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Sample records for candidate gene microarray

  1. Using microarrays to identify positional candidate genes for QTL: the case study of ACTH response in pigs

    DEFF Research Database (Denmark)

    Jouffe, Vincent; Rowe, Suzanne; Liaubet, Laurence;

    2009-01-01

    Background: Microarray studies can supplement QTL studies by suggesting potential candidate. Microarray studies can supplement QTL studies by suggesting potential candidate genes in the QTL regions, which by themselves are too large to provide a limited selection of candidate genes. Here we provi...

  2. Screening for candidate genes related to breast cancer with cDNA microarray analysis

    Institute of Scientific and Technical Information of China (English)

    Yu-Juan Xiang; Zhi-Gang Yu; Ming-Ming Guo; Qin-Ye Fu; Zhong-Bing Ma; De-Zong Gao; Qiang Zhang; Yu-Yang Li; Liang Li; Lu Liu; Chun-Miao Ye

    2015-01-01

    Objective: The aim of this study was to reveal the exact changes during the occurrence of breast cancer to explore significant new and promising genes or factors related to this disease. Methods: We compared the gene expression profiles of breast cancer tissues with its uninvolved normal breast tissues as controls using the cDNA microarray analysis in seven breast cancer patients. Further, one representative gene, named IFI30, was quanti-tatively analyzed by real-time PCR to confirm the result of the cDNA microarray analysis. Results: A total of 427 genes were identified with significantly differential expression, 221 genes were up-regulated and 206 genes were down-regulated. And the result of cDNA microarray analysis was validated by detection of IFI30 mRNA level changes by real-time PCR. Genes for cell proliferation, cell cycle, cell division, mitosis, apoptosis, and immune response were enriched in the up-regulated genes, while genes for cell adhesion, proteolysis, and transport were significantly enriched in the down-regulated genes in breast cancer tissues compared with normal breast tissues by a gene ontology analysis. Conclusion: Our present study revealed a range of differentially expressed genes between breast cancer tissues and normal breast tissues, and provide candidate genes for further study focusing on the pathogenesis and new biomarkers for breast cancer. Copyright © 2015, Chinese Medical Association Production. Production and hosting by Elsevier B.V. on behalf of KeAi Communications Co., Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

  3. Candidate Genes for Testicular Cancer Evaluated by In Situ Protein Expression Analyses on Tissue Microarrays

    Directory of Open Access Journals (Sweden)

    Rolf I. Skotheim

    2003-09-01

    Full Text Available By the use of high-throughput molecular technologies, the number of genes and proteins potentially relevant to testicular germ cell tumor (TGCT and other diseases will increase rapidly. In a recent transcriptional profiling, we demonstrated the overexpression of GRB7 and JUP in TGCTs, confirmed the reported overexpression of CCND2. We also have recent evidences for frequent genetic alterations of FHIT and epigenetic alterations of MGMT. To evaluate whether the expression of these genes is related to any clinicopathological variables, we constructed a tissue microarray with 510 testicular tissue cores from 279 patients diagnosed with TGCT, covering various histological subgroups and clinical stages. By immunohistochemistry, we found that JUP, GRB7, CCND2 proteins were rarely present in normal testis, but frequently expressed at high levels in TGCT. Additionally, all premalignant intratubular germ cell neoplasias were JUP-immunopositive. MGMT and FHIT were expressed by normal testicular tissues, but at significantly lower frequencies in TGCT. Except for CCND2, the expressions of all markers were significantly associated with various TGCT subtypes. In summary, we have developed a high-throughput tool for the evaluation of TGCT markers, utilized this to validate five candidate genes whose protein expressions were indeed deregulated in TGCT.

  4. Microarray Expression Data Identify DCC as a Candidate Gene for Early Meningioma Progression

    Science.gov (United States)

    Schulten, Hans-Juergen; Hussein, Deema; Al-Adwani, Fatima; Karim, Sajjad; Al-Maghrabi, Jaudah; Al-Sharif, Mona; Jamal, Awatif; Al-Ghamdi, Fahad; Baeesa, Saleh S.; Bangash, Mohammed; Chaudhary, Adeel; Al-Qahtani, Mohammed

