. This paper is intended for clinicians; it presents a structured analytic scheme for correlating and classifying this multidisciplinary information as it becomes available.

  16. The Y Chromosome

    Science.gov (United States)

    Offner, Susan

    2010-01-01

    The Y chromosome is of great interest to students and can be used to teach about many important biological concepts in addition to sex determination. This paper discusses mutation, recombination, mammalian sex determination, sex determination in general, and the evolution of sex determination in mammals. It includes a student activity that…

  17. Why Chromosome Palindromes?

    Directory of Open Access Journals (Sweden)

    Esther Betrán

    2012-01-01

    Full Text Available We look at sex-limited chromosome (Y or W evolution with particular emphasis on the importance of palindromes. Y chromosome palindromes consist of inverted duplicates that allow for local recombination in an otherwise nonrecombining chromosome. Since palindromes enable intrachromosomal gene conversion that can help eliminate deleterious mutations, they are often highlighted as mechanisms to protect against Y degeneration. However, the adaptive significance of recombination resides in its ability to decouple the evolutionary fates of linked mutations, leading to both a decrease in degeneration rate and an increase in adaptation rate. Our paper emphasizes the latter, that palindromes may exist to accelerate adaptation by increasing the potential targets and fixation rates of incoming beneficial mutations. This hypothesis helps reconcile two enigmatic features of the “palindromes as protectors” view: (1 genes that are not located in palindromes have been retained under purifying selection for tens of millions of years, and (2 under models that only consider deleterious mutations, gene conversion benefits duplicate gene maintenance but not initial fixation. We conclude by looking at ways to test the hypothesis that palindromes enhance the rate of adaptive evolution of Y-linked genes and whether this effect can be extended to palindromes on other chromosomes.

  18. Chromosomal Location and Expression of Green Fluorescent Protein (gfp) Gene in Microspore Derived Transgenic Barley (Hordeum vulgare L.)%转基因大麦中gfp基因的染色体位置及其表达

    Institute of Scientific and Technical Information of China (English)

    陈建民; Carlson A R; 万建民; Kasha K J

    2003-01-01

    通过对大麦小孢子进行基因枪轰击获得4株转绿色荧光蛋白基因(gfp)的植株(A、C、D、E),以gfp基因为探针进行荧光原位杂交(FISH)研究转化植株中转基因插入位置和基因表达.4个株系在染色体7L(5HL)的不同位置都有一个插入点,而E株系在染色体5S(7HS)还有第2个插入点.所有的转基因T0代植株都是半合子并在T1、T2代发生分离.D株系GFP未表达,但FISH和PCR分析表明gfp基因已成功插入其染色体.各株系在根尖和花粉中的GFP表达水平不同:C株系在花粉表达强而在根尖表达中等;A株系在花粉中等表达而在根尖表达较淡;E株系则在根尖高表达,花粉中等表达.A和C株系在根尖和花粉的GFP分离都表现单位点特性,而E株系的根尖分离表现重叠作用(15∶1)特征,但在花粉中表达GFP的频率低.PCR结果和3个分离株系的根尖表达结果一致.D和E株系的GFP表达不正常可能和gfp基因插入位置或基因的结构有关.%Four doubled haploid barley lines (A,C,D,E) derived from gfp (green fluorescent protein) transformation and selection following particle bombardment of microspores were studied for gene expression pattern and the location of genome inserts.The integration sites were detected by fluorescence in situ hybridization (FISH) using the gfp plasmid DNA as a probe.Plants from events A,C,D and E all have a single insert site on chromosome 7L(5HL) at different locations while line E has a second insert site on chromosome 5S(7HS).All original transgenic plants were hemizygous for the transgenes and segregated in the T1 and T2 generations.Although line D had no GFP expression,FISH and PCR could detect gfp gene on its chromosome in transformed plants.Expression levels of GFP varied with lines and tissues examined.Plants from line C showed good expression in pollen and an intermediate level in root tips.Plants from A have intermediate expression of GFP in the pollen and light expression in the

  19. Sir protein–independent repair of dicentric chromosomes in Saccharomyces cerevisiae

    Science.gov (United States)

    McCleary, David F.; Steakley, David Lee; Rine, Jasper

    2016-01-01

    Sir2 protein has been reported to be recruited to dicentric chromosomes under tension, and such chromosomes are reported to be especially vulnerable to breakage in sir2Δ mutants. We found that the loss of viability in such mutants was an indirect effect of the repression of nonhomologous end joining in Sir− mutants and that the apparent recruitment of Sir2 protein to chromosomes under tension was likely due to methodological weakness in early chromatin immunoprecipitation studies. PMID:27466318

  20. The X and Y chromosome in meiosis: how and why they keep silent

    Institute of Scientific and Technical Information of China (English)

    Godfried W van der Heijden; Maureen Eijpe; Willy M Baarends

    2011-01-01

    The XX/XY sex chromosomal system of mammals,including human,challenges the chromosome pairing mechanism during male meiosis.Pairing and subsequent separation of homologous chromosomes generates haploid cells from diploid cells during the meiotic divisions.One of the basic requirements for recognition between homologous chromosomes is DNA sequence identity.Since the X and Y chromosome share little homology,their quest for each other is difficult,and has special characteristics.During the lengthy meiotic prophase,all autosomal chromosomes synapse,by forming a special protein structure called the synaptonemal complex,which connects the chromosomal axes.In contrast,the X and Y chromosome synapse only in the short homologous pseudoautosomal regions,and form the so-called XY body.

  1. Release of chromosomes from the nuclear envelope: a universal mechanism for eukaryotic mitosis?

    Science.gov (United States)

    Kanoh, Junko

    2013-01-01

    Multiple domains of chromosomes are associated with the nuclear envelope (NE) in interphase. The association between chromosomes and the NE is involved in a variety of chromosomal reactions, such as gene expression and DNA repair. However, efficient chromosome movements are required for the fidelity of chromosome segregation in mitosis. Most higher eukaryotes perform open mitosis, in which the NE is broken down, enabling chromosomes to be released from the NE as well as spindle microtubules to access to kinetochores. By contrast, lower eukaryotes, such as Schizosaccharomyces pombe, perform closed mitosis, during which NE breakdown does not occur. In S. pombe, telomeres are tethered to the NE in interphase. Phosphorylation of the telomere-binding protein Rap1 at M phase promotes transient dissociation of telomeres from the NE, facilitating the faithful chromosome segregation. These findings imply a common mechanism for genome stability via the dissociation of chromosomes from the NE in eukaryotic mitosis.

  2. Association study of wheat grain protein composition reveals that gliadin and glutenin composition are trans-regulated by different chromosome regions.

    Science.gov (United States)

    Plessis, Anne; Ravel, Catherine; Bordes, Jacques; Balfourier, François; Martre, Pierre

    2013-09-01

    Wheat grain storage protein (GSP) content and composition are the main determinants of the end-use value of bread wheat (Triticum aestivum L.) grain. The accumulation of glutenins and gliadins, the two main classes of GSP in wheat, is believed to be mainly controlled at the transcriptional level through a network of transcription factors. This regulation network could lead to stable cross-environment allometric scaling relationships between the quantity of GSP classes/subunits and the total quantity of nitrogen per grain. This work conducted a genetic mapping study of GSP content and composition and allometric scaling parameters of grain N allocation using a bread wheat worldwide core collection grown in three environments. The core collection was genotyped with 873 markers for genome-wide association and 167 single nucleotide polymorphism markers in 51 candidate genes for candidate association. The candidate genes included 35 transcription factors (TFs) expressed in grain. This work identified 74 loci associated with 38 variables, of which 19 were candidate genes or were tightly linked with candidate genes. Besides structural GSP genes, several loci putatively trans-regulating GSP accumulation were identified. Seven candidate TFs, including four wheat orthologues of barley TFs that control hordein gene expression, were associated or in strong linkage disequilibrium with markers associated with the composition or quantity of glutenin or gliadin, or allometric grain N allocation parameters, confirming the importance of the transcriptional control of GSP accumulation. Genome-wide association results suggest that the genes regulating glutenin and gliadin compositions are mostly distinct from each other and operate differently.

  3. [Dicentric Y chromosome].

    Science.gov (United States)

    Abdelmoula, N Bouayed; Amouri, A

    2005-01-01

    Dicentric Y chromosomes are the most common Y structural abnormalities and their influence on gonadal and somatic development is extremely variable. Here, we report the third comprehensive review of the literature concerning dicentric Y chromosomes reported since 1994. We find 78 new cases for which molecular studies (PCR or FISH) have been widely applied to investigate SRY (68% of cases), GBY, ZFY, RFS4Y, GCY and different genes at AZF region. For dic(Yq), all cases (n = 20) were mosaic for 45,X and 4 of them were also mosaic for a 46,XY cell line. When breakpoints were available (15/20 cases), they were in Yp11. 50% of cases were phenotypic female and 20% phenotypic male while 20% of cases were reported with gonadal dysgenesis. Gonadal histology was defined in 8 cases but only in one case, gonadal tissu was genetically investigated because of gonadoblastoma. For dic(Yp) (n = 55), mosaicism concerned only 45,X cell line and was found in 50 cases while the remainder five cases were homogeneous. When breakpoints were available, it was at Yq11 in 50 cases and at Yq12 in two cases. 54% of cases were phenotypic female, 26% were phenotypic male and 18% were associated with genitalia ambiguous. SRY was analyzed in 33 cases, sequenced in 9 cases and was muted in only one case. Gonads were histologically explored in 34 cases and genetically investigated in 8 cases. Gonadoblastoma was found in only two cases. Through this review, it seems that phenotype-genotype correlations are still not possible and that homogeneous studies of dic(Y) in more patients using molecular tools for structural characterization of the rearranged Y chromosome and assessment of mosaicism in many organs are necessary to clarify the basis of the phenotypic heterogeneity of dicentric Y chromosomes and then to help phenotypic prediction of such chromosome rearrangement.

  4. Dynamics of X Chromosome Inactivation

    NARCIS (Netherlands)

    F. Loos (Friedemann)

    2015-01-01

    markdownabstract__Abstract__ Dosage compensation evolved to account for the difference in expression of sex chromosome-linked genes. In mammals dosage compensation is achieved by inactivation of one X chromosome during early female embryogenesis in a process called X chromosome inactivation (XCI).

  5. Chromosomal breakpoints characterization of two supernumerary ring chromosomes 20.

    Science.gov (United States)

    Guediche, N; Brisset, S; Benichou, J-J; Guérin, N; Mabboux, P; Maurin, M-L; Bas, C; Laroudie, M; Picone, O; Goldszmidt, D; Prévot, S; Labrune, P; Tachdjian, G

    2010-02-01

    The occurrence of an additional ring chromosome 20 is a rare chromosome abnormality, and no common phenotype has been yet described. We report on two new patients presenting with a supernumerary ring chromosome 20 both prenatally diagnosed. The first presented with intrauterine growth retardation and some craniofacial dysmorphism, and the second case had a normal phenotype except for obesity. Conventional cytogenetic studies showed for each patient a small supernumerary marker chromosome (SMC). Using fluorescence in situ hybridization, these SMCs corresponded to ring chromosomes 20 including a part of short and long arms of chromosome 20. Detailed molecular cytogenetic characterization showed different breakpoints (20p11.23 and 20q11.23 for Patient 1 and 20p11.21 and 20q11.21 for Patient 2) and sizes of the two ring chromosomes 20 (13.6 Mb for case 1 and 4.8 Mb for case 2). Review of the 13 case reports of an extra r(20) ascertained postnatally (8 cases) and prenatally (5 cases) showed varying degrees of phenotypic abnormalities. We document a detailed molecular cytogenetic chromosomal breakpoints characterization of two cases of supernumerary ring chromosomes 20. These results emphasize the need to characterize precisely chromosomal breakpoints of supernumerary ring chromosomes 20 in order to establish genotype-phenotype correlation. This report may be helpful for prediction of natural history and outcome, particularly in prenatal diagnosis.

  6. B chromosomes have a functional effect on female sex determination in Lake Victoria cichlid fishes.

    Science.gov (United States)

    Yoshida, Kohta; Terai, Yohey; Mizoiri, Shinji; Aibara, Mitsuto; Nishihara, Hidenori; Watanabe, Masakatsu; Kuroiwa, Asato; Hirai, Hirohisa; Hirai, Yuriko; Matsuda, Yoichi; Okada, Norihiro

    2011-08-01

    The endemic cichlid fishes in Lake Victoria are a model system for speciation through adaptive radiation. Although the evolution of the sex-determination system may also play a role in speciation, little is known about the sex-determination system of Lake Victoria cichlids. To understand the evolution of the sex-determination system in these fish, we performed cytogenetic analysis in 11 cichlid species from Lake Victoria. B chromosomes, which are present in addition to standard chromosomes, were found at a high prevalence rate (85%) in these cichlids. In one species, B chromosomes were female-specific. Cross-breeding using females with and without the B chromosomes demonstrated that the presence of the B chromosomes leads to a female-biased sex ratio in this species. Although B chromosomes were believed to be selfish genetic elements with little effect on phenotype and to lack protein-coding genes, the present study provides evidence that B chromosomes have a functional effect on female sex determination. FISH analysis using a BAC clone containing B chromosome DNA suggested that the B chromosomes are derived from sex chromosomes. Determination of the nucleotide sequences of this clone (104.5 kb) revealed the presence of several protein-coding genes in the B chromosome, suggesting that B chromosomes have the potential to contain functional genes. Because some sex chromosomes in amphibians and arthropods are thought to be derived from B chromosomes, the B chromosomes in Lake Victoria cichlids may represent an evolutionary transition toward the generation of sex chromosomes.

  7. B chromosomes have a functional effect on female sex determination in Lake Victoria cichlid fishes.

    Directory of Open Access Journals (Sweden)

    Kohta Yoshida

    2011-08-01

    Full Text Available The endemic cichlid fishes in Lake Victoria are a model system for speciation through adaptive radiation. Although the evolution of the sex-determination system may also play a role in speciation, little is known about the sex-determination system of Lake Victoria cichlids. To understand the evolution of the sex-determination system in these fish, we performed cytogenetic analysis in 11 cichlid species from Lake Victoria. B chromosomes, which are present in addition to standard chromosomes, were found at a high prevalence rate (85% in these cichlids. In one species, B chromosomes were female-specific. Cross-breeding using females with and without the B chromosomes demonstrated that the presence of the B chromosomes leads to a female-biased sex ratio in this species. Although B chromosomes were believed to be selfish genetic elements with little effect on phenotype and to lack protein-coding genes, the present study provides evidence that B chromosomes have a functional effect on female sex determination. FISH analysis using a BAC clone containing B chromosome DNA suggested that the B chromosomes are derived from sex chromosomes. Determination of the nucleotide sequences of this clone (104.5 kb revealed the presence of several protein-coding genes in the B chromosome, suggesting that B chromosomes have the potential to contain functional genes. Because some sex chromosomes in amphibians and arthropods are thought to be derived from B chromosomes, the B chromosomes in Lake Victoria cichlids may represent an evolutionary transition toward the generation of sex chromosomes.

  8. Filament depolymerization can pull a chromosome during bacterial mitosis

    Science.gov (United States)

    Banigan, Edward; Gelbart, Michael; Gitai, Zemer; Liu, Andrea; Wingreen, Ned

    2011-03-01

    Chromosome segregation is fundamental to all cells, but the force-generating mechanisms underlying chromosome translocation in bacteria remain mysterious. Caulobacter crescentus utilizes a depolymerization-driven process in which a ParA protein structure elongates from the new cell pole and binds to a ParB-decorated chromosome, and then retracts via disassembly, thus pulling the chromosome across the cell. This poses the question of how a depolymerizing structure can robustly pull the chromosome that is disassembling it. We perform Brownian dynamics simulations with a simple and physically consistent model of the ParABS system. The simulations suggest that the mechanism of translocation is ``self-diffusiophoretic'': by disassembling ParA, ParB generates a ParA concentration gradient so that the concentration of ParA is higher in front of the chromosome than behind it. Since the chromosome is attracted to ParA via ParB, it moves up the ParA gradient and across the cell. We find that translocation is controlled by the product of an effective relaxation time for the chromosome and the rate of ParA disassembly. Our results provide a physical explanation of the mechanism of depolymerization-driven translocation and suggest physical explanations for recent experimental observations.

  9. The DNA sequence of the human X chromosome.

    Science.gov (United States)

    Ross, Mark T; Grafham, Darren V; Coffey, Alison J; Scherer, Steven; McLay, Kirsten; Muzny, Donna; Platzer, Matthias; Howell, Gareth R; Burrows, Christine; Bird, Christine P; Frankish, Adam; Lovell, Frances L; Howe, Kevin L; Ashurst, Jennifer L; Fulton, Robert S; Sudbrak, Ralf; Wen, Gaiping; Jones, Matthew C; Hurles, Matthew E; Andrews, T Daniel; Scott, Carol E; Searle, Stephen; Ramser, Juliane; Whittaker, Adam; Deadman, Rebecca; Carter, Nigel P; Hunt, Sarah E; Chen, Rui; Cree, Andrew; Gunaratne, Preethi; Havlak, Paul; Hodgson, Anne; Metzker, Michael L; Richards, Stephen; Scott, Graham; Steffen, David; Sodergren, Erica; Wheeler, David A; Worley, Kim C; Ainscough, Rachael; Ambrose, Kerrie D; Ansari-Lari, M Ali; Aradhya, Swaroop; Ashwell, Robert I S; Babbage, Anne K; Bagguley, Claire L; Ballabio, Andrea; Banerjee, Ruby; Barker, Gary E; Barlow, Karen F; Barrett, Ian P; Bates, Karen N; Beare, David M; Beasley, Helen; Beasley, Oliver; Beck, Alfred; Bethel, Graeme; Blechschmidt, Karin; Brady, Nicola; Bray-Allen, Sarah; Bridgeman, Anne M; Brown, Andrew J; Brown, Mary J; Bonnin, David; Bruford, Elspeth A; Buhay, Christian; Burch, Paula; Burford, Deborah; Burgess, Joanne; Burrill, Wayne; Burton, John; Bye, Jackie M; Carder, Carol; Carrel, Laura; Chako, Joseph; Chapman, Joanne C; Chavez, Dean; Chen, Ellson; Chen, Guan; Chen, Yuan; Chen, Zhijian; Chinault, Craig; Ciccodicola, Alfredo; Clark, Sue Y; Clarke, Graham; Clee, Chris M; Clegg, Sheila; Clerc-Blankenburg, Kerstin; Clifford, Karen; Cobley, Vicky; Cole, Charlotte G; Conquer, Jen S; Corby, Nicole; Connor, Richard E; David, Robert; Davies, Joy; Davis, Clay; Davis, John; Delgado, Oliver; Deshazo, Denise; Dhami, Pawandeep; Ding, Yan; Dinh, Huyen; Dodsworth, Steve; Draper, Heather; Dugan-Rocha, Shannon; Dunham, Andrew; Dunn, Matthew; Durbin, K James; Dutta, Ireena; Eades, Tamsin; Ellwood, Matthew; Emery-Cohen, Alexandra; Errington, Helen; Evans, Kathryn L; Faulkner, Louisa; Francis, Fiona; Frankland, John; Fraser, Audrey E; Galgoczy, Petra; Gilbert, James; Gill, Rachel; Glöckner, Gernot; Gregory, Simon G; Gribble, Susan; Griffiths, Coline; Grocock, Russell; Gu, Yanghong; Gwilliam, Rhian; Hamilton, Cerissa; Hart, Elizabeth A; Hawes, Alicia; Heath, Paul D; Heitmann, Katja; Hennig, Steffen; Hernandez, Judith; Hinzmann, Bernd; Ho, Sarah; Hoffs, Michael; Howden, Phillip J; Huckle, Elizabeth J; Hume, Jennifer; Hunt, Paul J; Hunt, Adrienne R; Isherwood, Judith; Jacob, Leni; Johnson, David; Jones, Sally; de Jong, Pieter J; Joseph, Shirin S; Keenan, Stephen; Kelly, Susan; Kershaw, Joanne K; Khan, Ziad; Kioschis, Petra; Klages, Sven; Knights, Andrew J; Kosiura, Anna; Kovar-Smith, Christie; Laird, Gavin K; Langford, Cordelia; Lawlor, Stephanie; Leversha, Margaret; Lewis, Lora; Liu, Wen; Lloyd, Christine; Lloyd, David M; Loulseged, Hermela; Loveland, Jane E; Lovell, Jamieson D; Lozado, Ryan; Lu, Jing; Lyne, Rachael; Ma, Jie; Maheshwari, Manjula; Matthews, Lucy H; McDowall, Jennifer; McLaren, Stuart; McMurray, Amanda; Meidl, Patrick; Meitinger, Thomas; Milne, Sarah; Miner, George; Mistry, Shailesh L; Morgan, Margaret; Morris, Sidney; Müller, Ines; Mullikin, James C; Nguyen, Ngoc; Nordsiek, Gabriele; Nyakatura, Gerald; O'Dell, Christopher N; Okwuonu, Geoffery; Palmer, Sophie; Pandian, Richard; Parker, David; Parrish, Julia; Pasternak, Shiran; Patel, Dina; Pearce, Alex V; Pearson, Danita M; Pelan, Sarah E; Perez, Lesette; Porter, Keith M; Ramsey, Yvonne; Reichwald, Kathrin; Rhodes, Susan; Ridler, Kerry A; Schlessinger, David; Schueler, Mary G; Sehra, Harminder K; Shaw-Smith, Charles; Shen, Hua; Sheridan, Elizabeth M; Shownkeen, Ratna; Skuce, Carl D; Smith, Michelle L; Sotheran, Elizabeth C; Steingruber, Helen E; Steward, Charles A; Storey, Roy; Swann, R Mark; Swarbreck, David; Tabor, Paul E; Taudien, Stefan; Taylor, Tineace; Teague, Brian; Thomas, Karen; Thorpe, Andrea; Timms, Kirsten; Tracey, Alan; Trevanion, Steve; Tromans, Anthony C; d'Urso, Michele; Verduzco, Daniel; Villasana, Donna; Waldron, Lenee; Wall, Melanie; Wang, Qiaoyan; Warren, James; Warry, Georgina L; Wei, Xuehong; West, Anthony; Whitehead, Siobhan L; Whiteley, Mathew N; Wilkinson, Jane E; Willey, David L; Williams, Gabrielle; Williams, Leanne; Williamson, Angela; Williamson, Helen; Wilming, Laurens; Woodmansey, Rebecca L; Wray, Paul W; Yen, Jennifer; Zhang, Jingkun; Zhou, Jianling; Zoghbi, Huda; Zorilla, Sara; Buck, David; Reinhardt, Richard; Poustka, Annemarie; Rosenthal, André; Lehrach, Hans; Meindl, Alfons; Minx, Patrick J; Hillier, Ladeana W; Willard, Huntington F; Wilson, Richard K; Waterston, Robert H; Rice, Catherine M; Vaudin, Mark; Coulson, Alan; Nelson, David L; Weinstock, George; Sulston, John E; Durbin, Richard; Hubbard, Tim; Gibbs, Richard A; Beck, Stephan; Rogers, Jane; Bentley, David R

    2005-03-17

    The human X chromosome has a unique biology that was shaped by its evolution as the sex chromosome shared by males and females. We have determined 99.3% of the euchromatic sequence of the X chromosome. Our analysis illustrates the autosomal origin of the mammalian sex chromosomes, the stepwise process that led to the progressive loss of recombination between X and Y, and the extent of subsequent degradation of the Y chromosome. LINE1 repeat elements cover one-third of the X chromosome, with a distribution that is consistent with their proposed role as way stations in the process of X-chromosome inactivation. We found 1,098 genes in the sequence, of which 99 encode proteins expressed in testis and in various tumour types. A disproportionately high number of mendelian diseases are documented for the X chromosome. Of this number, 168 have been explained by mutations in 113 X-linked genes, which in many cases were characterized with the aid of the DNA sequence.

  10. Familial complex chromosomal rearrangement resulting in a recombinant chromosome.

    Science.gov (United States)

    Berend, Sue Ann; Bodamer, Olaf A F; Shapira, Stuart K; Shaffer, Lisa G; Bacino, Carlos A

    2002-05-15

    Familial complex chromosomal rearrangements (CCRs) are rare and tend to involve fewer breakpoints and fewer chromosomes than CCRs that are de novo in origin. We report on a CCR identified in a child with congenital heart disease and dysmorphic features. Initially, the child's karyotype was thought to involve a straightforward three-way translocation between chromosomes 3, 8, and 16. However, after analyzing the mother's chromosomes, the mother was found to have a more complex rearrangement that resulted in a recombinant chromosome in the child. The mother's karyotype included an inverted chromosome 2 and multiple translocations involving chromosomes 3, 5, 8, and 16. No evidence of deletion or duplication that could account for the clinical findings in the child was identified.

  11. Transcriptional Coactivator and Chromatin Protein PC4 Is Involved in Hippocampal Neurogenesis and Spatial Memory Extinction.

    Science.gov (United States)

    Swaminathan, Amrutha; Delage, Hélène; Chatterjee, Snehajyoti; Belgarbi-Dutron, Laurence; Cassel, Raphaelle; Martinez, Nicole; Cosquer, Brigitte; Kumari, Sujata; Mongelard, Fabien; Lannes, Béatrice; Cassel, Jean-Christophe; Boutillier, Anne-Laurence; Bouvet, Philippe; Kundu, Tapas K

    2016-09-23

    Although the elaborate combination of histone and non-histone protein complexes defines chromatin organization and hence regulates numerous nuclear processes, the role of chromatin organizing proteins remains unexplored at the organismal level. The highly abundant, multifunctional, chromatin-associated protein and transcriptional coactivator positive coactivator 4 (PC4/Sub1) is absolutely critical for life, because its absence leads to embryonic lethality. Here, we report results obtained with conditional PC4 knock-out (PC4(f/f) Nestin-Cre) mice where PC4 is knocked out specifically in the brain. Compared with the control (PC4(+/+) Nestin-Cre) mice, PC4(f/f) Nestin-Cre mice are smaller with decreased nocturnal activity but are fertile and show no motor dysfunction. Neurons in different areas of the brains of these mice show sensitivity to hypoxia/anoxia, and decreased adult neurogenesis was observed in the dentate gyrus. Interestingly, PC4(f/f) Nestin-Cre mice exhibit a severe deficit in spatial memory extinction, whereas acquisition and long term retention were unaffected. Gene expression analysis of the dorsal hippocampus of PC4(f/f) Nestin-Cre mice revealed dysregulated expression of several neural function-associated genes, and PC4 was consistently found to localize on the promoters of these genes, indicating that PC4 regulates their expression. These observations indicate that non-histone chromatin-associated proteins like PC4 play a significant role in neuronal plasticity.

  12. Correct end use during end joining of multiple chromosomal double strand breaks is influenced by repair protein RAD50, DNA-dependent protein kinase DNA-PKcs, and transcription context.

    Science.gov (United States)

    Gunn, Amanda; Bennardo, Nicole; Cheng, Anita; Stark, Jeremy M

    2011-12-09

    During repair of multiple chromosomal double strand breaks (DSBs), matching the correct DSB ends is essential to limit rearrangements. To investigate the maintenance of correct end use, we examined repair of two tandem noncohesive DSBs generated by endonuclease I-SceI and the 3' nonprocessive exonuclease Trex2, which can be expressed as an I-SceI-Trex2 fusion. We examined end joining (EJ) repair that maintains correct ends (proximal-EJ) versus using incorrect ends (distal-EJ), which provides a relative measure of incorrect end use (distal end use). Previous studies showed that ATM is important to limit distal end use. Here we show that DNA-PKcs kinase activity and RAD50 are also important to limit distal end use, but that H2AX is dispensable. In contrast, we find that ATM, DNA-PKcs, and RAD50 have distinct effects on repair events requiring end processing. Furthermore, we developed reporters to examine the effects of the transcription context on DSB repair, using an inducible promoter. We find that a DSB downstream from an active promoter shows a higher frequency of distal end use, and a greater reliance on ATM for limiting incorrect end use. Conversely, DSB transcription context does not affect end processing during EJ, the frequency of homology-directed repair, or the role of RAD50 and DNA-PKcs in limiting distal end use. We suggest that RAD50, DNA-PKcs kinase activity, and transcription context are each important to limit incorrect end use during EJ repair of multiple DSBs, but that these factors and conditions have distinct roles during repair events requiring end processing.

  13. Chromosome 19 International Workshop

    Energy Technology Data Exchange (ETDEWEB)

    Pericak-Vance, M.A. (Duke Univ., Durham, NC (United States). Medical Center); Ropers, H.H. (Univ. Hospital Nijmegen, (The Netherlands). Dept. of Human Genetics); Carrano, A.J. (Lawrence Livermore National Lab., CA (United States))

    1993-01-04

    The Second International Workshop on Human Chromosome 19 was hosted on January 25 and 26, 1992, by the Department of Human Genetics, University Hospital Nijmegen, The Netherlands, at the 'Meerdal Conference Center'. The workshop was supported by a grant from the European Community obtained through HUGO, the Dutch Research Organization (NWO) and the Muscular Dystrophy Association (MDA). Travel support for American participants was provided by the Department of Energy. The goals of this workshop were to produce genetic, physical and integrated maps of chromosome 19, to identify inconsistencies and gaps, and to discuss and exchange resources and techniques available for the completion of these maps. The second day of the meeting was largely devoted to region or disease specific efforts. In particular, the meeting served as a platform for assessing and discussing the recent progress made into the molecular elucidation of myotonic dystrophy.

  14. Mitotic chromosome compaction via active loop extrusion

    Science.gov (United States)

    Goloborodko, Anton; Imakaev, Maxim; Marko, John; Mirny, Leonid; MIT-Northwestern Team

    During cell division, two copies of each chromosome are segregated from each other and compacted more than hundred-fold into the canonical X-shaped structures. According to earlier microscopic observations and the recent Hi-C study, chromosomes are compacted into arrays of consecutive loops of ~100 kilobases. Mechanisms that lead to formation of such loop arrays are largely unknown. Here we propose that, during cell division, chromosomes can be compacted by enzymes that extrude loops on chromatin fibers. First, we use computer simulations and analytical modeling to show that a system of loop-extruding enzymes on a chromatin fiber self-organizes into an array of consecutive dynamic loops. Second, we model the process of loop extrusion in 3D and show that, coupled with the topo II strand-passing activity, it leads to robust compaction and segregation of sister chromatids. This mechanism of chromosomal condensation and segregation does not require additional proteins or specific DNA markup and is robust against variations in the number and properties of such loop extruding enzymes. Work at NU was supported by the NSF through Grants DMR-1206868 and MCB-1022117, and by the NIH through Grants GM105847 and CA193419. Work at MIT was supported by the NIH through Grants GM114190 R01HG003143.

  15. Regulation of chromosomal replication in Caulobacter crescentus.

    Science.gov (United States)

    Collier, Justine

    2012-03-01

    The alpha-proteobacterium Caulobacter crescentus is characterized by its asymmetric cell division, which gives rise to a replicating stalked cell and a non-replicating swarmer cell. Thus, the initiation of chromosomal replication is tightly regulated, temporally and spatially, to ensure that it is coordinated with cell differentiation and cell cycle progression. Waves of DnaA and CtrA activities control when and where the initiation of DNA replication will take place in C. crescentus cells. The conserved DnaA protein initiates chromosomal replication by directly binding to sites within the chromosomal origin (Cori), ensuring that DNA replication starts once and only once per cell cycle. The CtrA response regulator represses the initiation of DNA replication in swarmer cells and in the swarmer compartment of pre-divisional cells, probably by competing with DnaA for binding to Cori. CtrA and DnaA are controlled by multiple redundant regulatory pathways that include DNA methylation-dependent transcriptional regulation, temporally regulated proteolysis and the targeting of regulators to specific locations within the cell. Besides being critical regulators of chromosomal replication, CtrA and DnaA are also master transcriptional regulators that control the expression of many genes, thus connecting DNA replication with other events of the C. crescentus cell cycle.

  16. Synteny mapping of five human chromosome 7 genes on bovine chromosomes 4 and 21.

    Science.gov (United States)

    Antoniou, E; Womack, J E; Grosz, M D

    1999-01-01

    Five genes on human chromosome 7 (HSA 7) were assigned to bovine chromosome 21 (BTA 21) and 4 (BTA 4) using a bovine-rodent somatic hybrid cell panel. These five genes were alpha-I subunit of adenylate cyclase-inhibiting G-protein (GNAI1), alpha/beta preprotachykinin (TAC1), reelin (RELN), c-AMP dependant protein kinase type II beta regulatory chain (PRKAR2B) and apolipoprotein A1 regulatory protein 1 (TFCOUP2). Four genes mapped to BTA 4 (GNAI1, TAC1, RELN, PRKAR2B) while one gene mapped to BTA 21 (TFCOUP2). This study confirms the synteny conservation between HSA 7 and BTA 4, finely maps the breakpoints of conserved synteny on HSA 7 and defines a new synteny conservation between HSA 7 and BTA 21.

  17. Xist RNA is confined to the nuclear territory of the silenced X chromosome throughout the cell cycle

    NARCIS (Netherlands)

    Jonkers, Iris; Monkhorst, Kim; Rentmeester, Eveline; Grootegoed, J Anton; Grosveld, Frank; Gribnau, Joost

    2008-01-01

    In mammalian female cells, one X chromosome is inactivated to prevent a dose difference in the expression of X-encoded proteins between males and females. Xist RNA, required for X chromosome inactivation, is transcribed from the future inactivated X chromosome (Xi), where it spreads in cis, to initi

  18. The Escherichia coli cryptic prophage protein YfdR binds to DnaA and initiation of chromosomal replication is inhibited by overexpression of the gene cluster yfdQ-yfdR-yfdS-yfdT

    Directory of Open Access Journals (Sweden)

    Yaunori eNoguchi

    2016-03-01

    Full Text Available The initiation of bacterial chromosomal replication is regulated by multiple pathways. To explore novel regulators, we isolated multicopy suppressors for the cold-sensitive hda-185 ΔsfiA(sulA mutant. Hda is crucial for the negative regulation of the initiator DnaA and the hda-185 mutation causes severe replication overinitiation at the replication origin oriC. The SOS-associated division inhibitor SfiA inhibits FtsZ ring formation, an essential step for cell division during the SOS response, and ΔsfiA enhances the cold sensitivity of hda-185 cells in colony formation. One of the suppressors comprised the yfdQ-yfdR-yfdS-yfdT gene cluster carried on a cryptic prophage. Increased copy numbers of yfdQRT or yfdQRS inhibited not only hda-185-dependent overinitiation, but also replication overinitiation in a hyperactive dnaA mutant, and in a mutant lacking an oriC-binding initiation-inhibitor SeqA. In addition, increasing the copy number of the gene set inhibited the growth of cells bearing specific, initiation-impairing dnaA mutations. In wild-type cells, multicopy supply of yfdQRT or yfdQRS also inhibited replication initiation and increased hydroxyurea (HU-resistance, as seen in cells lacking DiaA, a stimulator of DnaA assembly on oriC. Deletion of the yfdQ-yfdR-yfdS-yfdT genes did not affect either HU resistance or initiation regulation. Furthermore, we found that DnaA bound specifically to YfdR in soluble protein extracts oversupplied with YfdQRST. Purified YfdR also bound to DnaA, and DnaA Phe46, an amino acid residue crucial for DnaA interactions with DiaA and DnaB replicative helicase was important for this interaction. Consistently, YfdR moderately inhibited DiaA-DnaA and DnaB-DnaA interactions. In addition, protein extracts oversupplied with YfdQRST inhibited replication initiation in vitro. Given the roles of yfdQ and yfdS in cell tolerance to specific environmental stresses, the yfdQ-yfdR-yfdS-yfdT genes might downregulate the initiator

  19. Multiple opposing constraints govern chromosome interactions during meiosis.

    Directory of Open Access Journals (Sweden)

    Doris Y Lui

    Full Text Available Homolog pairing and crossing over during meiosis I prophase is required for accurate chromosome segregation to form euploid gametes. The repair of Spo11-induced double-strand breaks (DSB using a homologous chromosome template is a major driver of pairing in many species, including fungi, plants, and mammals. Inappropriate pairing and crossing over at ectopic loci can lead to chromosome rearrangements and aneuploidy. How (or if inappropriate ectopic interactions are disrupted in favor of allelic interactions is not clear. Here we used an in vivo "collision" assay in budding yeast to test the contributions of cohesion and the organization and motion of chromosomes in the nucleus on promoting or antagonizing interactions between allelic and ectopic loci at interstitial chromosome sites. We found that deletion of the cohesin subunit Rec8, but not other chromosome axis proteins (e.g. Red1, Hop1, or Mek1, caused an increase in homolog-nonspecific chromosome interaction, even in the absence of Spo11. This effect was partially suppressed by expression of the mitotic cohesin paralog Scc1/Mdc1, implicating Rec8's role in cohesion rather than axis integrity in preventing nonspecific chromosome interactions. Disruption of telomere-led motion by treating cells with the actin polymerization inhibitor Latrunculin B (Lat B elevated nonspecific collisions in rec8Δ spo11Δ. Next, using a visual homolog-pairing assay, we found that the delay in homolog pairing in mutants defective for telomere-led chromosome motion (ndj1Δ or csm4Δ is enhanced in Lat B-treated cells, implicating actin in more than one process promoting homolog juxtaposition. We suggest that multiple, independent contributions of actin, cohesin, and telomere function are integrated to promote stable homolog-specific interactions and to destabilize weak nonspecific interactions by modulating the elastic spring-like properties of chromosomes.

  20. Filament depolymerization can explain chromosome pulling during bacterial mitosis.

    Science.gov (United States)

    Banigan, Edward J; Gelbart, Michael A; Gitai, Zemer; Wingreen, Ned S; Liu, Andrea J

    2011-09-01

    Chromosome segregation is fundamental to all cells, but the force-generating mechanisms underlying chromosome translocation in bacteria remain mysterious. Caulobacter crescentus utilizes a depolymerization-driven process in which a ParA protein structure elongates from the new cell pole, binds to a ParB-decorated chromosome, and then retracts via disassembly, pulling the chromosome across the cell. This poses the question of how a depolymerizing structure can robustly pull the chromosome that disassembles it. We perform Brownian dynamics simulations with a simple, physically consistent model of the ParABS system. The simulations suggest that the mechanism of translocation is "self-diffusiophoretic": by disassembling ParA, ParB generates a ParA concentration gradient so that the ParA concentration is higher in front of the chromosome than behind it. Since the chromosome is attracted to ParA via ParB, it moves up the ParA gradient and across the cell. We find that translocation is most robust when ParB binds side-on to ParA filaments. In this case, robust translocation occurs over a wide parameter range and is controlled by a single dimensionless quantity: the product of the rate of ParA disassembly and a characteristic relaxation time of the chromosome. This time scale measures the time it takes for the chromosome to recover its average shape after it is has been pulled. Our results suggest explanations for observed phenomena such as segregation failure, filament-length-dependent translocation velocity, and chromosomal compaction.