    2016-01-01

    Meningiomas are the most common primary brain tumors bearing in a minority of cases an aggressive phenotype. Although meningiomas are stratified according to their histology and clinical behavior, the underlying molecular genetics predicting aggressiveness are not thoroughly understood. We performed whole transcript expression profiling in 10 grade I and four grade II meningiomas, three of which invaded the brain. Microarray expression analysis identified deleted in colorectal cancer (DCC) as a differentially expressed gene (DEG) enabling us to cluster meningiomas into DCC low expression (3 grade I and 3 grade II tumors), DCC medium expression (2 grade I and 1 grade II tumors), and DCC high expression (5 grade I tumors) groups. Comparison between the DCC low expression and DCC high expression groups resulted in 416 DEGs (p-value 2). The most significantly downregulated genes in the DCC low expression group comprised DCC, phosphodiesterase 1C (PDE1C), calmodulin-dependent 70kDa olfactomedin 2 (OLFM2), glutathione S-transferase mu 5 (GSTM5), phosphotyrosine interaction domain containing 1 (PID1), sema domain, transmembrane domain (TM) and cytoplasmic domain, (semaphorin) 6D (SEMA6D), and indolethylamine N-methyltransferase (INMT). The most significantly upregulated genes comprised chromosome 5 open reading frame 63 (C5orf63), homeodomain interacting protein kinase 2 (HIPK2), and basic helix-loop-helix family, member e40 (BHLHE40). Biofunctional analysis identified as predicted top upstream regulators beta-estradiol, TGFB1, Tgf beta complex, LY294002, and dexamethasone and as predicted top regulator effectors NFkB, PIK3R1, and CREBBP. The microarray expression data served also for a comparison between meningiomas from female and male patients and for a comparison between brain invasive and non-invasive meningiomas resulting in a number of significant DEGs and related biofunctions. In conclusion, based on its expression levels, DCC may constitute a valid biomarker to

  5. cDNA Microarray Analysis Revealing Candidate Biomineralization Genes of the Pearl Oyster, Pinctada fucata martensii.

    Science.gov (United States)

    Shi, Yaohua; Zheng, Xing; Zhan, Xin; Wang, Aimin; Gu, Zhifeng

    2016-06-01

    Biomineralization is a common biological phenomenon resulting in strong tissue, such as bone, tooth, and shell. Pinctada fucata martensii is an ideal animal for the study of biomineralization. Here, microarray technique was used to identify biomineralization gene in mantle edge (ME), mantle center (MC), and both ME and MC (ME-MC) for this pearl oyster. Results revealed that 804, 306, and 1127 contigs expressed at least three times higher in ME, MC, and ME-MC as those in other tissues. Blast against non-redundant database showed that 130 contigs (16.17 %), 53 contigs (17.32 %), and 248 contigs (22.01 %) hit reference genes (E ≤ -10), among which 91 contigs, 48 contigs, and 168 contigs could be assigned to 32, 26, and 63 biomineralization genes in tissue of ME, MC, and ME-MC at a threshold of 3 times upregulated expression level. The ratios of biomineralization contigs to homologous contigs were similar at 3 times, 10 times, and 100 times of upregulated expression level in either ME, MC, or ME-MC. Moreover, the ratio of biomineralization contigs was highest in MC. Although mRNA distribution characters were similar to those in other studies for eight biomineralization genes of PFMG3, Pif, nacrein, MSI7, mantle gene 6, Pfty1, prismin, and the shematrin, most biomineralization genes presented different expression profiles from existing reports. These results provided massive fundamental information for further study of biomineralization gene function, and it may be helpful for revealing gene nets of biomineralization and the molecular mechanisms underlining formation of shell and pearl for the oyster. PMID:27184264

  6. Identification of candidate target genes of pituitary adenomas based on the DNA microarray.

    Science.gov (United States)

    Zhou, Wei; Ma, Chun-Xiao; Xing, Ya-Zhou; Yan, Zhao-Yue

    2016-03-01

    The present study aimed to explore molecular mechanisms involved in pituitary adenomas (PAs) and to discover target genes for their treatment. The gene expression profile GSE4488 was downloaded from the Gene Expression Omnibus database. Differentially expressed genes (DEGs) were identified using the Limma package and analyzed by two‑dimensional hierarchical clustering. Gene ontology (GO) and pathway enrichment analyses were performed in order to investigate the functions of DEGs. Subsequently, the protein‑protein interaction (PPI) network was constructed using Cytoscape software. DEGs were then mapped to the connectivity map database to identify molecular agents associated with the underlying mechanisms of PAs. A total of 340 upregulated and 49 downregulated DEGs in PA samples compared with those in normal controls were identified. Hierarchical clustering analysis showed that DEGs were highly differentially expressed, indicating their aptness for distinguishing PA samples from normal controls. Significant gene ontology terms were positive regulation of immune system-associated processes for downregulated DEGs and skeletal system development for upregulated DEGs. Pathways significantly enriched by DEGs included extracellular matrix (ECM)‑receptor interaction, the Hedgehog (Hh) signaling pathway and neuroactive ligand‑receptor interaction. The PPI network was constructed with 117 nodes, 123 edges and CD44 and Gli2 as hub nodes. Furthermore, depudecin, a small molecule drug, was identified to be mechanistically associated with PA. The genes CD44 and Gli2 have important roles in the progression of PAs via ECM‑receptor interaction and the Hh signaling pathway and are therefore potential target genes of PA. In addition, depudecin may be a candidate drug for the treatment of PAs. PMID:26782791