  1. Filament depolymerization can explain chromosome pulling during bacterial mitosis.

    Directory of Open Access Journals (Sweden)

    Edward J Banigan

    2011-09-01

    Full Text Available Chromosome segregation is fundamental to all cells, but the force-generating mechanisms underlying chromosome translocation in bacteria remain mysterious. Caulobacter crescentus utilizes a depolymerization-driven process in which a ParA protein structure elongates from the new cell pole, binds to a ParB-decorated chromosome, and then retracts via disassembly, pulling the chromosome across the cell. This poses the question of how a depolymerizing structure can robustly pull the chromosome that disassembles it. We perform Brownian dynamics simulations with a simple, physically consistent model of the ParABS system. The simulations suggest that the mechanism of translocation is "self-diffusiophoretic": by disassembling ParA, ParB generates a ParA concentration gradient so that the ParA concentration is higher in front of the chromosome than behind it. Since the chromosome is attracted to ParA via ParB, it moves up the ParA gradient and across the cell. We find that translocation is most robust when ParB binds side-on to ParA filaments. In this case, robust translocation occurs over a wide parameter range and is controlled by a single dimensionless quantity: the product of the rate of ParA disassembly and a characteristic relaxation time of the chromosome. This time scale measures the time it takes for the chromosome to recover its average shape after it is has been pulled. Our results suggest explanations for observed phenomena such as segregation failure, filament-length-dependent translocation velocity, and chromosomal compaction.

  2. Phosphorylation of chromosome core components may serve as axis marks for the status of chromosomal events during mammalian meiosis.

    Directory of Open Access Journals (Sweden)

    Tomoyuki Fukuda

    2012-02-01

    Full Text Available Meiotic recombination and chromosome synapsis between homologous chromosomes are essential for proper chromosome segregation at the first meiotic division. While recombination and synapsis, as well as checkpoints that monitor these two events, take place in the context of a prophase I-specific axial chromosome structure, it remains unclear how chromosome axis components contribute to these processes. We show here that many protein components of the meiotic chromosome axis, including SYCP2, SYCP3, HORMAD1, HORMAD2, SMC3, STAG3, and REC8, become post-translationally modified by phosphorylation during the prophase I stage. We found that HORMAD1 and SMC3 are phosphorylated at a consensus site for the ATM/ATR checkpoint kinase and that the phosphorylated forms of HORMAD1 and SMC3 localize preferentially to unsynapsed chromosomal regions where synapsis has not yet occurred, but not to synapsed or desynapsed regions. We investigated the genetic requirements for the phosphorylation events and revealed that the phosphorylation levels of HORMAD1, HORMAD2, and SMC3 are dramatically reduced in the absence of initiation of meiotic recombination, whereas BRCA1 and SYCP3 are required for normal levels of phosphorylation of HORMAD1 and HORMAD2, but not of SMC3. Interestingly, reduced HORMAD1 and HORMAD2 phosphorylation is associated with impaired targeting of the MSUC (meiotic silencing of unsynapsed chromatin machinery to unsynapsed chromosomes, suggesting that these post-translational events contribute to the regulation of the synapsis surveillance system. We propose that modifications of chromosome axis components serve as signals that facilitate chromosomal events including recombination, checkpoint control, transcription, and synapsis regulation.

  3. Formation of Chromosomal Domains by Loop Extrusion

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    Geoffrey Fudenberg

    2016-05-01

    Full Text Available Topologically associating domains (TADs are fundamental structural and functional building blocks of human interphase chromosomes, yet the mechanisms of TAD formation remain unclear. Here, we propose that loop extrusion underlies TAD formation. In this process, cis-acting loop-extruding factors, likely cohesins, form progressively larger loops but stall at TAD boundaries due to interactions with boundary proteins, including CTCF. Using polymer simulations, we show that this model produces TADs and finer-scale features of Hi-C data. Each TAD emerges from multiple loops dynamically formed through extrusion, contrary to typical illustrations of single static loops. Loop extrusion both explains diverse experimental observations—including the preferential orientation of CTCF motifs, enrichments of architectural proteins at TAD boundaries, and boundary deletion experiments—and makes specific predictions for the depletion of CTCF versus cohesin. Finally, loop extrusion has potentially far-ranging consequences for processes such as enhancer-promoter interactions, orientation-specific chromosomal looping, and compaction of mitotic chromosomes.

  4. A dynamic, mitotic-like mechanism for bacterial chromosome segregation.

    Science.gov (United States)

    Fogel, Michael A; Waldor, Matthew K

    2006-12-01

    The mechanisms that mediate chromosome segregation in bacteria are poorly understood. Despite evidence of dynamic movement of chromosome regions, to date, mitotic-like mechanisms that act on the bacterial chromosome have not been demonstrated. Here we provide evidence that the Vibrio cholerae ParAI and ParBI proteins are components of an apparatus that pulls the origin region of the large V. cholerae chromosome to the cell pole and anchors it there. ParBI interacts with a conserved origin-proximal, centromere-like site (parSI) that, following chromosome replication, segregates asymmetrically from one pole to the other. While segregating, parSI stretches far away from neighboring chromosomal loci. ParAI forms a dynamic band that extends from the pole to the segregating ParBI/parSI complex. Movement of ParBI/parSI across the cell occurs in concert with ParAI retraction. Deletion of parAI disrupts proper origin localization and segregation dynamics, and parSI no longer separates from nearby regions. These data suggest that ParAI forms a dynamic structure that pulls the ParBI-bound chromosome to the pole in a process analogous to anaphase of eukaryotic mitosis.

  5. An SMC ATPase mutant disrupts chromosome segregation in Caulobacter.

    Science.gov (United States)

    Schwartz, Monica A; Shapiro, Lucy

    2011-12-01

    Accurate replication and segregation of the bacterial genome are essential for cell cycle progression. We have identified a single amino acid substitution in the Caulobacter structural maintenance of chromosomes (SMC) protein that disrupts chromosome segregation and cell division. The E1076Q point mutation in the SMC ATPase domain caused a dominant-negative phenotype in which DNA replication was able to proceed, but duplicated parS centromeres, normally found at opposite cell poles, remained at one pole. The cellular positions of other chromosomal loci were in the wild-type order relative to the parS centromere, but chromosomes remained unsegregated and appeared to be stacked upon one another. Purified SMC-E1076Q was deficient in ATP hydrolysis and exhibited abnormally stable binding to DNA. We propose that SMC spuriously links the duplicated chromosome immediately after passage of the replication fork. In wild-type cells, ATP hydrolysis opens the SMC dimer, freeing one chromosome to segregate to the opposite pole. The loss of ATP hydrolysis causes the SMC-E1076Q dimer to remain bound to both chromosomes, inhibiting segregation.

  6. Intraspecific chromosome variability

    Directory of Open Access Journals (Sweden)

    N Dubinin

    2010-12-01

    Full Text Available (Editorial preface. The publication is presented in order to remind us of one of dramatic pages of the history of genetics. It re-opens for the contemporary reader a comprehensive work marking the priority change from plant cytogenetics to animal cytogenetics led by wide population studies which were conducted on Drosophila polytene chromosomes. The year of the publication (1937 became the point of irretrievable branching between the directions of Old World and New World genetics connected with the problems of chromosome variability and its significance for the evolution of the species. The famous book of T. Dobzhansky (1937 was published by Columbia University in the US under the title “Genetics and the origin of species”, and in the shadow of this American ‘skybuilding’ all other works grew dim. It is remarkable that both Dobzhansky and Dubinin come to similar conclusions about the role of chromosomes in speciation. This is not surprising given that they both might be considered as representatives of the Russian genetic school, by their birth and education. Interestingly, Dobzhansky had never referred to the full paper of Dubinin et al. (1937, though a previous short communication in Nature (1936 was included together with all former papers on the related subject. In full, the volume of the original publication printed in the Biological Journal in Moscow comprised 47 pages, in that number 41 pages of the Russian text accompanied by 16 Figs, a table and reference list, and, above all, 6 pages of the English summary. This final part in English is now reproduced in the authors’ version with the only addition being the reference list in the originally printed form.

  7. Chromosome assortment in Saccharum.

    Science.gov (United States)

    Al-Janabi, S M; Honeycutt, R J; Sobral, B W

    1994-12-01

    Recent work has revealed random chromosome pairing and assortment in Saccharum spontaneum L., the most widely distributed, and morphologically and cytologically variable of the species of Saccharum. This conclusion was based on the analysis of a segregating population from across between S. spontaneum 'SES 208' and a spontaneously-doubled haploid of itself, derived from anther culture. To determine whether polysomic inheritance is common in Saccharum and whether it is observed in a typical biparental cross, we studied chromosome pairing and assortment in 44 progeny of a cross between euploid, meiotically regular, 2n=80 forms of Saccharum officinarum 'LA Purple' and Saccharum robustum ' Mol 5829'. Papuan 2n=80 forms of S. robustum have been suggested as the immediate progenitor species for cultivated sugarcane (S. officinarum). A total of 738 loci in LA Purple and 720 loci in Mol 5829 were amplified and typed in the progeny by arbitrarily primed PCR using 45 primers. Fifty and 33 single-dose polymorphisms were identified in the S. officinarum and S. robustum genomes, respectively (χ 2 at 98%). Linkage analysis of single-dose polymorphisms in both genomes revealed linkages in repulsion and coupling phases. In the S. officinarum genome, a map hypothesis gave 7 linkage groups with 17 linked and 33 unlinked markers. Four of 13 pairwise linkages were in repulsion phase and 9 were in coupling phase. In the S. robustum genome, a map hypothesis gave 5 linkage groups, defined by 12 markers, with 21 markers unlinked, and 2 of 9 pairwise linkages were in repulsion phase. Therefore, complete polysomic inheritance was not observed in either species, suggesting that chromosomal behavior is different from that observed by linkage analysis of over 500 markers in the S. spontaneum map. Implications of this finding for evolution and breeding are discussed.

  8. [Cashmere goat bacterial artificial chromosome recombination and cell transfection system].

    Science.gov (United States)

    Huang, Tian; Cao, Zhongyang; Yang, Yaohui; Cao, Gengsheng

    2016-03-01

    The Cashmere goat is mainly used to produce cashmere, which is very popular for its delicate fiber, luscious softness and natural excellent warm property. Keratin associated protein (KAP) and bone morphogenetic protein (BMP) of the Cashmere goat play an important role in the proliferation and development of cashmere fiber follicle cells. Bacterial artificial chromosome containing kap6.3, kap8.1 and bmp4 genes were used to increase the production and quality of Cashmere. First, we constructed bacterial artificial chromosomes by homology recombination. Then Tol2 transposon was inserted into bacterial artificial chromosomes that were then transfected into Cashmere goat fibroblasts by Amaxa Nucleofector technology according to the manufacture's instructions. We successfully constructed the BAC-Tol2 vectors containing target genes. Each vector contained egfp report gene with UBC promoter, Neomycin resistant gene for cell screening and two loxp elements for resistance removing after transfected into cells. The bacterial artificial chromosome-Tol2 vectors showed a high efficiency of transfection that can reach 1% to 6% with a highest efficiency of 10%. We also obtained Cashmere goat fibroblasts integrated exogenous genes (kap6.3, kap8.1 and bmp4) preparing for the clone of Cashmere goat in the future. Our research demonstrates that the insertion of Tol2 transposons into bacterial artificial chromosomes improves the transfection efficiency and accuracy of bacterial artificial chromosome error-free recombination.

  9. Proposed Physical Mechanism of Chromosome Segregation in Caulobacter crescentus

    Science.gov (United States)

    Banigan, Edward; Gelbart, Michael; Gitai, Zemer; Liu, Andrea; Wingreen, Ned

    2010-03-01

    Chromosome segregation is a fundamental process for all cells, but the force-generating mechanisms that drive chromosome movements in bacteria are especially unclear. In Caulobacter crescentus, recent work has demonstrated that a structure made up of the ParA protein elongates from one cell pole and interacts with ParB, a protein binding to the chromosome near the origin of replication (ori). ParB disassembles ParA, causing ParA to pull ParB, and thus, the ori to the opposite end of the cell. We performed Brownian dynamics simulations of this system in order to uncover the physical mechanism of this motion. We find that motion of the ori is robust to several variations of the model as long as a steady-state concentration gradient of ParA is established in the moving frame of the ParB-decorated chromosome. We suggest that the mechanism is ``self-diffusiophoretic'': by disassembling ParA, ParB creates a concentration gradient of ParA so that the ParA concentration is higher in front of the chromosome than behind it. Since the chromosome is attracted to ParA via ParB, it moves up the gradient in the desired direction.

  10. RNAi pathway participates in chromosome segregation in mammalian cells.

    Science.gov (United States)

    Huang, Chuan; Wang, Xiaolin; Liu, Xu; Cao, Shuhuan; Shan, Ge

    2015-01-01

    The RNAi machinery is a mighty regulator in a myriad of life events. Despite lines of evidence that small RNAs and components of the RNAi pathway may be associated with structure and behavior of mitotic chromosomes in diverse organisms, a direct role of the RNAi pathway in mammalian mitotic chromosome segregation remains elusive. Here we report that Dicer and AGO2, two central components of the mammalian RNAi pathway, participate in the chromosome segregation. Knockdown of Dicer or AGO2 results in a higher incidence of chromosome lagging, and this effect is independent from microRNAs as examined with DGCR8 knockout cells. Further investigation has revealed that α-satellite RNA, a noncoding RNA derived from centromeric repeat region, is managed by AGO2 under the guidance of endogenous small interference RNAs (ASAT siRNAs) generated by Dicer. Furthermore, the slicer activity of AGO2 is essential for the chromosome segregation. Level and distribution of chromosome-associated α-satellite RNA have crucial regulatory effect on the localization of centromeric proteins such as centromere protein C1 (CENPC1). With these results, we also provide a paradigm in which the RNAi pathway participates in vital cellular events through the maintenance of level and distribution of noncoding RNAs in cells.

  11. Caenorhabditis elegans histone methyltransferase MET-2 shields the male X chromosome from checkpoint machinery and mediates meiotic sex chromosome inactivation.

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    Paula M Checchi

    2011-09-01

    Full Text Available Meiosis is a specialized form of cellular division that results in the precise halving of the genome to produce gametes for sexual reproduction. Checkpoints function during meiosis to detect errors and subsequently to activate a signaling cascade that prevents the formation of aneuploid gametes. Indeed, asynapsis of a homologous chromosome pair elicits a checkpoint response that can in turn trigger germline apoptosis. In a heterogametic germ line, however, sex chromosomes proceed through meiosis with unsynapsed regions and are not recognized by checkpoint machinery. We conducted a directed RNAi screen in Caenorhabditis elegans to identify regulatory factors that prevent recognition of heteromorphic sex chromosomes as unpaired and uncovered a role for the SET domain histone H3 lysine 9 histone methyltransferase (HMTase MET-2 and two additional HMTases in shielding the male X from checkpoint machinery. We found that MET-2 also mediates the transcriptional silencing program of meiotic sex chromosome inactivation (MSCI but not meiotic silencing of unsynapsed chromatin (MSUC, suggesting that these processes are distinct. Further, MSCI and checkpoint shielding can be uncoupled, as double-strand breaks targeted to an unpaired, transcriptionally silenced extra-chromosomal array induce checkpoint activation in germ lines depleted for met-2. In summary, our data uncover a mechanism by which repressive chromatin architecture enables checkpoint proteins to distinguish between the partnerless male X chromosome and asynapsed chromosomes thereby shielding the lone X from inappropriate activation of an apoptotic program.

  12. Caenorhabditis elegans histone methyltransferase MET-2 shields the male X chromosome from checkpoint machinery and mediates meiotic sex chromosome inactivation.

    Science.gov (United States)

    Checchi, Paula M; Engebrecht, JoAnne

    2011-09-01

    Meiosis is a specialized form of cellular division that results in the precise halving of the genome to produce gametes for sexual reproduction. Checkpoints function during meiosis to detect errors and subsequently to activate a signaling cascade that prevents the formation of aneuploid gametes. Indeed, asynapsis of a homologous chromosome pair elicits a checkpoint response that can in turn trigger germline apoptosis. In a heterogametic germ line, however, sex chromosomes proceed through meiosis with unsynapsed regions and are not recognized by checkpoint machinery. We conducted a directed RNAi screen in Caenorhabditis elegans to identify regulatory factors that prevent recognition of heteromorphic sex chromosomes as unpaired and uncovered a role for the SET domain histone H3 lysine 9 histone methyltransferase (HMTase) MET-2 and two additional HMTases in shielding the male X from checkpoint machinery. We found that MET-2 also mediates the transcriptional silencing program of meiotic sex chromosome inactivation (MSCI) but not meiotic silencing of unsynapsed chromatin (MSUC), suggesting that these processes are distinct. Further, MSCI and checkpoint shielding can be uncoupled, as double-strand breaks targeted to an unpaired, transcriptionally silenced extra-chromosomal array induce checkpoint activation in germ lines depleted for met-2. In summary, our data uncover a mechanism by which repressive chromatin architecture enables checkpoint proteins to distinguish between the partnerless male X chromosome and asynapsed chromosomes thereby shielding the lone X from inappropriate activation of an apoptotic program.

  13. Functional gene groups are concentrated within chromosomes, among chromosomes and in the nuclear space of the human genome.

    Science.gov (United States)

    Thévenin, Annelyse; Ein-Dor, Liat; Ozery-Flato, Michal; Shamir, Ron

    2014-09-01

    Genomes undergo changes in organization as a result of gene duplications, chromosomal rearrangements and local mutations, among other mechanisms. In contrast to prokaryotes, in which genes of a common function are often organized in operons and reside contiguously along the genome, most eukaryotes show much weaker clustering of genes by function, except for few concrete functional groups. We set out to check systematically if there is a relation between gene function and gene organization in the human genome. We test this question for three types of functional groups: pairs of interacting proteins, complexes and pathways. We find a significant concentration of functional groups both in terms of their distance within the same chromosome and in terms of their dispersal over several chromosomes. Moreover, using Hi-C contact map of the tendency of chromosomal segments to appear close in the 3D space of the nucleus, we show that members of the same functional group that reside on distinct chromosomes tend to co-localize in space. The result holds for all three types of functional groups that we tested. Hence, the human genome shows substantial concentration of functional groups within chromosomes and across chromosomes in space.

  14. [Chromosome composition of wheat-rye lines and the influence of rye chromosomes on disease resistance and agronomic traits].

    Science.gov (United States)

    Chumanova, E V; Efremova, T T; Trubacheeva, N V; Arbuzova, V S; Rosseeva, L P

    2014-11-01

    Identification of the chromosomal composition of common wheat lines with rye chromosomes was carried out using genomic in situ hybridization and 1RS- and 5P-specific PCR markers. It was demonstrated that wheat chromosomes 5A or 5D were substituted by rye chromosome 5R in the wheat-rye lines. It was established that one of the lines with complex disease resistance contained rye chromosome 5R and T1RS.1BL, while another line was found to contain, in addition to T1RS.1BL, a new Robertsonian translocation, T5AS.5RL. Substitution of the wheat chromosome 5A with the dominant Vrn-A1 gene for the Onokhoiskaya rye chromosome 5R led to lengthening of the germination-heading period or to a change in the type of development. A negative influence of T1RS.1BL on SDS sedimentation volume and grain hardness was demonstrated, along with a positive effect of the combination of T1RS. BL and 5R(5D) substitution on grain protein content. Quantitative traits of the 5R(5A) and 5R(5D) substitution lines were at the level of recipient cultivars. A line with two translocations, T1RS.1BL + T5AS.5R1, appeared to be more productive as compared to the line carrying T1RS.1BL in combination with the 5R(5D) substitution.

  15. The spindle checkpoint and chromosome segregation in meiosis.

    Science.gov (United States)

    Gorbsky, Gary J

    2015-07-01

    The spindle checkpoint is a key regulator of chromosome segregation in mitosis and meiosis. Its function is to prevent precocious anaphase onset before chromosomes have achieved bipolar attachment to the spindle. The spindle checkpoint comprises a complex set of signaling pathways that integrate microtubule dynamics, biomechanical forces at the kinetochores, and intricate regulation of protein interactions and post-translational modifications. Historically, many key observations that gave rise to the initial concepts of the spindle checkpoint were made in meiotic systems. In contrast with mitosis, the two distinct chromosome segregation events of meiosis present a special challenge for the regulation of checkpoint signaling. Preservation of fidelity in chromosome segregation in meiosis, controlled by the spindle checkpoint, also has a significant impact in human health. This review highlights the contributions from meiotic systems in understanding the spindle checkpoint as well as the role of checkpoint signaling in controlling the complex divisions of meiosis.

  16. Chromosome Connections: Compelling Clues to Common Ancestry

    Science.gov (United States)

    Flammer, Larry

    2013-01-01

    Students compare banding patterns on hominid chromosomes and see striking evidence of their common ancestry. To test this, human chromosome no. 2 is matched with two shorter chimpanzee chromosomes, leading to the hypothesis that human chromosome 2 resulted from the fusion of the two shorter chromosomes. Students test that hypothesis by looking for…

  17. Chromosomal rearrangement interferes with meiotic X chromosome inactivation.

    Science.gov (United States)

    Homolka, David; Ivanek, Robert; Capkova, Jana; Jansa, Petr; Forejt, Jiri

    2007-10-01

    Heterozygosity for certain mouse and human chromosomal rearrangements is characterized by the incomplete meiotic synapsis of rearranged chromosomes, by their colocalization with the XY body in primary spermatocytes, and by male-limited sterility. Previously, we argued that such X-autosomal associations could interfere with meiotic sex chromosome inactivation. Recently, supporting evidence has reported modifications of histones in rearranged chromosomes by a process called the meiotic silencing of unsynapsed chromatin (MSUC). Here, we report on the transcriptional down-regulation of genes within the unsynapsed region of the rearranged mouse chromosome 17, and on the subsequent disturbance of X chromosome inactivation. The partial transcriptional suppression of genes in the unsynapsed chromatin was most prominent prior to the mid-pachytene stage of primary spermatocytes. Later, during the mid-late pachytene, the rearranged autosomes colocalized with the XY body, and the X chromosome failed to undergo proper transcriptional silencing. Our findings provide direct evidence on the MSUC acting at the mRNA level, and implicate that autosomal asynapsis in meiosis may cause male sterility by interfering with meiotic sex chromosome inactivation.

  18. Dependence of the structure and mechanics of metaphase chromosomes on oxidized cysteines.

    Science.gov (United States)

    Eastland, Adrienne; Hornick, Jessica; Kawamura, Ryo; Nanavati, Dhaval; Marko, John F

    2016-09-01

    We have found that reagents that reduce oxidized cysteines lead to destabilization of metaphase chromosome folding, suggesting that chemically linked cysteine residues may play a structural role in mitotic chromosome organization, in accord with classical studies by Dounce et al. (J Theor Biol 42:275-285, 1973) and Sumner (J Cell Sci 70:177-188, 1984a). Human chromosomes isolated into buffer unfold when exposed to dithiothreitol (DTT) or tris(2-carboxyethyl)phosphine (TCEP). In micromanipulation experiments which allow us to examine the mechanics of individual metaphase chromosomes, we have found that the gel-like elastic stiffness of native metaphase chromosomes is dramatically suppressed by DTT and TCEP, even before the chromosomes become appreciably unfolded. We also report protein labeling experiments on human metaphase chromosomes which allow us to tag oxidized and reduction-sensitive cysteine residues. PAGE analysis using fluorescent labels shows a small number of labeled bands. Mass spectrometry analysis of similarly labeled proteins provides a list of candidates for proteins with oxidized cysteines involved in chromosome organization, notably including components of condensin I, cohesin, the nucleosome-interacting proteins RCC1 and RCC2, as well as the RNA/DNA-binding protein NONO/p54NRB.

  19. Evidence for a Xer/dif system for chromosome resolution in archaea.

    Directory of Open Access Journals (Sweden)

    Diego Cortez

    2010-10-01

    Full Text Available Homologous recombination events between circular chromosomes, occurring during or after replication, can generate dimers that need to be converted to monomers prior to their segregation at cell division. In Escherichia coli, chromosome dimers are converted to monomers by two paralogous site-specific tyrosine recombinases of the Xer family (XerC/D. The Xer recombinases act at a specific dif site located in the replication termination region, assisted by the cell division protein FtsK. This chromosome resolution system has been predicted in most Bacteria and further characterized for some species. Archaea have circular chromosomes and an active homologous recombination system and should therefore resolve chromosome dimers. Most archaea harbour a single homologue of bacterial XerC/D proteins (XerA, but not of FtsK. Therefore, the role of XerA in chromosome resolution was unclear. Here, we have identified dif-like sites in archaeal genomes by using a combination of modeling and comparative genomics approaches. These sites are systematically located in replication termination regions. We validated our in silico prediction by showing that the XerA protein of Pyrococcus abyssi specifically recombines plasmids containing the predicted dif site in vitro. In contrast to the bacterial system, XerA can recombine dif sites in the absence of protein partners. Whereas Archaea and Bacteria use a completely different set of proteins for chromosome replication, our data strongly suggest that XerA is most likely used for chromosome resolution in Archaea.

  20. High Mobility Group Box Protein-1 in Wound Repair

    Directory of Open Access Journals (Sweden)

    Mauro Patrone

    2012-09-01

    Full Text Available High-mobility group box 1 protein (HMGB1, a member of highly conserved non-histone DNA binding protein family, has been studied as transcription factor and growth factor. Secreted extracellularly by activated monocytes and macrophages or passively released by necrotic or damaged cells, extracellular HMGB1 is a potent mediator of inflammation. Extracellular HMGB1 has apparently contrasting biological actions: it sustains inflammation (with the possible establishment of autoimmunity or of self-maintaining tissue damage, but it also activates and recruits stem cells, boosting tissue repair. Here, we focus on the role of HMGB1 in physiological and pathological responses, the mechanisms by which it contributes to tissue repair and therapeutic strategies base on targeting HMGB1.

  1. A gene-protein assay for human epidermal growth factor receptor 2 (HER2: brightfield tricolor visualization of HER2 protein, the HER2 gene, and chromosome 17 centromere (CEN17 in formalin-fixed, paraffin-embedded breast cancer tissue sections

    Directory of Open Access Journals (Sweden)

    Nitta Hiroaki

    2012-05-01

    Full Text Available Abstract Background The eligibility of breast cancer patients for human epidermal growth factor receptor 2 (HER2-directed therapies is determined by the HER2 gene amplification and/or HER2 protein overexpression status of the breast tumor as determined by in situ hybridization (ISH or immunohistochemistry (IHC, respectively. Our objective was to combine the US Food and Drug Administration (FDA-approved HER2 & chromosome 17 centromere (CEN17 brightfield ISH (BISH and HER2 IHC assays into a single automated HER2 gene-protein assay allowing simultaneous detection of all three targets in a single tissue section. Methods The HER2 gene-protein assay was optimized using formalin-fixed, paraffin-embedded (FFPE samples of the xenograft tumors MCF7 [HER2 negative (non-amplified gene, protein negative] and Calu-3 [HER2 positive (amplified gene, protein positive]. HER2 IHC was performed using a rabbit monoclonal anti-HER2 antibody (clone 4B5 and a conventional 3,3'-diaminobenzidine IHC detection. The HER2 & CEN17 BISH signals were visualized using horseradish peroxidase-based silver and alkaline phosphatase-based red detection systems, respectively with a cocktail of 2,4-dinitrophenyl-labeled HER2 and digoxigenin-labeled CEN17 probes. The performance of the gene-protein assay on tissue microarray slides containing 189 randomly selected FFPE clinical breast cancer tissue cores was compared to that of the separate HER2 IHC and HER2 & CEN17 BISH assays. Results HER2 protein detection was optimal when the HER2 IHC protocol was used before (rather than after the BISH protocol. The sequential use of HER2 IHC and HER2 & CEN17 BISH detection steps on FFPE xenograft tumor sections appropriately co-localized the HER2 protein, HER2 gene, and CEN17 signals after mitigating the silver background staining by using a naphthol phosphate-containing hybridization buffer for the hybridization step. The HER2 protein and HER2 gene status obtained using the multiplex HER2 gene-protein

  2. Farnesyltransferase inhibitor treatment restores chromosome territory positions and active chromosome dynamics in Hutchinson-Gilford progeria syndrome cells

    Science.gov (United States)

    2011-01-01

    Background Hutchinson-Gilford progeria syndrome (HGPS) is a premature ageing syndrome that affects children leading to premature death, usually from heart infarction or strokes, making this syndrome similar to normative ageing. HGPS is commonly caused by a mutation in the A-type lamin gene, LMNA (G608G). This leads to the expression of an aberrant truncated lamin A protein, progerin. Progerin cannot be processed as wild-type pre-lamin A and remains farnesylated, leading to its aberrant behavior during interphase and mitosis. Farnesyltransferase inhibitors prevent the accumulation of farnesylated progerin, producing a less toxic protein. Results We have found that in proliferating fibroblasts derived from HGPS patients the nuclear location of interphase chromosomes differs from control proliferating cells and mimics that of control quiescent fibroblasts, with smaller chromosomes toward the nuclear interior and larger chromosomes toward the nuclear periphery. For this study we have treated HGPS fibroblasts with farnesyltransferase inhibitors and analyzed the nuclear location of individual chromosome territories. We have found that after exposure to farnesyltransferase inhibitors mis-localized chromosome territories were restored to a nuclear position akin to chromosomes in proliferating control cells. Furthermore, not only has this treatment afforded chromosomes to be repositioned but has also restored the machinery that controls their rapid movement upon serum removal. This machinery contains nuclear myosin 1β, whose distribution is also restored after farnesyltransferase inhibitor treatment of HGPS cells. Conclusions This study not only progresses the understanding of genome behavior in HGPS cells but demonstrates that interphase chromosome movement requires processed lamin A. PMID:21838864

  3. Genetics Home Reference: Y chromosome infertility

    Science.gov (United States)

    ... Home Health Conditions Y chromosome infertility Y chromosome infertility Enable Javascript to view the expand/collapse boxes. ... PDF Open All Close All Description Y chromosome infertility is a condition that affects the production of ...

  4. Chromosome choreography: the meiotic ballet.

    Science.gov (United States)

    Page, Scott L; Hawley, R Scott

    2003-08-08

    The separation of homologous chromosomes during meiosis in eukaryotes is the physical basis of Mendelian inheritance. The core of the meiotic process is a specialized nuclear division (meiosis I) in which homologs pair with each other, recombine, and then segregate from each other. The processes of chromosome alignment and pairing allow for homolog recognition. Reciprocal meiotic recombination ensures meiotic chromosome segregation by converting sister chromatid cohesion into mechanisms that hold homologous chromosomes together. Finally, the ability of sister kinetochores to orient to a single pole at metaphase I allows the separation of homologs to two different daughter cells. Failures to properly accomplish this elegant chromosome dance result in aneuploidy, a major cause of miscarriage and birth defects in human beings.

  5. Schizophrenia and chromosomal deletions

    Energy Technology Data Exchange (ETDEWEB)

    Lindsay, E.A.; Baldini, A. [Baylor College of Medicine, Houston, TX (United States); Morris, M. A. [Univ. of Geneva School of Medicine, NY (United States)] [and others

    1995-06-01

    Recent genetic linkage analysis studies have suggested the presence of a schizophrenia locus on the chromosomal region 22q11-q13. Schizophrenia has also been frequently observed in patients affected with velo-cardio-facial syndrome (VCFS), a disorder frequently associated with deletions within 22q11.1. It has been hypothesized that psychosis in VCFS may be due to deletion of the catechol-o-methyl transferase gene. Prompted by these observations, we screened for 22q11 deletions in a population of 100 schizophrenics selected from the Maryland Epidemiological Sample. Our results show that there are schizophrenic patients carrying a deletion of 22q11.1 and a mild VCFS phenotype that might remain unrecognized. These findings should encourage a search for a schizophrenia-susceptibility gene within the deleted region and alert those in clinical practice to the possible presence of a mild VCFS phenotype associated with schizophrenia. 9 refs.

  6. Mapping genes on human chromosome 20

    Energy Technology Data Exchange (ETDEWEB)

    Keith, T.; Phipps, P.; Serino, K. [Collaborative Research, Inc., Waltham, MA (United States)] [and others

    1994-09-01

    While a substantial number of genes have been physically localized to human chromosome 20, few have been genetically mapped. In the process of developing a genetic linkage map of chromosome 20, we have mapped microsatellite polymorphisms associated with six genes. Three of these had highly informative polymorphisms (greater than 0.70) that were originally identified by other investigators. These include avian sarcoma oncogene homolog (SRC), ribophorin II (RPN2), and phosphoenolpyruvate carboxykinase (PCK1). Polymorphisms associated with two genes were determined following a screen of their DNA sequences in GenBank. These include dinucleotide polymorphisms in introl II of cystatin c (CST3) and in the promoter region of neuroendocrine convertase 2 (NEC2) with heterozygosities of 0.52 and 0.54, respectively. A sixth gene, prodynorphin (PDYN) was mapped following the identification of a dinucleotide repeat polymorphism (heterozygosity of 0.35) in a cosmid subclone from a YAC homologous to the original phage clone. CA-positive cosmid subclones from a YAC for an additional gene, guanine nucleotide binding protein, alpha (GNAS10), have been identified and sequencing is in progress. Similar efforts were utilized to identify a microsatellite polymorphism from a half-YAC cloned by W. Brown and localized by FISH to 20pter. This polymorphism is highly informative, with a heterozygosity of 0.83, and serves to delimit the genetic map of the short arm of this chromosome.

  7. Chromatid Painting for Chromosomal Inversion Detection Project

    Data.gov (United States)

    National Aeronautics and Space Administration — We propose the continued development of a novel approach to the detection of chromosomal inversions. Transmissible chromosome aberrations (translocations and...

  8. CHROMOSOMAL MAPPING IN STRAINS OF STAPHYLOCOCCUS AUREUS,

    Science.gov (United States)

    STAPHYLOCOCCUS AUREUS , CHROMOSOMES), (*CHROMOSOMES, MAPPING), NITROSO COMPOUNDS, GUANIDINES, GENETICS, MUTATIONS, DRUGS, TOLERANCES(PHYSIOLOGY), TEST METHODS, DEOXYRIBONUCLEIC ACIDS, INHIBITION, RESISTANCE(BIOLOGY).

  9. Chromatid Painting for Chromosomal Inversion Detection Project

    Data.gov (United States)

    National Aeronautics and Space Administration — We propose a novel approach to the detection of chromosomal inversions. Transmissible chromosome aberrations (translocations and inversions) have profound genetic...

  10. The role of BUBR1 in the maintenance of chromosomal stability

    NARCIS (Netherlands)

    Suijkerbuijk, S.J.E.

    2012-01-01

    The majority of solid tumours contain an incorrect number of chromosomes. This state, called aneuploidy, can be caused by defects in chromosome segregation during the division of cells. Prevention against aneuploidy is dependent on BUBR1. This protein is an essential component of a surveillance mech

  11. Localization to Chromosomes of Structural Genes for the Major Protease Inhibitors of Barley Grains

    DEFF Research Database (Denmark)

    Hejgaard, Jørn; Bjørn, S.E.; Nielsen, Gunnar Gissel

    1984-01-01

    Wheat-barley chromosome addition lines were compared by isoelectric focusing of protein extracts to identify chromosomes carrying loci for the major immunochemically distinct protease inhibitors of barley grains. Structural genes for the following inhibitors were localized: an inhibitor of both...

  12. Chromosomal localization of the human and mouse hyaluronan synthase genes

    Energy Technology Data Exchange (ETDEWEB)

    Spicer, A.P.; McDonald, J.A. [Mayo Clinic Scottsdale, AZ (United States); Seldin, M.F. [Univ. of California Davis, CA (United States)] [and others

    1997-05-01

    We have recently identified a new vertebrate gene family encoding putative hyaluronan (HA) synthases. Three highly conserved related genes have been identified, designated HAS1, HAS2, and HAS3 in humans and Has1, Has2, and Has3 in the mouse. All three genes encode predicted plasma membrane proteins with multiple transmembrane domains and approximately 25% amino acid sequence identity to the Streptococcus pyogenes HA synthase, HasA. Furthermore, expression of any one HAS gene in transfected mammalian cells leads to high levels of HA biosynthesis. We now report the chromosomal localization of the three HAS genes in human and in mouse. The genes localized to three different positions within both the human and the mouse genomes. HAS1 was localized to the human chromosome 19q13.3-q13.4 boundary and Has1 to mouse Chr 17. HAS2 was localized to human chromosome 8q24.12 and Has2 to mouse Chr 15. HAS3 was localized to human chromosome 16q22.1 and Has3 to mouse Chr 8. The map position for HAS1 reinforces the recently reported relationship between a small region of human chromosome 19q and proximal mouse chromosome 17. HAS2 mapped outside the predicted critical region delineated for the Langer-Giedion syndrome and can thus be excluded as a candidate gene for this genetic syndrome. 33 refs., 2 figs.

  13. Functions of spindle check-point and its relationship to chromosome instability

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    It is generally believed that the equal distribution of genetic materials to two daughter cells during mitosis is the key to cell health and development. During the dynamic process, spindle checkpoint plays a very important role in chromosome movements and final sister chromatid separation. The equal and precise segregation of chromosomes contributes to the genomic stability while aberrant separations result in chromosome instability that causes pathogenesis of certain diseases such as Down's syndrome and cancers. Kinetochore and its regulatory proteins consist of the spindle checkpoint and determine the spatial and temporal orders of chromosome segregation.

  14. Gametocidal chromosomes enhancing chromosome aberration in common wheat induced by 5-azacytidine.

    Science.gov (United States)

    Su, W-Y; Cong, W-W; Shu, Y-J; Wang, D; Xu, G-H; Guo, C-H

    2013-07-08

    The gametocidal (Gc) chromosome from Aegilops spp induces chromosome mutation, which is introduced into common wheat as a tool of chromosome manipulation for genetic improvement. The Gc chromosome functions similar to a restriction-modification system in bacteria, in which DNA methylation is an important regulator. We treated root tips of wheat carrying Gc chromosomes with the hypomethylation agent 5-azacytidine; chromosome breakage and micronuclei were observed in these root tips. The frequency of aberrations differed in wheat containing different Gc chromosomes, suggesting different functions inducing chromosome breakage. Gc chromosome 3C caused the greatest degree of chromosome aberration, while Gc chromosome 3C(SAT) and 2C caused only slight chromosome aberration. Gc chromosome 3C induced different degrees of chromosome aberration in wheat varieties Triticum aestivum var. Chinese Spring and Norin 26, demonstrating an inhibition function in common wheat.

  15. Mechanisms of telomere loss and their consequences for chromosome instability

    Directory of Open Access Journals (Sweden)

    Keiko eMuraki

    2012-10-01

    Full Text Available The ends of chromosomes in mammals, called telomeres, are composed of a 6 base pair repeat sequence, TTAGGG, which is added on by the enzyme telomerase. In combination with a protein complex called shelterin, these telomeric repeat sequences form a cap that protects the ends of chromosomes. Due to insufficient telomerase expression, telomeres shorten gradually with each cell division in human somatic cells, which limits the number of times they can divide. The extensive cell division involved in cancer cell progression therefore requires that cancer cells must acquire the ability to maintain telomeres, either through expression of telomerase, or through an alternative mechanism involving recombination. It is commonly thought that the source of many chromosome rearrangements in cancer cells is a result of the extensive telomere shortening that occurs prior to the expression of telomerase. However, despite the expression of telomerase, tumor cells can continue to show chromosome instability due to telomere loss. Dysfunctional telomeres in cancer cells can result from oncogene-induced replication stress, which results in double-strand breaks (DSBs at fragile sites, including telomeres. DSBs near telomeres are especially prone to chromosome rearrangements, because telomeric regions are deficient in DSB repair. The deficiency in DSB repair near telomeres is also an important mechanism for ionizing radiation-induced replicative senescence in normal human cells. In addition, DSBs near telomeres can result in chromosome instability in mouse embryonic stem cells, suggesting that telomere loss can contribute to heritable chromosome rearrangements. Consistent with this possibility, telomeric regions in humans are highly heterogeneous, and chromosome rearrangements near telomeres are commonly involved in human genetic disease. Understanding the mechanisms of telomere loss will therefore provide important insights into both human cancer and genetic disease.

  16. Nonspecific interactions of chromatin with immunoglobulin G and protein A, and their impact on purification performance.

    Science.gov (United States)

    Gagnon, Pete; Nian, Rui; Lee, Jeremy; Tan, Lihan; Latiff, Sarah Maria Abdul; Lim, Chiew Ling; Chuah, Cindy; Bi, Xuezhi; Yang, Yuansheng; Zhang, Wei; Gan, Hui Theng

    2014-05-02

    Chromatin released from dead host cells during in vitro production of IgG monoclonal antibodies exists mostly in complex hetero-aggregates consisting of nucleosomal arrays (DNA+histone proteins), non-histone proteins, and aberrant forms of IgG. They bind immobilized protein A more aggressively than IgG, through their nucleosomal histone components, and hinder access of IgG to Fc-specific binding sites, thereby reducing dynamic binding capacity. The majority of host cell contaminants in eluted IgG are leachates from chromatin hetero-aggregates that remain bound to protein A. Formation of turbidity in eluted IgG during pH titration is caused by neutral-pH insolubility of chromatin hetero-aggregates. NaOH is required at 500 mM to remove accumulated chromatin. A chromatin-directed clarification method removed 99% of histones, 90% of non-histone proteins, achieved a 6 log reduction of DNA, 4 log reduction of lipid-enveloped virus, and 5 log reduction of non-enveloped retrovirus, while conserving 98% of the native IgG. This suspended most of performance compromises imposed on protein A. IgG binding capacity increased ~20%. Host protein contamination was reduced about 100-fold compared to protein A loaded with harvest clarified by centrifugation and microfiltration. Aggregates were reduced to less than 0.05%. Turbidity of eluted IgG upon pH neutralization was nearly eliminated. Column cleaning was facilitated by minimizing the accumulation of chromatin.

  17. Chromosome segregation in Vibrio cholerae.

    Science.gov (United States)

    Ramachandran, Revathy; Jha, Jyoti; Chattoraj, Dhruba K

    2014-01-01

    The study of chromosome segregation is currently one of the most exciting research frontiers in cell biology. In this review, we discuss our current knowledge of the chromosome segregation process in Vibrio cholerae, based primarily on findings from fluorescence microscopy experiments. This bacterium is of special interest because of its eukaryotic feature of having a divided genome, a feature shared with 10% of known bacteria. We also discuss how the segregation mechanisms of V. cholerae compare with those in other bacteria, and highlight some of the remaining questions regarding the process of bacterial chromosome segregation.

  18. Numerous transitions of sex chromosomes in Diptera.

    Science.gov (United States)

    Vicoso, Beatriz; Bachtrog, Doris

    2015-04-01

    Many species groups, including mammals and many insects, determine sex using heteromorphic sex chromosomes. Diptera flies, which include the model Drosophila melanogaster, generally have XY sex chromosomes and a conserved karyotype consisting of six chromosomal arms (five large rods and a small dot), but superficially similar karyotypes may conceal the true extent of sex chromosome variation. Here, we use whole-genome analysis in 37 fly species belonging to 22 different families of Diptera and uncover tremendous hidden diversity in sex chromosome karyotypes among flies. We identify over a dozen different sex chromosome configurations, and the small dot chromosome is repeatedly used as the sex chromosome, which presumably reflects the ancestral karyotype of higher Diptera. However, we identify species with undifferentiated sex chromosomes, others in which a different chromosome replaced the dot as a sex chromosome or in which up to three chromosomal elements became incorporated into the sex chromosomes, and others yet with female heterogamety (ZW sex chromosomes). Transcriptome analysis shows that dosage compensation has evolved multiple times in flies, consistently through up-regulation of the single X in males. However, X chromosomes generally show a deficiency of genes with male-biased expression, possibly reflecting sex-specific selective pressures. These species thus provide a rich resource to study sex chromosome biology in a comparative manner and show that similar selective forces have shaped the unique evolution of sex chromosomes in diverse fly taxa.

  19. Organizing the bacterial chromosome for division

    Science.gov (United States)

    Broedersz, Chase

    2014-03-01

    The chromosome is highly organized in space in many bacteria, although the origin and function of this organization remain unclear. This organization is further complicated by the necessity for chromosome replication and segregation. Partitioning proteins of the ParABS system mediate chromosomal and plasmid segregation in a variety of bacteria. This segregation machinery includes a large ParB-DNA complex consisting of roughly 1000 ParB dimers, which localizes around one or a few centromere-like parS sites near the origin of replication. Despite the apparent simplicity of this segregation machinery as compared to eukaryotic segregations systems, puzzles remain: In particular, what is the nature of interactions among DNA-bound ParB proteins, and how do these determine the organizational and functional properties of the ParB-DNA partitioning complex? A crucial aspect of this question is whether ParB spreads along the DNA to form a filamentous protein-DNA complex with a 1D character, or rather assembles to form a 3D complex on the DNA. Furthermore, it remains unclear how the presence of only one or even a few parS sites can lead to robust formation and localization of such a large protein-DNA complex. We developed a simple model for interacting proteins on DNA, and found that a combination of 1D spreading bonds and a 3D bridging bond between ParB proteins constitutes the minimal model for condensation of a 3D ParB-DNA complex. These combined interactions provide an effective surface tension that prevents fragmentation of the ParB-DNA complex. Thus, ParB spreads to form multiple 1D domains on the DNA, connected in 3D by bridging interactions to assemble into a 3D ParB-DNA condensate. Importantly, this model accounts for recent experiments on ParB-induced gene-silencing and the effect of a DNA ``roadblock'' on ParB localization. Furthermore, our model provides a simple mechanism to explain how a single parS site is both necessary and sufficient for the formation and

  20. X chromosome control of meiotic chromosome synapsis in mouse inter-subspecific hybrids.

    Directory of Open Access Journals (Sweden)

    Tanmoy Bhattacharyya

    2014-02-01

    Full Text Available Hybrid sterility (HS belongs to reproductive isolation barriers that safeguard the integrity of species in statu nascendi. Although hybrid sterility occurs almost universally among animal and plant species, most of our current knowledge comes from the classical genetic studies on Drosophila interspecific crosses or introgressions. With the house mouse subspecies Mus m. musculus and Mus m. domesticus as a model, new research tools have become available for studies of the molecular mechanisms and genetic networks underlying HS. Here we used QTL analysis and intersubspecific chromosome substitution strains to identify a 4.7 Mb critical region on Chromosome X (Chr X harboring the Hstx2 HS locus, which causes asymmetrical spermatogenic arrest in reciprocal intersubspecific F1 hybrids. Subsequently, we mapped autosomal loci on Chrs 3, 9 and 13 that can abolish this asymmetry. Combination of immunofluorescent visualization of the proteins of synaptonemal complexes with whole-chromosome DNA FISH on pachytene spreads revealed that heterosubspecific, unlike consubspecific, homologous chromosomes are predisposed to asynapsis in F1 hybrid male and female meiosis. The asynapsis is under the trans- control of Hstx2 and Hst1/Prdm9 hybrid sterility genes in pachynemas of male but not female hybrids. The finding concurred with the fertility of intersubpecific F1 hybrid females homozygous for the Hstx2(Mmm allele and resolved the apparent conflict with the dominance theory of Haldane's rule. We propose that meiotic asynapsis in intersubspecific hybrids is a consequence of cis-acting mismatch between homologous chromosomes modulated by the trans-acting Hstx2 and Prdm9 hybrid male sterility genes.

  1. Double-strand break repair on sex chromosomes: challenges during male meiotic prophase.

    Science.gov (United States)

    Lu, Lin-Yu; Yu, Xiaochun

    2015-01-01

    During meiotic prophase, DNA double-strand break (DSB) repair-mediated homologous recombination (HR) occurs for exchange of genetic information between homologous chromosomes. Unlike autosomes or female sex chromosomes, human male sex chromosomes X and Y share little homology. Although DSBs are generated throughout male sex chromosomes, homologous recombination does not occur for most regions and DSB repair process is significantly prolonged. As a result, male sex chromosomes are coated with many DNA damage response proteins and form a unique chromatin structure known as the XY body. Interestingly, associated with the prolonged DSB repair, transcription is repressed in the XY body but not in autosomes, a phenomenon known as meiotic sex chromosome inactivation (MSCI), which is critical for male meiosis. Here using mice as model organisms, we briefly summarize recent progress on DSB repair in meiotic prophase and focus on the mechanism and function of DNA damage response in the XY body.

  2. Tropomyosin is localized in the nuclear matrix and chromosome scaffold of physarum polycephalum

    Institute of Scientific and Technical Information of China (English)

    ZENGXIANLU; XIAOGUANGWANG; 等

    1999-01-01

    The nuclei and chromosomes were isolated from plasmodia of Physarum polycephalum.The nuclear matrix and chromosome scaffold were obtained after the DNA and most of the proteins were extracted with DNase I and 2 M NaCl.SD-PAGE analyses revealed that the nuclear matrix and chromosome scaffold contained a 37 kD polypeptide which is equivalent to tropomyosin in molecular weight.Immunofluorescence observations upon slide preparations labeled with anti-tropomyosin antibody showed that the nuclear matrix and chromosome scaffold emanated bright fluorescence,suggesting the presence of the antigen in them.Immunodotting results confirmed the presence of tropomyosin in the nuclear matrix and chromosome scaffold.Immunoelectron microscopic observations further demonstrated that tropomyosin was dispersively distributed in the interphase nuclei and metaphase chromosomes.

  3. HIM-8 binds to the X chromosome pairing center and mediateschromosome-specific meiotic synapsis

    Energy Technology Data Exchange (ETDEWEB)

    Phillips, Carolyn M.; Wong, Chihunt; Bhalla, Needhi; Carlton,Peter M.; Weiser, Pinky; Meneely, Philip M.; Dernburg, Abby F.

    2005-06-05

    The him-8 gene is essential for proper meiotic segregationof the X chromosomes in C. elegans. Herewe show that loss of him-8function causes profound X-chromosome-specific defects in homolog pairingand synapsis.him-8 encodes a C2H2 zinc finger protein that is expressedduring meiosis andconcentrates at a site on the X chromosome known as themeiotic Pairing Center (PC). A role for HIM-8 in PC function is supportedby genetic interactions between PC lesions and him-8 mutations.HIM-8-bound chromosome sites associate with the nuclear envelope (NE)throughout meiotic prophase. Surprisingly, a point mutation in him-8 thatretains both chromosome binding and NE localization fails to stabilizepairing or promote synapsis. These observations indicate thatstabilization of homolog pairing is an active process in which thetethering of chromosome sites to the NE may be necessary but is notsufficient.

  4. Chromosome fragility in Freemartin cattle

    Directory of Open Access Journals (Sweden)

    V. Barbieri

    2010-04-01

    Full Text Available The aim of the present study was to verify chromosome fragility in freemartin cattle using chromosome aberration (CA and sister chromatid exchange (SCE tests. A total of eighteen co-twins were investigated. Fourteen animals were identified as cytogenetically chimeric (2n=60, XX/XY while 4 were classified as normal. Freemartin cattle showed a higher percentage of aneuploid cells (18.64% and highly significant statistical differences (P < 0.001 in mean values of gaps (4.53 ± 2.05, chromatid breaks (0.26 ± 0.51, and significant statistical differences (P < 0.005 in mean values of chromosome breaks (0.12 ± 0.43 when compared to 10 control animals from single births (aneuploid cells, 11.20%; gaps, 2.01 ± 1.42; chromatid breaks, 0.05 ± 0.22; chromosome breaks, 0.02 ± 0.14.

  5. Chromosome Segregation in Vibrio cholerae

    OpenAIRE

    Ramachandran, R.; Jha, J.; Chattoraj, DK

    2014-01-01

    The study of chromosome segregation is currently one of the most exciting research frontiers in cell biology. In this review, we discuss our current knowledge of the chromosome segregation process in Vibrio cholerae, based primarily on findings from fluorescence microscopy experiments. This bacterium is of special interest because of its eukaryotic feature of having a divided genome, a feature shared with 10% of known bacteria. We also discuss how the segregation mechanisms of V. cholerae com...

  6. B chromosomes and sex in animals.

    Science.gov (United States)

    Camacho, J P M; Schmid, M; Cabrero, J

    2011-01-01

    Supernumerary (B) chromosomes are dispensable elements found in many eukaryote genomes in addition to standard (A) chromosomes. In many respects, B chromosomes resemble sex chromosomes, so that a common ancestry for them has frequently been suggested. For instance, B chromosomes in grasshoppers, and other insects, show a pycnotic cycle of condensation-decondensation during meiosis remarkably similar to that of the X chromosome. In some cases, B chromosome size is even very similar to that of the X chromosome. These resemblances have led to suggest the X as the B ancestor in many cases. In addition, sex chromosome origin from B chromosomes has also been suggested. In this article, we review the existing evidence for both evolutionary pathways, as well as sex differences for B frequency at adult and embryo progeny levels, B chromosome effects or B chromosome transmission. In addition, we review cases found in the literature showing sex-ratio distortion associated with B chromosome presence, the most extreme case being the paternal sex ratio (PSR) chromosomes in some Hymenoptera. We finally analyse the possibility of B chromosome regularisation within the host genome and, as a consequence of it, whether B chromosomes can become regular members of the host genome.

  7. Origin and domestication of papaya Yh chromosome

    Science.gov (United States)

    Sex in papaya is controlled by a pair of nascent sex chromosomes. Females are XX, and two slightly different Y chromosomes distinguish males (XY) and hermaphrodites (XYh). The hermaphrodite-specific region of the Yh chromosome (HSY) and its X chromosome counterpart were sequenced and analyzed previo...

  8. Numerically abnormal chromosome constitutions in humans

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1993-12-31

    Chapter 24, discusses numerically abnormal chromosome constitutions in humans. This involves abnormalities of human chromosome number, including polyploidy (when the number of sets of chromosomes increases) and aneuploidy (when the number of individual normal chromosomes changes). Chapter sections discuss the following chromosomal abnormalities: human triploids, imprinting and uniparental disomy, human tetraploids, hydatidiform moles, anomalies caused by chromosomal imbalance, 13 trisomy (D{sub 1} trisomy, Patau syndrome), 21 trisomy (Down syndrome), 18 trisomy syndrome (Edwards syndrome), other autosomal aneuploidy syndromes, and spontaneous abortions. The chapter concludes with remarks on the nonrandom participation of chromosomes in trisomy. 69 refs., 3 figs., 4 tabs.

  9. Organization and segregation of bacterial chromosomes.

    Science.gov (United States)

    Wang, Xindan; Montero Llopis, Paula; Rudner, David Z

    2013-03-01

    The bacterial chromosome must be compacted more than 1,000-fold to fit into the compartment in which it resides. How it is condensed, organized and ultimately segregated has been a puzzle for over half a century. Recent advances in live-cell imaging and genome-scale analyses have led to new insights into these problems. We argue that the key feature of compaction is the orderly folding of DNA along adjacent segments and that this organization provides easy and efficient access for protein-DNA transactions and has a central role in driving segregation. Similar principles and common proteins are used in eukaryotes to condense and to resolve sister chromatids at metaphase.

  10. Flow karyotyping and sorting of human chromosomes

    Energy Technology Data Exchange (ETDEWEB)

    Gray, J.W.; Lucas, J.; Peters, D.; Pinkel, D.; Trask, B.; van den Engh, G.; Van Dilla, M.A.

    1986-07-16

    Flow cytometry and sorting are becoming increasingly useful as tools for chromosome classfication and for the detection of numerical and structural chromosome aberrations. Chromosomes of a single type can be purified with these tools to facilitate gene mapping or production of chromosome specific recombinant DNA libraries. For analysis of chromosomes with flow cytometry, the chromosomes are extracted from mitotic cells, stained with one or more fluorescent dyes and classified one-by-one according to their dye content(s). Thus, the flow approach is fundamentally different than conventional karyotyping where chromosomes are classified within the context of a metaphase spread. Flow sorting allows purification of chromosomes that can be distinguished flow cytometrically. The authors describe the basic principles of flow cytometric chromosome classification i.e. flow karyotyping, and chromosome sorting and describe several applications. 30 refs., 8 figs.

  11. Chromosomal imbalances in successive moments of human bladder urothelial carcinoma

    DEFF Research Database (Denmark)

    Nascimento e Pontes, Merielen Garcia; da Silveira, Sara Martorelli; Trindade Filho, José Carlos de Souza;

    2013-01-01

    in 16p12, in line with suggestions that these chromosome regions contain genes critical for urinary bladder carcinogenesis. Within a same patient, tumors and their respective recurrences showed common genomic losses and gains, which implies that the genomic profile acquired by primary tumors...... cells expressing the p53 protein, suggesting that the apparently normal urothelium was genomically unstable. No numerical alterations of the chromosomes 7, 17, and 9p21 region were found by FISH during the periods "free-of-neoplasia." Our data are informative for further studies to better understand...

  12. Control of bacterial chromosome replication by non-coding regions outside the origin

    DEFF Research Database (Denmark)

    Frimodt-Møller, Jakob; Charbon, Godefroid; Løbner-Olesen, Anders

    2016-01-01

    Chromosome replication in Eubacteria is initiated by initiator protein(s) binding to specific sites within the replication origin, oriC. Recently, initiator protein binding to chromosomal regions outside the origin has attracted renewed attention; as such binding sites contribute to control...... the frequency of initiations. These outside-oriC binding sites function in several different ways: by steric hindrances of replication fork assembly, by titration of initiator proteins away from the origin, by performing a chaperone-like activity for inactivation- or activation of initiator proteins...

  13. The gene for calcium-modulating cyclophilin ligand (CAMLG) is located on human Chromosome 5q23 and a syntenic region of mouse chromosome 13

    Energy Technology Data Exchange (ETDEWEB)

    Bram, R.J.; Valentine, V.; Shapiro, D.N. [St. Jude Children`s Research Hospital, Memphis, TN (United States)]|[Univ. of Tennessee, Memphis, TN (United States)] [and others

    1996-01-15

    The CAMLG gene encodes a novel cyclophilin B-binding protein called calcium-modulating cyclophilin ligand, which appears to be involved in the regulation of calcium signaling in T lymphocytes and other cells. The murine homolog, Caml, was localized by interspecific backcross analysis in the middle of chromosome 13. By fluorescence in situ hybridization, this gene was localized to human chromosome 5 in a region (q23) known to be syntenic to mouse chromosome 13. These results provide further evidence supporting the extensive homology between human chromosome 5q and mouse chromosome 13. In addition, the results will provide a basis for further evaluation of cytogenetic anomalies that may contribute to inherited defects in calcium signaling or immune system function. 15 refs., 2 figs.

  14. Development of Mammalian Cell Lines with lac Operator-Tagged Chromosomes

    OpenAIRE

    sprotocols

    2014-01-01

    Authors: Yuri G. Strukov and Andrew S. Belmont This protocol was adapted from “Development of Mammalian Cell Lines with lac Operator-Tagged Chromosomes,” Chapter 25, in[ *Live Cell Imaging* ](http://www.cshlpress.com/link/livecelp.htm)(eds. Goldman and Spector). Cold Spring Harbor Laboratory Press, Cold Spring Harbor, NY, USA, 2005. ### INTRODUCTION The discovery and use of fluorescent proteins to label chromosomal proteins has yielded basic structural information as well as insig...

  15. Origin and evolution of B chromosomes in the cichlid fish Astatotilapia latifasciata based on integrated genomic analyses.

    Science.gov (United States)

    Valente, Guilherme T; Conte, Matthew A; Fantinatti, Bruno E A; Cabral-de-Mello, Diogo C; Carvalho, Robson F; Vicari, Marcelo R; Kocher, Thomas D; Martins, Cesar

    2014-08-01

    Approximately 15% of eukaryotes contain supernumerary B chromosomes. When present, B chromosomes frequently represent as much as 5% of the genome. Despite thousands of reports describing the distribution of supernumeraries in various taxa, a comprehensive theory for the origin, maintenance, and evolution of B chromosomes has not emerged. Here, we sequence the complete genomes of individual cichlid fish (Astatotilapia latifasciata) with and without B chromosomes, as well as microdissected B chromosomes, to identify DNA sequences on the B. B sequences were further analyzed through quantitative polymerase chain reaction and in situ hybridization. We find that the B chromosome contains thousands of sequences duplicated from essentially every chromosome in the ancestral karyotype. Although most genes on the B chromosome are fragmented, a few are largely intact, and we detect evidence that at least three of them are transcriptionally active. We propose a model in which the B chromosome originated early in the evolutionary history of Lake Victoria cichlids from a small fragment of one autosome. DNA sequences originating from several autosomes, including protein-coding genes and transposable elements, subsequently inserted into this proto-B. We propose that intact B chromosome genes involved with microtubule organization, kinetochore structure, recombination and progression through the cell cycle may play a role in driving the transmission of the B chromosome. Furthermore, our work suggests that karyotyping is an essential step prior to genome sequencing to avoid problems in genome assembly and analytical biases created by the presence of high copy number sequences on the B chromosome.

  16. A spindle-like apparatus guides bacterial chromosome segregation.

    Science.gov (United States)

    Ptacin, Jerod L; Lee, Steven F; Garner, Ethan C; Toro, Esteban; Eckart, Michael; Comolli, Luis R; Moerner, W E; Shapiro, Lucy

    2010-08-01

    Until recently, a dedicated mitotic apparatus that segregates newly replicated chromosomes into daughter cells was believed to be unique to eukaryotic cells. Here we demonstrate that the bacterium Caulobacter crescentus segregates its chromosome using a partitioning (Par) apparatus that has surprising similarities to eukaryotic spindles. We show that the C. crescentus ATPase ParA forms linear polymers in vitro and assembles into a narrow linear structure in vivo. The centromere-binding protein ParB binds to and destabilizes ParA structures in vitro. We propose that this ParB-stimulated ParA depolymerization activity moves the centromere to the opposite cell pole through a burnt bridge Brownian ratchet mechanism. Finally, we identify the pole-specific TipN protein as a new component of the Par system that is required to maintain the directionality of DNA transfer towards the new cell pole. Our results elucidate a bacterial chromosome segregation mechanism that features basic operating principles similar to eukaryotic mitotic machines, including a multivalent protein complex at the centromere that stimulates the dynamic disassembly of polymers to move chromosomes into daughter compartments.

  17. Chromosome therapy. Correction of large chromosomal aberrations by inducing ring chromosomes in induced pluripotent stem cells (iPSCs).

    Science.gov (United States)

    Kim, Taehyun; Bershteyn, Marina; Wynshaw-Boris, Anthony

    2014-01-01

    The fusion of the short (p) and long (q) arms of a chromosome is referred to as a "ring chromosome." Ring chromosome disorders occur in approximately 1 in 50,000-100,000 patients. Ring chromosomes can result in birth defects, mental disabilities, and growth retardation if additional genes are deleted during the formation of the ring. Due to the severity of these large-scale aberrations affecting multiple contiguous genes, no possible therapeutic strategies for ring chromosome disorders have so far been proposed. Our recent study (Bershteyn et al.) using patient-derived fibroblast lines containing ring chromosomes, found that cellular reprogramming of these fibroblasts into induced pluripotent stem cells (iPSCs) resulted in the cell-autonomous correction of the ring chromosomal aberration via compensatory uniparental disomy (UPD). These observations have important implications for studying the mechanism of chromosomal number control and may lead to the development of effective therapies for other, more common, chromosomal aberrations.

  18. The DNA Sequence And Comparative Analysis Of Human Chromosome5

    Energy Technology Data Exchange (ETDEWEB)

    Schmutz, Jeremy; Martin, Joel; Terry, Astrid; Couronne, Olivier; Grimwood, Jane; Lowry, Steve; Gordon, Laurie A.; Scott, Duncan; Xie,Gary; Huang, Wayne; Hellsten, Uffe; Tran-Gyamfi, Mary; She, Xinwei; Prabhakar, Shyam; Aerts, Andrea; Altherr, Michael; Bajorek, Eva; Black,Stacey; Branscomb, Elbert; Caoile, Chenier; Challacombe, Jean F.; Chan,Yee Man; Denys, Mirian; Detter, John C.; Escobar, Julio; Flowers, Dave; Fotopulos, Dea; Glavina, Tijana; Gomez, Maria; Gonzales, Eidelyn; Goodstein, David; Grigoriev, Igor; Groza, Matthew; Hammon, Nancy; Hawkins, Trevor; Haydu, Lauren; Israni, Sanjay; Jett, Jamie; Kadner,Kristen; Kimball, Heather; Kobayashi, Arthur; Lopez, Frederick; Lou,Yunian; Martinez, Diego; Medina, Catherine; Morgan, Jenna; Nandkeshwar,Richard; Noonan, James P.; Pitluck, Sam; Pollard, Martin; Predki, Paul; Priest, James; Ramirez, Lucia; Retterer, James; Rodriguez, Alex; Rogers,Stephanie; Salamov, Asaf; Salazar, Angelica; Thayer, Nina; Tice, Hope; Tsai, Ming; Ustaszewska, Anna; Vo, Nu; Wheeler, Jeremy; Wu, Kevin; Yang,Joan; Dickson, Mark; Cheng, Jan-Fang; Eichler, Evan E.; Olsen, Anne; Pennacchio, Len A.; Rokhsar, Daniel S.; Richardson, Paul; Lucas, SusanM.; Myers, Richard M.; Rubin, Edward M.

    2004-08-01

    Chromosome 5 is one of the largest human chromosomes and contains numerous intrachromosomal duplications, yet it has one of the lowest gene densities. This is partially explained by numerous gene-poor regions that display a remarkable degree of noncoding conservation with non-mammalian vertebrates, suggesting that they are functionally constrained. In total, we compiled 177.7 million base pairs of highly accurate finished sequence containing 923 manually curated protein-coding genes including the protocadherin and interleukin gene families. We also completely sequenced versions of the large chromosome-5-specific internal duplications. These duplications are very recent evolutionary events and probably have a mechanistic role in human physiological variation, as deletions in these regions are the cause of debilitating disorders including spinal muscular atrophy.

  19. The sequence and analysis of duplication rich human chromosome 16

    Energy Technology Data Exchange (ETDEWEB)

    Martin, J; Han, C; Gordon, L A; Terry, A; Prabhakar, S; She, X; Xie, G; Hellsten, U; Chan, Y M; Altherr, M; Couronne, O; Aerts, A; Bajorek, E; Black, S; Blumer, H; Branscomb, E; Brown, N; Bruno, W J; Buckingham, J; Callen, D F; Campbell, C S; Campbell, M L; Campbell, E W; Caoile, C; Challacombe, J F; Chasteen, L A; Chertkov, O; Chi, H C; Christensen, M; Clark, L M; Cohn, J D; Denys, M; Detter, J C; Dickson, M; Dimitrijevic-Bussod, M; Escobar, J; Fawcett, J J; Flowers, D; Fotopulos, D; Glavina, T; Gomez, M; Gonzales, E; Goodstein, D; Goodwin, L A; Grady, D L; Grigoriev, I; Groza, M; Hammon, N; Hawkins, T; Haydu, L; Hildebrand, C E; Huang, W; Israni, S; Jett, J; Jewett, P B; Kadner, K; Kimball, H; Kobayashi, A; Krawczyk, M; Leyba, T; Longmire, J L; Lopez, F; Lou, Y; Lowry, S; Ludeman, T; Manohar, C F; Mark, G A; McMurray, K L; Meincke, L J; Morgan, J; Moyzis, R K; Mundt, M O; Munk, A C; Nandkeshwar, R D; Pitluck, S; Pollard, M; Predki, P; Parson-Quintana, B; Ramirez, L; Rash, S; Retterer, J; Ricke, D O; Robinson, D; Rodriguez, A; Salamov, A; Saunders, E H; Scott, D; Shough, T; Stallings, R L; Stalvey, M; Sutherland, R D; Tapia, R; Tesmer, J G; Thayer, N; Thompson, L S; Tice, H; Torney, D C; Tran-Gyamfi, M; Tsai, M; Ulanovsky, L E; Ustaszewska, A; Vo, N; White, P S; Williams, A L; Wills, P L; Wu, J; Wu, K; Yang, J; DeJong, P; Bruce, D; Doggett, N A; Deaven, L; Schmutz, J; Grimwood, J; Richardson, P; Rokhsar, D S; Eichler, E E; Gilna, P; Lucas, S M; Myers, R M; Rubin, E M; Pennacchio, L A

    2005-04-06

    Human chromosome 16 features one of the highest levels of segmentally duplicated sequence among the human autosomes. We report here the 78,884,754 base pairs of finished chromosome 16 sequence, representing over 99.9% of its euchromatin. Manual annotation revealed 880 protein-coding genes confirmed by 1,637 aligned transcripts, 19 tRNA genes, 341 pseudogenes, and 3 RNA pseudogenes. These genes include metallothionein, cadherin, and iroquois gene families, as well as the disease genes for polycystic kidney disease and acute myelomonocytic leukemia. Several large-scale structural polymorphisms spanning hundreds of kilobase pairs were identified and result in gene content differences among humans. While the segmental duplications of chromosome 16 are enriched in the relatively gene poor pericentromere of the p-arm, some are involved in recent gene duplication and conversion events likely to have had an impact on the evolution of primates and human disease susceptibility.

  20. Resolution of Multimeric Forms of Circular Plasmids and Chromosomes.

    Science.gov (United States)

    Crozat, Estelle; Fournes, Florian; Cornet, François; Hallet, Bernard; Rousseau, Philippe

    2014-10-01

    One of the disadvantages of circular plasmids and chromosomes is their high sensitivity to rearrangements caused by homologous recombination. Odd numbers of crossing-over occurring during or after replication of a circular replicon result in the formation of a dimeric molecule in which the two copies of the replicon are fused. If they are not converted back to monomers, the dimers of replicons may fail to correctly segregate at the time of cell division. Resolution of multimeric forms of circular plasmids and chromosomes is mediated by site-specific recombination, and the enzymes that catalyze this type of reaction fall into two families of proteins: the serine and tyrosine recombinase families. Here we give an overview of the variety of site-specific resolution systems found on circular plasmids and chromosomes.

  1. The Divergence of Neandertal and Modern Human Y Chromosomes.

    Science.gov (United States)

    Mendez, Fernando L; Poznik, G David; Castellano, Sergi; Bustamante, Carlos D

    2016-04-07

    Sequencing the genomes of extinct hominids has reshaped our understanding of modern human origins. Here, we analyze ∼120 kb of exome-captured Y-chromosome DNA from a Neandertal individual from El Sidrón, Spain. We investigate its divergence from orthologous chimpanzee and modern human sequences and find strong support for a model that places the Neandertal lineage as an outgroup to modern human Y chromosomes-including A00, the highly divergent basal haplogroup. We estimate that the time to the most recent common ancestor (TMRCA) of Neandertal and modern human Y chromosomes is ∼588 thousand years ago (kya) (95% confidence interval [CI]: 447-806 kya). This is ∼2.1 (95% CI: 1.7-2.9) times longer than the TMRCA of A00 and other extant modern human Y-chromosome lineages. This estimate suggests that the Y-chromosome divergence mirrors the population divergence of Neandertals and modern human ancestors, and it refutes alternative scenarios of a relatively recent or super-archaic origin of Neandertal Y chromosomes. The fact that the Neandertal Y we describe has never been observed in modern humans suggests that the lineage is most likely extinct. We identify protein-coding differences between Neandertal and modern human Y chromosomes, including potentially damaging changes to PCDH11Y, TMSB4Y, USP9Y, and KDM5D. Three of these changes are missense mutations in genes that produce male-specific minor histocompatibility (H-Y) antigens. Antigens derived from KDM5D, for example, are thought to elicit a maternal immune response during gestation. It is possible that incompatibilities at one or more of these genes played a role in the reproductive isolation of the two groups.

  2. POF regulates the expression of genes on the fourth chromosome in Drosophila melanogaster by binding to nascent RNA.

    Science.gov (United States)

    Johansson, Anna-Mia; Stenberg, Per; Allgardsson, Anders; Larsson, Jan

    2012-06-01

    In Drosophila, two chromosome-wide compensatory systems have been characterized: the dosage compensation system that acts on the male X chromosome and the chromosome-specific regulation of genes located on the heterochromatic fourth chromosome. Dosage compensation in Drosophila is accomplished by hypertranscription of the single male X chromosome mediated by the male-specific lethal (MSL) complex. The mechanism of this compensation is suggested to involve enhanced transcriptional elongation mediated by the MSL complex, while the mechanism of compensation mediated by the painting of fourth (POF) protein on the fourth chromosome has remained elusive. Here, we show that POF binds to nascent RNA, and this binding is associated with increased transcription output from chromosome 4. We also show that genes located in heterochromatic regions spend less time in transition from the site of transcription to the nuclear envelope. These results provide useful insights into the means by which genes in heterochromatic regions can overcome the repressive influence of their hostile environment.

  3. Inherited unbalanced structural chromosome abnormalities at prenatal chromosome analysis are rarely ascertained through recurrent miscarriage

    NARCIS (Netherlands)

    Franssen, M. T. M.; Korevaar, J. C.; Tjoa, W. M.; Leschot, N. J.; Bossuyt, P. M. M.; Knegt, A. C.; Suykerbuyk, R. F.; Hochstenbach, R.; van der Veen, F.; Goddijn, M.

    2008-01-01

    Objective To determine the mode of ascertainment of inherited unbalanced structural chromosome abnormalities detected at prenatal chromosome analysis. Methods From the databases of three centres for clinical genetics in the Netherlands, all cases of inherited unbalanced structural chromosome abnorma

  4. Dean flow fractionation of chromosomes

    Science.gov (United States)

    Hockin, Matt; Sant, Himanshu J.; Capecchi, Mario; Gale, Bruce K.

    2016-03-01

    Efforts to transfer intact mammalian chromosomes between cells have been attempted for more than 50 years with the consistent result being transfer of sub unit length pieces regardless of method. Inertial microfluidics is a new field that has shown much promise in addressing the fractionation of particles in the 2-20 μm size range (with unknown limits) and separations are based upon particles being carried by curving confined flows (within a spiral shaped, often rectangular flow chamber) and migrating to stable "equilibrium" positions of varying distance from a chamber wall depending on the balance of dean and lift forces. We fabricated spiral channels for inertial microfluidic separations using a standard soft lithography process. The concentration of chromosomes, small contaminant DNA and large cell debris in each outlets were evaluated using microscope (60X) and a flow cytometer. Using Dean Flow Fractionation, we were able to focus 4.5 times more chromosomes in outlet 2 compared to outlet 4 where most of the large debris is found. We recover 16% of the chromosomes in outlet #1- 50% in 2, 23% in 3 and 11% in 4. It should be noted that these estimates of recovery do not capture one piece of information- it actually may be that the chromosomes at each outlet are physically different and work needs to be done to verify this potential.

  5. Chromosome segregation in plant meiosis

    Directory of Open Access Journals (Sweden)

    Linda eZamariola

    2014-06-01

    Full Text Available Faithful chromosome segregation in meiosis is essential for ploidy stability over sexual life cycles. In plants, defective chromosome segregation caused by gene mutations or other factors leads to the formation of unbalanced or unreduced gametes creating aneuploid or polyploid progeny, respectively. Accurate segregation requires the coordinated execution of conserved processes occurring throughout the two meiotic cell divisions. Synapsis and recombination ensure the establishment of chiasmata that hold homologous chromosomes together allowing their correct segregation in the first meiotic division, which is also tightly regulated by cell-cycle dependent release of cohesin and monopolar attachment of sister kinetochores to microtubules. In meiosis II, bi-orientation of sister kinetochores and proper spindle orientation correctly segregate chromosomes in four haploid cells. Checkpoint mechanisms acting at kinetochores control the accuracy of kinetochore-microtubule attachment, thus ensuring the completion of segregation. Here we review the current knowledge on the processes taking place during chromosome segregation in plant meiosis, focusing on the characterization of the molecular factors involved.

  6. The DNA sequence and biology of human chromosome 19

    Energy Technology Data Exchange (ETDEWEB)

    Grimwood, Jane; Gordon, Laurie A.; Olsen, Anne; Terry, Astrid; Schmutz, Jeremy; Lamerdin, Jane; Hellsten, Uffe; Goodstein, David; Couronne, Olivier; Tran-Gyamfi, Mary; Aerts, Andrea; Altherr, Michael; Ashworth, Linda; Bajorek, Eva; Black, Stacey; Branscomb, Elbert; Caenepeel, Sean; Carrano, Anthony; Caoile, Chenier; Chan, Yee Man; Christensen, Mari; Cleland, Catherine A.; Copeland, Alex; Dalin, Eileen; Dehal, Paramvir; Denys, Mirian; Detter, John C.; Escobar, Julio; Flowers, Dave; Fotopulos, Dea; Garcia, Carmen; Georgescu, Anca M.; Glavina, Tijana; Gomez, Maria; Gonzales, Eldelyn; Groza, Matthew; Hammon, Nancy; Hawkins, Trevor; Haydu, Lauren; Ho, Issac; Huang, Wayne; Israni, Sanjay; Jett, Jamie; Kadner, Kristen; Kimball, Heather; Kobayashi, Arthur; Larionov, Vladimer; Leem, Sun-Hee; Lopez, Frederick; Lou, Yunian; Lowry, Steve; Malfatti, Stephanie; Martinez, Diego; McCready, Paula; Medina, Catherine; Morgan, Jenna; Nelson, Kathryn; Nolan, Matt; Ovcharenko, Ivan; Pitluck, Sam; Pollard, Martin; Popkie, Anthony P.; Predki, Paul; Quan, Glenda; Ramirez, Lucia; Rash, Sam; Retterer, James; Rodriguez, Alex; Rogers, Stephanine; Salamov, Asaf; Salazar, Angelica; She, Xinwei; Smith, Doug; Slezak, Tom; Solovyev, Victor; Thayer, Nina; Tice, Hope; Tsai, Ming; Ustaszewska, Anna; Vo, Nu; Wagner, Mark; Wheeler, Jeremy; Wu, Kevin; Xie, Gary; Yang, Joan; Dubchak, Inna; Furey, Terrence S.; DeJong, Pieter; Dickson, Mark; Gordon, David; Eichler, Evan E.; Pennacchio, Len A.; Richardson, Paul; Stubbs, Lisa; Rokhsar, Daniel S.; Myers, Richard M.; Rubin, Edward M.; Lucas, Susan M.