  7. Single Nucleotide Polymorphism Microarray Analysis in Cortisol-Secreting Adrenocortical Adenomas Identifies New Candidate Genes and Pathways

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    Cristina L. Ronchi

    2012-03-01

    Full Text Available The genetic mechanisms underlying adrenocortical tumor development are still largely unknown. We used high-resolution single nucleotide polymorphism microarrays (Affymetrix SNP 6.0 to detect copy number alterations (CNAs and copy-neutral losses of heterozygosity (cnLOH in 15 cortisol-secreting adrenocortical adenomas with matched blood samples. We focused on microalterations aiming to discover new candidate genes involved in early tumorigenesis and/or autonomous cortisol secretion. We identified 962 CNAs with a median of 18 CNAs per sample. Half of them involved noncoding regions, 89% were less than 100 kb, and 28% were found in at least two samples. The most frequently gained regions were 5p15.33, 6q16.1, 7p22.3-22.2, 8q24.3, 9q34.2-34.3, 11p15.5, 11q11, 12q12, 16q24.3, 20p11.1-20q21.11, and Xq28 (≥20% of cases, most of them being identified in the same three adenomas. These regions contained among others genes like NOTCH1, CYP11B2, HRAS, and IGF2. Recurrent losses were less common and smaller than gains, being mostly localized at 1p, 6q, and 11q. Pathway analysis revealed that Notch signaling was the most frequently altered. We identified 46 recurrent CNAs that each affected a single gene (31 gains and 15 losses, including genes involved in steroidogenesis (CYP11B1 or tumorigenesis (CTNNB1, EPHA7, SGK1, STIL, FHIT. Finally, 20 small cnLOH in four cases affecting 15 known genes were found. Our findings provide the first high-resolution genome-wide view of chromosomal changes in cortisol-secreting adenomas and identify novel candidate genes, such as HRAS, EPHA7, and SGK1. Furthermore, they implicate that the Notch1 signaling pathway might be involved in the molecular pathogenesis of adrenocortical tumors.

  8. Optimization of candidate-gene SNP-genotyping by flexible oligonucleotide microarrays; analyzing variations in immune regulator genes of hay-fever samples

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    Beier Markus

    2007-08-01

    Full Text Available Abstract Background Genetic variants in immune regulator genes have been associated with numerous diseases, including allergies and cancer. Increasing evidence suggests a substantially elevated disease risk in individuals who carry a combination of disease-relevant single nucleotide polymorphisms (SNPs. For the genotyping of immune regulator genes, such as cytokines, chemokines and transcription factors, an oligonucleotide microarray for the analysis of 99 relevant SNPs was established. Since the microarray design was based on a platform that permits flexible in situ oligonucleotide synthesis, a set of optimally performing probes could be defined by a selection approach that combined computational and experimental aspects. Results While the in silico process eliminated 9% of the initial probe set, which had been picked purely on the basis of potential association with disease, the subsequent experimental validation excluded more than twice as many. The performance of the optimized microarray was demonstrated in a pilot study. The genotypes of 19 hay-fever patients (aged 40–44 with high IgE levels against inhalant antigens were compared to the results obtained with 19 age- and sex-matched controls. For several variants, allele-frequency differences of more than 10% were identified. Conclusion Based on the ability to improve empirically a chip design, the application of candidate-SNP typing represents a viable approach in the context of molecular epidemiological studies.

  9. Transcriptomic identification of candidate genes involved in sunflower responses to chilling and salt stresses based on cDNA microarray analysis

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    Paniego Norma

    2008-01-01

    Full Text Available Abstract Background Considering that sunflower production is expanding to arid regions, tolerance to abiotic stresses as drought, low temperatures and salinity arises as one of the main constrains nowadays. Differential organ-specific sunflower ESTs (expressed sequence tags were previously generated by a subtractive hybridization method that included a considerable number of putative abiotic stress associated sequences. The objective of this work is to analyze concerted gene expression profiles of organ-specific ESTs by fluorescence microarray assay, in response to high sodium chloride concentration and chilling treatments with the aim to identify and follow up candidate genes for early responses to abiotic stress in sunflower. Results Abiotic-related expressed genes were the target of this characterization through a gene expression analysis using an organ-specific cDNA fluorescence microarray approach in response to high salinity and low temperatures. The experiment included three independent replicates from leaf samples. We analyzed 317 unigenes previously isolated from differential organ-specific cDNA libraries from leaf, stem and flower at R1 and R4 developmental stage. A statistical analysis based on mean comparison by ANOVA and ordination by Principal Component Analysis allowed the detection of 80 candidate genes for either salinity and/or chilling stresses. Out of them, 50 genes were up or down regulated under both stresses, supporting common regulatory mechanisms and general responses to chilling and salinity. Interestingly 15 and 12 sequences were up regulated or down regulated specifically in one stress but not in the other, respectively. These genes are potentially involved in different regulatory mechanisms including transcription/translation/protein degradation/protein folding/ROS production or ROS-scavenging. Differential gene expression patterns were confirmed by qRT-PCR for 12.5% of the microarray candidate sequences. Conclusion

  10. How does exposure to nickel and cadmium affect the transcriptome of yellow perch (Perca flavescens) – Results from a 1000 candidate-gene microarray

    Energy Technology Data Exchange (ETDEWEB)

    Bougas, Bérénice, E-mail: Berenice.Bougas@ete.inrs.ca [Institut National de la Recherche Scientifique, Centre INRS Eau Terre et Environnement, 490, rue de la Couronne, Québec, Québec G1K 9A9 (Canada); Département de biologie, Institut de Biologie Intégrative et des Systèmes (IBIS), Université Laval, Québec, Québec G1V 0A6 (Canada); Normandeau, Eric [Département de biologie, Institut de Biologie Intégrative et des Systèmes (IBIS), Université Laval, Québec, Québec G1V 0A6 (Canada); Pierron, Fabien [Université de Bordeaux, EPOC, UMR 5805, F-33400 Talence (France); CNRS, EPOC, UMR 5805, F-33400 Talence (France); Campbell, Peter G.C. [Institut National de la Recherche Scientifique, Centre INRS Eau Terre et Environnement, 490, rue de la Couronne, Québec, Québec G1K 9A9 (Canada); Bernatchez, Louis [Département de biologie, Institut de Biologie Intégrative et des Systèmes (IBIS), Université Laval, Québec, Québec G1V 0A6 (Canada); Couture, Patrice [Institut National de la Recherche Scientifique, Centre INRS Eau Terre et Environnement, 490, rue de la Couronne, Québec, Québec G1K 9A9 (Canada)

    2013-10-15

    Highlights: •The transcriptional responses of Perca flavescens to both metal and non metal stressors were measured with a 1000 candidate-gene microarray. •475, 287 and 176 genes were differentially transcribed depending on temperature, Ni and Cd concentrations, respectively. •Genes involved in iron metabolism, transcriptional and translational processes, vitamin metabolism, blood coagulation, and calcium transport were impacted by metals. •The developed microarray contributes to a better characterization of the impact of different stressors on the transcriptome. -- Abstract: The molecular mechanisms underlying nickel (Ni) and cadmium (Cd) toxicity and their specific effects on fish are poorly understood. Documenting gene transcription profiles offers a powerful approach toward identifying the molecular mechanisms affected by these metals and to discover biomarkers of their toxicity. However, confounding environmental factors can complicate the interpretation of the results and the detection of biomarkers for fish captured in their natural environment. In the present study, a 1000 candidate-gene microarray, developed from a previous RNA-seq study on a subset of individual fish from contrasting level of metal contamination, was used to investigate the transcriptional response to metal (Ni and Cd) and non metal (temperature, oxygen, and diet) stressors in yellow perch (Perca flavescens). Specifically, we aimed at (1) identifying transcriptional signatures specific to Ni and Cd exposure, (2) investigating the mechanisms of their toxicity, and (3) developing a predictive tool to identify the sublethal effects of Ni and Cd contaminants in fish sampled from natural environments. A total of 475 genes displayed significantly different transcription levels when temperature varied while 287 and 176 genes were differentially transcribed at different concentrations of Ni and Cd, respectively. These metals were found to mainly affect the transcription level of genes

  11. How does exposure to nickel and cadmium affect the transcriptome of yellow perch (Perca flavescens) – Results from a 1000 candidate-gene microarray

    International Nuclear Information System (INIS)