    2003-09-15

    Chromosome 19 has the highest gene density of all human chromosomes, more than double the genome-wide average. The large clustered gene families, corresponding high G1C content, CpG islands and density of repetitive DNA indicate a chromosome rich in biological and evolutionary significance. Here we describe 55.8 million base pairs of highly accurate finished sequence representing 99.9 percent of the euchromatin portion of the chromosome. Manual curation of gene loci reveals 1,461 protein-coding genes and 321 pseudogenes. Among these are genes directly implicated in mendelian disorders, including familial hypercholesterolaemia and insulin-resistant diabetes. Nearly one-quarter of these genes belong to tandemly arranged families, encompassing more than 25 percent of the chromosome. Comparative analyses show a fascinating picture of conservation and divergence, revealing large blocks of gene orthology with rodents, scattered regions with more recent gene family expansions and deletions, a nd segments of coding and non-coding conservation with the distant fish species Takifugu.

  7. The DNA sequence and biology of human chromosome 19

    Energy Technology Data Exchange (ETDEWEB)

    Grimwood, J; Gordon, L A; Olsen, A; Terry, A; Schmutz, J; Lamerdin, J; Hellsten, U; Goodstein, D; Couronne, O; Tran-Gyamfi, M

    2004-04-06

    Chromosome 19 has the highest gene density of all human chromosomes, more than double the genome-wide average. The large clustered gene families, corresponding high GC content, CpG islands and density of repetitive DNA indicate a chromosome rich in biological and evolutionary significance. Here we describe 55.8 million base pairs of highly accurate finished sequence representing 99.9% of the euchromatin portion of the chromosome. Manual curation of gene loci reveals 1,461 protein-coding genes and 321 pseudogenes. Among these are genes directly implicated in Mendelian disorders, including familial hypercholesterolemia and insulin-resistant diabetes. Nearly one quarter of these genes belong to tandemly arranged families, encompassing more than 25% of the chromosome. Comparative analyses show a fascinating picture of conservation and divergence, revealing large blocks of gene orthology with rodents, scattered regions with more recent gene family expansions and deletions, and segments of coding and non-coding conservation with the distant fish species Takifugu.

  8. The DNA sequence and biology of human chromosome 19.

    Science.gov (United States)

    Grimwood, Jane; Gordon, Laurie A; Olsen, Anne; Terry, Astrid; Schmutz, Jeremy; Lamerdin, Jane; Hellsten, Uffe; Goodstein, David; Couronne, Olivier; Tran-Gyamfi, Mary; Aerts, Andrea; Altherr, Michael; Ashworth, Linda; Bajorek, Eva; Black, Stacey; Branscomb, Elbert; Caenepeel, Sean; Carrano, Anthony; Caoile, Chenier; Chan, Yee Man; Christensen, Mari; Cleland, Catherine A; Copeland, Alex; Dalin, Eileen; Dehal, Paramvir; Denys, Mirian; Detter, John C; Escobar, Julio; Flowers, Dave; Fotopulos, Dea; Garcia, Carmen; Georgescu, Anca M; Glavina, Tijana; Gomez, Maria; Gonzales, Eidelyn; Groza, Matthew; Hammon, Nancy; Hawkins, Trevor; Haydu, Lauren; Ho, Isaac; Huang, Wayne; Israni, Sanjay; Jett, Jamie; Kadner, Kristen; Kimball, Heather; Kobayashi, Arthur; Larionov, Vladimer; Leem, Sun-Hee; Lopez, Frederick; Lou, Yunian; Lowry, Steve; Malfatti, Stephanie; Martinez, Diego; McCready, Paula; Medina, Catherine; Morgan, Jenna; Nelson, Kathryn; Nolan, Matt; Ovcharenko, Ivan; Pitluck, Sam; Pollard, Martin; Popkie, Anthony P; Predki, Paul; Quan, Glenda; Ramirez, Lucia; Rash, Sam; Retterer, James; Rodriguez, Alex; Rogers, Stephanine; Salamov, Asaf; Salazar, Angelica; She, Xinwei; Smith, Doug; Slezak, Tom; Solovyev, Victor; Thayer, Nina; Tice, Hope; Tsai, Ming; Ustaszewska, Anna; Vo, Nu; Wagner, Mark; Wheeler, Jeremy; Wu, Kevin; Xie, Gary; Yang, Joan; Dubchak, Inna; Furey, Terrence S; DeJong, Pieter; Dickson, Mark; Gordon, David; Eichler, Evan E; Pennacchio, Len A; Richardson, Paul; Stubbs, Lisa; Rokhsar, Daniel S; Myers, Richard M; Rubin, Edward M; Lucas, Susan M

    2004-04-01

    Chromosome 19 has the highest gene density of all human chromosomes, more than double the genome-wide average. The large clustered gene families, corresponding high G + C content, CpG islands and density of repetitive DNA indicate a chromosome rich in biological and evolutionary significance. Here we describe 55.8 million base pairs of highly accurate finished sequence representing 99.9% of the euchromatin portion of the chromosome. Manual curation of gene loci reveals 1,461 protein-coding genes and 321 pseudogenes. Among these are genes directly implicated in mendelian disorders, including familial hypercholesterolaemia and insulin-resistant diabetes. Nearly one-quarter of these genes belong to tandemly arranged families, encompassing more than 25% of the chromosome. Comparative analyses show a fascinating picture of conservation and divergence, revealing large blocks of gene orthology with rodents, scattered regions with more recent gene family expansions and deletions, and segments of coding and non-coding conservation with the distant fish species Takifugu.

  9. The Reduction of Chromosome Number in Meiosis Is Determined by Properties Built into the Chromosomes

    OpenAIRE

    Paliulis, Leocadia V.; Nicklas, R. Bruce

    2000-01-01

    In meiosis I, two chromatids move to each spindle pole. Then, in meiosis II, the two are distributed, one to each future gamete. This requires that meiosis I chromosomes attach to the spindle differently than meiosis II chromosomes and that they regulate chromosome cohesion differently. We investigated whether the information that dictates the division type of the chromosome comes from the whole cell, the spindle, or the chromosome itself. Also, we determined when chromosomes can switch from ...

  10. The terminal region of the E. coli chromosome localises at the periphery of the nucleoid

    Directory of Open Access Journals (Sweden)

    Stouf Mathieu

    2011-02-01

    Full Text Available Abstract Background Bacterial chromosomes are organised into a compact and dynamic structures termed nucleoids. Cytological studies in model rod-shaped bacteria show that the different regions of the chromosome display distinct and specific sub-cellular positioning and choreographies during the course of the cell cycle. The localisation of chromosome loci along the length of the cell has been described. However, positioning of loci across the width of the cell has not been determined. Results Here, we show that it is possible to assess the mean positioning of chromosomal loci across the width of the cell using two-dimension images from wide-field fluorescence microscopy. Observed apparent distributions of fluorescent-tagged loci of the E. coli chromosome along the cell diameter were compared with simulated distributions calculated using a range of cell width positioning models. Using this method, we detected the migration of chromosome loci towards the cell periphery induced by production of the bacteriophage T4 Ndd protein. In the absence of Ndd production, loci outside the replication terminus were located either randomly along the nucleoid width or towards the cell centre whereas loci inside the replication terminus were located at the periphery of the nucleoid in contrast to other loci. Conclusions Our approach allows to reliably observing the positioning of chromosome loci along the width of E. coli cells. The terminal region of the chromosome is preferentially located at the periphery of the nucleoid consistent with its specific roles in chromosome organisation and dynamics.

  11. Identical functional organization of nonpolytene and polytene chromosomes in Drosophila melanogaster.

    Directory of Open Access Journals (Sweden)

    Tatyana Yu Vatolina

    Full Text Available Salivary gland polytene chromosomes demonstrate banding pattern, genetic meaning of which is an enigma for decades. Till now it is not known how to mark the band/interband borders on physical map of DNA and structures of polytene chromosomes are not characterized in molecular and genetic terms. It is not known either similar banding pattern exists in chromosomes of regular diploid mitotically dividing nonpolytene cells. Using the newly developed approach permitting to identify the interband material and localization data of interband-specific proteins from modENCODE and other genome-wide projects, we identify physical limits of bands and interbands in small cytological region 9F13-10B3 of the X chromosome in D. melanogaster, as well as characterize their general molecular features. Our results suggests that the polytene and interphase cell line chromosomes have practically the same patterns of bands and interbands reflecting, probably, the basic principle of interphase chromosome organization. Two types of bands have been described in chromosomes, early and late-replicating, which differ in many aspects of their protein and genetic content. As appeared, origin recognition complexes are located almost totally in the interbands of chromosomes.

  12. A History of the Discovery of Random X Chromosome Inactivation in the Human Female and its Significance

    Directory of Open Access Journals (Sweden)

    Sophia Balderman

    2011-07-01

    Full Text Available Genetic determinants of sex in placental mammals developed by the evolution of primordial autosomes into the male and female sex chromosomes. The Y chromosome determines maleness by the action of the gene SRY, which encodes a protein that initiates a sequence of events prompting the embryonic gonads to develop into testes. The X chromosome in the absence of a Y chromosome results in a female by permitting the conversion of the embryonic gonads into ovaries. We trace the historical progress that resulted in the discovery that one X chromosome in the female is randomly inactivated in early embryogenesis, accomplishing approximate equivalency of X chromosome gene dosage in both sexes. This event results in half of the somatic cells in a tissue containing proteins encoded by the genes of the maternal X chromosome and half having proteins encoded by the genes of the paternal X chromosome, on average, accounting for the phenotype of a female heterozygote with an X chromosome mutation. The hypothesis of X chromosome inactivation as a random event early in embryogenesis was first described as a result of studies of variegated coat color in female mice. Similar results were found in women using the X chromosome-linked gene, glucose-6-phosphate dehydrogenase, studied in red cells. The random inactivation of the X chromosome-bearing genes for isoenzyme types A and B of glucose-6-phosphate dehydrogenase was used to establish the clonal origin of neoplasms in informative women with leiomyomas. Behind these discoveries are the stories of the men and women scientists whose research enlightened these aspects of X chromosome function and their implication for medicine.

  13. The dynamics of signal amplification by macromolecular assemblies for the control of chromosome segregation

    Directory of Open Access Journals (Sweden)

    Semin eLee

    2014-09-01

    Full Text Available The control of chromosome segregation relies on the spindle assembly checkpoint (SAC, a complex regulatory system that ensures the high fidelity of chromosome segregation in higher organisms by delaying the onset of anaphase until each chromosome is properly bi-oriented on the mitotic spindle. Central to this process is the establishment of multiple yet specific protein-protein interactions in a narrow time-space window. Here we discuss the highly dynamic nature of multi-protein complexes that control chromosome segregation in which an intricate network of weak but cooperative interactions modulate signal amplification to ensure a proper SAC response. We also discuss the current structural understanding of the communication between the SAC and the kinetochore; how transient interactions can regulate the assembly and disassembly of the SAC as well as the challenges and opportunities for the definition and the manipulation of the flow of information in SAC signaling.

  14. Diversity of breakpoints of variant Philadelphia chromosomes in chronic myeloid leukemia in Brazilian patients

    Directory of Open Access Journals (Sweden)

    Maria de Lourdes Lopes Ferrari Chauffaille

    2015-02-01

    Full Text Available Background: Chronic myeloid leukemia is a myeloproliferative disorder characterized by the Philadelphia chromosome or t(9;22(q34.1;q11.2, resulting in the break-point cluster regionAbelson tyrosine kinase fusion gene, which encodes a constitutively active tyrosine kinase protein. The Philadelphia chromosome is detected by karyotyping in around 90% of chronic myeloid leukemia patients, but 5-10% may have variant types. Variant Philadelphia chromosomes are characterized by the involvement of another chromosome in addition to chromosome 9 or 22. It can be a simple type of variant when one other chromosome is involved, or complex, in which two or more chromosomes take part in the translocation. Few studies have reported the incidence of variant Philadelphia chromosomes or the breakpoints involved among Brazilian chronic myeloid leukemia patients. Objective: The aim of this report is to describe the diversity of the variant Philadelphia chromosomes found and highlight some interesting breakpoint candidates for further studies. Methods: the Cytogenetics Section Database was searched for all cases with diagnoses of chronic myeloid leukemia during a 12-year period and all the variant Philadelphia chromosomes were listed. Results: Fifty (5.17% cases out of 1071 Philadelphia-positive chronic myeloid leukemia were variants. The most frequently involved chromosome was 17, followed by chromosomes: 1, 20, 6, 11, 2, 10, 12 and 15. Conclusion: Among all the breakpoints seen in this survey, six had previously been described: 11p15, 14q32, 15q11.2, 16p13.1, 17p13 and 17q21. The fact that some regions get more fre- quently involved in such rare rearrangements calls attention to possible predisposition that should be further studied. Nevertheless, the pathological implication of these variants remains unclear.

  15. Antagonistic spindle motors and MAPs regulate metaphase spindle length and chromosome segregation.

    Science.gov (United States)

    Syrovatkina, Viktoriya; Fu, Chuanhai; Tran, Phong T

    2013-12-02

    Metaphase describes a phase of mitosis where chromosomes are attached and oriented on the bipolar spindle for subsequent segregation at anaphase. In diverse cell types, the metaphase spindle is maintained at characteristic constant length [1-3]. Metaphase spindle length is proposed to be regulated by a balance of pushing and pulling forces generated by distinct sets of spindle microtubules (MTs) and their interactions with motors and MT-associated proteins (MAPs). Spindle length is further proposed to be important for chromosome segregation fidelity, as cells with shorter- or longer-than-normal metaphase spindles, generated through deletion or inhibition of individual mitotic motors or MAPs, showed chromosome segregation defects. To test the force-balance model of spindle length control and its effect on chromosome segregation, we applied fast microfluidic temperature control with live-cell imaging to monitor the effect of deleting or switching off different combinations of antagonistic force contributors in the fission yeast metaphase spindle. We show that the spindle midzone proteins kinesin-5 cut7p and MT bundler ase1p contribute to outward-pushing forces and that the spindle kinetochore proteins kinesin-8 klp5/6p and dam1p contribute to inward-pulling forces. Removing these proteins individually led to aberrant metaphase spindle length and chromosome segregation defects. Removing these proteins in antagonistic combination rescued the defective spindle length and in some combinations also partially rescued chromosome segregation defects.

  16. Chromosomal localization of the gonadotropin-releasing hormone receptor gene to human chromosome 4q13. 1-q21. 1 and mouse chromosome 5

    Energy Technology Data Exchange (ETDEWEB)

    Kaiser, U.B.; Dushkin, H.; Beier, D.R.; Chin, W.W. (Harvard Medical School, Boston, MA (United States)); Altherr, M.R. (Los Alamos National Lab., NM (United States))

    1994-04-01

    The gonadotropin-releasing hormone receptor (GRHR) is a G-protein-coupled receptor on the cell surface of pituitary gonadotropes, where it serves to transduce signals from the extracellular ligand, the hypothalamic factor gonadotropin-releasing hormone, and to modulate the synthesis and secretion of luteinizing hormone and follicle-stimulating hormone. The authors have localized the GRHR gene to the q13.1-q21.1 region of the human chromosome 4 using mapping panels of human/rodent somatic cell hybrids containing different human chromosomes or different regions of human chromosome 4. Furthermore, using linkage analysis of single-strand conformational polymorphisms, the murine GRHR gene was localized to mouse chromosome 5, linked to the endogenous retroviral marker Pmv-11. This is consistent with the evolutionary conservation of homology between these two regions, as has been previously suggested from comparative mapping of several other loci. The localization of the GRHR gene may be useful in the study of disorders of reproduction. 22 refs., 2 figs.

  17. Contrasting Levels of Molecular Evolution on the Mouse X Chromosome.

    Science.gov (United States)

    Larson, Erica L; Vanderpool, Dan; Keeble, Sara; Zhou, Meng; Sarver, Brice A J; Smith, Andrew D; Dean, Matthew D; Good, Jeffrey M

    2016-08-01

    The mammalian X chromosome has unusual evolutionary dynamics compared to autosomes. Faster-X evolution of spermatogenic protein-coding genes is known to be most pronounced for genes expressed late in spermatogenesis, but it is unclear if these patterns extend to other forms of molecular divergence. We tested for faster-X evolution in mice spanning three different forms of molecular evolution-divergence in protein sequence, gene expression, and DNA methylation-across different developmental stages of spermatogenesis. We used FACS to isolate individual cell populations and then generated cell-specific transcriptome profiles across different stages of spermatogenesis in two subspecies of house mice (Mus musculus), thereby overcoming a fundamental limitation of previous studies on whole tissues. We found faster-X protein evolution at all stages of spermatogenesis and faster-late protein evolution for both X-linked and autosomal genes. In contrast, there was less expression divergence late in spermatogenesis (slower late) on the X chromosome and for autosomal genes expressed primarily in testis (testis-biased). We argue that slower-late expression divergence reflects strong regulatory constraints imposed during this critical stage of sperm development and that these constraints are particularly acute on the tightly regulated sex chromosomes. We also found slower-X DNA methylation divergence based on genome-wide bisulfite sequencing of sperm from two species of mice (M. musculus and M. spretus), although it is unclear whether slower-X DNA methylation reflects development constraints in sperm or other X-linked phenomena. Our study clarifies key differences in patterns of regulatory and protein evolution across spermatogenesis that are likely to have important consequences for mammalian sex chromosome evolution, male fertility, and speciation.

  18. Protection of Drosophila chromosome ends through minimal telomere capping.

    Science.gov (United States)

    Dubruille, Raphaëlle; Loppin, Benjamin

    2015-05-15

    In Drosophila, telomere-capping proteins have the remarkable capacity to recognize chromosome ends in a sequence-independent manner. This epigenetic protection is essential to prevent catastrophic ligations of chromosome extremities. Interestingly, capping proteins occupy a large telomere chromatin domain of several kilobases; however, the functional relevance of this to end protection is unknown. Here, we investigate the role of the large capping domain by manipulating HOAP (encoded by caravaggio) capping-protein expression in the male germ cells, where telomere protection can be challenged without compromising viability. We show that the exhaustion of HOAP results in a dramatic reduction of other capping proteins at telomeres, including K81 [encoded by ms(3)K81], which is essential for male fertility. Strikingly however, we demonstrate that, although capping complexes are barely detected in HOAP-depleted male germ cells, telomere protection and male fertility are not dramatically affected. Our study thus demonstrates that efficient protection of Drosophila telomeres can be achieved with surprisingly low amounts of capping complexes. We propose that these complexes prevent fusions by acting at the very extremity of chromosomes, reminiscent of the protection conferred by extremely short telomeric arrays in yeast or mammalian systems.

  19. Pachytene asynapsis drives meiotic sex chromosome inactivation and leads to substantial postmeiotic repression in spermatids.

    Science.gov (United States)

    Turner, James M A; Mahadevaiah, Shantha K; Ellis, Peter J I; Mitchell, Michael J; Burgoyne, Paul S

    2006-04-01

    Transcriptional silencing of the sex chromosomes during male meiosis (MSCI) is conserved among organisms with limited sex chromosome synapsis, including mammals. Since the 1990s the prevailing view has been that MSCI in mammals is transient, with sex chromosome reactivation occurring as cells exit meiosis. Recently, we found that any chromosome region unsynapsed during pachytene of male and female mouse meiosis is subject to transcriptional silencing (MSUC), and we hypothesized that MSCI is an inevitable consequence of this more general meiotic silencing mechanism. Here, we provide direct evidence that asynapsis does indeed drive MSCI. We also show that a substantial degree of transcriptional repression of the sex chromosomes is retained postmeiotically, and we provide evidence that this postmeiotic repression is a downstream consequence of MSCI/MSUC. While this postmeiotic repression occurs after the loss of MSUC-related proteins at the end of prophase, other histone modifications associated with transcriptional repression have by then become established.

  20. MreB actin-mediated segregation of a specific region of a bacterial chromosome.

    Science.gov (United States)

    Gitai, Zemer; Dye, Natalie Anne; Reisenauer, Ann; Wachi, Masaaki; Shapiro, Lucy

    2005-02-11

    Faithful chromosome segregation is an essential component of cell division in all organisms. The eukaryotic mitotic machinery uses the cytoskeleton to move specific chromosomal regions. To investigate the potential role of the actin-like MreB protein in bacterial chromosome segregation, we first demonstrate that MreB is the direct target of the small molecule A22. We then demonstrate that A22 completely blocks the movement of newly replicated loci near the origin of replication but has no qualitative or quantitative effect on the segregation of other loci if added after origin segregation. MreB selectively interacts, directly or indirectly, with origin-proximal regions of the chromosome, arguing that the origin-proximal region segregates via an MreB-dependent mechanism not used by the rest of the chromosome.

  1. A new region of conservation is defined between human and mouse X chromosomes

    Energy Technology Data Exchange (ETDEWEB)

    Dinulos, M.B.; Disteche, C.M. [Univ. of Washington, Seattle, WA (United States); Bassi, M.T. [Univ. of Siena (Italy)] [and others

    1996-07-01

    Comparative mapping of the X chromosome in eutherian mammals have revealed distinct regions of conservation as well as evolutionary rearrangements between human and mouse. Recently, we and others mapped the murine homologue of CLCN4 (Chloride channel 4) to band F4 of the X chromosome in Mus spretus but to chromosome 7 in laboratory strains. We now report the mapping of the murine homologues of APXL (Apical protein Xenopus laevis-like) and OA1 (Ocular albinism type I), two genes that are located on the human X chromosome at band p22.3 and in close proximity to CLCN4. Interestingly, Oa1 and Apxl map to bands F2-F3 in both M. spretus and the laboratory strain C57BL/6J, defining a new rearrangement between human and mouse X chromosomes. 17 refs., 2 figs., 1 tab.

  2. Vibrio chromosome-specific families

    DEFF Research Database (Denmark)

    Lukjancenko, Oksana; Ussery, David

    2014-01-01

    We have compared chromosome-specific genes in a set of 18 finished Vibrio genomes, and, in addition, also calculated the pan- and core-genomes from a data set of more than 250 draft Vibrio genome sequences. These genomes come from 9 known species and 2 unknown species. Within the finished...

  3. Chromosome Territory Modeller and Viewer.

    Science.gov (United States)

    Tkacz, Magdalena A; Chromiński, Kornel; Idziak-Helmcke, Dominika; Robaszkiewicz, Ewa; Hasterok, Robert

    2016-01-01

    This paper presents ChroTeMo, a tool for chromosome territory modelling, accompanied by ChroTeVi-a chromosome territory visualisation software that uses the data obtained by ChroTeMo. These tools have been developed in order to complement the molecular cytogenetic research of interphase nucleus structure in a model grass Brachypodium distachyon. Although the modelling tool has been initially created for one particular species, it has universal application. The proposed version of ChroTeMo allows for generating a model of chromosome territory distribution in any given plant or animal species after setting the initial, species-specific parameters. ChroTeMo has been developed as a fully probabilistic modeller. Due to this feature, the comparison between the experimental data on the structure of a nucleus and the results obtained from ChroTeMo can indicate whether the distribution of chromosomes inside a nucleus is also fully probabilistic or is subjected to certain non-random patterns. The presented tools have been written in Python, so they are multiplatform, portable and easy to read. Moreover, if necessary they can be further developed by users writing their portions of code. The source code, documentation, and wiki, as well as the issue tracker and the list of related articles that use ChroTeMo and ChroTeVi, are accessible in a public repository at Github under GPL 3.0 license.

  4. CHROMOSOMAL MULTIPLICITY IN BURKHOLDERIA CEPACIA

    Science.gov (United States)

    We have used CHEF gel electrophoresis to screen preparations of large DNA from different Burkholderia cepacia isolates for the presence of DNA species corresponding to the linearized forms of the three chromosomes of 3.4,2.5, and 0.9 Mb identified in B. cepacia strain 17616. DNA ...

  5. Chromosome synteny in cucumis species

    Science.gov (United States)

    Cucumber, Cucumis sativus L. (2n = 2x = 14) and melon, C. melo L. (2n = 2x = 24) are two important vegetable species in the genus Cucumis (family Cucurbitaceae). Two inter-fertile botanical varieties with 14 chromosomes, the cultivated C. sativus var. sativus L. and the wild C. sativus var. hardwick...

  6. Chromosomal disorders and male infertility

    Institute of Scientific and Technical Information of China (English)

    Gary L Harton; Helen G Tempest

    2012-01-01

    infertility in humans is surprisingly common occurring in approximately 15% of the population wishing to start a family.Despite this,the molecular and genetic factors underlying the cause of infertility remain largely undiscovered.Nevertheless,more and more genetic factors associated with infertility are being identified.This review will focus on our current understanding of the chromosomal basis of male infertility specifically:chromosomal aneuploidy,structural and numerical karyotype abnormalities and Y chromosomal microdeletions.Chromosomal aneuploidy is the leading cause of pregnancy loss and developmental disabilities in humans.Aneuploidy is predominantly maternal in origin,but concerns have been raised regarding the safety of intracytoplasmic sperm injection as infertile men have significantly higher levels of sperm aneuploidy compared to their fertile counterparts.Males with numerical or structural karyotype abnormalities are also at an increased risk of producing aneuploid sperm.Our current understanding of how sperm aneuploidy translates to embryo aneuploidy will be reviewed,as well as the application of preimplantation genetic diagnosis (PGD) in such cases.Clinical recommendations where possible will be made,as well as discussion of the use of emerging array technology in PGD and its potential applications in male infertility.

  7. Secondary chromosomal changes in 34 Philadelphia-chromosome-positive chronic myelocytic leukemia patients from the Mexican West.

    Science.gov (United States)

    Meza Espinoza, Juan Pablo; Judith Picos Cárdenas, Verónica; Gutiérrez-Angulo, Melva; González García, Juan Ramón

    2004-01-15

    The clonal evolution in t(9;22)-positive chronic myelocytic leukemia (CML) is well established. Four major changes occur in more than 70% of patients: +8, i(17q), +19, and an extra Philadelphia chromosome. The frequencies of secondary chromosomal changes in 34 patients from the states of Jalisco, Nayarit, Michoacán, and Colima (the Mexican West) with Philadelphia-chromosome-positive CML were assessed. The most frequent abnormalities were tetraploidy (12 cases); +8, inv(3)(q21q26), and octoploidy (3 cases each); and +der(22)(2 cases). Some translocations not previously associated with CML were observed, such as t(2;7)(p12;q36), t(3;6)(q26;p25), t(3;17)(q26;p13), and t(6;17)(q21;q23 approximately q25). Significant differences were found for +8 with respect to population results from Japan and from southern, eastern, and western Europe; for i(17)(q10) from eastern Europe; for +19 from Japan and western Europe; and for +der(22) from Japan, southern Europe, and western Europe. Although polyploidy could result from endomitosis, there is no direct evidence that the BCR/ABL protein influences such a process; however, protein kinases such as MAPK, which are involved in endomitosis, are activated by the BCR/ABL protein, and so the BCR/ABL protein could promote endomitosis through the MAPK pathway.

  8. The Divergence of Neandertal and Modern Human Y Chromosomes

    Science.gov (United States)

    Mendez, Fernando L.; Poznik, G. David; Castellano, Sergi; Bustamante, Carlos D.

    2016-01-01

    Sequencing the genomes of extinct hominids has reshaped our understanding of modern human origins. Here, we analyze ∼120 kb of exome-captured Y-chromosome DNA from a Neandertal individual from El Sidrón, Spain. We investigate its divergence from orthologous chimpanzee and modern human sequences and find strong support for a model that places the Neandertal lineage as an outgroup to modern human Y chromosomes—including A00, the highly divergent basal haplogroup. We estimate that the time to the most recent common ancestor (TMRCA) of Neandertal and modern human Y chromosomes is ∼588 thousand years ago (kya) (95% confidence interval [CI]: 447–806 kya). This is ∼2.1 (95% CI: 1.7–2.9) times longer than the TMRCA of A00 and other extant modern human Y-chromosome lineages. This estimate suggests that the Y-chromosome divergence mirrors the population divergence of Neandertals and modern human ancestors, and it refutes alternative scenarios of a relatively recent or super-archaic origin of Neandertal Y chromosomes. The fact that the Neandertal Y we describe has never been observed in modern humans suggests that the lineage is most likely extinct. We identify protein-coding differences between Neandertal and modern human Y chromosomes, including potentially damaging changes to PCDH11Y, TMSB4Y, USP9Y, and KDM5D. Three of these changes are missense mutations in genes that produce male-specific minor histocompatibility (H-Y) antigens. Antigens derived from KDM5D, for example, are thought to elicit a maternal immune response during gestation. It is possible that incompatibilities at one or more of these genes played a role in the reproductive isolation of the two groups. PMID:27058445

  9. SMC is recruited to oriC by ParB and promotes chromosome segregation in Streptococcus pneumoniae

    NARCIS (Netherlands)

    Minnen, Anita; Attaiech, Laetitia; Thon, Maria; Gruber, Stephan; Veening, Jan-Willem

    2011-01-01

    Segregation of replicated chromosomes is an essential process in all organisms. How bacteria, such as the oval-shaped human pathogen Streptococcus pneumoniae, efficiently segregate their chromosomes is poorly understood. Here we show that the pneumococcal homologue of the DNA-binding protein ParB re

  10. A Plain English Map of the Human Chromosomes.

    Science.gov (United States)

    Offner, Susan

    1992-01-01

    Presents a chromosome map for 19 known chromosomes in human genetics. Describes the characteristics attributed to the genetic codes for each of the chromosomes and discusses the teaching applications of the chromosome map. (MDH)

  11. Familial transmission of a ring chromosome 21

    DEFF Research Database (Denmark)

    Hertz, Jens Michael

    1987-01-01

    A ring chromosome 21 was found in a phenotypically normal mother and her son. The clinical findings in the son were bilateral retention of the testes and a slightly delayed puberty onset. Consequences of a ring formation of a chromosome 21 in phenotypically normal patients are presented...... and discussed, and the previously reported cases of familially transmitted G-group ring chromosomes are reviewed....

  12. Female meiotic sex chromosome inactivation in chicken

    NARCIS (Netherlands)

    S. Schoenmakers (Sam); E. Wassenaar (Evelyne); J.W. Hoogerbrugge (Jos); J.S.E. Laven (Joop); J.A. Grootegoed (Anton); W.M. Baarends (Willy)

    2009-01-01

    textabstractDuring meiotic prophase in male mammals, the heterologous X and Y chromosomes remain largely unsynapsed, and meiotic sex chromosome inactivation (MSCI) leads to formation of the transcriptionally silenced XY body. In birds, the heterogametic sex is female, carrying Z and W chromosomes (Z

  13. Replisome Assembly at Bacterial Chromosomes and Iteron Plasmids

    Directory of Open Access Journals (Sweden)

    Katarzyna Ewa Wegrzyn

    2016-08-01

    Full Text Available The proper initiation and occurrence of DNA synthesis depends on the formation and rearrangements of nucleoprotein complexes within the origin of DNA replication. In this review article, we present the current knowledge on the molecular mechanism of replication complex assembly at the origin of bacterial chromosome and plasmid replicon containing direct repeats (iterons within the origin sequence. We describe recent findings on chromosomal and plasmid replication initiators, DnaA and Rep proteins, respectively, and their sequence-specific interactions with double and single stranded DNA. Also, we discuss the current understanding of the activities of DnaA and Rep proteins required for replisome assembly that is fundamental to the duplication and stability of genetic information in bacterial cells.

  14. Drosophila SAF-B links the nuclear matrix, chromosomes, and transcriptional activity.

    Directory of Open Access Journals (Sweden)

    Catalina Alfonso-Parra

    Full Text Available Induction of gene expression is correlated with alterations in nuclear organization, including proximity to other active genes, to the nuclear cortex, and to cytologically distinct domains of the nucleus. Chromosomes are tethered to the insoluble nuclear scaffold/matrix through interaction with Scaffold/Matrix Attachment Region (SAR/MAR binding proteins. Identification and characterization of proteins involved in establishing or maintaining chromosome-scaffold interactions is necessary to understand how the nucleus is organized and how dynamic changes in attachment are correlated with alterations in gene expression. We identified and characterized one such scaffold attachment factor, a Drosophila homolog of mammalian SAF-B. The large nuclei and chromosomes of Drosophila have allowed us to show that SAF-B inhabits distinct subnuclear compartments, forms weblike continua in nuclei of salivary glands, and interacts with discrete chromosomal loci in interphase nuclei. These interactions appear mediated either by DNA-protein interactions, or through RNA-protein interactions that can be altered during changes in gene expression programs. Extraction of soluble nuclear proteins and DNA leaves SAF-B intact, showing that this scaffold/matrix-attachment protein is a durable component of the nuclear matrix. Together, we have shown that SAF-B links the nuclear scaffold, chromosomes, and transcriptional activity.

  15. Lack of a Y-Chromosomal Complement in the Majority of Gestational Trophoblastic Neoplasms

    Directory of Open Access Journals (Sweden)

    Kai Lee Yap

    2010-01-01

    Full Text Available Gestational trophoblastic neoplasms (GTNs are a rare group of neoplastic diseases composed of choriocarcinomas, placental site trophoblastic tumors (PSTTs and epithelioid trophoblastic tumors (ETTs. Since these tumors are derivatives of fetal trophoblastic tissue, approximately 50% of GTN cases are expected to originate from a male conceptus and carry a Y-chromosomal complement according to a balanced sex ratio. To investigate this hypothesis, we carried out a comprehensive analysis by genotyping a relatively large sample size of 51 GTN cases using three independent sex chromosome genetic markers; Amelogenin, Protein Kinase and Zinc Finger have X and Y homologues that are distinguishable by their PCR product size. We found that all cases contained the X-chromosomal complement while only five (10% of 51 tumors harbored the Y-chromosomal complement. Specifically, Y-chromosomal signals were detected in one (5% of 19 choriocarcinomas, one (7% of 15 PSTTs and three (18% of 17 ETTs. The histopathological features of those with a Y-chromosome were similar to those without. Our results demonstrate the presence of a Y-chromosomal complement in GTNs, albeit a low 10% of cases. This shortfall of Y-chromosomal complements in GTNs may reinforce the notion that the majority of GTNs are derived from previous molar gestations.

  16. Searching chromosomal landmarks in Indian lentils through EMA-based Giemsa staining method.

    Science.gov (United States)

    Jha, Timir Baran; Halder, Mihir

    2016-09-01

    Lentil is one of the oldest protein-rich food crop with only one cultivated and six wild species. India is one important cultivator, producer and consumer of lentils and possesses a large number of germplasms. All species of lentil show 2n = 14 chromosomes. The primary objective of the present paper is to search chromosomal landmarks through enzymatic maceration and air drying (EMA)-based Giemsa staining method in five Indian lentil species not reported elsewhere at a time. Additionally, gametic chromosome analysis, tendril formation and seed morphology have been studied to ascertain interspecific relationships in lentils. Chromosome analysis in Lens culinaris, Lens orientalis and Lens odemensis revealed that they contain intercalary sat chromosome and similar karyotypic formula, while Lens nigricans and Lens lamottei showed presence of terminal sat chromosomes not reported earlier. This distinct morphological feature in L. nigricans and L. lamottei may be considered as chromosomal landmark. Meiotic analysis showed n = 7 bivalents in L. culinaris, L. nigricans and L. lamottei. No tendril formation was observed in L. culinaris, L. orientalis and L. odemensis while L. nigricans and L. lamottei developed very prominent tendrils. Based on chromosomal analysis, tendril formation and seed morphology, the five lentil species can be separated into two distinct groups. The outcome of this research may enrich conventional and biotechnological breeding programmes in lentil and may facilitate an easy and alternative method for identification of interspecific hybrids.

  17. The Smc5-Smc6 complex is required to remove chromosome junctions in meiosis.

    Directory of Open Access Journals (Sweden)

    Sarah Farmer

    Full Text Available Meiosis, a specialized cell division with a single cycle of DNA replication round and two consecutive rounds of nuclear segregation, allows for the exchange of genetic material between parental chromosomes and the formation of haploid gametes. The structural maintenance of chromosome (SMC proteins aid manipulation of chromosome structures inside cells. Eukaryotic SMC complexes include cohesin, condensin and the Smc5-Smc6 complex. Meiotic roles have been discovered for cohesin and condensin. However, although Smc5-Smc6 is known to be required for successful meiotic divisions, the meiotic functions of the complex are not well understood. Here we show that the Smc5-Smc6 complex localizes to specific chromosome regions during meiotic prophase I. We report that meiotic cells lacking Smc5-Smc6 undergo catastrophic meiotic divisions as a consequence of unresolved linkages between chromosomes. Surprisingly, meiotic segregation defects are not rescued by abrogation of Spo11-induced meiotic recombination, indicating that at least some chromosome linkages in smc5-smc6 mutants originate from other cellular processes. These results demonstrate that, as in mitosis, Smc5-Smc6 is required to ensure proper chromosome segregation during meiosis by preventing aberrant recombination intermediates between homologous chromosomes.

  18. Loss of pRB causes centromere dysfunction and chromosomal instability.

    Science.gov (United States)

    Manning, Amity L; Longworth, Michelle S; Dyson, Nicholas J

    2010-07-01

    Chromosome instability (CIN) is a common feature of tumor cells. By monitoring chromosome segregation, we show that depletion of the retinoblastoma protein (pRB) causes rates of missegregation comparable with those seen in CIN tumor cells. The retinoblastoma tumor suppressor is frequently inactivated in human cancers and is best known for its regulation of the G1/S-phase transition. Recent studies have shown that pRB inactivation also slows mitotic progression and promotes aneuploidy, but reasons for these phenotypes are not well understood. Here we describe the underlying mitotic defects of pRB-deficient cells that cause chromosome missegregation. Analysis of mitotic cells reveals that pRB depletion compromises centromeric localization of CAP-D3/condensin II and chromosome cohesion, leading to an increase in intercentromeric distance and deformation of centromeric structure. These defects promote merotelic attachment, resulting in failure of chromosome congression and an increased propensity for lagging chromosomes following mitotic delay. While complete loss of centromere function or chromosome cohesion would have catastrophic consequences, these more moderate defects allow pRB-deficient cells to proliferate but undermine the fidelity of mitosis, leading to whole-chromosome gains and losses. These observations explain an important consequence of RB1 inactivation, and suggest that subtle defects in centromere function are a frequent source of merotely and CIN in cancer.