    Highlights: •The transcriptional responses of Perca flavescens to both metal and non metal stressors were measured with a 1000 candidate-gene microarray. •475, 287 and 176 genes were differentially transcribed depending on temperature, Ni and Cd concentrations, respectively. •Genes involved in iron metabolism, transcriptional and translational processes, vitamin metabolism, blood coagulation, and calcium transport were impacted by metals. •The developed microarray contributes to a better characterization of the impact of different stressors on the transcriptome. -- Abstract: The molecular mechanisms underlying nickel (Ni) and cadmium (Cd) toxicity and their specific effects on fish are poorly understood. Documenting gene transcription profiles offers a powerful approach toward identifying the molecular mechanisms affected by these metals and to discover biomarkers of their toxicity. However, confounding environmental factors can complicate the interpretation of the results and the detection of biomarkers for fish captured in their natural environment. In the present study, a 1000 candidate-gene microarray, developed from a previous RNA-seq study on a subset of individual fish from contrasting level of metal contamination, was used to investigate the transcriptional response to metal (Ni and Cd) and non metal (temperature, oxygen, and diet) stressors in yellow perch (Perca flavescens). Specifically, we aimed at (1) identifying transcriptional signatures specific to Ni and Cd exposure, (2) investigating the mechanisms of their toxicity, and (3) developing a predictive tool to identify the sublethal effects of Ni and Cd contaminants in fish sampled from natural environments. A total of 475 genes displayed significantly different transcription levels when temperature varied while 287 and 176 genes were differentially transcribed at different concentrations of Ni and Cd, respectively. These metals were found to mainly affect the transcription level of genes

  12. Identifying type 1 diabetes candidate genes by DNA microarray analysis of islet-specific CD4+ T cells

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    Gregory J. Berry

    2015-09-01

    Full Text Available Type 1 diabetes (T1D is a T cell-mediated autoimmune disease resulting from the destruction of insulin-producing pancreatic beta cells and is fatal unless treated with insulin. During the last four decades, multiple insulin-dependent diabetes (Idd susceptibility/resistance loci that regulate T1D development have been identified in humans and non-obese diabetic (NOD mice, an established animal model for T1D. However, the exact mechanisms by which these loci confer diabetes risk and the identity of the causative genes remain largely elusive. To identify genes and molecular mechanisms that control the function of diabetogenic T cells, we conducted DNA microarray analysis in islet-specific CD4+ T cells from BDC2.5 TCR transgenic NOD mice that contain the Idd9 locus from T1D-susceptible NOD mice or T1D-resistant C57BL/10 mice. Here we describe in detail the contents and analyses for these gene expression data associated with our previous study [1]. Gene expression data are available at the Gene Expression Omnibus (GEO repository from the National Center for Biotechnology Information (accession number GSE64674.

  13. The 'PUCE CAFE' Project: the First 15K Coffee Microarray, a New Tool for Discovering Candidate Genes correlated to Agronomic and Quality Traits

    Directory of Open Access Journals (Sweden)

    Leroy Thierry

    2011-01-01

    Full Text Available Abstract Background Understanding the genetic elements that contribute to key aspects of coffee biology will have an impact on future agronomical improvements for this economically important tree. During the past years, EST collections were generated in Coffee, opening the possibility to create new tools for functional genomics. Results The "PUCE CAFE" Project, organized by the scientific consortium NESTLE/IRD/CIRAD, has developed an oligo-based microarray using 15,721 unigenes derived from published coffee EST sequences mostly obtained from different stages of fruit development and leaves in Coffea Canephora (Robusta. Hybridizations for two independent experiments served to compare global gene expression profiles in three types of tissue matter (mature beans, leaves and flowers in C. canephora as well as in the leaves of three different coffee species (C. canephora, C. eugenoides and C. arabica. Microarray construction, statistical analyses and validation by Q-PCR analysis are presented in this study. Conclusion We have generated the first 15 K coffee array during this PUCE CAFE project, granted by Génoplante (the French consortium for plant genomics. This new tool will help study functional genomics in a wide range of experiments on various plant tissues, such as analyzing bean maturation or resistance to pathogens or drought. Furthermore, the use of this array has proven to be valid in different coffee species (diploid or tetraploid, drastically enlarging its impact for high-throughput gene expression in the community of coffee research.

  14. Microarray Data Analysis of Gene Expression Evolution

    OpenAIRE

    Honghuang Lin

    2009-01-01

    Microarrays are becoming a widely used tool to study gene expression evolution. A recent paper by Wang and Rekaya describes a comprehensive study of gene expression evolution by microarray.1 The work provides a perspective to study gene expression evolution in terms of functional enrichment and promoter conservation. It was found that gene expression patterns are highly conserved in some biological processes, but the correlation between promoter and gene expression is insignificant. This scop...

  15. Microarray analysis of di-n-butyl phthalate and 17α ethinyl-oestradiol responses in three-spined stickleback testes reveals novel candidate genes for endocrine disruption.