  19. "Micro-deletions" of the human Y chromosome and their relationship with male infertility

    Institute of Scientific and Technical Information of China (English)

    Zheng Li; Christopher J Haines; Yibing Han

    2008-01-01

    The Y chromosome evolves from an autochromosome and accumulates male-related genes including sex-determining region of Y-chromosome (SRY) and several spermatogenesis-related genes.The human Y chromosome (60 Mb long) is largely composed of repeti-tive sequences that give it a heterochromatic appearance,and it consists of pseudoautosomal,euchromatic,and heterochromatic regions.Located on the two extremities of the Y chromosome,pseudoautosomal regions 1 and 2 (PAR1 and PAR2,2.6 Mb and 320 bp long,re-spectively) are homologs with the termini of the X chromosome.The euchromatic region and some of the repeat-rich heterochromatic parts of the Y chromosome are called "male-specific Y" (MSY),which occupy more than 95% of the whole Y chromosome.After evolu-tion,the Y chromosome becomes the smallest in size with the least number of genes but with the most number of copies of genes that are mostly spermatogenesis-related.The Y chromosome is characterized by highly repetitive sequences (including direct repeats,inverted repeats,and palindromes) and high polymorphism.Several gene rearrangements on the Y chromosome occur during evolution owing to its specific gene structure.The consequences of such rearrangements are not only loss but also gain of specific genes.One hundred and fifty three haplotypes have been discovered in the human Y chromosome.The structure of the Y chromosome in the GenBank belongs to haplotype R1.There are 220 genes (104 coding genes,111 pseudogenes,and 5 other uncategorized genes) according to the most recent count.The 104 coding genes encode a total of about 48 proteins/protein families (including putative proteins/protein families).Among them,16 gene products have been discovered in the azoospermia factor region (AZF) and are related to spermatogenesis.It has been dis-covered that one subset of gene rearrangements on the Y chromosome,"micro-deletions",is a major cause of male infertility in some populations.However,controversies exist about different Y

  20. Cytogenetic analysis of quinoa chromosomes using nanoscale imaging and spectroscopy techniques

    Science.gov (United States)

    Yangquanwei, Zhong; Neethirajan, Suresh; Karunakaran, Chithra

    2013-11-01

    Here we present a high-resolution chromosomal spectral map derived from synchrotron-based soft X-ray spectromicroscopy applied to quinoa species. The label-free characterization of quinoa metaphase chromosomes shows that it consists of organized substructures of DNA-protein complex. The analysis of spectra of chromosomes using the scanning transmission X-ray microscope (STXM) and its superposition of the pattern with the atomic force microscopy (AFM) and scanning electron microscopy (SEM) images proves that it is possible to precisely locate the gene loci and the DNA packaging inside the chromosomes. STXM has been successfully used to distinguish and quantify the DNA and protein components inside the quinoa chromosomes by visualizing the interphase at up to 30-nm spatial resolution. Our study represents the successful attempt of non-intrusive interrogation and integrating imaging techniques of chromosomes using synchrotron STXM and AFM techniques. The methodology developed for 3-D imaging of chromosomes with chemical specificity and temporal resolution will allow the nanoscale imaging tools to emerge from scientific research and development into broad practical applications such as gene loci tools and biomarker libraries.

  1. Critically short telomeres in acute myeloid leukemia with loss or gain of parts of chromosomes.

    Science.gov (United States)

    Swiggers, Susan J J; Kuijpers, Marianne A; de Cort, Maartje J M; Beverloo, H Berna; Zijlmans, J Mark J M

    2006-03-01

    Telomeres, nucleoprotein complexes at chromosome ends, protect chromosomes against end-to-end fusion. Previous in vitro studies in human fibroblast models indicated that telomere dysfunction results in chromosome instability. Loss of telomere function can result either from critical shortening of telomeric DNA or from loss of distinct telomere-capping proteins. It is less clear whether telomere dysfunction has an important role in human cancer development in vivo. Acute myeloid leukemia (AML) is a good model to study mechanisms that generate chromosome instability in human cancer development because distinct groups of AML are characterized either by aberrations that theoretically could result from telomere dysfunction (terminal deletions, gains/losses of chromosome parts, nonreciprocal translocations), or aberrations that are unlikely to result from telomere dysfunction (e.g., reciprocal translocations or inversions). Here we demonstrate that AML with multiple chromosome aberrations that theoretically could result from telomere dysfunction is invariably characterized by critically short telomeres. Short telomeres in this group are not associated with low telomerase activity or decreased expression of essential telomeric capping proteins TRF2 and POT1. In contrast, telomerase activity levels are significantly higher in AML with short telomeres. Notably, short telomeres in the presence of high telomerase may relate to significantly higher expression of TRF1, a negative regulator of telomere length. Our observations suggest that, consistent with previous in vitro fibroblast models, age-related critical telomere shortening may have a role in generating chromosome instability in human AML development.

  2. Cytogenetic analysis of quinoa chromosomes using nanoscale imaging and spectroscopy techniques.

    Science.gov (United States)

    Yangquanwei, Zhong; Neethirajan, Suresh; Karunakaran, Chithra

    2013-01-01

    Here we present a high-resolution chromosomal spectral map derived from synchrotron-based soft X-ray spectromicroscopy applied to quinoa species. The label-free characterization of quinoa metaphase chromosomes shows that it consists of organized substructures of DNA-protein complex. The analysis of spectra of chromosomes using the scanning transmission X-ray microscope (STXM) and its superposition of the pattern with the atomic force microscopy (AFM) and scanning electron microscopy (SEM) images proves that it is possible to precisely locate the gene loci and the DNA packaging inside the chromosomes. STXM has been successfully used to distinguish and quantify the DNA and protein components inside the quinoa chromosomes by visualizing the interphase at up to 30-nm spatial resolution. Our study represents the successful attempt of non-intrusive interrogation and integrating imaging techniques of chromosomes using synchrotron STXM and AFM techniques. The methodology developed for 3-D imaging of chromosomes with chemical specificity and temporal resolution will allow the nanoscale imaging tools to emerge from scientific research and development into broad practical applications such as gene loci tools and biomarker libraries.

  3. The origin of human chromosome 2 analyzed by comparative chromosome mapping with a DNA microlibrary

    OpenAIRE

    Wienberg, Johannes; Jauch, Anna; Lüdecke, H J; Senger, G.; Horsthemke, B; Claussen, U.; Cremer, Thomas; Arnold, N; Lengauer, Christoph

    1994-01-01

    Fluorescencein situ hybridization (FISH) of microlibraries established from distinct chromosome subregions can test the evolutionary conservation of chromosome bands as well as chromosomal rearrangements that occurred during primate evolution and will help to clarify phylogenetic relationships. We used a DNA library established by microdissection and microcloning from the entire long arm of human chromosome 2 for fluorescencein situ hybridization and comparative mapping of the chromosomes of ...

  4. Chromosomal instability in Streptomyces avermitilis: major deletion in the central region and stable circularized chromosome

    Directory of Open Access Journals (Sweden)

    Wen Ying

    2010-07-01

    Full Text Available Abstract Background The chromosome of Streptomyces has been shown to be unstable, frequently undergoing gross chromosomal rearrangements. However, the mechanisms underlying this phenomenon remain unclear, with previous studies focused on two chromosomal ends as targets for rearrangements. Here we investigated chromosomal instability of Streptomyces avermitilis, an important producer of avermectins, and characterized four gross chromosomal rearrangement events, including a major deletion in the central region. The present findings provide a valuable contribution to the mechanistic study of genetic instability in Streptomyces. Results Thirty randomly-selected "bald" mutants derived from the wild-type strain all contained gross chromosomal rearrangements of various types. One of the bald mutants, SA1-8, had the same linear chromosomal structure as the high avermectin-producing mutant 76-9. Chromosomes of both strains displayed at least three independent chromosomal rearrangements, including chromosomal arm replacement to form new 88-kb terminal inverted repeats (TIRs, and two major deletions. One of the deletions eliminated the 36-kb central region of the chromosome, but surprisingly did not affect viability of the cells. The other deletion (74-kb was internal to the right chromosomal arm. The chromosome of another bald mutant, SA1-6, was circularized with deletions at both ends. No obvious homology was found in all fusion sequences. Generational stability analysis showed that the chromosomal structure of SA1-8 and SA1-6 was stable. Conclusions Various chromosomal rearrangements, including chromosomal arm replacement, interstitial deletions and chromosomal circularization, occurred in S. avermitilis by non-homologous recombination. The finding of an inner deletion involving in the central region of S. avermitilis chromosome suggests that the entire Streptomyces chromosome may be the target for rearrangements, which are not limited, as previously

  5. Y-chromosome polymorphism: Possible largest Y chromosome in man?

    Energy Technology Data Exchange (ETDEWEB)

    Murthy, D.S.K.; Al-Awadi, S.A.; Bastaki, L. [Kuwait Medical Genetics Centre, Sulaibikat (Kuwait)] [and others

    1994-09-01

    The role of variations (inversions/deletion or duplication) in the heterochromatin in gonadal development and function, reproductive fitness, and malignant disease has been extensively studied. However, the causal-relationship of large Y (Yqh+) and repeated fetal loss has not been established unequivocally. An Arab couple (?Bedouin origin) with a history of repeated abortions were investigated. Karyotype analysis of the husband showed a very large Y chromosome, confirmed by GTG-, QFQ- and CBG-banding techniques. C-banding showed discontinuous distribution of the heterochromatin blocks separated by pale bands. The origin of the large heterochromatin segment could be due to tandem duplication of the Yq region or translocation (Yq:Yq). No other relatives (males) of the propositus have been available for investigation. Polymorphism of the Y chromosome could be attributed to evolutionary changes from an ancestral type, either by deletion or duplication of the heterochromatin segment. More detailed studies on isolated, aboriginal/tribal human populations will enable us to better understand the significance of the Y chromosome polymorphism.

  6. Transcription analysis of the dnaA gene and oriC region of the chromosome of Mycobacterium smegmatis and Mycobacterium bovis BCG, and its regulation by the DnaA protein.

    Science.gov (United States)

    Salazar, Leiria; Guerrero, Elba; Casart, Yveth; Turcios, Lilia; Bartoli, Fulvia

    2003-03-01

    The regions flanking the Mycobacterium dnaA gene have extensive sequence conservation, and comprise various DnaA boxes. Comparative analysis of the dnaA promoter and oriC region from several mycobacterial species revealed that the localization, spacing and orientation of the DnaA boxes are conserved. Detailed transcriptional analysis in M. smegmatis and M. bovis BCG shows that the dnaN gene of both species and the dnaA gene of M. bovis BCG are transcribed from two promoters, whereas the dnaA gene of M. smegmatis is transcribed from a single promoter. RT-PCR with total RNA showed that dnaA and dnaN were expressed in both species at all growth stages. Analysis of the promoter activity using dnaA-gfp fusion plasmids and DnaA expression plasmids indicates that the dnaA gene is autoregulated, although the degree of transcriptional autorepression was moderate. Transcription was also detected in the vicinity of oriC of M. bovis BCG, but not of M. smegmatis. These results suggest that a more complex transcriptional mechanism may be involved in the slow-growing mycobacteria, which regulates the expression of dnaA and initiation of chromosomal DNA replication.

  7. Formation of chromosomal domains in interphase by loop extrusion

    Science.gov (United States)

    Fudenberg, Geoffrey

    While genomes are often considered as one-dimensional sequences, interphase chromosomes are organized in three dimensions with an essential role for regulating gene expression. Recent studies have shown that Topologically Associating Domains (TADs) are fundamental structural and functional building blocks of human interphase chromosomes. Despite observations that architectural proteins, including CTCF, demarcate and maintain the borders of TADs, the mechanisms underlying TAD formation remain unknown. Here we propose that loop extrusion underlies the formation TADs. In this process, cis-acting loop-extruding factors, likely cohesins, form progressively larger loops, but stall at TAD boundaries due to interactions with boundary proteins, including CTCF. This process dynamically forms loops of various sizes within but not between TADs. Using polymer simulations, we find that loop extrusion can produce TADs as determined by our analyses of the highest-resolution experimental data. Moreover, we find that loop extrusion can explain many diverse experimental observations, including: the preferential orientation of CTCF motifs and enrichments of architectural proteins at TAD boundaries; TAD boundary deletion experiments; and experiments with knockdown or depletion of CTCF, cohesin, and cohesin-loading factors. Together, the emerging picture from our work is that TADs are formed by rapidly associating, growing, and dissociating loops, presenting a clear framework for understanding interphase chromosomal organization.

  8. Chromosome congression explained by nanoscale electrostatics.

    Science.gov (United States)

    Gagliardi, L John; Shain, Daniel H

    2014-02-24

    Nanoscale electrostatic microtubule disassembly forces between positively charged molecules in kinetochores and negative charges on plus ends of microtubules have been implicated in poleward chromosome motions and may also contribute to antipoleward chromosome movements. We propose that chromosome congression can be understood in terms of antipoleward nanoscale electrostatic microtubule assembly forces between negatively charged microtubule plus ends and like-charged chromosome arms, acting in conjunction with poleward microtubule disassembly forces. Several other aspects of post-attachment prometaphase chromosome motions, as well as metaphase oscillations, are consistently explained within this framework.

  9. The Chromosomes of Birds during Meiosis.

    Science.gov (United States)

    Pigozzi, María I

    2016-01-01

    The cytological analysis of meiotic chromosomes is an exceptional tool to approach complex processes such as synapsis and recombination during the division. Chromosome studies of meiosis have been especially valuable in birds, where naturally occurring mutants or experimental knock-out animals are not available to fully investigate the basic mechanisms of major meiotic events. This review highlights the main contributions of synaptonemal complex and lampbrush chromosome research to the current knowledge of avian meiosis, with special emphasis on the organization of chromosomes during prophase I, the impact of chromosome rearrangements during meiosis, and distinctive features of the ZW pair.

  10. Polymer models of chromosome (re)organization

    Science.gov (United States)

    Mirny, Leonid

    Chromosome Conformation Capture technique (Hi-C) provides comprehensive information about frequencies of spatial interactions between genomic loci. Inferring 3D organization of chromosomes from these data is a challenging biophysical problem. We develop a top-down approach to biophysical modeling of chromosomes. Starting with a minimal set of biologically motivated interactions we build ensembles of polymer conformations that can reproduce major features observed in Hi-C experiments. I will present our work on modeling organization of human metaphase and interphase chromosomes. Our works suggests that active processes of loop extrusion can be a universal mechanism responsible for formation of domains in interphase and chromosome compaction in metaphase.

  11. Chromosome painting of Z and W sex chromosomes in Characidium (Characiformes, Crenuchidae).

    Science.gov (United States)

    Pazian, Marlon F; Shimabukuro-Dias, Cristiane Kioko; Pansonato-Alves, José Carlos; Oliveira, Claudio; Foresti, Fausto

    2013-03-01

    Some species of the genus Characidium have heteromorphic ZZ/ZW sex chromosomes with a totally heterochromatic W chromosome. Methods for chromosome microdissection associated with chromosome painting have become important tools for cytogenetic studies in Neotropical fish. In Characidium cf. fasciatum, the Z chromosome contains a pericentromeric heterochromatin block, whereas the W chromosome is completely heterochromatic. Therefore, a probe was produced from the W chromosome through microdissection and degenerate oligonucleotide-primed polymerase chain reaction amplification. FISH was performed using the W probe on the chromosomes of specimens of this species. This revealed expressive marks in the pericentromeric region of the Z chromosome as well as a completely painted W chromosome. When applying the same probe on chromosome preparations of C. cf. gomesi and Characidium sp., a pattern similar to C. cf. fasciatum was found, while C. cf. zebra, C. cf. lagosantense and Crenuchus spilurus species showed no hybridization signals. Structural changes in the chromosomes of an ancestral sexual system in the group that includes the species C. cf. gomesi, C. cf. fasciatum and Characidium sp., could have contributed to the process of speciation and could represent a causal mechanism of chromosomal diversification in this group. The heterochromatinization process possibly began in homomorphic and homologous chromosomes of an ancestral form, and this process could have given rise to the current patterns found in the species with sex chromosome heteromorphism.

  12. TP53-dependent chromosome instability is associated with transient reductions in telomere length in immortal telomerase-positive cell lines

    Science.gov (United States)

    Schwartz, J. L.; Jordan, R.; Liber, H.; Murnane, J. P.; Evans, H. H.

    2001-01-01

    Telomere shortening in telomerase-negative somatic cells leads to the activation of the TP53 protein and the elimination of potentially unstable cells. We examined the effect of TP53 gene expression on both telomere metabolism and chromosome stability in immortal, telomerase-positive cell lines. Telomere length, telomerase activity, and chromosome instability were measured in multiple clones isolated from three related human B-lymphoblast cell lines that vary in TP53 expression; TK6 cells express wild-type TP53, WTK1 cells overexpress a mutant form of TP53, and NH32 cells express no TP53 protein. Clonal variations in both telomere length and chromosome stability were observed, and shorter telomeres were associated with higher levels of chromosome instability. The shortest telomeres were found in WTK1- and NH32-derived cells, and these cells had 5- to 10-fold higher levels of chromosome instability. The primary marker of instability was the presence of dicentric chromosomes. Aneuploidy and other stable chromosome alterations were also found in clones showing high levels of dicentrics. Polyploidy was found only in WTK1-derived cells. Both telomere length and chromosome instability fluctuated in the different cell populations with time in culture, presumably as unstable cells and cells with short telomeres were eliminated from the growing population. Our results suggest that transient reductions in telomere lengths may be common in immortal cell lines and that these alterations in telomere metabolism can have a profound effect on chromosome stability. Copyright 2000 Wiley-Liss, Inc.

  13. Targeting protein lysine methylation and demethylation in cancers

    Institute of Scientific and Technical Information of China (English)

    Yunlong He; Ilia Korboukh; Jian Jin; Jing Huang

    2012-01-01

    During the last decade,we saw an explosion of studies investigating the role of lysine methylation/demethylation of histones and non-histone proteins,such as p53,NF-kappaB,and E2F1.These ‘Ying-Yang' post-translational modifications are important to fine-tuning the activity of these proteins. Lysine methylation and demethylation are catalyzed by protein lysine methyltransferases (PKMTs) and protein lysine demethylases (PKDMs).PKMTs,PKDMs,and their substrates have been shown to play important roles in cancers.Although the underlying mechanisms of tumorigenesis are still largely unknown,growing evidence is starting to link aberrant regulation of methylation to tumorigenesis.This review focuses on summarizing the recent progress in understanding of the function of protein lysine methylation,and in the discovery of small molecule inhibitors for PKMTs and PKDMs.We also discuss the potential and the caveats of targeting protein lysine methylation for the treatment of cancer.

  14. Prokaryotic ParA-ParB-parS system links bacterial chromosome segregation with the cell cycle.

    Science.gov (United States)

    Mierzejewska, Jolanta; Jagura-Burdzy, Grażyna

    2012-01-01

    While the essential role of episomal par loci in plasmid DNA partitioning has long been appreciated, the function of chromosomally encoded par loci is less clear. The chromosomal parA-parB genes are conserved throughout the bacterial kingdom and encode proteins homologous to those of the plasmidic Type I active partitioning systems. The third conserved element, the centromere-like sequence called parS, occurs in several copies in the chromosome. Recent studies show that the ParA-ParB-parS system is a key player of a mitosis-like process ensuring proper intracellular localization of certain chromosomal regions such as oriC domain and their active and directed segregation. Moreover, the chromosomal par systems link chromosome segregation with initiation of DNA replication and the cell cycle.

  15. Chromosomal patterns in human malignant astrocytomas.

    Science.gov (United States)

    Rey, J A; Bello, M J; de Campos, J M; Kusak, M E; Ramos, C; Benitez, J

    1987-12-01

    Cytogenetic analysis by direct and/or in vitro preparations was performed on 34 malignant astrocytomas. Thirty tumors showed near-diploid chromosome numbers, whereas, tritetraploid chromosome complements were present in four tumors. The most frequent chromosomal changes implied numerical deviations by a gain of chromosomes #7, #19, and #20, and by losses of #10, #22, and Y. Structural rearrangements were present in stem- or side lines of 24 tumors. Although no common chromosomal rearrangement seems to exist among those tumors, chromosomes #1, #6, #7, and #9 were predominantly involved. Polysomy and structural rearrangements of chromosome #7 could be related to the overexpression of epidermal growth factor gene, previously observed in some malignant gliomas.

  16. Flow cytometric detection of aberrant chromosomes

    Energy Technology Data Exchange (ETDEWEB)

    Gray, J.W.; Lucas, J.; Yu, L.C.; Langlois, R.

    1983-05-11

    This report describes the quantification of chromosomal aberrations by flow cytometry. Both homogeneously and heterogeneously occurring chromosome aberrations were studied. Homogeneously occurring aberrations were noted in chromosomes isolated from human colon carcinoma (LoVo) cells, stained with Hoechst 33258 and chromomycin A3 and analyzed using dual beam flow cytometry. The resulting bivariate flow karyotype showed a homogeneously occurring marker chromosome of intermediate size. Heterogeneously occurring aberrations were quantified by slit-scan flow cytometry in chromosomes isolated from control and irradiated Chinese hamster cells and stained with propidium iodide. Heterogeneously occurring dicentric chromosomes were detected by their shapes (two centrometers). The frequencies of such chromosomes estimated by slit-scan flow cytometry correlated well with the frequencies determined by visual microscopy.

  17. Chromosome X aneuploidy in Brazilian schizophrenic patients.

    Science.gov (United States)

    de Moraes, Leopoldo Silva; Khayat, André Salim; de Lima, Patrícia Danielle Lima; Lima, Eleonidas Moura; Pinto, Giovanny Rebouças; Leal, Mariana Ferreira; de Arruda Cardoso Smith, Marília; Burbano, Rommel Rodríguez

    2010-01-01

    The identification of cytogenetic abnormalities in schizophrenic patients may provide clues to the genes involved in this disease. For this reason, a chromosomal analysis of samples from 62 schizophrenics and 70 controls was performed with trypsin-Giemsa banding and fluorescence in situ hybridization of the X chromosome. A clonal pericentric inversion on chromosome 9 was detected in one male patient, and we also discovered mosaicism associated with X chromosome aneuploidy in female patients, primarily detected in schizophrenic and normal female controls over 40 years old. When compared with age-matched female controls, the frequency of X chromosome loss was not significantly different between schizophrenics and controls, except for the 40- to 49-year-old age group. Our findings suggest that the X chromosome loss seen in schizophrenic patients is inherent to the normal cellular aging process. However, our data also suggest that X chromosome gain may be correlated with schizophrenia in this Brazilian population.

  18. Chromosomal instability determines taxane response

    DEFF Research Database (Denmark)

    Swanton, C.; Nicke, B.; Schuett, M.;

    2009-01-01

    -positive breast cancer and occurs frequently in basal-like and Her2-positive cases. In diploid cells, but not in chromosomally unstable cells, paclitaxel causes repression of CIN-survival genes, followed by cell death. In the OV01 ovarian cancer clinical trial, a high level of CIN was associated with taxane...... chromosomal instability (CIN). Silencing 22/50 of these genes, many of which are involved in DNA repair, caused cancer cell death, suggesting that these genes are involved in the survival of aneuploid cells. Overexpression of these "CIN-survival'' genes is associated with poor outcome in estrogen receptor...... resistance but carboplatin sensitivity, indicating that CIN may determine MTS response in vivo. Thus, pretherapeutic assessment of CIN may optimize treatment stratification and clinical trial design using these agents....

  19. VHL loss causes spindle misorientation and chromosome instability.

    Science.gov (United States)

    Thoma, Claudio R; Toso, Alberto; Gutbrodt, Katrin L; Reggi, Sabina P; Frew, Ian J; Schraml, Peter; Hergovich, Alexander; Moch, Holger; Meraldi, Patrick; Krek, Wilhelm

    2009-08-01

    Error-free mitosis depends on fidelity-monitoring checkpoint systems that ensure correct temporal and spatial coordination of chromosome segregation by the microtubule spindle apparatus. Defects in these checkpoint systems can lead to genomic instability, an important aspect of tumorigenesis. Here we show that the von Hippel-Lindau (VHL) tumour suppressor protein, pVHL, which is inactivated in hereditary and sporadic forms of renal cell carcinoma, localizes to the mitotic spindle in mammalian cells and its functional inactivation provokes spindle misorientation, spindle checkpoint weakening and chromosomal instability. Spindle misorientation is linked to unstable astral microtubules and is supressed by the restoration of wild-type pVHL in pVHL-deficient cells, but not in naturally-occurring VHL disease mutants that are defective in microtubule stabilization. Impaired spindle checkpoint function and chromosomal instability are the result of reduced Mad2 (mitotic arrest deficient 2) levels actuated by pVHL-inactivation and are rescued by re-expression of either Mad2 or pVHL in VHL-defective cells. An association between VHL inactivation, reduced Mad2 levels and increased aneuploidy was also found in human renal cancer, implying that the newly identified functions of pVHL in promoting proper spindle orientation and chromosomal stability probably contribute to tumour suppression.

  20. Simulating the Entropic Collapse of Coarse-Grained Chromosomes

    Science.gov (United States)

    Shendruk, Tyler N.; Bertrand, Martin; de Haan, Hendrick W.; Harden, James L.; Slater, Gary W.

    2015-02-01

    Depletion forces play a role in the compaction and de-compation of chromosomal material in simple cells but it remains debatable whether they are sufficient to account for chromosomal collapse. We present coarse-grained molecular dynamics simulations, which reveal that depletion-induced attraction is sufficient to cause the collapse of a flexible chain of large structural monomers immersed in a bath of smaller depletants. These simulations use an explicit coarse-grained computational model that treats both the supercoiled DNA structural monomers and the smaller protein crowding agents as combinatorial, truncated Lennard-Jones spheres. By presenting a simple theoretical model, we quantitatively cast the action of depletants on supercoiled bacterial DNA as an effective solvent quality. The rapid collapse of the simulated flexible chromosome at the predicted volume fraction of depletants is a continous phase transition. Additional physical effects to such simple chromosome models, such as enthalpic interactions between structural monomers or chain rigidity, are required if the collapse is to be a first-order phase transition.

  1. Microdissection and chromosome painting of the alien chromosome in an addition line of wheat-Thinopyrum intermedium

    Science.gov (United States)

    The chromosome painting is an efficient tool for chromosome research. However, plant chromosome painting is relatively underdeveloped. In this study, chromosome painting was developed and used to identify alien chromosomes in TAi-27, a wheat-Thinopyrum intermedium addition line, and chromosomes of...

  2. The Effect of Triazine Herbicide Atrazine on the Chromosome Structure, Protein Content and Compositions in Oryza sativa L.%三氮苯类除草剂对水稻染色体结构、蛋白质含量及组分的影响

    Institute of Scientific and Technical Information of China (English)

    彭永康; 邹灵芝; 王振英; 金洪英; 冯正勇

    2006-01-01

    比较研究了不同浓度三氮苯类除草剂对水稻幼苗生长、叶绿素及可溶性蛋白质含量、根尖分生组织染色体结构、分生组织和叶绿体蛋白质组分的影响.结果表明,在0.1 mg /L Atrazine处理水稻后培养1周,幼苗高度由(10.8±1.7 ) cm(对照)降至 (8.2±0.7) cm,叶绿素含量由(1.07±0.013) mg/g FW(对照)降至(0 .97±0.013) mg/g FW, 可溶性蛋白由40.4 mg/g FW(对照)降至29.3 mg/g FW.Atrazin e可明显影响染色体结构,以0.01 mg/L处理水稻时,有0.68%的细胞中发现染色体凝集,0 .86%的细胞中有微核存在,该现象出现频率随Atrazine处理浓度的提高而增加.用2D-PAG E分析,在0.1 mg/L Atrazine处理后,根尖分生组织中2种新的蛋白质组分诱导产生,8种蛋白质组分消失,1种叶绿体蛋白质组分消失,3种蛋白质组分含量减少.Atrazine引起幼苗生长,叶绿素和可溶性蛋白质含量及根尖分生组织、叶绿体蛋白质组分变化的临界剂量为0 .1 mg/L,引起水稻染色体凝集和微核形成的临界剂量为0.001 mg/L.%In this paper, the comparative studies on the effects of triazine herbicide Atrazine on seedlings growth, contents of chlorophyll and soluble protein, chromosome structure of root meristem, protein compositions of root meristems and chloroplast have been made in Oryza sativa. The seedlings growth was obviously reduced from (10.8±1.7) cm (control) to (8.2± 0.7) cm, chlorophyll contents were decreased from (1.07±0.013) mg/g FW(control) to (0.97±0.013) mg/g FW, and soluble protein contents were decreased from 40.4 mg/g FW (control) to 29.3 mg/g FW when seedlings were treated with 0.1 mg/L Atrazine for 7 days. 0.68% cells with chromosome condensation and 0.86 % cells with micronuclei were revealed in root meristems when the root meristems were treated with 0.01 mg/L Atrazine. The frequency of chromosome condensation and micronuclei formation were increased with the increase of Atrazine concentration from 0.001 mg

  3. Bacterial Chromosome Organization and Segregation

    OpenAIRE

    Toro, Esteban; Shapiro, Lucy

    2010-01-01

    Bacterial chromosomes are generally ∼1000 times longer than the cells in which they reside, and concurrent replication, segregation, and transcription/translation of this crowded mass of DNA poses a challenging organizational problem. Recent advances in cell-imaging technology with subdiffraction resolution have revealed that the bacterial nucleoid is reliably oriented and highly organized within the cell. Such organization is transmitted from one generation to the next by progressive segrega...

  4. Environmental pollution, chromosomes, and health

    Science.gov (United States)

    Bell, Peter M.

    In mid-May, 1980, President Carter declared a state of emergency at the Love Canal area, near Niagara Falls, New York. The reason for this was for the U.S. to underwrite the relocation costs ($3-5 million) of some 2500 residents who, according to a report by the EPA (Environmental Protection Agency) may have suffered damaged chromosomes. These injuries were apparently caused by contact with toxic wastes that had been dumped in the area in the years prior to development for housing.That the toxic compounds exist in the Love Canal and Niagara Falls subsurface zones, including public water supplies, appears to be established fact. That the residents of the Love Canal area suffered chromosomal damage may be established fact as well. Whether or not these two findings can be linked to ill health of the residents is another matter. Recently, the EPA report has been described as having ‘close to zero scientific significance,’ and has been ‘discredited’(Science, 208, 123a, 1980). The reasons for this disparity go beyond differences of opinion, beyond possible inadequacies of the EPA study, and even beyond problems that probably will arise from future studies, including those now in the planning stages. The problem is that even if victims have easily recognizable injuries from toxic substances (injury that apparently has not occurred to Love Canal residents), medical science usually cannot show a causal relationship. Even chromosomal damage is, at best, difficult to interpret. In ideal studies of significant populations and control groups, the association of toxic chemical to chromosome damage and to cancer and birth defects is indirect and, up to now, has been shown to have little or no significance to an individual member of the exposed population.

  5. Chromosome aberration assays in Allium

    Energy Technology Data Exchange (ETDEWEB)

    Grant, W.F.

    1982-01-01

    The common onion (Allium cepa) is an excellent plant for the assay of chromosome aberrations after chemical treatment. Other species of Allium (A. cepa var. proliferum, A. carinatum, A. fistulosum and A. sativum) have also been used but to a much lesser extent. Protocols have been given for using root tips from either bulbs or seeds of Allium cepa to study the cytological end-points, such as chromosome breaks and exchanges, which follow the testing of chemicals in somatic cells. It is considered that both mitotic and meiotic end-points should be used to a greater extent in assaying the cytogenetic effects of a chemical. From a literature survey, 148 chemicals are tabulated that have been assayed in 164 Allium tests for their clastogenic effect. Of the 164 assays which have been carried out, 75 are reported as giving a positive reaction, 49 positive and with a dose response, 1 positive and temperature-related, 9 borderline positive, and 30 negative; 76% of the chemicals gave a definite positive response. It is proposed that the Allium test be included among those tests routinely used for assessing chromosomal damage induced by chemicals.

  6. Initiation of chromosomal replication in predatory bacterium Bdellovibrio bacteriovorus

    Directory of Open Access Journals (Sweden)

    Lukasz Makowski

    2016-11-01

    Full Text Available Bdellovibrio bacteriovorus is a small Gram-negative predatory bacterium that attacks other Gram-negative bacteria, including many animal, human, and plant pathogens. This bacterium exhibits a peculiar biphasic life cycle during which two different types of cells are produced: non-replicating highly motile cells (the free-living phase and replicating cells (the intracellular-growth phase. The process of chromosomal replication in B. bacteriovorus must therefore be temporally and spatially regulated to ensure that it is coordinated with cell differentiation and cell cycle progression. Recently, B. bacteriovorus has received considerable research interest due to its intriguing life cycle and great potential as a prospective antimicrobial agent. Although we know that chromosomal replication in bacteria is mainly regulated at the initiation step, no data exists about this process in B. bacteriovorus. We report the first characterization of key elements of initiation of chromosomal replication – DnaA protein and oriC region from the predatory bacterium, B. bacteriovorus. In vitro studies using different approaches demonstrate that the B. bacteriovorus oriC (BdoriC is specifically bound and unwound by the DnaA protein. Sequence comparison of the DnaA-binding sites enabled us to propose a consensus sequence for the B. bacteriovorus DnaA box (5’-NN(A/TTCCACA-3’. Surprisingly, in vitro analysis revealed that BdoriC is also bound and unwound by the host DnaA proteins (relatively distantly related from B. bacteriovorus. We compared the architecture of the DnaA–oriC complexes (orisomes in homologous (oriC and DnaA from B. bacteriovorus and heterologous (BdoriC and DnaA from prey, E. coli or P. aeruginosa systems. This work provides important new entry points toward improving our understanding of the initiation of chromosomal replication in this predatory bacterium.

  7. Mechanical continuity and reversible chromosome disassembly within intact genomes removed from living cells

    Science.gov (United States)

    Maniotis, A. J.; Bojanowski, K.; Ingber, D. E.

    1997-01-01

    Chromatin is thought to be structurally discontinuous because it is packaged into morphologically distinct chromosomes that appear physically isolated from one another in metaphase preparations used for cytogenetic studies. However, analysis of chromosome positioning and movement suggest that different chromosomes often behave as if they were physically connected in interphase as well as mitosis. To address this paradox directly, we used a microsurgical technique to physically remove nucleoplasm or chromosomes from living cells under isotonic conditions. Using this approach, we found that pulling a single nucleolus or chromosome out from interphase or mitotic cells resulted in sequential removal of the remaining nucleoli and chromosomes, interconnected by a continuous elastic thread. Enzymatic treatments of interphase nucleoplasm and chromosome chains held under tension revealed that mechanical continuity within the chromatin was mediated by elements sensitive to DNase or micrococcal nuclease, but not RNases, formamide at high temperature, or proteases. In contrast, mechanical coupling between mitotic chromosomes and the surrounding cytoplasm appeared to be mediated by gelsolin-sensitive microfilaments. Furthermore, when ion concentrations were raised and lowered, both the chromosomes and the interconnecting strands underwent multiple rounds of decondensation and recondensation. As a result of these dynamic structural alterations, the mitotic chains also became sensitive to disruption by restriction enzymes. Ion-induced chromosome decondensation could be blocked by treatment with DNA binding dyes, agents that reduce protein disulfide linkages within nuclear matrix, or an antibody directed against histones. Fully decondensed chromatin strands also could be induced to recondense into chromosomes with pre-existing size, shape, number, and position by adding anti-histone antibodies. Conversely, removal of histones by proteolysis or heparin treatment produced chromosome

  8. Chromosomal divergence and evolutionary inferences in Rhodniini based on the chromosomal location of ribosomal genes

    Directory of Open Access Journals (Sweden)

    Sebastian Pita

    2013-05-01

    Full Text Available In this study, we used fluorescence in situ hybridisation to determine the chromosomal location of 45S rDNA clusters in 10 species of the tribe Rhodniini (Hemiptera: Reduviidae: Triatominae. The results showed striking inter and intraspecific variability, with the location of the rDNA clusters restricted to sex chromosomes with two patterns: either on one (X chromosome or both sex chromosomes (X and Y chromosomes. This variation occurs within a genus that has an unchanging diploid chromosome number (2n = 22, including 20 autosomes and 2 sex chromosomes and a similar chromosome size and genomic DNA content, reflecting a genome dynamic not revealed by these chromosome traits. The rDNA variation in closely related species and the intraspecific polymorphism in Rhodnius ecuadoriensis suggested that the chromosomal position of rDNA clusters might be a useful marker to identify recently diverged species or populations. We discuss the ancestral position of ribosomal genes in the tribe Rhodniini and the possible mechanisms involved in the variation of the rDNA clusters, including the loss of rDNA loci on the Y chromosome, transposition and ectopic pairing. The last two processes involve chromosomal exchanges between both sex chromosomes, in contrast to the widely accepted idea that the achiasmatic sex chromosomes of Heteroptera do not interchange sequences.

  9. Whole chromosome painting of B chromosomes of the red-eye tetra Moenkhausia sanctaefilomenae (Teleostei, Characidae).

    Science.gov (United States)

    Scudeler, Patricia Elda Sobrinho; Diniz, Débora; Wasko, Adriane Pinto; Oliveira, Claudio; Foresti, Fausto

    2015-01-01

    B chromosomes are dispensable genomic elements found in different groups of animals and plants. In the present study, a whole chromosome probe was generated from a specific heterochromatic B chromosome occurring in cells of the characidae fish Moenkhausia sanctaefilomenae (Steindachner, 1907). The chromosome painting probes were used in fluorescence in situ hybridization (FISH) experiments for the assessment of metaphase chromosomes obtained from individuals from three populations of Moenkhausia sanctaefilomenae. The results revealed that DNA sequences were shared between a specific B chromosome and many chromosomes of the A complement in all populations analyzed, suggesting a possible intra-specific origin of these B chromosomes. However, no hybridization signals were observed in other B chromosomes found in the same individuals, implying a possible independent origin of B chromosome variants in this species. FISH experiments using 18S rDNA probes revealed the presence of non-active ribosomal genes in some B chromosomes and in some chromosomes of the A complement, suggesting that at least two types of B chromosomes had an independent origin. The role of heterochromatic segments and ribosomal sequences in the origin of B chromosomes were discussed.

  10. DEAD-box RNA helicase Belle/DDX3 and the RNA interference pathway promote mitotic chromosome segregation.

    Science.gov (United States)

    Pek, Jun Wei; Kai, Toshie

    2011-07-19

    During mitosis, faithful inheritance of genetic material is achieved by chromosome segregation, as mediated by the condensin I and II complexes. Failed chromosome segregation can result in neoplasm formation, infertility, and birth defects. Recently, the germ-line-specific DEAD-box RNA helicase Vasa was demonstrated to promote mitotic chromosome segregation in Drosophila by facilitating robust chromosomal localization of Barren (Barr), a condensin I component. This mitotic function of Vasa is mediated by Aubergine and Spindle-E, which are two germ-line components of the Piwi-interacting RNA pathway. Faithful segregation of chromosomes should be executed both in germ-line and somatic cells. However, whether a similar mechanism also functions in promoting chromosome segregation in somatic cells has not been elucidated. Here, we present evidence that belle (vasa paralog) and the RNA interference pathway regulate chromosome segregation in Drosophila somatic cells. During mitosis, belle promotes robust Barr chromosomal localization and chromosome segregation. Belle's localization to condensing chromosomes depends on dicer-2 and argonaute2. Coimmunoprecipitation experiments indicated that Belle interacts with Barr and Argonaute2 and is enriched at endogenous siRNA (endo-siRNA)-generating loci. Our results suggest that Belle functions in promoting chromosome segregation in Drosophila somatic cells via the endo-siRNA pathway. DDX3 (human homolog of belle) and DICER function in promoting chromosome segregation and hCAP-H (human homolog of Barr) localization in HeLa cells, indicating a conserved function for those proteins in human cells. Our results suggest that the RNA helicase Belle/DDX3 and the RNA interference pathway perform a common role in regulating chromosome segregation in Drosophila and human somatic cells.

  11. Rapid cloning and bioinformatic analysis of spinach Y chromosome-specific EST sequences

    Indian Academy of Sciences (India)

    Chuan-Liang Deng; Wei-Li Zhang; Ying Cao; Shao-Jing Wang; Shu-Fen Li; Wu-Jun Gao; Long-Dou Lu

    2015-12-01

    The genome of spinach single chromosome complement is about 1000 Mbp, which is the model material to study the molecular mechanisms of plant sex differentiation. The cytological study showed that the biggest spinach chromosome (chromosome 1) was taken as spinach sex chromosome. It had three alleles of sex-related , m and . Many researchers have been trying to clone the sex-determining genes and investigated the molecular mechanism of spinach sex differentiation. However, there are no successful cloned reports about these genes. A new technology combining chromosome microdissection with hybridization-specific amplification (HSA) was adopted. The spinach Y chromosome degenerate oligonucleotide primed-PCR (DOP-PCR) products were hybridized with cDNA of the male spinach flowers in florescence. The female spinach genome was taken as blocker and cDNA library specifically expressed in Y chromosome was constructed. Moreover, expressed sequence tag (EST) sequences in cDNA library were cloned, sequenced and bioinformatics was analysed. There were 63 valid EST sequences obtained in this study. The fragment size was between 53 and 486 bp. BLASTn homologous alignment indicated that 12 EST sequences had homologous sequences of nucleic acids, the rest were new sequences. BLASTx homologous alignment indicated that 16 EST sequences had homologous protein-encoding nucleic acid sequence. The spinach Y chromosome-specific EST sequences laid the foundation for cloning the functional genes, specifically expressed in spinach Y chromosome. Meanwhile, the establishment of the technology system in the research provided a reference for rapid cloning of other biological sex chromosome-specific EST sequences.

  12. The multiple roles of Bub1 in chromosome segregation during mitosis and meiosis

    Energy Technology Data Exchange (ETDEWEB)

    Marchetti, Francesco; Venkatachalam, Sundaresan

    2009-06-19

    Aneuploidy, any deviation from an exact multiple of the haploid number of chromosomes, is a common occurrence in cancer and represents the most frequent chromosomal disorder in newborns. Eukaryotes have evolved mechanisms to assure the fidelity of chromosome segregation during cell division that include a multiplicity of checks and controls. One of the main cell division control mechanisms is the spindle assembly checkpoint (SAC) that monitors the proper attachment of chromosomes to spindle fibers and prevents anaphase until all kinetochores are properly attached. The mammalian SAC is composed by at least 14 evolutionary-conserved proteins that work in a coordinated fashion to monitor the establishment of amphitelic attachment of all chromosomes before allowing cell division to occur. Among the SAC proteins, the budding uninhibited by benzimidazole protein 1 (Bub1), is a highly conserved protein of prominent importance for the proper functioning of the SAC. Studies have revealed many roles for Bub1 in both mitosis and meiosis, including the localization of other SAC proteins to the kinetochore, SAC signaling, metaphase congression and the protection of the sister chromatid cohesion. Recent data show striking sex specific differences in the response to alterations in Bub1 activity. Proper Bub1 functioning is particularly important during oogenesis in preventing the generation of aneuploid gametes that can have detrimental effects on the health status of the fetus and the newborn. These data suggest that Bub1 is a master regulator of SAC and chromosomal segregation in both mitosis and meiosis. Elucidating its many essential functions in regulating proper chromosome segregation can have important consequences for preventing tumorigenesis and developmental abnormalities.

  13. Chromosome aberrations induced by zebularine in triticale.

    Science.gov (United States)

    Ma, Xuhui; Wang, Qing; Wang, Yanzhi; Ma, Jieyun; Wu, Nan; Ni, Shuang; Luo, Tengxiao; Zhuang, Lifang; Chu, Chenggen; Cho, Seong-Woo; Tsujimoto, Hisashi; Qi, Zengjun

    2016-07-01

    Chromosome engineering is an important approach for generating wheat germplasm. Efficient development of chromosome aberrations will facilitate the introgression and application of alien genes in wheat. In this study, zebularine, a DNA methylation transferase inhibitor, was successfully used to induce chromosome aberrations in the octoploid triticale cultivar Jinghui#1. Dry seeds were soaked in zebularine solutions (250, 500, and 750 μmol/L) for 24 h, and the 500 μmol/L treatment was tested in three additional treatment times, i.e., 12, 36, and 48 h. All treatments induced aberrations involving wheat and rye chromosomes. Of the 920 cells observed in 67 M1 plants, 340 (37.0%) carried 817 aberrations with an average of 0.89 aberrations per cell (range: 0-12). The aberrations included probable deletions, telosomes and acentric fragments (49.0%), large segmental translocations (28.9%), small segmental translocations (17.1%), intercalary translocations (2.6%), long chromosomes that could carry more than one centromere (2.0%), and ring chromosomes (0.5%). Of 510 M2 plants analyzed, 110 (21.6%) were found to carry stable aberrations. Such aberrations included 79 with varied rye chromosome numbers, 7 with wheat and rye chromosome translocations, 15 with possible rye telosomes/deletions, and 9 with complex aberrations involving variation in rye chromosome number and wheat-rye translocations. These indicated that aberrations induced by zebularine can be steadily transmitted, suggesting that zebularine is a new efficient agent for chromosome manipulation.

  14. The importance of having two X chromosomes.

    Science.gov (United States)

    Arnold, Arthur P; Reue, Karen; Eghbali, Mansoureh; Vilain, Eric; Chen, Xuqi; Ghahramani, Negar; Itoh, Yuichiro; Li, Jingyuan; Link, Jenny C; Ngun, Tuck; Williams-Burris, Shayna M

    2016-02-19

    Historically, it was thought that the number of X chromosomes plays little role in causing sex differences in traits. Recently, selected mouse models have been used increasingly to compare mice with the same type of gonad but with one versus two copies of the X chromosome. Study of these models demonstrates that mice with one X chromosome can be strikingly different from those with two X chromosomes, when the differences are not attributable to confounding group differences in gonadal hormones. The number of X chromosomes affects adiposity and metabolic disease, cardiovascular ischaemia/reperfusion injury and behaviour. The effects of X chromosome number are likely the result of inherent differences in expression of X genes that escape inactivation, and are therefore expressed from both X chromosomes in XX mice, resulting in a higher level of expression when two X chromosomes are present. The effects of X chromosome number contribute to sex differences in disease phenotypes, and may explain some features of X chromosome aneuploidies such as in Turner and Klinefelter syndromes.

  15. Cytogenetic Characterization of the TM4 Mouse Sertoli Cell Line. II. Chromosome Microdissection, FISH, Scanning Electron Microscopy, and Confocal Laser Scanning Microscopy.

    Science.gov (United States)

    Schmid, Michael; Guttenbach, Martina; Steinlein, Claus; Wanner, Gerhard; Houben, Andreas

    2015-01-01

    The chromosomes and interphase cell nuclei of the permanent mouse Sertoli cell line TM4 were examined by chromosome microdissection, FISH, scanning electron microscopy, and confocal laser scanning microscopy. The already known marker chromosomes m1-m5 were confirmed, and 2 new large marker chromosomes m6 and m7 were characterized. The minute heterochromatic marker chromosomes m4 and m5 were microdissected and their DNA amplified by DOP-PCR. FISH of this DNA probe on TM4 metaphase chromosomes demonstrated that the m4 and m5 marker chromosomes have derived from the centromeric regions of normal telocentric mouse chromosomes. Ectopic pairing of the m4 and m5 marker chromosomes with the centromeric region of any of the other chromosomes (centromeric associations) was apparent in ∼60% of the metaphases. Scanning electron microscopy revealed DNA-protein bridges connecting the centromeric regions of normal chromosomes and the associated m4 and m5 marker chromosomes. Interphase cell nuclei of TM4 Sertoli cells did not exhibit the characteristic morphology of Sertoli cells in the testes of adult mice as shown by fluorescence microscopy and confocal laser scanning microscopy.

  16. Chromosome analysis of arsenic affected cattle

    Directory of Open Access Journals (Sweden)

    S. Shekhar

    2014-10-01

    Full Text Available Aim: The aim was to study the chromosome analysis of arsenic affected cattle. Materials and Methods: 27 female cattle (21 arsenic affected and 6 normal were selected for cytogenetical study. The blood samples were collected, incubated, and cultured using appropriate media and specific methods. The samples were analyzed for chromosome number and morphology, relative length of the chromosome, arm ratio, and centromere index of X chromosome and chromosomal abnormalities in arsenic affected cattle to that of normal ones. Results: The diploid number of metaphase chromosomes in arsenic affected cattle as well as in normal cattle were all 2n=60, 58 being autosomes and 2 being sex chromosomes. From the centromeric position, karyotyping studies revealed that all the 29 pair of autosomes was found to be acrocentric or telocentric, and the sex chromosomes (XX were submetacentric in both normal and arsenic affected cattle. The relative length of all the autosome pairs and sex chrosomosome pair was found to be higher in normal than that of arsenic affected cattle. The mean arm ratio of X-chromosome was higher in normal than that of arsenic affected cattle, but it is reverse in case of centromere index value of X-chromosome. There was no significant difference of arm ratio and centromere index of X-chromosomes between arsenic affected and normal cattle. No chromosomal abnormalities were found in arsenic affected cattle. Conclusion: The chromosome analysis of arsenic affected cattle in West Bengal reported for the first time in this present study which may serve as a guideline for future studies in other species. These reference values will also help in comparison of cytological studies of arsenic affected cattle to that of various toxicants.

  17. Assessment of Protein Binding of 5-Hydroxythalidomide Bioactivated in Humanized Mice with Human P450 3A-Chromosome or Hepatocytes by Two-Dimensional Electrophoresis/Accelerator Mass Spectrometry.

    Science.gov (United States)

    Yamazaki, Hiroshi; Suemizu, Hiroshi; Kazuki, Yasuhiro; Oofusa, Ken; Kuribayashi, Shunji; Shimizu, Makiko; Ninomiya, Shinichi; Horie, Toru; Shibata, Norio; Guengerich, F Peter

    2016-08-15

    Bioactivation of 5-hydroxy-[carbonyl-(14)C]thalidomide, a known metabolite of thalidomide, by human artificial or native cytochrome P450 3A enzymes, and nonspecific binding in livers of mice was assessed using two-dimensional electrophoresis combined with accelerator mass spectrometry. The apparent major target proteins were liver microsomal cytochrome c oxidase subunit 6B1 and ATP synthase subunit α in mice containing humanized P450 3A genes or transplanted humanized liver. Liver cytosolic retinal dehydrogenase 1 and glutathione transferase A1 were targets in humanized mice with P450 3A and hepatocytes, respectively. 5-Hydroxythalidomide is bioactivated by human P450 3A enzymes and trapped with proteins nonspecifically in humanized mice.

  18. Scaling Chromosomes for an Evolutionary Karyotype: A Chromosomal Tradeoff between Size and Number across Woody Species.

    Science.gov (United States)

    Liang, Guolu; Chen, Hong

    2015-01-01

    This study aims to examine the expected scaling relationships between chromosome size and number across woody species and to clarify the importance of the scaling for the maintenance of chromosome diversity by analyzing the scaling at the inter- & intra-chromosomal level. To achieve for the goals, chromosome trait data were extracted for 191 woody species (including 56 evergreen species and 135 deciduous species) from the available literature. Cross-species analyses revealed a tradeoff among chromosomes between chromosome size and number, demonstrating there is selective mechanism crossing chromosomes among woody species. And the explanations for the result were presented from intra- to inter-chromosome contexts that the scaling may be compromises among scale symmetry, mechanical requirements, and resource allocation across chromosomes. Therein, a 3/4 scaling pattern was observed between total chromosomes and m-chromosomes within nucleus which may imply total chromosomes may evolve from more to less. In addition, the primary evolutionary trend of karyotype and the role of m-chromosomes in the process of karyotype evolution were also discussed.

  19. Microdissection and chromosome painting of X and B chromosomes in Locusta migratoria.

    Science.gov (United States)

    Teruel, María; Cabrero, Josefa; Montiel, Eugenia E; Acosta, Manuel J; Sánchez, Antonio; Camacho, Juan Pedro M

    2009-01-01

    Acquisition of knowledge of the nature and DNA content of B chromosomes has been triggered by a collection of molecular techniques, one of which, microdissection, has provided interesting results in a number of B chromosome systems. Here we provide the first data on the molecular composition of B chromosomes in Locusta migratoria, after microdissection of the B and X chromosomes, DNA amplification by one (B) or two (X) different methods, and chromosome painting. The results showed that B chromosomes share at least two types of repetitive DNA sequences with the A chromosomes, suggesting that Bs in this species most likely arose intraspecifically. One of these repetitive DNAs is located on the heterochromatic distal half of the B chromosome and in the pericentromeric regions of about half of the A chromosomes, including the X. The other type of repetitive DNA is located interspersedly over the non-centromeric euchromatic regions of all A chromosomes and in an interstitial part of the proximal euchromatic half of the B chromosome. Chromosome painting, however, did not provide results sufficiently reliable to determine, in this species, which A chromosome gave rise to the B; this might be done by detailed analysis of the microdissected DNA sequences.

  20. Chromosome-specific segmentation revealed by structural analysis of individually isolated chromosomes.

    Science.gov (United States)

    Kitada, Kunio; Taima, Akira; Ogasawara, Kiyomoto; Metsugi, Shouichi; Aikawa, Satoko

    2011-04-01

    Analysis of structural rearrangements at the individual chromosomal level is still technologically challenging. Here we optimized a chromosome isolation method using fluorescent marker-assisted laser-capture and laser-beam microdissection and applied it to structural analysis of two aberrant chromosomes found in a lung cancer cell line. A high-density array-comparative genomic hybridization (array-CGH) analysis of DNA samples prepared from each of the chromosomes revealed that these two chromosomes contained 296 and 263 segments, respectively, ranging from 1.5 kb to 784.3 kb in size, derived from different portions of chromosome 8. Among these segments, 242 were common in both aberrant chromosomes, but 75 were found to be chromosome-specific. Sequences of 263 junction sites connecting the ends of segments were determined using a PCR/Sanger-sequencing procedure. Overlapping microhomologies were found at 169 junction sites. Junction partners came from various portions of chromosome 8 and no biased pattern in the positional distribution of junction partners was detected. These structural characteristics suggested the occurrence of random fragmentation of the entire chromosome 8 followed by random rejoining of these fragments. Based on that, we proposed a model to explain how these aberrant chromosomes are formed. Through these structural analyses, it was demonstrated that the optimized chromosome isolation method described here can provide high-quality chromosomal DNA for high resolution array-CGH analysis and probably for massively parallel sequencing analysis.

  1. Sexual maldevelopment and sex reversal, chromosomal causes.

    Science.gov (United States)

    Magenis, R Ellen

    2006-01-01

    The SRY gene on the Y chromosome is the testis determining factor (TDF). It is therefore the initial male determining factor. However, phenotypic sex determination includes a cascade of genes located on autosomes as well as sex chromosomes. Aberrations of these genes may cause sexual maldevelopment or sex reversal. Abnormalities may include single gene mutations and gene loss or gain-changes may involve only sex organs or may be part of syndromes. These changes may also arise as chromosome abnormalities involving contiguous genes. Eight cases with chromosomal abnormalities involving different causative mechanisms are described herein. The most common cause is nondisjunction, including loss or gain of sex chromosomes. Less common causes are mispairing and crossing over in meiosis, chromosome breaks with repair, nonhomologous pairing due to low copy repeats and crossing over, and translocation (familial or de novo) with segregation. Cases include: [see: text].

  2. Phosphorylation of CDK2 on threonine 160 influences silencing of sex chromosome during male meiosis.

    Science.gov (United States)

    Wang, Lu; Liu, Wenjing; Zhao, Weidong; Song, Gendi; Wang, Guishuan; Wang, Xiaorong; Sun, Fei

    2014-06-01

    In mammalian meiosis, the X and Y chromosomes are largely unsynapsed and transcriptionally silenced during the pachytene stage of meiotic prophase (meiotic sex chromosome inactivation), forming a specialized nuclear territory called sex or XY body. An increasing number of proteins and noncoding RNAs were found to localize to the sex body and take part in influencing expression of sex chromosome genes. Cyclin-dependent kinase 2 (Cdk2 (-/-)) spermatocytes show incomplete sex chromosome pairing. Here, we further showed that phosphorylation of CDK2 isoform 1 (p-CDK2(39) [39 kDa]) on threonine 160 localizes to the sites of asynapsis and the sex body, interacting with phosphorylated gamma-H2AX. Meanwhile, p-CDK2(39) is frequently mislocalized throughout the sex body, and meiotic sex chromosome inactivation is disrupted in PWK×C57BL/6J hybrid mice. Furthermore, pachytene spermatocytes treated with mevastatin (an inhibitor of p-CDK2) showed overexpression of sex chromosome-linked genes. Our results highlight an important role for p-CDK2(39) in influencing silencing of the sex chromosomes during male meiosis by interacting with gamma-H2AX.

  3. Mechanics of kinetochore microtubules and their interactions with chromosomes during cell division

    Science.gov (United States)

    Nazockdast, Ehssan; Fürthauer, Sebastian; Redemann, Stephanie; Baumgart, Johannes; Lindow, Norbert; Kratz, Andrea; Prohaska, Steffen; Müller-Reichert, Thomas; Shelley, Michael

    2016-11-01

    The accurate segregation of chromosomes, and subsequent cell division, in Eukaryotic cells is achieved by the interactions of an assembly of microtubules (MTs) and motor-proteins, known as the mitotic spindle. We use a combination of our computational platform for simulating cytoskeletal assemblies and our structural data from high-resolution electron tomography of the mitotic spindle, to study the kinetics and mechanics of MTs in the spindle, and their interactions with chromosomes during chromosome segregation in the first cell division in C.elegans embryo. We focus on kinetochore MTs, or KMTs, which have one end attached to a chromosome. KMTs are thought to be a key mechanical component in chromosome segregation. Using exploratory simulations of MT growth, bending, hydrodynamic interactions, and attachment to chromosomes, we propose a mechanical model for KMT-chromosome interactions that reproduces observed KMT length and shape distributions from electron tomography. We find that including detailed hydrodynamic interactions between KMTs is essential for agreement with the experimental observations.

  4. Meiotic recombination analyses of individual chromosomes in male domestic pigs (Sus scrofa domestica).

    Science.gov (United States)

    Mary, Nicolas; Barasc, Harmonie; Ferchaud, Stéphane; Billon, Yvon; Meslier, Frédéric; Robelin, David; Calgaro, Anne; Loustau-Dudez, Anne-Marie; Bonnet, Nathalie; Yerle, Martine; Acloque, Hervé; Ducos, Alain; Pinton, Alain

    2014-01-01

    For the first time in the domestic pig, meiotic recombination along the 18 porcine autosomes was directly studied by immunolocalization of MLH1 protein. In total, 7,848 synaptonemal complexes from 436 spermatocytes were analyzed, and 13,969 recombination sites were mapped. Individual chromosomes for 113 of the 436 cells (representing 2,034 synaptonemal complexes) were identified by immunostaining and fluorescence in situ hybridization (FISH). The average total length of autosomal synaptonemal complexes per cell was 190.3 µm, with 32.0 recombination sites (crossovers), on average, per cell. The number of crossovers and the lengths of the autosomal synaptonemal complexes showed significant intra- (i.e. between cells) and inter-individual variations. The distributions of recombination sites within each chromosomal category were similar: crossovers in metacentric and submetacentric chromosomes were concentrated in the telomeric regions of the p- and q-arms, whereas two hotspots were located near the centromere and in the telomeric region of acrocentrics. Lack of MLH1 foci was mainly observed in the smaller chromosomes, particularly chromosome 18 (SSC18) and the sex chromosomes. All autosomes displayed positive interference, with a large variability between the chromosomes.

  5. Alternative Splicing of CHEK2 and Codeletion with NF2 Promote Chromosomal Instability in Meningioma

    Directory of Open Access Journals (Sweden)

    Hong Wei Yang

    2012-01-01

    Full Text Available Mutations of the NF2 gene on chromosome 22q are thought to initiate tumorigenesis in nearly 50% of meningiomas, and 22q deletion is the earliest and most frequent large-scale chromosomal abnormality observed in these tumors. In aggressive meningiomas, 22q deletions are generally accompanied by the presence of large-scale segmental abnormalities involving other chromosomes, but the reasons for this association are unknown. We find that large-scale chromosomal alterations accumulate during meningioma progression primarily in tumors harboring 22q deletions, suggesting 22q-associated chromosomal instability. Here we show frequent codeletion of the DNA repair and tumor suppressor gene, CHEK2, in combination with NF2 on chromosome 22q in a majority of aggressive meningiomas. In addition, tumor-specific splicing of CHEK2 in meningioma leads to decreased functional Chk2 protein expression. We show that enforced Chk2 knockdown in meningioma cells decreases DNA repair. Furthermore, Chk2 depletion increases centrosome amplification, thereby promoting chromosomal instability. Taken together, these data indicate that alternative splicing and frequent codeletion of CHEK2 and NF2 contribute to the genomic instability and associated development of aggressive biologic behavior in meningiomas.

  6. Histone H2AFX Links Meiotic Chromosome Asynapsis to Prophase I Oocyte Loss in Mammals.

    Directory of Open Access Journals (Sweden)

    Jeffrey M Cloutier

    2015-10-01

    Full Text Available Chromosome abnormalities are common in the human population, causing germ cell loss at meiotic prophase I and infertility. The mechanisms driving this loss are unknown, but persistent meiotic DNA damage and asynapsis may be triggers. Here we investigate the contribution of these lesions to oocyte elimination in mice with chromosome abnormalities, e.g. Turner syndrome (XO and translocations. We show that asynapsed chromosomes trigger oocyte elimination at diplonema, which is linked to the presence of phosphorylated H2AFX (γH2AFX. We find that DNA double-strand break (DSB foci disappear on asynapsed chromosomes during pachynema, excluding persistent DNA damage as a likely cause, and demonstrating the existence in mammalian oocytes of a repair pathway for asynapsis-associated DNA DSBs. Importantly, deletion or point mutation of H2afx restores oocyte numbers in XO females to wild type (XX levels. Unexpectedly, we find that asynapsed supernumerary chromosomes do not elicit prophase I loss, despite being enriched for γH2AFX and other checkpoint proteins. These results suggest that oocyte loss cannot be explained simply by asynapsis checkpoint models, but is related to the gene content of asynapsed chromosomes. A similar mechanistic basis for oocyte loss may operate in humans with chromosome abnormalities.

  7. Histone H2AFX Links Meiotic Chromosome Asynapsis to Prophase I Oocyte Loss in Mammals.

    Science.gov (United States)

    Cloutier, Jeffrey M; Mahadevaiah, Shantha K; ElInati, Elias; Nussenzweig, André; Tóth, Attila; Turner, James M A

    2015-10-01

    Chromosome abnormalities are common in the human population, causing germ cell loss at meiotic prophase I and infertility. The mechanisms driving this loss are unknown, but persistent meiotic DNA damage and asynapsis may be triggers. Here we investigate the contribution of these lesions to oocyte elimination in mice with chromosome abnormalities, e.g. Turner syndrome (XO) and translocations. We show that asynapsed chromosomes trigger oocyte elimination at diplonema, which is linked to the presence of phosphorylated H2AFX (γH2AFX). We find that DNA double-strand break (DSB) foci disappear on asynapsed chromosomes during pachynema, excluding persistent DNA damage as a likely cause, and demonstrating the existence in mammalian oocytes of a repair pathway for asynapsis-associated DNA DSBs. Importantly, deletion or point mutation of H2afx restores oocyte numbers in XO females to wild type (XX) levels. Unexpectedly, we find that asynapsed supernumerary chromosomes do not elicit prophase I loss, despite being enriched for γH2AFX and other checkpoint proteins. These results suggest that oocyte loss cannot be explained simply by asynapsis checkpoint models, but is related to the gene content of asynapsed chromosomes. A similar mechanistic basis for oocyte loss may operate in humans with chromosome abnormalities.

  8. Ontogeny of Unstable Chromosomes Generated by Telomere Error in Budding Yeast

    Science.gov (United States)

    Weinert, Ted

    2016-01-01

    DNA replication errors at certain sites in the genome initiate chromosome instability that ultimately leads to stable genomic rearrangements. Where instability begins is often unclear. And, early instability may form unstable chromosome intermediates whose transient nature also hinders mechanistic understanding. We report here a budding yeast model that reveals the genetic ontogeny of genome rearrangements, from initial replication error to unstable chromosome formation to their resolution. Remarkably, the initial error often arises in or near the telomere, and frequently forms unstable chromosomes. Early unstable chromosomes may then resolve to an internal "collection site" where a dicentric forms and resolves to an isochromosome (other outcomes are possible at each step). The initial telomere-proximal unstable chromosome is increased in mutants in telomerase subunits, Tel1, and even Rad9, with no known telomere-specific function. Defects in Tel1 and in Rrm3, a checkpoint protein kinase with a role in telomere maintenance and a DNA helicase, respectively, synergize dramatically to generate unstable chromosomes, further illustrating the consequence of replication error in the telomere. Collectively, our results suggest telomeric replication errors may be a common cause of seemingly unrelated genomic rearrangements located hundreds of kilobases away. PMID:27716774

  9. Ontogeny of Unstable Chromosomes Generated by Telomere Error in Budding Yeast.

    Science.gov (United States)

    Beyer, Tracey; Weinert, Ted

    2016-10-01

    DNA replication errors at certain sites in the genome initiate chromosome instability that ultimately leads to stable genomic rearrangements. Where instability begins is often unclear. And, early instability may form unstable chromosome intermediates whose transient nature also hinders mechanistic understanding. We report here a budding yeast model that reveals the genetic ontogeny of genome rearrangements, from initial replication error to unstable chromosome formation to their resolution. Remarkably, the initial error often arises in or near the telomere, and frequently forms unstable chromosomes. Early unstable chromosomes may then resolve to an internal "collection site" where a dicentric forms and resolves to an isochromosome (other outcomes are possible at each step). The initial telomere-proximal unstable chromosome is increased in mutants in telomerase subunits, Tel1, and even Rad9, with no known telomere-specific function. Defects in Tel1 and in Rrm3, a checkpoint protein kinase with a role in telomere maintenance and a DNA helicase, respectively, synergize dramatically to generate unstable chromosomes, further illustrating the consequence of replication error in the telomere. Collectively, our results suggest telomeric replication errors may be a common cause of seemingly unrelated genomic rearrangements located hundreds of kilobases away.

  10. The sequence and analysis of duplication rich human chromosome 16

    Energy Technology Data Exchange (ETDEWEB)

    Martin, Joel; Han, Cliff; Gordon, Laurie A.; Terry, Astrid; Prabhakar, Shyam; She, Xinwei; Xie, Gary; Hellsten, Uffe; Man Chan, Yee; Altherr, Michael; Couronne, Olivier; Aerts, Andrea; Bajorek, Eva; Black, Stacey; Blumer, Heather; Branscomb, Elbert; Brown, Nancy C.; Bruno, William J.; Buckingham, Judith M.; Callen, David F.; Campbell, Connie S.; Campbell, Mary L.; Campbell, Evelyn W.; Caoile, Chenier; Challacombe, Jean F.; Chasteen, Leslie A.; Chertkov, Olga; Chi, Han C.; Christensen, Mari; Clark, Lynn M.; Cohn, Judith D.; Denys, Mirian; Detter, John C.; Dickson, Mark; Dimitrijevic-Bussod, Mira; Escobar, Julio; Fawcett, Joseph J.; Flowers, Dave; Fotopulos, Dea; Glavina, Tijana; Gomez, Maria; Gonzales, Eidelyn; Goodstein, David; Goodwin, Lynne A.; Grady, Deborah L.; Grigoriev, Igor; Groza, Matthew; Hammon, Nancy; Hawkins, Trevor; Haydu, Lauren; Hildebrand, Carl E.; Huang, Wayne; Israni, Sanjay; Jett, Jamie; Jewett, Phillip E.; Kadner, Kristen; Kimball, Heather; Kobayashi, Arthur; Krawczyk, Marie-Claude; Leyba, Tina; Longmire, Jonathan L.; Lopez, Frederick; Lou, Yunian; Lowry, Steve; Ludeman, Thom; Mark, Graham A.; Mcmurray, Kimberly L.; Meincke, Linda J.; Morgan, Jenna; Moyzis, Robert K.; Mundt, Mark O.; Munk, A. Christine; Nandkeshwar, Richard D.; Pitluck, Sam; Pollard, Martin; Predki, Paul; Parson-Quintana, Beverly; Ramirez, Lucia; Rash, Sam; Retterer, James; Ricke, Darryl O.; Robinson, Donna L.; Rodriguez, Alex; Salamov, Asaf; Saunders, Elizabeth H.; Scott, Duncan; Shough, Timothy; Stallings, Raymond L.; Stalvey, Malinda; Sutherland, Robert D.; Tapia, Roxanne; Tesmer, Judith G.; Thayer, Nina; Thompson, Linda S.; Tice, Hope; Torney, David C.; Tran-Gyamfi, Mary; Tsai, Ming; Ulanovsky, Levy E.; Ustaszewska, Anna; Vo, Nu; White, P. Scott; Williams, Albert L.; Wills, Patricia L.; Wu, Jung-Rung; Wu, Kevin; Yang, Joan; DeJong, Pieter; Bruce, David; Doggett, Norman; Deaven, Larry; Schmutz, Jeremy; Grimwood, Jane; Richardson, Paul; et al.

    2004-08-01

    We report here the 78,884,754 base pairs of finished human chromosome 16 sequence, representing over 99.9 percent of its euchromatin. Manual annotation revealed 880 protein coding genes confirmed by 1,637 aligned transcripts, 19 tRNA genes, 341 pseudogenes and 3 RNA pseudogenes. These genes include metallothionein, cadherin and iroquois gene families, as well as the disease genes for polycystic kidney disease and acute myelomonocytic leukemia. Several large-scale structural polymorphisms spanning hundreds of kilobasepairs were identified and result in gene content differences across humans. One of the unique features of chromosome 16 is its high level of segmental duplication, ranked among the highest of the human autosomes. While the segmental duplications are enriched in the relatively gene poor pericentromere of the p-arm, some are involved in recent gene duplication and conversion events which are likely to have had an impact on the evolution of primates and human disease susceptibility.

  11. The Sequence and Analysis of Duplication Rich Human Chromosome 16

    Science.gov (United States)

    Martin, Joel; Han, Cliff; Gordon, Laurie A.; Terry, Astrid; Prabhakar, Shyam; She, Xinwei; Xie, Gary; Hellsten, Uffe; Man Chan, Yee; Altherr, Michael; Couronne, Olivier; Aerts, Andrea; Bajorek, Eva; Black, Stacey; Blumer, Heather; Branscomb, Elbert; Brown, Nancy C.; Bruno, William J.; Buckingham, Judith M.; Callen, David F.; Campbell, Connie S.; Campbell, Mary L.; Campbell, Evelyn W.; Caoile, Chenier; Challacombe, Jean F.; Chasteen, Leslie A.; Chertkov, Olga; Chi, Han C.; Christensen, Mari; Clark, Lynn M.; Cohn, Judith D.; Denys, Mirian; Detter, John C.; Dickson, Mark; Dimitrijevic-Bussod, Mira; Escobar, Julio; Fawcett, Joseph J.; Flowers, Dave; Fotopulos, Dea; Glavina, Tijana; Gomez, Maria; Gonzales, Eidelyn; Goodstein, David; Goodwin, Lynne A.; Grady, Deborah L.; Grigoriev, Igor; Groza, Matthew; Hammon, Nancy; Hawkins, Trevor; Haydu, Lauren; Hildebrand, Carl E.; Huang, Wayne; Israni, Sanjay; Jett, Jamie; Jewett, Phillip E.; Kadner, Kristen; Kimball, Heather; Kobayashi, Arthur; Krawczyk, Marie-Claude; Leyba, Tina; Longmire, Jonathan L.; Lopez, Frederick; Lou, Yunian; Lowry, Steve; Ludeman, Thom; Mark, Graham A.; Mcmurray, Kimberly L.; Meincke, Linda J.; Morgan, Jenna; Moyzis, Robert K.; Mundt, Mark O.; Munk, A. Christine; Nandkeshwar, Richard D.; Pitluck, Sam; Pollard, Martin; Predki, Paul; Parson-Quintana, Beverly; Ramirez, Lucia; Rash, Sam; Retterer, James; Ricke, Darryl O.; Robinson, Donna L.; Rodriguez, Alex; Salamov, Asaf; Saunders, Elizabeth H.; Scott, Duncan; Shough, Timothy; Stallings, Raymond L.; Stalvey, Malinda; Sutherland, Robert D.; Tapia, Roxanne; Tesmer, Judith G.; Thayer, Nina; Thompson, Linda S.; Tice, Hope; Torney, David C.; Tran-Gyamfi, Mary; Tsai, Ming; Ulanovsky, Levy E.; Ustaszewska, Anna; Vo, Nu; White, P. Scott; Williams, Albert L.; Wills, Patricia L.; Wu, Jung-Rung; Wu, Kevin; Yang, Joan; DeJong, Pieter; Bruce, David; Doggett, Norman; Deaven, Larry; Schmutz, Jeremy; Grimwood, Jane; Richardson, Paul; et al.

    2004-01-01

    We report here the 78,884,754 base pairs of finished human chromosome 16 sequence, representing over 99.9 percent of its euchromatin. Manual annotation revealed 880 protein coding genes confirmed by 1,637 aligned transcripts, 19 tRNA genes, 341 pseudogenes and 3 RNA pseudogenes. These genes include metallothionein, cadherin and iroquois gene families, as well as the disease genes for polycystic kidney disease and acute myelomonocytic leukemia. Several large-scale structural polymorphisms spanning hundreds of kilobasepairs were identified and result in gene content differences across humans. One of the unique features of chromosome 16 is its high level of segmental duplication, ranked among the highest of the human autosomes. While the segmental duplications are enriched in the relatively gene poor pericentromere of the p-arm, some are involved in recent gene duplication and conversion events which are likely to have had an impact on the evolution of primates and human disease susceptibility.

  12. Fitness cost of chromosomal drug resistance-conferring mutations.

    Science.gov (United States)

    Sander, Peter; Springer, Burkhard; Prammananan, Therdsak; Sturmfels, Antje; Kappler, Martin; Pletschette, Michel; Böttger, Erik C

    2002-05-01

    To study the cost of chromosomal drug resistance mutations to bacteria, we investigated the fitness cost of mutations that confer resistance to different classes of antibiotics affecting bacterial protein synthesis (aminocyclitols, 2-deoxystreptamines, macrolides). We used a model system based on an in vitro competition assay with defined Mycobacterium smegmatis laboratory mutants; selected mutations were introduced by genetic techniques to address the possibility that compensatory mutations ameliorate the resistance cost. We found that the chromosomal drug resistance mutations studied often had only a small fitness cost; compensatory mutations were not involved in low-cost or no-cost resistance mutations. When drug resistance mutations found in clinical isolates were considered, selection of those mutations that have little or no fitness cost in the in vitro competition assay seems to occur. These results argue against expectations that link decreased levels of antibiotic consumption with the decline in the level of resistance.

  13. Chromosomal rearrangements in Tourette syndrome

    DEFF Research Database (Denmark)

    Bertelsen, Birgitte; Debes, Nanette Mol; Hjermind, Lena E

    2013-01-01

    Tourette syndrome (TS) is a childhood-onset complex neurobiological disorder characterized by a combination of persistent motor and vocal tics and frequent presence of other neuropsychiatric comorbidities. TS shares the fate of other complex disorders, where the genetic etiology is largely unknown......, and identification of susceptibility genes through linkage and association studies has been complicated due to inherent difficulties such as no clear mode of inheritance, genetic heterogeneity, and apparently incomplete penetrance. Positional cloning through mapping of disease-related chromosome rearrangements has...

  14. Meiosis I: When Chromosomes Undergo Extreme Makeover

    OpenAIRE

    Miller, Matthew P; Amon, Angelika; Ünal, Elçin

    2013-01-01

    The ultimate success of cell division relies on the accurate partitioning of the genetic material. Errors in this process occur in nearly all tumors and are the leading cause of miscarriages and congenital birth defects in humans. Two cell divisions, mitosis and meiosis, use common as well as unique mechanisms to ensure faithful chromosome segregation. In mitosis, alternating rounds of DNA replication and chromosome segregation preserves the chromosome complement of the progenitor cell. In co...

  15. Chromosomal Fragmentation in "Escherichia Coli": Its Absence in "mutT" Mutants and Its Mechanisms in "seqA" Mutants

    Science.gov (United States)

    Rotman, Ella Rose

    2009-01-01

    Chromosomal fragmentation in "Escherichia coli" is a lethal event for the cell unless mended by the recombinational repair proteins RecA, RecBCD, and RuvABC. Certain mutations exacerbate problems that cause the cell to be dependent on the recombinational repair proteins for viability. We tested whether the absence of the MutT protein caused…

  16. Dgcr8 and Dicer are essential for sex chromosome integrity during meiosis in males.

    Science.gov (United States)

    Modzelewski, Andrew J; Hilz, Stephanie; Crate, Elizabeth A; Schweidenback, Caterina T H; Fogarty, Elizabeth A; Grenier, Jennifer K; Freire, Raimundo; Cohen, Paula E; Grimson, Andrew

    2015-06-15

    Small RNAs play crucial roles in regulating gene expression during mammalian meiosis. To investigate the function of microRNAs (miRNAs) and small interfering RNAs (siRNAs) during meiosis in males, we generated germ-cell-specific conditional deletions of Dgcr8 and Dicer in mice. Analysis of spermatocytes from both conditional knockout lines revealed that there were frequent chromosomal fusions during meiosis, always involving one or both sex chromosomes. RNA sequencing indicates upregulation of Atm in spermatocytes from miRNA-deficient mice, and immunofluorescence imaging demonstrates an increased abundance of activated ATM kinase and mislocalization of phosphorylated MDC1, an ATM phosphorylation substrate. The Atm 3'UTR contains many potential microRNA target sites, and, notably, target sites for several miRNAs depleted in both conditional knockout mice were highly effective at promoting repression. RNF8, a telomere-associated protein whose localization is controlled by the MDC1-ATM kinase cascade, normally associates with the sex chromosomes during pachytene, but in both conditional knockouts redistributed to the autosomes. Taken together, these results suggest that Atm dysregulation in microRNA-deficient germ lines contributes to the redistribution of proteins involved in chromosomal stability from the sex chromosomes to the autosomes, resulting in sex chromosome fusions during meiotic prophase I.