    Science.gov (United States)

    Prokkola, Jenni M; Katsiadaki, Ioanna; Sebire, Marion; Elphinstone-Davis, Jessica; Pausio, Sanna; Nikinmaa, Mikko; Leder, Erica H

    2016-02-01

    Phthalate esters are plasticizers frequently found in wastewater effluents. Previous studies on phthalates have reported anti-androgenic activity in mammals, causing concerns of their potential effects on the reproduction of aquatic organisms. Another group of environmental endocrine disrupters, steroidal estrogens, are known to inhibit steroid biosynthesis in the gonads, but the effects related to spermatogenesis are not well understood in fish. In this study, three-spined sticklebacks were exposed to di-n-butyl phthalate (DBP) and 17α ethinyl-oestradiol (EE2) at nominal concentrations 35μg/L and 40ng/L, respectively, for four days. The aim of the study was to obtain insight into the acute transcriptional responses putatively associated with endocrine disruption. RNA samples from eight individual male fish per treatment (including controls) were used in microarray analysis, covering the expression of approximately 21,000 genes. In the EE2 treatment the results show transcriptional downregulation of genes associated with steroid biosynthesis pathway and up-regulation of genes involved in pathways related to epidermal growth factor signaling and xenobiotic metabolism. The transcriptional response to DBP was in general weaker than to EE2, but based on enrichment analysis, we suggest adverse effects on retinoid metabolism, creatine kinase activity and cell adhesion. Among the genes showing highest fold changes after DBP treatment compared to control was the teleost fish -specific cytochrome P450 17A2. Overall, this study promotes our understanding on molecular responses to anti-androgens and estrogens in fish testes. PMID:26476330

  16. Screening and analysis of candidate gene expression in asthma using microarray technology%基因芯片技术对哮喘病人相关基因的筛选和分析

    Institute of Scientific and Technical Information of China (English)

    贾少丹; 纪霞; 张为忠; 邢明青; 李靖; 王海燕; 张伟毅; 包振民

    2012-01-01

    Objective To screen different gene expressions in peripheral blood mononuclear cells between asthma patients and normal people by DNA microarray in order to provide molecular markers for early diagnosis and prevention of asthma. Methods Participants with asthma (re = 16) and healthy controls (n = 16) underwent peripheral blood collection. Monocytes were isolated using Ficoll-Paque and extracted for total RNA by QIAGEN Rneasy Kit. Then we used the Cy3 to mark the cDNA of normal people and asthma patients respectively, and used the Agilent Homo microarray chips containing 41,000 genes/ESTs to screen gene expression differentially according to the screening criteria of Ratio≥2 and Ratio≤ -2. At last, we used Gene spring software to analyze the biologic function of the candidate genes. Results By using this DNA microarray technology, 4177 candidate genes in the asthma patients were found from 34183 target genes, which expressed twice higher than those in the normal people. 19 gene expressions correlating to asthma were found with twice fold differences, as compared with the normal. Analysis showed that these differentially expressed genes mainly related to the following pathways like inflammation response, immune response, defense responses, wound responses and external stimuli. Conclusions Through screening and analysis of important candidate genes involved in asthma, we are able to investigate and explore the pathogenesis of asthma and to prevent asthma effectively in the future.%目的 利用基因芯片技术寻找哮喘病患者与正常人外周血单核细胞之间差异表达基因,拟为哮喘的早期诊断及预防提供分子标记.方法 用淋巴细胞分离液分别提取16例哮喘病患者与16例正常人外周血单核细胞,用QIAGEN Rneasy Kit提取纯化样本总RNA,并合成用荧光标记的cRNA,分别与含有41 000条基因序列的全基因芯片杂交,以基因表达倍数值≥2.0和基因表达倍数值≤-2.0为阈值来确定差异

  17. Comparison of gene expression microarray data with count-based RNA measurements informs microarray interpretation

    OpenAIRE

    Richard, Arianne C.; Lyons, Paul A.; Peters, James E.; Biasci, Daniele; Flint, Shaun M; James C Lee; McKinney, Eoin F; Siegel, Richard M.; Smith, Kenneth GC

    2014-01-01

    Background Although numerous investigations have compared gene expression microarray platforms, preprocessing methods and batch correction algorithms using constructed spike-in or dilution datasets, there remains a paucity of studies examining the properties of microarray data using diverse biological samples. Most microarray experiments seek to identify subtle differences between samples with variable background noise, a scenario poorly represented by constructed datasets. Thus, microarray u...