  17. Movement of chromosomes with severed kinetochore microtubules.

    Science.gov (United States)

    Forer, Arthur; Johansen, Kristen M; Johansen, Jørgen

    2015-05-01

    Experiments dating from 1966 and thereafter showed that anaphase chromosomes continued to move poleward after their kinetochore microtubules were severed by ultraviolet microbeam irradiation. These observations were initially met with scepticism as they contradicted the prevailing view that kinetochore fibre microtubules pulled chromosomes to the pole. However, recent experiments using visible light laser microbeam irradiations have corroborated these earlier experiments as anaphase chromosomes again were shown to move poleward after their kinetochore microtubules were severed. Thus, multiple independent studies using different techniques have shown that chromosomes can indeed move poleward without direct microtubule connections to the pole, with only a kinetochore 'stub' of microtubules. An issue not yet settled is: what propels the disconnected chromosome? There are two not necessarily mutually exclusive proposals in the literature: (1) chromosome movement is propelled by the kinetochore stub interacting with non-kinetochore microtubules and (2) chromosome movement is propelled by a spindle matrix acting on the stub. In this review, we summarise the data indicating that chromosomes can move with severed kinetochore microtubules and we discuss proposed mechanisms for chromosome movement with severed kinetochore microtubules.

  18. Cognitive and medical features of chromosomal aneuploidy.

    Science.gov (United States)

    Hutaff-Lee, Christa; Cordeiro, Lisa; Tartaglia, Nicole

    2013-01-01

    This chapter describes the physical characteristics, medical complications, and cognitive and psychological profiles that are associated with chromosomal aneuploidy conditions, a group of conditions in which individuals are born with one or more additional chromosome. Overall, chromosomal aneuploidy conditions occur in approximately 1 in 250 children. Information regarding autosomal disorders including trisomy 21 (Down syndrome), trisomy 13 (Patau syndrome), and trisomy 18 (Edward syndrome) are presented. Sex chromosome aneuploidy conditions such as Klinefelter syndrome (47,XXY), XYY, trisomy X, and Turner syndrome (45,X), in addition to less frequently occurring tetrasomy and pentasomy conditions are also covered. Treatment recommendations and suggestions for future research directions are discussed.

  19. Research on automatic human chromosome image analysis

    Science.gov (United States)

    Ming, Delie; Tian, Jinwen; Liu, Jian

    2007-11-01

    Human chromosome karyotyping is one of the essential tasks in cytogenetics, especially in genetic syndrome diagnoses. In this thesis, an automatic procedure is introduced for human chromosome image analysis. According to different status of touching and overlapping chromosomes, several segmentation methods are proposed to achieve the best results. Medial axis is extracted by the middle point algorithm. Chromosome band is enhanced by the algorithm based on multiscale B-spline wavelets, extracted by average gray profile, gradient profile and shape profile, and calculated by the WDD (Weighted Density Distribution) descriptors. The multilayer classifier is used in classification. Experiment results demonstrate that the algorithms perform well.

  20. Meiotic chromosome abnormalities in human spermatogenesis.

    Science.gov (United States)

    Martin, Renée H

    2006-08-01

    The last few years have witnessed an explosion in the information about chromosome abnormalities in human sperm and the meiotic events that predispose to these abnormalities. We have determined that all chromosomes are susceptible to nondisjunction, but chromosomes 21 and 22 and, especially, the sex chromosomes have an increased frequency of aneuploidy. Studies are just beginning on the effects of potential mutagens on the chromosomal constitution of human sperm. The effects of pesticides and cancer therapeutic agents have been reviewed. In the last decade, there has been a great impetus to study chromosome abnormalities in sperm from infertile men because the advent of intracytoplasmic sperm injection (ICSI) made it possible for these men to father pregnancies. A large number of studies have demonstrated that infertile men have an increased frequency of chromosomally abnormal sperm and children, even when they have a normal somatic karyotype. Meiotic studies on the pachytene stage of spermatogenesis have demonstrated that infertile men have impaired chromosome synapsis, a significantly decreased frequency of recombination, and an increased frequency of chromosomes completely lacking a recombination site. Such errors make these cells susceptible to meiotic arrest and the production of aneuploid gametes.

  1. Somatic pairing of chromosome 19 in renal oncocytoma is associated with deregulated EGLN2-mediated [corrected] oxygen-sensing response.

    Directory of Open Access Journals (Sweden)

    Julie M Koeman

    Full Text Available Chromosomal abnormalities, such as structural and numerical abnormalities, are a common occurrence in cancer. The close association of homologous chromosomes during interphase, a phenomenon termed somatic chromosome pairing, has been observed in cancerous cells, but the functional consequences of somatic pairing have not been established. Gene expression profiling studies revealed that somatic pairing of chromosome 19 is a recurrent chromosomal abnormality in renal oncocytoma, a neoplasia of the adult kidney. Somatic pairing was associated with significant disruption of gene expression within the paired regions and resulted in the deregulation of the prolyl-hydroxylase EGLN2 [corrected] a key protein that regulates the oxygen-dependent degradation of hypoxia-inducible factor (HIF. Overexpression of EGLN2 [corrected] in renal oncocytoma increased ubiquitin-mediated destruction of HIF and concomitantly suppressed the expression of several HIF-target genes, including the pro-death BNIP3L gene. The transcriptional changes that are associated with somatic pairing of chromosome 19 mimic the transcriptional changes that occur following DNA amplification. Therefore, in addition to numerical and structural chromosomal abnormalities, alterations in chromosomal spatial dynamics should be considered as genomic events that are associated with tumorigenesis. The identification of EGLN2 as a significantly deregulated gene that maps within the paired chromosome region directly implicates defects in the oxygen-sensing network to the biology of renal oncocytoma.

  2. Tug-of-war between opposing molecular motors explains chromosomal oscillation during mitosis.

    Science.gov (United States)

    Sutradhar, S; Paul, R

    2014-03-07

    Chromosomes move towards and away from the centrosomes during the mitosis. This oscillation is observed when the kinetochore, a specific protein structure on the chromosome is captured by centrosome-nucleated polymer called microtubules. We present a computational model, incorporating activities of various molecular motors and microtubule dynamics, to demonstrate the observed oscillation. The model is robust and is not restricted to any particular cell type. Quantifying the average velocity, amplitude and periodicity of the chromosomal oscillation, we compare numerical results with the available experimental data. Our analysis supports a tug-of-war like mechanism between opposing motors that changes the course of chromosomal oscillation. It turns out that, various modes of oscillation can be fully understood by assembling the dynamics of molecular motors. Near the stall regime, when opposing motors are engaged in a tug-of-war, sufficiently large kinetochore-microtubule generated force may prolong the stall durations.

  3. Physical Model of Segregation of E.coli Chromosomes using Molecular Dynamics

    Science.gov (United States)

    Alnahhas, Faisal; Kharel, Savan

    2016-03-01

    Chromosome segregation is one of the most interesting physical processes during a bacterial cell cycle. We will use molecular dynamics simulations which will help us understand how strongly confined polymer segregates. In the presentation, we will discuss how segregation of initially overlapping circular chromosome occurs during a cell cycle. In particular, we will describe the role played by entropic mechanism in the demixing of overlapping circular polymer confined in a cylindrical boundary. We discuss how our polymer chains modeled as an E-coli chromosome experiences an effective repulsion, which ultimately leads to partition driven by the entropic forces. Also, we will also discuss how the segregation of circular chromosome in cylindrical confinement differs from a spherical confinement. Finally, we will discuss the role played by proteins and supercoiling in during the segregation process.

  4. Neocentric X-chromosome in a girl with Turner-like syndrome

    Directory of Open Access Journals (Sweden)

    Hemmat Morteza

    2012-06-01

    Full Text Available Abstract Background Neocentromeres are rare human chromosomal aberrations in which a new centromere has formed in a previously non-centromeric location. We report the finding of a structurally abnormal X chromosome with a neocentromere in a 15-year-old girl with clinical features suggestive of Turner syndrome, including short stature and primary amenorrhea. Result G-banded chromosome analysis revealed a mosaic female karyotype involving two abnormal cell lines. One cell line (84% of analyzed metaphases had a structurally abnormal X chromosome (duplication of the long arm and deletion of the short arm and a normal X chromosome. The other cell line (16% of cells exhibited monosomy X. C-banding studies were negative for the abnormal X chromosome. FISH analysis revealed lack of hybridization of the abnormal X chromosome with both the X centromere-specific probe and the “all human centromeres” probe, a pattern consistent with lack of the X chromosome endogenous centromere. A FISH study using an XIST gene probe revealed the presence of two XIST genes, one on each long arm of the iso(Xq, required for inactivation of the abnormal X chromosome. R-banding also demonstrated inactivation of the abnormal X chromosome. An assay for centromeric protein C (CENP-C was positive on both the normal and the abnormal X chromosomes. The position of CENP-C in the abnormal X chromosome defined a neocentromere, which explains its mitotic stability. The karyotype is thus designated as 46,X,neo(X(qter- > q12::q12- > q21.2- > neo- > q21.2- > qter[42]/45,X[8], which is consistent with stigmata of Turner syndrome. The mother of this patient has a normal karyotype; however, the father was not available for study. Conclusion To our knowledge, this is the first case of mosaic Turner syndrome involving an analphoid iso(Xq chromosome with a proven neocentromere among 90 previously described cases with a proven neocentromere.

  5. Increased chromosome radiosensitivity during pregnancy

    Energy Technology Data Exchange (ETDEWEB)

    Ricoul, Michelle; Sabatier, Laure; Dutrillaux, Bernard [Commissariat a l`Energie Atomique, Laboratoire de Radiobiologie et Oncologie, DRR, DSV, Fontenay aux roses (France)

    1997-03-04

    It was necessary to consider the risks of exposure of pregnant women, not only in relation to the child, but also in relation to their own hypersensitivity. We have demonstrated that pregnancy increases radiosensitivity of chromosome in the mouse at the end of gestation. This is of importance since it may have implications on radioprotection of pregnant women and give experimental guidelines to the problems of hypersensitivity to drugs and cancer aggravation during pregnancy. Blood obtained from women at various times of pregnancy was exposed to ionizing radiations. By comparison to non-pregnant women, an increase in chromosome breakage was observed in metaphases from lymphocytes, after short-term culture in the presence of the serum of the same donor. Immediately after delivery, this increase in radiosensitivity disappeared. In a prospective study, serial analyses showed a very strong correlation between the amount of pregnancy hormones, progesterone in particular, and the increase in radiosensitivity. Pregnant women may have an increased sensitivity to ionizing radiation during the second half of their pregnancy. This study provides the first evidence in human that radiosensitivity may vary in relation to physiological conditions.

  6. Chromosomal replicons of higher plants

    Energy Technology Data Exchange (ETDEWEB)

    Van' t Hof, J.

    1987-03-16

    This brief discussion of replicons of higher plants offers a glimpse into the properties of chromosomal DNA replication. It gives evidence that the S phase of unrelated plant species is comprised of temporally ordered replicon families that increase in number with genome size. This orderly process, which assures a normal inheritance of genetic material to recipient daughter cells, is maintained at the level of replicon clusters by two mutually exclusive mechanisms, one involving the rate at which single replicons replicate their allotment of DNA, and another by means of the tempo-pause. The same two mechanisms are used by cells to alter the pattern of chromosomal DNA replication just prior to and during normal development. Both mechanisms are genetically determined and produce genetic effects when disturbed of disrupted by additional non-conforming DNAs. Further insight into how these two mechanisms operate requires more molecular information about the nature of replicons and the factors that govern when a replicon family replicates. Plant material is a rich and ideal source for this information just awaiting exploitation. 63 refs.

  7. Chromosomal phenotypes and submicroscopic abnormalities

    Directory of Open Access Journals (Sweden)

    Devriendt Koen

    2004-01-01

    Full Text Available Abstract The finding, during the last decade, that several common, clinically delineated syndromes are caused by submicroscopic deletions or, more rarely, by duplications, has provided a powerful tool in the annotation of the human genome. Since most microdeletion/microduplication syndromes are defined by a common deleted/duplicated region, abnormal dosage of genes located within these regions can explain the phenotypic similarities among individuals with a specific syndrome. As such, they provide a unique resource towards the genetic dissection of complex phenotypes such as congenital heart defects, mental and growth retardation and abnormal behaviour. In addition, the study of phenotypic differences in individuals with the same microdeletion syndrome may also become a treasury for the identification of modifying factors for complex phenotypes. The molecular analysis of these chromosomal anomalies has led to a growing understanding of their mechanisms of origin. Novel tools to uncover additional submicroscopic chromosomal anomalies at a higher resolution and higher speed, as well as the novel tools at hand for deciphering the modifying factors and epistatic interactors, are 'on the doorstep' and will, besides their obvious diagnostic role, play a pivotal role in the genetic dissection of complex phenotypes.

  8. Conservation of chromosomes syntenic with avian autosomes in squamate reptiles revealed by comparative chromosome painting.

    Science.gov (United States)

    Pokorná, Martina; Giovannotti, Massimo; Kratochvíl, Lukáš; Caputo, Vincenzo; Olmo, Ettore; Ferguson-Smith, Malcolm A; Rens, Willem

    2012-08-01

    In contrast to mammals, birds exhibit a slow rate of chromosomal evolution. It is not clear whether high chromosome conservation is an evolutionary novelty of birds or was inherited from an earlier avian ancestor. The evolutionary conservatism of macrochromosomes between birds and turtles supports the latter possibility; however, the rate of chromosomal evolution is largely unknown in other sauropsids. In squamates, we previously reported strong conservatism of the chromosomes syntenic with the avian Z, which could reflect a peculiarity of this part of the genome. The chromosome 1 of iguanians and snakes is largely syntenic with chromosomes 3, 5 and 7 of the avian ancestral karyotype. In this project, we used comparative chromosome painting to determine how widely this synteny is conserved across nine families covering most of the main lineages of Squamata. The results suggest that the association of the avian ancestral chromosomes 3, 5 and 7 can be dated back to at least the early Jurassic and could be an ancestral characteristic for Unidentata (Serpentes, Iguania, Anguimorpha, Laterata and Scinciformata). In Squamata chromosome conservatism therefore also holds for the parts of the genome which are homologous to bird autosomes, and following on from this, a slow rate of chromosomal evolution could be a common characteristic of all sauropsids. The large evolutionary stasis in chromosome organization in birds therefore seems to be inherited from their ancestors, and it is particularly striking in comparison with mammals, probably the only major tetrapod lineage with an increased rate of chromosomal rearrangements as a whole.

  9. Recruiting a microtubule-binding complex to DNA directs chromosome segregation in budding yeast

    OpenAIRE

    Murray, Andrew W.; Lacefield, Soni; Lau, Tsz Cham Derek

    2009-01-01

    Accurate chromosome segregation depends on the kinetochore, the complex of proteins that link microtubules to centromeric DNA1. The budding yeast kinetochore consists of more than 80 proteins assembled on a 125bp region of DNA1. We studied the assembly and function of kinetochore components by fusing individual kinetochore proteins to the lactose repressor (LacI) and testing their ability to improve the segregation of a plasmid carrying tandem repeats of the lactose operator (LacO). Targeting...

  10. Structure of metaphase chromosomes: a role for effects of macromolecular crowding.

    Directory of Open Access Journals (Sweden)

    Ronald Hancock

    Full Text Available In metaphase chromosomes, chromatin is compacted to a concentration of several hundred mg/ml by mechanisms which remain elusive. Effects mediated by the ionic environment are considered most frequently because mono- and di-valent cations cause polynucleosome chains to form compact ~30-nm diameter fibres in vitro, but this conformation is not detected in chromosomes in situ. A further unconsidered factor is predicted to influence the compaction of chromosomes, namely the forces which arise from crowding by macromolecules in the surrounding cytoplasm whose measured concentration is 100-200 mg/ml. To mimic these conditions, chromosomes were released from mitotic CHO cells in solutions containing an inert volume-occupying macromolecule (8 kDa polyethylene glycol, 10.5 kDa dextran, or 70 kDa Ficoll in 100 µM K-Hepes buffer, with contaminating cations at only low micromolar concentrations. Optical and electron microscopy showed that these chromosomes conserved their characteristic structure and compaction, and their volume varied inversely with the concentration of a crowding macromolecule. They showed a canonical nucleosomal structure and contained the characteristic proteins topoisomerase IIα and the condensin subunit SMC2. These observations, together with evidence that the cytoplasm is crowded in vivo, suggest that macromolecular crowding effects should be considered a significant and perhaps major factor in compacting chromosomes. This model may explain why ~30-nm fibres characteristic of cation-mediated compaction are not seen in chromosomes in situ. Considering that crowding by cytoplasmic macromolecules maintains the compaction of bacterial chromosomes and has been proposed to form the liquid crystalline chromosomes of dinoflagellates, a crowded environment may be an essential characteristic of all genomes.

  11. Structure of metaphase chromosomes: a role for effects of macromolecular crowding.

    Science.gov (United States)

    Hancock, Ronald

    2012-01-01

    In metaphase chromosomes, chromatin is compacted to a concentration of several hundred mg/ml by mechanisms which remain elusive. Effects mediated by the ionic environment are considered most frequently because mono- and di-valent cations cause polynucleosome chains to form compact ~30-nm diameter fibres in vitro, but this conformation is not detected in chromosomes in situ. A further unconsidered factor is predicted to influence the compaction of chromosomes, namely the forces which arise from crowding by macromolecules in the surrounding cytoplasm whose measured concentration is 100-200 mg/ml. To mimic these conditions, chromosomes were released from mitotic CHO cells in solutions containing an inert volume-occupying macromolecule (8 kDa polyethylene glycol, 10.5 kDa dextran, or 70 kDa Ficoll) in 100 µM K-Hepes buffer, with contaminating cations at only low micromolar concentrations. Optical and electron microscopy showed that these chromosomes conserved their characteristic structure and compaction, and their volume varied inversely with the concentration of a crowding macromolecule. They showed a canonical nucleosomal structure and contained the characteristic proteins topoisomerase IIα and the condensin subunit SMC2. These observations, together with evidence that the cytoplasm is crowded in vivo, suggest that macromolecular crowding effects should be considered a significant and perhaps major factor in compacting chromosomes. This model may explain why ~30-nm fibres characteristic of cation-mediated compaction are not seen in chromosomes in situ. Considering that crowding by cytoplasmic macromolecules maintains the compaction of bacterial chromosomes and has been proposed to form the liquid crystalline chromosomes of dinoflagellates, a crowded environment may be an essential characteristic of all genomes.

  12. The CENP-A NAC/CAD kinetochore complex controls chromosome congression and spindle bipolarity.

    Science.gov (United States)

    McClelland, Sarah E; Borusu, Satyarebala; Amaro, Ana C; Winter, Jennifer R; Belwal, Mukta; McAinsh, Andrew D; Meraldi, Patrick

    2007-12-12

    Kinetochores are complex protein machines that link chromosomes to spindle microtubules and contain a structural core composed of two conserved protein-protein interaction networks: the well-characterized KMN (KNL1/MIND/NDC80) and the recently identified CENP-A NAC/CAD. Here we show that the CENP-A NAC/CAD subunits can be assigned to one of two different functional classes; depletion of Class I proteins (Mcm21R(CENP-O) and Fta1R(CENP-L)) causes a failure in bipolar spindle assembly. In contrast, depletion of Class II proteins (CENP-H, Chl4R(CENP-N), CENP-I and Sim4R(CENP-K)) prevents binding of Class I proteins and causes chromosome congression defects, but does not perturb spindle formation. Co-depletion of Class I and Class II proteins restores spindle bipolarity, suggesting that Class I proteins regulate or counteract the function of Class II proteins. We also demonstrate that CENP-A NAC/CAD and KMN regulate kinetochore-microtubule attachments independently, even though CENP-A NAC/CAD can modulate NDC80 levels at kinetochores. Based on our results, we propose that the cooperative action of CENP-A NAC/CAD subunits and the KMN network drives efficient chromosome segregation and bipolar spindle assembly during mitosis.

  13. Chromosomal painting and ZW sex chromosomes differentiation in Characidium (Characiformes, Crenuchidae

    Directory of Open Access Journals (Sweden)

    Artoni Roberto F

    2011-07-01

    Full Text Available Abstract Background The Characidium (a Neotropical fish group have a conserved diploid number (2n = 50, but show remarkable differences among species and populations in relation to sex chromosome systems and location of nucleolus organizer regions (NOR. In this study, we isolated a W-specific probe for the Characidium and characterized six Characidium species/populations using cytogenetic procedures. We analyzed the origin and differentiation of sex and NOR-bearing chromosomes by chromosome painting in populations of Characidium to reveal their evolution, phylogeny, and biogeography. Results A W-specific probe for efficient chromosome painting was isolated by microdissection and degenerate oligonucleotide primed-polymerase chain reaction (DOP-PCR amplification of W chromosomes from C. gomesi. The W probe generated weak signals dispersed on the proto sex chromosomes in C. zebra, dispersed signals in both W and Z chromosomes in C. lauroi and, in C. gomesi populations revealed a proximal site on the long arms of the Z chromosome and the entire W chromosome. All populations showed small terminal W probe sites in some autosomes. The 18S rDNA revealed distinctive patterns for each analyzed species/population with regard to proto sex chromosome, sex chromosome pair, and autosome location. Conclusions The results from dual-color fluorescence in situ hybridization (dual-color FISH using W and 18S rDNA probes allowed us to infer the putative evolutionary pathways for the differentiation of sex chromosomes and NORs, from structural rearrangements in a sex proto-chromosome, followed by gene erosion and heterochromatin amplification, morphological differentiation of the sex chromosomal pair, and NOR transposition, giving rise to the distinctive patterns observed among species/populations of Characidium. Biogeographic isolation and differentiation of sex chromosomes seem to have played a major role in the speciation process in this group of fish.

  14. Identification of the nuclear matrix and chromosome scaffold in dinoflagellate Crypthecodinium cohnii

    Institute of Scientific and Technical Information of China (English)

    CAISHUTAO; CONGMEIZENG; 等

    1992-01-01

    Dinolflagellate is one of the primitive eukaryotes,whose nucleus may represent one of the transition stages from prokaryotic nucleoid to typical eukaryotic nucleus,Using selective extraction together with embeddment-free section and whole mount electron microscopy,a delicate nuclear matrix filament network was shown,for the first time,in dinoflagellate Crypthecodinium cohnii nucleus,Chromosome residues are connected with nuclear matrix filaments to form a complete network spreading over the nucleus,Moreover,we demonstrated that the dinoflagellate chromosome retains a protein scafflod after the depletion of DNA and soluble proteins.This scaffold preserves the characterstic morphology of the chromosome.Two dimensional electrophoreses indicated that the nuclear matrix and chromosome scaffold are mainly composed of acidic proteins.Our results demonstrated that a framework similar th the nuclear matrix and chromosome scaffold in mammalian cells appears in this primitive eukaryote,suggesting that these structures may have been originated from the early stages of eukaryote evolution.

  15. Spindle formation, chromosome segregation and the spindle checkpoint in mammalian oocytes and susceptibility to meiotic error.

    Science.gov (United States)

    Vogt, E; Kirsch-Volders, M; Parry, J; Eichenlaub-Ritter, U

    2008-03-12

    The spindle assembly checkpoint (SAC) monitors attachment to microtubules and tension on chromosomes in mitosis and meiosis. It represents a surveillance mechanism that halts cells in M-phase in the presence of unattached chromosomes, associated with accumulation of checkpoint components, in particular, Mad2, at the kinetochores. A complex between the anaphase promoting factor/cylosome (APC/C), its accessory protein Cdc20 and proteins of the SAC renders APC/C inactive, usually until all chromosomes are properly assembled at the spindle equator (chromosome congression) and under tension from spindle fibres. Upon release from the SAC the APC/C can target proteins like cyclin B and securin for degradation by the proteasome. Securin degradation causes activation of separase proteolytic enzyme, and in mitosis cleavage of cohesin proteins at the centromeres and arms of sister chromatids. In meiosis I only the cohesin proteins at the sister chromatid arms are cleaved. This requires meiosis specific components and tight regulation by kinase and phosphatase activities. There is no S-phase between meiotic divisions. Second meiosis resembles mitosis. Mammalian oocytes arrest constitutively at metaphase II in presence of aligned chromosomes, which is due to the activity of the cytostatic factor (CSF). The SAC has been identified in spermatogenesis and oogenesis, but gender-differences may contribute to sex-specific differential responses to aneugens. The age-related reduction in expression of components of the SAC in mammalian oocytes may act synergistically with spindle and other cell organelles' dysfunction, and a partial loss of cohesion between sister chromatids to predispose oocytes to errors in chromosome segregation. This might affect dose-response to aneugens. In view of the tendency to have children at advanced maternal ages it appears relevant to pursue studies on consequences of ageing on the susceptibility of human oocytes to the induction of meiotic error by

  16. Chromosome mapping of dragline silk genes in the genomes of widow spiders (Araneae, Theridiidae.

    Directory of Open Access Journals (Sweden)

    Yonghui Zhao

    Full Text Available With its incredible strength and toughness, spider dragline silk is widely lauded for its impressive material properties. Dragline silk is composed of two structural proteins, MaSp1 and MaSp2, which are encoded by members of the spidroin gene family. While previous studies have characterized the genes that encode the constituent proteins of spider silks, nothing is known about the physical location of these genes. We determined karyotypes and sex chromosome organization for the widow spiders, Latrodectus hesperus and L. geometricus (Araneae, Theridiidae. We then used fluorescence in situ hybridization to map the genomic locations of the genes for the silk proteins that compose the remarkable spider dragline. These genes included three loci for the MaSp1 protein and the single locus for the MaSp2 protein. In addition, we mapped a MaSp1 pseudogene. All the MaSp1 gene copies and pseudogene localized to a single chromosomal region while MaSp2 was located on a different chromosome of L. hesperus. Using probes derived from L. hesperus, we comparatively mapped all three MaSp1 loci to a single region of a L. geometricus chromosome. As with L. hesperus, MaSp2 was found on a separate L. geometricus chromosome, thus again unlinked to the MaSp1 loci. These results indicate orthology of the corresponding chromosomal regions in the two widow genomes. Moreover, the occurrence of multiple MaSp1 loci in a conserved gene cluster across species suggests that MaSp1 proliferated by tandem duplication in a common ancestor of L. geometricus and L. hesperus. Unequal crossover events during recombination could have given rise to the gene copies and could also maintain sequence similarity among gene copies over time. Further comparative mapping with taxa of increasing divergence from Latrodectus will pinpoint when the MaSp1 duplication events occurred and the phylogenetic distribution of silk gene linkage patterns.

  17. Inheritance of a ring 14 chromosome.

    Science.gov (United States)

    Riley, S B; Buckton, K E; Ratcliffe, S G; Syme, J

    1981-06-01

    A family is described in which the mother, her two live offspring, and a therapeutically aborted fetus each had a ring 14 chromosomes. The two children were mentally retarded and the mother's intelligence was at the lower end of the normal range. In addition, the mother had two spontaneous abortions, one of which was shown to be chromosomally normal.

  18. Inheritance of a ring 14 chromosome.

    OpenAIRE

    Riley, S B; Buckton, K E; Ratcliffe, S G; Syme, J.

    1981-01-01

    A family is described in which the mother, her two live offspring, and a therapeutically aborted fetus each had a ring 14 chromosomes. The two children were mentally retarded and the mother's intelligence was at the lower end of the normal range. In addition, the mother had two spontaneous abortions, one of which was shown to be chromosomally normal.

  19. Human male meiotic sex chromosome inactivation

    NARCIS (Netherlands)

    Vries, M. de; Vosters, S.; Merkx, G.F.M.; Hauwers, K.W.M. d'; Wansink, D.G.; Ramos, L.; Boer, P. de

    2012-01-01

    In mammalian male gametogenesis the sex chromosomes are distinctive in both gene activity and epigenetic strategy. At first meiotic prophase the heteromorphic X and Y chromosomes are placed in a separate chromatin domain called the XY body. In this process, X,Y chromatin becomes highly phosphorylate

  20. Dynamics of chromosome segregation in Escherichia coli

    DEFF Research Database (Denmark)

    Nielsen, Henrik Jørck

    2007-01-01

    Since the 1960’es the conformation and segregation of the chromosome in Escherichia coli has been a subject of interest for many scientists. However, after 40 years of research, we still know incredibly little about how the chromosome is organized inside the cell, how it manages to duplicate...

  1. Chromosome condensation: weaving an untangled web.

    Science.gov (United States)

    Thadani, Rahul; Uhlmann, Frank

    2015-08-03

    The compaction of diffuse interphase chromatin into stable mitotic chromosomes enables the segregation of replicated DNA to daughter cells. Two new studies characterise, both in vivo and in vitro, the essential contribution of the vertebrate condensin complex to chromosome organisation.

  2. Chromosomal Aneuploidies and Early Embryonic Developmental Arrest

    Directory of Open Access Journals (Sweden)

    Maria Maurer

    2015-07-01

    Full Text Available Background: Selecting the best embryo for transfer, with the highest chance of achieving a vital pregnancy, is a major goal in current in vitro fertilization (IVF technology. The high rate of embryonic developmental arrest during IVF treatment is one of the limitations in achieving this goal. Chromosomal abnormalities are possibly linked with chromosomal arrest and selection against abnormal fertilization products. The objective of this study was to evaluate the frequency and type of chromosomal abnormalities in preimplantation embryos with developmental arrest. Materials and Methods: This cohort study included blastomeres of embryos with early developmental arrest that were biopsied and analyzed by fluorescence in-situ hybridization (FISH with probes for chromosomes 13, 16, 18, 21 and 22. Forty-five couples undergoing IVF treatment were included, and 119 arrested embryos were biopsied. All probes were obtained from the Kinderwunsch Zentrum, Linz, Austria, between August 2009 and August 2011. Results: Of these embryos, 31.6% were normal for all chromosomes tested, and 68.4% were abnormal. Eleven embryos were uniformly aneuploid, 20 were polyploid, 3 were haploid, 11 displayed mosaicism and 22 embryos exhibited chaotic chromosomal complement. Conclusion: Nearly 70% of arrested embryos exhibit chromosomal errors, making chromosomal abnormalities a major cause of embryonic arrest and may be a further explanation for the high developmental failure rates during culture of the embryos in the IVF setting.

  3. Genomic Dark Matter Illuminated: Anopheles Y Chromosomes.

    Science.gov (United States)

    Redmond, Seth N; Neafsey, Daniel E

    2016-08-01

    Hall et al. have strategically used long-read sequencing technology to characterize the structure and highly repetitive content of the Y chromosome in Anopheles malaria mosquitoes. Their work confirms that this important but elusive heterochromatic sex chromosome is evolving extremely rapidly and harbors a remarkably small number of genes.

  4. Non-disjunction of chromosome 13

    DEFF Research Database (Denmark)

    Bugge, Merete; Collins, Andrew; Hertz, Jens Michael

    2007-01-01

    recombination in both maternal MI and MII errors and the former is associated with a significant number of tetrads (33%) that are nullichiasmate, which do not appear to be a feature of normal chromosome 13 meiosis. This study supports the evidence for subtle chromosome-specific influences on the mechanisms...

  5. Paradigm Lost: The Human Chromosome Story.

    Science.gov (United States)

    Unger, Lawrence; Blystone, Robert V.

    1996-01-01

    Discusses whether the discovery in 1956 that humans have a chromosome number of 46, as opposed to 47 or 48 as previously thought, fits into a paradigm shift of the Kuhnian type. Concludes that Kuhn probably would not have considered the chromosome number shift to be large enough to be a focus for one of his paradigms. (AIM)

  6. Chromosome Segregation: Organizing Overlap at the Midzone

    NARCIS (Netherlands)

    Janson, M.E.; Tran, P.T.

    2008-01-01

    Sets of overlapping microtubules support the segregation of chromosomes by linking the poles of mitotic spindles. Recent work examines the effect of putting these linkages under pressure by the activation of dicentric chromosomes and sheds new light on the structural role of several well-known spind

  7. DETECTION OF CHROMOSOME ABERRATIONS IN TWELVE PRIMARY GASTRIC CANCERS BY DIRECT CHROMOSOME ANALYSIS AND FISH

    Institute of Scientific and Technical Information of China (English)

    1999-01-01

    Direct chromosome analysis and FISH were performed on twelve primary gastric carcinomas. Two of them had simple chromosome changes: 48,XX, +8, +20, and 49, XY, +2, +8, +9, and the others had complicated chromosome changes, which includes much more numerical and structural chromosome aberrations. Frequent structural changes in the complicated types involved chromosome 7, 3, 1, 5 and 12 etc. The del 7q was noted in eight cases. The del (3p) and del (1p) were noted in six and five cases, respectively. The results provide some important clues for isolation of the genes related to gastric cancer.

  8. Small supernumerary marker chromosomes (sSMC) in humans; are there B chromosomes hidden among them

    OpenAIRE

    Ogilvie Caroline; Kosyakova Nadezda; Mrasek Kristin; Liehr Thomas; Vermeesch Joris; Trifonov Vladimir; Rubtsov Nikolai

    2008-01-01

    Abstract Background Small supernumerary marker chromosomes (sSMC) and B-chromosomes represent a heterogeneous collection of chromosomes added to the typical karyotype, and which are both small in size. They may consist of heterochromatic and/or euchromatic material. Also a predominance of maternal transmission was reported for both groups. Even though sSMC and B-chromosomes show some similarity it is still an open question if B-chromosomes are present among the heterogeneous group of sSMC. Ac...

  9. Temporal genomic evolution of bird sex chromosomes

    DEFF Research Database (Denmark)

    Wang, Zongji; Zhang, Jilin; Yang, Wei;

    2014-01-01

    BACKGROUND: Sex chromosomes exhibit many unusual patterns in sequence and gene expression relative to autosomes. Birds have evolved a female heterogametic sex system (male ZZ, female ZW), through stepwise suppression of recombination between chrZ and chrW. To address the broad patterns and complex...... driving forces of Z chromosome evolution, we analyze here 45 newly available bird genomes and four species' transcriptomes, over their course of recombination loss between the sex chromosomes. RESULTS: We show Z chromosomes in general have a significantly higher substitution rate in introns and synonymous...... ('fast-Z' evolution). And species with a lower level of intronic heterozygosities tend to evolve even faster on the Z chromosome. Further analysis of fast-evolving genes' enriched functional categories and sex-biased expression patterns support that, fast-Z evolution in birds is mainly driven by genetic...

  10. Advances in understanding paternally transmitted Chromosomal Abnormalities

    Energy Technology Data Exchange (ETDEWEB)

    Marchetti, F; Sloter, E; Wyrobek, A J

    2001-03-01

    Multicolor FISH has been adapted for detecting the major types of chromosomal abnormalities in human sperm including aneuploidies for clinically-relevant chromosomes, chromosomal aberrations including breaks and rearrangements, and other numerical abnormalities. The various sperm FISH assays have been used to evaluate healthy men, men of advanced age, and men who have received mutagenic cancer therapy. The mouse has also been used as a model to investigate the mechanism of paternally transmitted genetic damage. Sperm FISH for the mouse has been used to detect chromosomally abnormal mouse sperm, while the PAINT/DAPI analysis of mouse zygotes has been used to evaluate the types of chromosomal defects that can be paternally transmitted to the embryo and their effects on embryonic development.

  11. Temporal genomic evolution of bird sex chromosomes

    DEFF Research Database (Denmark)

    Wang, Zongji; Zhang, Jilin; Yang, Wei;

    2014-01-01

    BACKGROUND: Sex chromosomes exhibit many unusual patterns in sequence and gene expression relative to autosomes. Birds have evolved a female heterogametic sex system (male ZZ, female ZW), through stepwise suppression of recombination between chrZ and chrW. To address the broad patterns and complex...... driving forces of Z chromosome evolution, we analyze here 45 newly available bird genomes and four species' transcriptomes, over their course of recombination loss between the sex chromosomes. RESULTS: We show Z chromosomes in general have a significantly higher substitution rate in introns and synonymous...... changes with that of introns, between chrZ and autosomes or regions with increasing ages of becoming Z-linked, therefore codon usage bias in birds is probably driven by the mutational bias. On the other hand, Z chromosomes also evolve significantly faster at nonsynonymous sites relative to autosomes...

  12. Review of the Y chromosome and hypertension

    Directory of Open Access Journals (Sweden)

    D. Ely

    2000-06-01

    Full Text Available The Y chromosome from spontaneously hypertensive rats (SHR has a locus that raises blood pressure 20-25 mmHg. Associated with the SHR Y chromosome effect is a 4-week earlier pubertal rise of testosterone and dependence upon the androgen receptor for the full blood pressure effect. Several indices of enhanced sympathetic nervous system (SNS activity are also associated with the SHR Y chromosome. Blockade of SNS outflow reduced the blood pressure effect. Salt sensitivity was increased by the Y chromosome as was salt appetite which was SNS dependent. A strong correlation (r = 0.57, P<0.001 was demonstrable between plasma testosterone and angiotensin II. Coronary collagen increased with blood pressure and the presence of the SHR Y chromosome. A promising candidate gene for the Y effect is the Sry locus (testis determining factor, a transcription factor which may also have other functions.

  13. Unusual maternal uniparental isodisomic x chromosome mosaicism with asymmetric y chromosomal rearrangement.

    Science.gov (United States)

    Lee, B Y; Kim, S Y; Park, J Y; Choi, E Y; Kim, D J; Kim, J W; Ryu, H M; Cho, Y H; Park, S Y; Seo, J T

    2014-01-01

    Infertile men with azoospermia commonly have associated microdeletions in the azoospermia factor (AZF) region of the Y chromosome, sex chromosome mosaicism, or sex chromosome rearrangements. In this study, we describe an unusual 46,XX and 45,X mosaicism with a rare Y chromosome rearrangement in a phenotypically normal male patient. The patient's karyotype was 46,XX[50]/45,X[25]/46,X,der(Y)(pter→q11.222::p11.2→pter)[25]. The derivative Y chromosome had a deletion at Yq11.222 and was duplicated at Yp11.2. Two copies of the SRY gene were confirmed by fluorescence in situ hybridization analysis, and complete deletion of the AZFb and AZFc regions was shown by multiplex-PCR for microdeletion analysis. Both X chromosomes of the predominant mosaic cell line (46,XX) were isodisomic and derived from the maternal gamete, as determined by examination of short tandem repeat markers. We postulate that the derivative Y chromosome might have been generated during paternal meiosis or early embryogenesis. Also, we suggest that the very rare mosaicism of isodisomic X chromosomes might be formed during maternal meiosis II or during postzygotic division derived from the 46,X,der(Y)/ 45,X lineage because of the instability of the derivative Y chromosome. To our knowledge, this is the first confirmatory study to verify the origin of a sex chromosome mosaicism with a Y chromosome rearrangement.