  18. Identification of prior candidate genes for Sclerotinia local resistance in Brassica napus using Arabidopsis cDNA microarray and Brassica-Arabidopsis comparative mapping

    Institute of Scientific and Technical Information of China (English)

    LIU; Renhu; ZHAO; Jianwei; XIAO; Yong; MENG; Jinling

    2005-01-01

    Arabidopsis cDNA arrays were used to screen the local-defense-associated genes in oilseed rape (Brassica napus L.) at the challenge of Sclerotinia sclerotiorum. 61 genes with two-fold expression changes were screened out from the local tissue around the necrosis. Among them, 36 unique genes were up-regulated and 25 unique genes were down-regulated. RT-PCR and Northern blot results were consistent with the array results, suggesting Arabidopsis arrays were useful for transcriptional profiling of B. napus genes. Some of these genes were located in the interval of some QTLs for Sclerotinia resistance in B. napus by Brassica- Arabidopsis comparative mapping. These genes may have priority to be pursued for more intensive research.

  19. Candidate gene prioritization with Endeavour.

    Science.gov (United States)

    Tranchevent, Léon-Charles; Ardeshirdavani, Amin; ElShal, Sarah; Alcaide, Daniel; Aerts, Jan; Auboeuf, Didier; Moreau, Yves

    2016-07-01

    Genomic studies and high-throughput experiments often produce large lists of candidate genes among which only a small fraction are truly relevant to the disease, phenotype or biological process of interest. Gene prioritization tackles this problem by ranking candidate genes by profiling candidates across multiple genomic data sources and integrating this heterogeneous information into a global ranking. We describe an extended version of our gene prioritization method, Endeavour, now available for six species and integrating 75 data sources. The performance (Area Under the Curve) of Endeavour on cross-validation benchmarks using 'gold standard' gene sets varies from 88% (for human phenotypes) to 95% (for worm gene function). In addition, we have also validated our approach using a time-stamped benchmark derived from the Human Phenotype Ontology, which provides a setting close to prospective validation. With this benchmark, using 3854 novel gene-phenotype associations, we observe a performance of 82%. Altogether, our results indicate that this extended version of Endeavour efficiently prioritizes candidate genes. The Endeavour web server is freely available at https://endeavour.esat.kuleuven.be/. PMID:27131783

  20. DNA Microarray Assessment of Putative Borrelia burgdorferi Lipoprotein Genes

    OpenAIRE

    Liang, Fang Ting; Nelson, F. Kenneth; Fikrig, Erol

    2002-01-01

    A DNA microarray containing fragments of 137 Borrelia burgdorferi B31 putative lipoprotein genes was used to examine Lyme disease spirochetes. DNA from B. burgdorferi sensu stricto B31, 297, and N40; Borrelia garinii IP90; and Borrelia afzelii P/Gau was fluorescently labeled and hybridized to the microarray, demonstrating the degree to which the individual putative lipoprotein genes were conserved among the genospecies. These data show that a DNA microarray can globally examine the genes enco...

  1. Parsimonious selection of useful genes in microarray gene expression data

    OpenAIRE

    González Navarro, Félix Fernando; Belanche Muñoz, Luis Antonio

    2011-01-01

    Machine Learning methods have of late made significant efforts to solving multidisciplinary problems in the field of cancer classification in microarray gene expression data. These tasks are characterized by a large number of features and a few observations, making the modeling a non-trivial undertaking. In this work we apply entropic filter methods for gene selection, in combination with several off-the-shelf classifiers. The introduction of bootstrap resampling techniques permits the achiev...

  2. Role of Permutations in Significance Analysis of Microarray and Clustering of Significant Microarray Gene list

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    Tejashree Damle

    2012-03-01

    Full Text Available Microarray is the gene expression data that represent gene in different biological states. Methods are needed to determine the significance of these changes while accounting for the enormous number of genes. Significance analysis of microarrays (SAM is a statistical technique for determining whether changes in gene expression are statistically significant. During the SAM procedure permutation of microarray data is considered to observe the changes in the overall expression level of data. With increasing number of permutations false discovery rate for gene set varies. In our work we took microarray data of Normal Glucose Tolerance (NGT, and Diabetes Mellitus (DM Type II. In this paper we proposed the result of permutations during execution of SAM algorithm. The hierarchical clustering is applied for observing expression levels of significant data and visualize it with heat map.

  3. AffyMiner: mining differentially expressed genes and biological knowledge in GeneChip microarray data

    OpenAIRE

    Xia Yuannan; Nguyen The V; Lu Guoqing; Fromm Michael

    2006-01-01

    Abstract Background DNA microarrays are a powerful tool for monitoring the expression of tens of thousands of genes simultaneously. With the advance of microarray technology, the challenge issue becomes how to analyze a large amount of microarray data and make biological sense of them. Affymetrix GeneChips are widely used microarrays, where a variety of statistical algorithms have been explored and used for detecting significant genes in the experiment. These methods rely solely on the quanti...