  14. Comparative analysis by chromosome painting of the sex chromosomes in arvicolid rodents.

    Science.gov (United States)

    Acosta, M J; Romero-Fernández, I; Sánchez, A; Marchal, J A

    2011-01-01

    Sex chromosome evolution in mammals has been extensively investigated through chromosome-painting analyses. In some rodent species from the subfamily Arvicolinae the sex chromosomes contain remarkable features such as giant size, a consequence of heterochromatic enlargement, or asynaptic behaviour during male meiosis. Here, we have made a comparative study of the sex chromosomes in 6 arvicolid species using different probes from the X and Y chromosomes of 3 species, in order to gain knowledge about intra- or interspecific preservation of euchromatic regions. Our results clearly reveal poor conservation of the euchromatic region of the Y chromosome within these species, while the euchromatin on the X chromosome is extremely well preserved. Furthermore, we detected no clear correlation between the synaptic/asynaptic behaviour of the sex chromosomes, and the presence or absence of sequence homology within their euchromatic regions. Notably, our study has shown a new relationship between the giant sex chromosomes of 2 species, Microtus agrestis and Microtus cabrerae, that is, both X and Y share a novel region of common sequences in the euchromatin that is not present in the other species analysed. This interspecific euchromatic conservation, limited to the giant sex chromosomes, could point towards a common evolutionary origin for the heterochromatic enlargement process that has characterized the evolution of the sex chromosomes in some arvicolid species.

  15. Energy Landscapes of Folding Chromosomes

    Science.gov (United States)

    Zhang, Bin

    The genome, the blueprint of life, contains nearly all the information needed to build and maintain an entire organism. A comprehensive understanding of the genome is of paramount interest to human health and will advance progress in many areas, including life sciences, medicine, and biotechnology. The overarching goal of my research is to understand the structure-dynamics-function relationships of the human genome. In this talk, I will be presenting our efforts in moving towards that goal, with a particular emphasis on studying the three-dimensional organization, the structure of the genome with multi-scale approaches. Specifically, I will discuss the reconstruction of genome structures at both interphase and metaphase by making use of data from chromosome conformation capture experiments. Computationally modeling of chromatin fiber at atomistic level from first principles will also be presented as our effort for studying the genome structure from bottom up.

  16. New Y chromosomes and early stages of sex chromosome differentiation: sex determination in Megaselia

    Indian Academy of Sciences (India)

    Walther Traut

    2010-09-01

    The phorid fly Megaselia scalaris is a laboratory model for the turnover and early differentiation of sex chromosomes. Isolates from the field have an XY sex-determining mechanism with chromosome pair 2 acting as X and Y chromosomes. The sex chromosomes are homomorphic but display early signs of sex chromosome differentiation: a low level of molecular differences between X and Y. The male-determining function $(M)$, maps to the distal part of the Y chromosome’s short arm. In laboratory cultures, new Y chromosomes with no signs of a molecular differentiation arise at a low rate, probably by transposition of to these chromosomes. Downstream of the primary signal, the homologue of the Drosophila doublesex (dsx) is part of the sex-determining pathway while Sex-lethal (Sxl), though structurally conserved, is not.

  17. Novel gene acquisition on carnivore Y chromosomes.

    Directory of Open Access Journals (Sweden)

    William J Murphy

    2006-03-01

    Full Text Available Despite its importance in harboring genes critical for spermatogenesis and male-specific functions, the Y chromosome has been largely excluded as a priority in recent mammalian genome sequencing projects. Only the human and chimpanzee Y chromosomes have been well characterized at the sequence level. This is primarily due to the presumed low overall gene content and highly repetitive nature of the Y chromosome and the ensuing difficulties using a shotgun sequence approach for assembly. Here we used direct cDNA selection to isolate and evaluate the extent of novel Y chromosome gene acquisition in the genome of the domestic cat, a species from a different mammalian superorder than human, chimpanzee, and mouse (currently being sequenced. We discovered four novel Y chromosome genes that do not have functional copies in the finished human male-specific region of the Y or on other mammalian Y chromosomes explored thus far. Two genes are derived from putative autosomal progenitors, and the other two have X chromosome homologs from different evolutionary strata. All four genes were shown to be multicopy and expressed predominantly or exclusively in testes, suggesting that their duplication and specialization for testis function were selected for because they enhance spermatogenesis. Two of these genes have testis-expressed, Y-borne copies in the dog genome as well. The absence of the four newly described genes on other characterized mammalian Y chromosomes demonstrates the gene novelty on this chromosome between mammalian orders, suggesting it harbors many lineage-specific genes that may go undetected by traditional comparative genomic approaches. Specific plans to identify the male-specific genes encoded in the Y chromosome of mammals should be a priority.

  18. The X chromosome and immune associated genes.

    Science.gov (United States)

    Bianchi, Ilaria; Lleo, Ana; Gershwin, M Eric; Invernizzi, Pietro

    2012-05-01

    The X chromosome is known to contain the largest number of immune-related genes of the whole human genome. For this reason, X chromosome has recently become subject of great interest and attention and numerous studies have been aimed at understanding the role of genes on the X chromosome in triggering and maintaining the autoimmune aggression. Autoimmune diseases are indeed a growing heath burden affecting cumulatively up to 10% of the general population. It is intriguing that most X-linked primary immune deficiencies carry significant autoimmune manifestations, thus illustrating the critical role played by products of single gene located on the X chromosome in the onset, function and homeostasis of the immune system. Again, the plethora of autoimmune stigmata observed in patients with Turner syndrome, a disease due to the lack of one X chromosome or the presence of major X chromosome deletions, indicate that X-linked genes play a unique and major role in autoimmunity. There have been several reports on a role of X chromosome gene dosage through inactivation or duplication in women with autoimmune diseases, for example through a higher rate of circulating cells with a single X chromosome (i.e. with X monosomy). Finally, a challenge for researchers in the coming years will be to dissect the role for the large number of X-linked microRNAs from the perspective of autoimmune disease development. Taken together, X chromosome might well constitute the common trait of the susceptibility to autoimmune diseases, other than to explain the female preponderance of these conditions. This review will focus on the available evidence on X chromosome changes and discuss their potential implications and limitations.

  19. Bridging Chromosomal Architecture and Pathophysiology of Streptococcus pneumoniae

    Science.gov (United States)

    Ferrándiz, María J.; de la Campa, Adela G.

    2017-01-01

    The chromosome of Streptococcus pneumoniae is organized into topological domains based on its transcriptional response to DNA relaxation: Up-regulated (UP), down-regulated (DOWN), nonregulated (NR), and AT-rich. In the present work, NR genes found to have highly conserved chromosomal locations (17% of the genome) were categorized as members of position-conserved nonregulated (pcNR) domains, while NR genes with a variable position (36% of the genome) were classified as members of position-variable nonregulated (pvNR) domains. On average, pcNR domains showed high transcription rates, optimized codon usage, and were found to contain only a small number of RUP/BOX/SPLICE repeats. They were also poor in exogenous genes but enriched in leading strand genes that code for proteins involved in primary metabolism with central roles within the interactome. In contrast, pvNR genes coding for cell wall proteins, paralogs, virulence factors and immunogenic candidates for protein-based vaccines were found to be overrepresented. DOWN domains were enriched in genes essential for infection. Many UP and DOWN domain genes were seen to be activated during different stages of competence, whereas pcNR genes tended to be repressed until the competence was switched off. Pneumococcal genes appear to be subject to a topology-driven selection pressure that defines the chromosomal location of genes involved in metabolism, virulence and competence. The pcNR domains are interleaved between UP and DOWN domains according to a pattern that suggests the existence of macrodomain entities. The term “topogenomics” is here proposed to describe the study of the topological rules of genomes and their relationship with physiology. PMID:28158485

  20. Spare PRELI gene loci: failsafe chromosome insurance?

    Directory of Open Access Journals (Sweden)

    Wenbin Ma

    Full Text Available BACKGROUND: LEA (late embryogenesis abundant proteins encode conserved N-terminal mitochondrial signal domains and C-terminal (A/TAEKAK motif repeats, long-presumed to confer cell resistance to stress and death cues. This prompted the hypothesis that LEA proteins are central to mitochondria mechanisms that connect bioenergetics with cell responses to stress and death signaling. In support of this hypothesis, recent studies have demonstrated that mammalian LEA protein PRELI can act as a biochemical hub, which upholds mitochondria energy metabolism, while concomitantly promoting B cell resistance to stress and induced death. Hence, it is important to define in vivo the physiological relevance of PRELI expression. METHODS AND FINDINGS: Given the ubiquitous PRELI expression during mouse development, embryo lethality could be anticipated. Thus, conditional gene targeting was engineered by insertion of flanking loxP (flox/Cre recognition sites on PRELI chromosome 13 (Chr 13 locus to abort its expression in a tissue-specific manner. After obtaining mouse lines with homozygous PRELI floxed alleles (PRELI(f/f, the animals were crossed with CD19-driven Cre-recombinase transgenic mice to investigate whether PRELI inactivation could affect B-lymphocyte physiology and survival. Mice with homozygous B cell-specific PRELI deletion (CD19-Cre/Chr13 PRELI(-/- bred normally and did not show any signs of morbidity. Histopathology and flow cytometry analyses revealed that cell lineage identity, morphology, and viability were indistinguishable between wild type CD19-Cre/Chr13 PRELI(+/+ and CD19-Cre/Chr13 PRELI(-/- deficient mice. Furthermore, B cell PRELI gene expression seemed unaffected by Chr13 PRELI gene targeting. However, identification of additional PRELI loci in mouse Chr1 and Chr5 provided an explanation for the paradox between LEA-dependent cytoprotection and the seemingly futile consequences of Chr 13 PRELI gene inactivation. Importantly, PRELI expression

  1. Structural and physical aspects of bacterial chromosome segregation.

    Science.gov (United States)

    Woldringh, Conrad L; Nanninga, Nanne

    2006-11-01

    Microscopic observations on the bacterial nucleoid suggest that the chromosome occurs in the cell as a compact nucleoid phase separate from the cytoplasm. Physical theory likewise predicts a phase separation, taking into consideration DNA supercoiling, nucleoid-binding proteins, and excluded-volume interactions between DNA and cytoplasmic proteins. Specific DNA loci, visualized as oriC-GFP spots in the densely packed nucleoid, exhibit a very low diffusion coefficient indicating that they are virtually immobile and may primarily be moved by overall length growth. Such gradual movement could be effectuated by replication, transertion (combined transcription, translation, and insertion of proteins), and actin- (MreB) directed surface synthesis. Differences in the movement and positioning of gene loci between Escherichia coli and Caulobacter crescentus are discussed. We propose that a low diffusion coefficient could explain the linear positioning of genes in the nucleoid and that differential transcriptional activity could induce different mobilities between either replichores (E. coli) or daughter strands (C. crescentus). The transertion process, possibly in combination with MreB cytoskeletal tracks, could overcome the compaction forces and move specific chromosomal regions and the nucleoid as a whole without invoking a dedicated mechanism.

  2. The bacterial chromosome: architecture and action of bacterial SMC and SMC-like complexes.

    Science.gov (United States)

    Nolivos, Sophie; Sherratt, David

    2014-05-01

    Structural Maintenance of Chromosomes (SMC) protein complexes are found in all three domains of life. They are characterized by a distinctive and conserved architecture in which a globular ATPase 'head' domain is formed by the N- and C-terminal regions of the SMC protein coming together, with a c. 50-nm-long antiparallel coiled-coil separating the head from a dimerization 'hinge'. Dimerization gives both V- and O-shaped SMC dimers. The distinctive architecture points to a conserved biochemical mechanism of action. However, the details of this mechanism are incomplete, and the precise ways in which this mechanism leads to the biological functions of these complexes in chromosome organization and processing remain unclear. In this review, we introduce the properties of bacterial SMC complexes, compare them with eukaryotic complexes and discuss how their likely biochemical action relates to their roles in chromosome organization and segregation.

  3. Chromosome 13 dementia syndromes as models of neurodegeneration

    DEFF Research Database (Denmark)

    Ghiso, J.; Revesz, T.; Holton, J.;

    2001-01-01

    Two hereditary conditions, familial British dementia (FBD) and familial Danish dementia (FDD), are associated with amyloid deposition in the central nervous system and neurodegeneration. The two amyloid proteins, ABri and ADan, are degradation products of the same precursor molecule BriPP bearing....... These issues argue for the primary importance of the amyloid deposits in the mechanism(s) of neuronal cell loss. We propose FBD and FDD, the chromosome 13 dementia syndromes, as models to study the molecular basis of neurofibrillary degeneration, cell death and amyloid formation in the brain....

  4. Structure and chromosomal localization of the human thrombospondin gene.

    Science.gov (United States)

    Wolf, F W; Eddy, R L; Shows, T B; Dixit, V M

    1990-04-01

    Thrombospondin (THBS1) is a large modular glycoprotein component of the extracellular matrix and contains a variety of distinct domains, including three repeating subunits (types I, II, and III) that share homology to an assortment of other proteins. Determination of THBS1 gene structure has revealed that the type I repeat modules are encoded by symmetrical exons and that the heparin-binding domain is encoded by a single exon. To further elucidate the higher level organization of THBS1, the gene was localized to the q11-qter region of chromosome 15.

  5. Can corruption of chromosome cohesion create a conduit to cancer?

    Science.gov (United States)

    Xu, Huiling; Tomaszewski, Jonathan M; McKay, Michael J

    2011-03-01

    Cohesin is a conserved multisubunit protein complex with diverse cellular roles, making key contributions to the coordination of chromosome segregation, the DNA damage response and chromatin regulation by epigenetic mechanisms. Much has been learned in recent years about the roles of cohesin in a physiological context, whereas its potential and emerging role in tumour initiation and/or progression has received relatively little attention. In this Opinion article we examine how cohesin deregulation could contribute to cancer development on the basis of its physiological roles.

  6. Interphase Chromosome Conformation and Chromatin-Chromatin Interactions in Human Epithelial Cells Cultured Under Different Gravity Conditions

    Science.gov (United States)

    Zhang, Ye; Wong, Michael; Hada, Megumi; Wu, Honglu

    2015-01-01

    Microgravity has been shown to alter global gene expression patterns and protein levels both in cultured cells and animal models. It has been suggested that the packaging of chromatin fibers in the interphase nucleus is closely related to genome function, and the changes in transcriptional activity are tightly correlated with changes in chromatin folding. This study explores the changes of chromatin conformation and chromatin-chromatin interactions in the simulated microgravity environment, and investigates their correlation to the expression of genes located at different regions of the chromosome. To investigate the folding of chromatin in interphase under various culture conditions, human epithelial cells, fibroblasts, and lymphocytes were fixed in the G1 phase. Interphase chromosomes were hybridized with a multicolor banding in situ hybridization (mBAND) probe for chromosome 3 which distinguishes six regions of the chromosome as separate colors. After images were captured with a laser scanning confocal microscope, the 3-dimensional structure of interphase chromosome 3 was reconstructed at multi-mega base pair scale. In order to determine the effects of microgravity on chromosome conformation and orientation, measures such as distance between homologous pairs, relative orientation of chromosome arms about a shared midpoint, and orientation of arms within individual chromosomes were all considered as potentially impacted by simulated microgravity conditions. The studies revealed non-random folding of chromatin in interphase, and suggested an association of interphase chromatin folding with radiation-induced chromosome aberration hotspots. Interestingly, the distributions of genes with expression changes over chromosome 3 in cells cultured under microgravity environment are apparently clustered on specific loci and chromosomes. This data provides important insights into how mammalian cells respond to microgravity at molecular level.

  7. Alterations at chromosome 17 loci in peripheral nerve sheath tumors

    Energy Technology Data Exchange (ETDEWEB)

    Lothe, R.A.; Slettan, A.; Saeter, G. [Norwegian Radium Hospital, Oslo (Norway)] [and others

    1995-01-01

    Little is known about the molecular genetic changes in malignant peripheral nerve sheath tumors (MPNST). Inactivation of the TP53 gene in l7p has been reported in a few tumors. The MPNST is one of the manifestations of neurofibromatosis 1 (NF1), suggesting that the NF1 gene in 17q might be important. We present a study of 15 neurofibromas and MPNST from nine individuals. Seven patients had NF1 and six of these developed MPNST. Genetic alterations at nine polymorphic loci on chromosome 17 were examined. Allelic imbalance was detected only in the malignant tumors from NF1 patients (4/6). Complete loss of heterozygosity of 17q loci was found in three of these tumors, all including loci within the NF1 gene. Two of the malignant tumors also showed deletions on 17p. No mutations were detected within exon 5-8 of the TP53 in any of the MPNST, and none of them were TP53 protein-positive using immunostaining with mono- and polyclonal antibodies against TP53. The numbers of chromosome 17 present in each tumor were evaluated by use of fluorescence in situ hybridization (FISH) on interphase nuclei with a centromere-specific probe. A deviation from the disomic status of chromosome 17 was observed in two of the MPNST from NF1 patients. These results support the hypothesis of inactivation of both NF1 gene alleles during development of MPNST in patients with NF1. In contrast to other reports, we did not find evidence for a homozygous mutated condition of the TP53 gene in the same tumors. Finally, FISH analysis was in accordance with the DNA analysis in the deduction of the numbers of chromosome 17 in these tumors. 29 refs., 3 figs., 2 tabs.

  8. Whole-genome and chromosome evolution associated with host adaptation and speciation of the wheat pathogen Mycosphaerella graminicola.

    Directory of Open Access Journals (Sweden)

    Eva H Stukenbrock

    2010-12-01

    Full Text Available The fungus Mycosphaerella graminicola has been a pathogen of wheat since host domestication 10,000-12,000 years ago in the Fertile Crescent. The wheat-infecting lineage emerged from closely related Mycosphaerella pathogens infecting wild grasses. We use a comparative genomics approach to assess how the process of host specialization affected the genome structure of M. graminicola since divergence from the closest known progenitor species named M. graminicola S1. The genome of S1 was obtained by Illumina sequencing resulting in a 35 Mb draft genome sequence of 32X. Assembled contigs were aligned to the previously sequenced M. graminicola genome. The alignment covered >90% of the non-repetitive portion of the M. graminicola genome with an average divergence of 7%. The sequenced M. graminicola strain is known to harbor thirteen essential chromosomes plus eight dispensable chromosomes. We found evidence that structural rearrangements significantly affected the dispensable chromosomes while the essential chromosomes were syntenic. At the nucleotide level, the essential and dispensable chromosomes have evolved differently. The average synonymous substitution rate in dispensable chromosomes is considerably lower than in essential chromosomes, whereas the average non-synonymous substitution rate is three times higher. Differences in molecular evolution can be related to different transmission and recombination patterns, as well as to differences in effective population sizes of essential and dispensable chromosomes. In order to identify genes potentially involved in host specialization or speciation, we calculated ratios of synonymous and non-synonymous substitution rates in the >9,500 aligned protein coding genes. The genes are generally under strong purifying selection. We identified 43 candidate genes showing evidence of positive selection, one encoding a potential pathogen effector protein. We conclude that divergence of these pathogens was

  9. Heterochromatic threads connect oscillating chromosomes during prometaphase I in Drosophila oocytes.

    Directory of Open Access Journals (Sweden)

    Stacie E Hughes

    2009-01-01

    Full Text Available In Drosophila oocytes achiasmate homologs are faithfully segregated to opposite poles at meiosis I via a process referred to as achiasmate homologous segregation. We observed that achiasmate homologs display dynamic movements on the meiotic spindle during mid-prometaphase. An analysis of living prometaphase oocytes revealed both the rejoining of achiasmate X chromosomes initially located on opposite half-spindles and the separation toward opposite poles of two X chromosomes that were initially located on the same half spindle. When the two achiasmate X chromosomes were positioned on opposite halves of the spindle their kinetochores appeared to display proper co-orientation. However, when both Xs were located on the same half spindle their kinetochores appeared to be oriented in the same direction. Thus, the prometaphase movement of achiasmate chromosomes is a congression-like process in which the two homologs undergo both separation and rejoining events that result in the either loss or establishment of proper kinetochore co-orientation. During this period of dynamic chromosome movement, the achiasmate homologs were connected by heterochromatic threads that can span large distances relative to the length of the developing spindle. Additionally, the passenger complex proteins Incenp and Aurora B appeared to localize to these heterochromatic threads. We propose that these threads assist in the rejoining of homologs and the congression of the migrating achiasmate homologs back to the main chromosomal mass prior to metaphase arrest.

  10. The cohesion stabilizer sororin favors DNA repair and chromosome segregation during mouse oocyte meiosis.

    Science.gov (United States)

    Huang, Chun-Jie; Yuan, Yi-Feng; Wu, Di; Khan, Faheem Ahmed; Jiao, Xiao-Fei; Huo, Li-Jun

    2017-03-01

    Maintenance and timely termination of cohesion on chromosomes ensures accurate chromosome segregation to guard against aneuploidy in mammalian oocytes and subsequent chromosomally abnormal pregnancies. Sororin, a cohesion stabilizer whose relevance in antagonizing the anti-cohesive property of Wings-apart like protein (Wapl), has been characterized in mitosis; however, the role of Sororin remains unclear during mammalian oocyte meiosis. Here, we show that Sororin is required for DNA damage repair and cohesion maintenance on chromosomes, and consequently, for mouse oocyte meiotic program. Sororin is constantly expressed throughout meiosis and accumulates on chromatins at germinal vesicle (GV) stage/G2 phase. It localizes onto centromeres from germinal vesicle breakdown (GVBD) to metaphase II stage. Inactivation of Sororin compromises the GVBD and first polar body extrusion (PBE). Furthermore, Sororin inactivation induces DNA damage indicated by positive γH2AX foci in GV oocytes and precocious chromatin segregation in MII oocytes. Finally, our data indicate that PlK1 and MPF dissociate Sororin from chromosome arms without affecting its centromeric localization. Our results define Sororin as a determinant during mouse oocyte meiotic maturation by favoring DNA damage repair and chromosome separation, and thereby, maintaining the genome stability and generating haploid gametes.

  11. Differing requirements for RAD51 and DMC1 in meiotic pairing of centromeres and chromosome arms in Arabidopsis thaliana.

    Directory of Open Access Journals (Sweden)

    Olivier Da Ines

    Full Text Available During meiosis homologous chromosomes pair, recombine, and synapse, thus ensuring accurate chromosome segregation and the halving of ploidy necessary for gametogenesis. The processes permitting a chromosome to pair only with its homologue are not fully understood, but successful pairing of homologous chromosomes is tightly linked to recombination. In Arabidopsis thaliana, meiotic prophase of rad51, xrcc3, and rad51C mutants appears normal up to the zygotene/pachytene stage, after which the genome fragments, leading to sterility. To better understand the relationship between recombination and chromosome pairing, we have analysed meiotic chromosome pairing in these and in dmc1 mutant lines. Our data show a differing requirement for these proteins in pairing of centromeric regions and chromosome arms. No homologous pairing of mid-arm or distal regions was observed in rad51, xrcc3, and rad51C mutants. However, homologous centromeres do pair in these mutants and we show that this does depend upon recombination, principally on DMC1. This centromere pairing extends well beyond the heterochromatic centromere region and, surprisingly, does not require XRCC3 and RAD51C. In addition to clarifying and bringing the roles of centromeres in meiotic synapsis to the fore, this analysis thus separates the roles in meiotic synapsis of DMC1 and RAD51 and the meiotic RAD51 paralogs, XRCC3 and RAD51C, with respect to different chromosome domains.

  12. [Y chromosome structural abnormalities and Turner's syndrome].

    Science.gov (United States)

    Ravel, C; Siffroi, J-P

    2009-06-01

    Although specifically male, the human Y chromosome may be observed in female karyotypes, mostly in women with Turner syndrome stigmata. In women with isolated gonadal dysgenesis but otherwise normal stature, the testis determining factor or SRY gene may have been removed from the Y chromosome or may be mutated. In other women with Turner syndrome, the karyotype is usually abnormal and shows a frequent 45,X/46,XY mosaicism. In these cases, the phenotype depends on the ratio between Y positive and 45,X cell lines in the body. When in mosaicism, Y chromosomes are likely to carry structural abnormalities which explain mitotic instability, such as the existence of two centromeres. Dicentric Y isochromosomes for the short arm (idic[Yp]) or ring Y chromosomes (r[Y]) are the most frequent abnormal Y chromosomes found in infertile patients and in Turner syndrome in mosaic with 45,X cells. Although monocentric, deleted Y chromosomes for the long arm and those carrying microdeletions in the AZF region are also instable and are frequently associated with a 45,X cell line. Management of infertile patients carrying such abnormal Y chromosomes must take into account the risk and the consequences of a mosaicism in the offspring.

  13. Developmental regulation of X-chromosome inactivation.

    Science.gov (United States)

    Payer, Bernhard

    2016-08-01

    With the emergence of sex-determination by sex chromosomes, which differ in composition and number between males and females, appeared the need to equalize X-chromosomal gene dosage between the sexes. Mammals have devised the strategy of X-chromosome inactivation (XCI), in which one of the two X-chromosomes is rendered transcriptionally silent in females. In the mouse, the best-studied model organism with respect to XCI, this inactivation process occurs in different forms, imprinted and random, interspersed by periods of X-chromosome reactivation (XCR), which is needed to switch between the different modes of XCI. In this review, I describe the recent advances with respect to the developmental control of XCI and XCR and in particular their link to differentiation and pluripotency. Furthermore, I review the mechanisms, which influence the timing and choice, with which one of the two X-chromosomes is chosen for inactivation during random XCI. This has an impact on how females are mosaics with regard to which X-chromosome is active in different cells, which has implications on the severity of diseases caused by X-linked mutations.

  14. Engineered human dicentric chromosomes show centromere plasticity.

    Science.gov (United States)

    Higgins, Anne W; Gustashaw, Karen M; Willard, Huntington F

    2005-01-01

    The centromere is essential for the faithful distribution of a cell's genetic material to subsequent generations. Despite intense scrutiny, the precise genetic and epigenetic basis for centromere function is still unknown. Here, we have used engineered dicentric human chromosomes to investigate mammalian centromere structure and function. We describe three classes of dicentric chromosomes isolated in different cell lines: functionally monocentric chromosomes, in which one of the two genetically identical centromeres is consistently inactivated; functionally dicentric chromosomes, in which both centromeres are consistently active; and dicentric chromosomes heterogeneous with respect to centromere activity. A study of serial single cell clones from heterogeneous cell lines revealed that while centromere activity is usually clonal, the centromere state (i.e. functionally monocentric or dicentric) in some lines can switch within a growing population of cells. Because pulsed field gel analysis indicated that the DNA at the centromeres of these chromosomes did not change detectably, this switching of the centromere state is most likely due to epigenetic changes. Inactivation of one of the two active centromeres in a functionally dicentric chromosome was observed in a percentage of cells after treatment with Trichostatin A, an inhibitor of histone deacetylation. This study provides evidence that the activity of human centromeres, while largely stable, can be subject to dynamic change, most likely due to epigenetic modification.

  15. Chromosome I duplications in Caenorhabditis elegans

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    McKim, K.S.; Rose, A.M. (Univ. of British Columbia, Vancouver (Canada))

    1990-01-01

    We have isolated and characterized 76 duplications of chromosome I in the genome of Caenorhabditis elegans. The region studied is the 20 map unit left half of the chromosome. Sixty-two duplications were induced with gamma radiation and 14 arose spontaneously. The latter class was apparently the result of spontaneous breaks within the parental duplication. The majority of duplications behave as if they are free. Three duplications are attached to identifiable sequences from other chromosomes. The duplication breakpoints have been mapped by complementation analysis relative to genes on chromosome I. Nineteen duplication breakpoints and seven deficiency breakpoints divide the left half of the chromosome into 24 regions. We have studied the relationship between duplication size and segregational stability. While size is an important determinant of mitotic stability, it is not the only one. We observed clear exceptions to a size-stability correlation. In addition to size, duplication stability may be influenced by specific sequences or chromosome structure. The majority of the duplications were stable enough to be powerful tools for gene mapping. Therefore the duplications described here will be useful in the genetic characterization of chromosome I and the techniques we have developed can be adapted to other regions of the genome.

  16. Large-scale reconstruction of 3D structures of human chromosomes from chromosomal contact data.

    Science.gov (United States)

    Trieu, Tuan; Cheng, Jianlin

    2014-04-01

    Chromosomes are not positioned randomly within a nucleus, but instead, they adopt preferred spatial conformations to facilitate necessary long-range gene-gene interactions and regulations. Thus, obtaining the 3D shape of chromosomes of a genome is critical for understanding how the genome folds, functions and how its genes interact and are regulated. Here, we describe a method to reconstruct preferred 3D structures of individual chromosomes of the human genome from chromosomal contact data generated by the Hi-C chromosome conformation capturing technique. A novel parameterized objective function was designed for modeling chromosome structures, which was optimized by a gradient descent method to generate chromosomal structural models that could satisfy as many intra-chromosomal contacts as possible. We applied the objective function and the corresponding optimization method to two Hi-C chromosomal data sets of both a healthy and a cancerous human B-cell to construct 3D models of individual chromosomes at resolutions of 1 MB and 200 KB, respectively. The parameters used with the method were calibrated according to an independent fluorescence in situ hybridization experimental data. The structural models generated by our method could satisfy a high percentage of contacts (pairs of loci in interaction) and non-contacts (pairs of loci not in interaction) and were compatible with the known two-compartment organization of human chromatin structures. Furthermore, structural models generated at different resolutions and from randomly permuted data sets were consistent.

  17. Analysis of chromosome conservation in Lemur catta studied by chromosome paints and BAC/PAC probes.

    Science.gov (United States)

    Cardone, Maria Francesca; Ventura, Mario; Tempesta, Sergio; Rocchi, Mariano; Archidiacono, Nicoletta

    2002-12-01

    A panel of human chromosome painting probes and bacterial and P1 artificial chromosome (BAC/PAC) clones were used in fluorescence in situ hybridization (FISH) experiments to investigate the chromosome conservation of the ring-tailed lemur (Lemur catta, LCA) with respect to human. Whole chromosome paints specific for human chromosomes 7, 9, 11, 13, 14, 17, 18, 20, 21, and X were found to identify a single chromosome or an uninterrupted chromosomal region in LCA. A large set of partial chromosome paints and BAC/PAC probes were then used to refine the characterization of the rearrangements differentiating the two karyotypes. The results were also used to reconstruct the ancestral Lemuridae karyotype. Lemur catta, indeed, can be used as an outgroup, allowing symplesiomorphic (ancestral) rearrangements to be distinguished from apomorphic (derived) rearrangements in lemurs. Some LCA chromosomes are difficult to distinguish morphologically. The 'anchorage' of most LCA chromosomes to specific probes will contribute to the standardization of the karyotype of this species.

  18. Mammalian X chromosome inactivation evolved as a dosage-compensation mechanism for dosage-sensitive genes on the X chromosome.

    Science.gov (United States)

    Pessia, Eugénie; Makino, Takashi; Bailly-Bechet, Marc; McLysaght, Aoife; Marais, Gabriel A B

    2012-04-03

    How and why female somatic X-chromosome inactivation (XCI) evolved in mammals remains poorly understood. It has been proposed that XCI is a dosage-compensation mechanism that evolved to equalize expression levels of X-linked genes in females (2X) and males (1X), with a prior twofold increase in expression of X-linked genes in both sexes ("Ohno's hypothesis"). Whereas the parity of X chromosome expression between the sexes has been clearly demonstrated, tests for the doubling of expression levels globally along the X chromosome have returned contradictory results. However, changes in gene dosage during sex-chromosome evolution are not expected to impact on all genes equally, and should have greater consequences for dosage-sensitive genes. We show that, for genes encoding components of large protein complexes (≥ 7 members)--a class of genes that is expected to be dosage-sensitive--expression of X-linked genes is similar to that of autosomal genes within the complex. These data support Ohno's hypothesis that XCI acts as a dosage-compensation mechanism, and allow us to refine Ohno's model of XCI evolution. We also explore the contribution of dosage-sensitive genes to X aneuploidy phenotypes in humans, such as Turner (X0) and Klinefelter (XXY) syndromes. X aneuploidy in humans is common and is known to have mild effects because most of the supernumerary X genes are inactivated and not affected by aneuploidy. Only genes escaping XCI experience dosage changes in X-aneuploidy patients. We combined data on dosage sensitivity and XCI to compute a list of candidate genes for X-aneuploidy syndromes.

  19. High-resolution mapping and transcriptional activity analysis of chicken centromere sequences on giant lampbrush chromosomes.

    Science.gov (United States)

    Krasikova, Alla; Fukagawa, Tatsuo; Zlotina, Anna

    2012-12-01

    Exploration into morphofunctional organisation of centromere DNA sequences is important for understanding the mechanisms of kinetochore specification and assembly. In-depth epigenetic analysis of DNA fragments associated with centromeric nucleosome proteins has demonstrated unique features of centromere organisation in chicken karyotype: there are both mature centromeres, which comprise chromosome-specific homogeneous arrays of tandem repeats, and recently evolved primitive centromeres, which consist of non-tandemly organised DNA sequences. In this work, we describe the arrangement and transcriptional activity of chicken centromere repeats for Cen1, Cen2, Cen3, Cen4, Cen7, Cen8, and Cen11 and non-repetitive centromere sequences of chromosomes 5, 27, and Z using highly elongated lampbrush chromosomes, which are characteristic of the diplotene stage of oogenesis. The degree of chromatin packaging and fine spatial organisations of tandemly repetitive and non-tandemly repetitive centromeric sequences significantly differ at the lampbrush stage. Using DNA/RNA FISH, we have demonstrated that during the lampbrush stage, DNA sequences are transcribed within the centromere regions of chromosomes that lack centromere-specific tandem repeats. In contrast, chromosome-specific centromeric repeats Cen1, Cen2, Cen3, Cen4, Cen7, Cen8, and Cen11 do not demonstrate any transcriptional activity during the lampbrush stage. In addition, we found that CNM repeat cluster localises adjacent to non-repetitive centromeric sequences in chicken microchromosome 27 indicating that centromere region in this chromosome is repeat-rich. Cross-species FISH allowed localisation of the sequences homologous to centromeric DNA of chicken chromosomes 5 and 27 in centromere regions of quail orthologous chromosomes.

  20. Nucleolar organization, ribosomal DNA array stability, and acrocentric chromosome integrity are linked to telomere function.

    Directory of Open Access Journals (Sweden)

    Kaitlin M Stimpson

    Full Text Available The short arms of the ten acrocentric human chromosomes share several repetitive DNAs, including ribosomal RNA genes (rDNA. The rDNA arrays correspond to nucleolar organizing regions that coalesce each cell cycle to form the nucleolus. Telomere disruption by expressing a mutant version of telomere binding protein TRF2 (dnTRF2 causes non-random acrocentric fusions, as well as large-scale nucleolar defects. The mechanisms responsible for acrocentric chromosome sensitivity to dysfunctional telomeres are unclear. In this study, we show that TRF2 normally associates with the nucleolus and rDNA. However, when telomeres are crippled by dnTRF2 or RNAi knockdown of TRF2, gross nucleolar and chromosomal changes occur. We used the controllable dnTRF2 system to precisely dissect the timing and progression of nucleolar and chromosomal instability induced by telomere dysfunction, demonstrating that nucleolar changes precede the DNA damage and morphological changes that occur at acrocentric short arms. The rDNA repeat arrays on the short arms decondense, and are coated by RNA polymerase I transcription binding factor UBF, physically linking acrocentrics to one another as they become fusogenic. These results highlight the importance of telomere function in nucleolar stability and structural integrity of acrocentric chromosomes, particularly the rDNA arrays. Telomeric stress is widely accepted to cause DNA damage at chromosome ends, but our findings suggest that it also disrupts chromosome structure beyond the telomere region, specifically within the rDNA arrays located on acrocentric chromosomes. These results have relevance for Robertsonian translocation formation in humans and mechanisms by which acrocentric-acrocentric fusions are promoted by DNA damage and repair.

  1. Hormad1 mutation disrupts synaptonemal complex formation, recombination, and chromosome segregation in mammalian meiosis.

    Science.gov (United States)

    Shin, Yong-Hyun; Choi, Youngsok; Erdin, Serpil Uckac; Yatsenko, Svetlana A; Kloc, Malgorzata; Yang, Fang; Wang, P Jeremy; Meistrich, Marvin L; Rajkovic, Aleksandar

    2010-11-04

    Meiosis is unique to germ cells and essential for reproduction. During the first meiotic division, homologous chromosomes pair, recombine, and form chiasmata. The homologues connect via axial elements and numerous transverse filaments to form the synaptonemal complex. The synaptonemal complex is a critical component for chromosome pairing, segregation, and recombination. We previously identified a novel germ cell-specific HORMA domain encoding gene, Hormad1, a member of the synaptonemal complex and a mammalian counterpart to the yeast meiotic HORMA domain protein Hop1. Hormad1 is essential for mammalian gametogenesis as knockout male and female mice are infertile. Hormad1 deficient (Hormad1(-/) (-)) testes exhibit meiotic arrest in the early pachytene stage, and synaptonemal complexes cannot be visualized by electron microscopy. Hormad1 deficiency does not affect localization of other synaptonemal complex proteins, SYCP2 and SYCP3, but disrupts homologous chromosome pairing. Double stranded break formation and early recombination events are disrupted in Hormad1(-/) (-) testes and ovaries as shown by the drastic decrease in the γH2AX, DMC1, RAD51, and RPA foci. HORMAD1 co-localizes with γH2AX to the sex body during pachytene. BRCA1, ATR, and γH2AX co-localize to the sex body and participate in meiotic sex chromosome inactivation and transcriptional silencing. Hormad1 deficiency abolishes γH2AX, ATR, and BRCA1 localization to the sex chromosomes and causes transcriptional de-repression on the X chromosome. Unlike testes, Hormad1(-/) (-) ovaries have seemingly normal ovarian folliculogenesis after puberty. However, embryos generated from Hormad1(-/) (-) oocytes are hyper- and hypodiploid at the 2 cell and 8 cell stage, and they arrest at the blastocyst stage. HORMAD1 is therefore a critical component of the synaptonemal complex that affects synapsis, recombination, and meiotic sex chromosome inactivation and transcriptional silencing.

  2. Hormad1 mutation disrupts synaptonemal complex formation, recombination, and chromosome segregation in mammalian meiosis.

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