  4. Emerging Use of Gene Expression Microarrays in Plant Physiology

    OpenAIRE

    Wullschleger, Stan D.; Difazio, Stephen P.

    2003-01-01

    Microarrays have become an important technology for the global analysis of gene expression in humans, animals, plants, and microbes. Implemented in the context of a well-designed experiment, cDNA and oligonucleotide arrays can provide highthroughput, simultaneous analysis of transcript abundance for hundreds, if not thousands, of genes. However, despite widespread acceptance, the use of microarrays as a tool to better understand processes of interest to the plant physiologist is still being e...

  5. Statistical Quality Control of Microarray Gene Expression Data

    Directory of Open Access Journals (Sweden)

    Shen Lu

    2011-12-01

    Full Text Available This paper is about how to control the quality of microarray expression data. Since gene-expression microarrays have become almost as widely used as measurement tools in biological research, we survey microarray experimental data to see possibilities and problems to control microarray expression data. We use both variable measure and attribute measure to visualize microarray expression data. According to the attribute data's structure, we use control charts to visualize fold change and t-test attributes in order to find the root causes. Then, we build data mining prediction models to evaluate the output. According to the accuracy of the prediction model, we can prove control charts can effectively visualize root causes.

  6. Cattle Candidate Genes for Milk Production Traits

    OpenAIRE

    Kadlec,Tomáš

    2012-01-01

    The aim of this thesis is to make an overview of important candidate genes affecting milk yield and milk quality parameters, with an emphasis on genes associated with the quantity and quality of milk proteins and milk fat.

  7. Regularized gene selection in cancer microarray meta-analysis

    Directory of Open Access Journals (Sweden)

    Huang Jian

    2009-01-01

    Full Text Available Abstract Background In cancer studies, it is common that multiple microarray experiments are conducted to measure the same clinical outcome and expressions of the same set of genes. An important goal of such experiments is to identify a subset of genes that can potentially serve as predictive markers for cancer development and progression. Analyses of individual experiments may lead to unreliable gene selection results because of the small sample sizes. Meta analysis can be used to pool multiple experiments, increase statistical power, and achieve more reliable gene selection. The meta analysis of cancer microarray data is challenging because of the high dimensionality of gene expressions and the differences in experimental settings amongst different experiments. Results We propose a Meta Threshold Gradient Descent Regularization (MTGDR approach for gene selection in the meta analysis of cancer microarray data. The MTGDR has many advantages over existing approaches. It allows different experiments to have different experimental settings. It can account for the joint effects of multiple genes on cancer, and it can select the same set of cancer-associated genes across multiple experiments. Simulation studies and analyses of multiple pancreatic and liver cancer experiments demonstrate the superior performance of the MTGDR. Conclusion The MTGDR provides an effective way of analyzing multiple cancer microarray studies and selecting reliable cancer-associated genes.

  8. A Gene Expression Barcode for Microarray Data

    OpenAIRE

    Zilliox, Michael J.; Irizarry, Rafael A.

    2007-01-01

    The ability to measure genome-wide expression holds great promise for characterizing cells and distinguishing diseased from normal tissues. Thus far, microarray technology has only been useful for measuring relative expression between two or more samples, which has handicapped its ability to classify tissue types. This paper presents the first method that can successfully predict tissue type based on data from a single hybridization. A preliminary web-tool is available at http://rafalab.jhsph...

  9. Comparison of gene coverage of mouse oligonucleotide microarray platforms

    Directory of Open Access Journals (Sweden)

    Medrano Juan F

    2006-03-01

    Full Text Available Abstract Background The increasing use of DNA microarrays for genetical genomics studies generates a need for platforms with complete coverage of the genome. We have compared the effective gene coverage in the mouse genome of different commercial and noncommercial oligonucleotide microarray platforms by performing an in-house gene annotation of probes. We only used information about probes that is available from vendors and followed a process that any researcher may take to find the gene targeted by a given probe. In order to make consistent comparisons between platforms, probes in each microarray were annotated with an Entrez Gene id and the chromosomal position for each gene was obtained from the UCSC Genome Browser Database. Gene coverage was estimated as the percentage of Entrez Genes with a unique position in the UCSC Genome database that is tested by a given microarray platform. Results A MySQL relational database was created to store the mapping information for 25,416 mouse genes and for the probes in five microarray platforms (gene coverage level in parenthesis: Affymetrix430 2.0 (75.6%, ABI Genome Survey (81.24%, Agilent (79.33%, Codelink (78.09%, Sentrix (90.47%; and four array-ready oligosets: Sigma (47.95%, Operon v.3 (69.89%, Operon v.4 (84.03%, and MEEBO (84.03%. The differences in coverage between platforms were highly conserved across chromosomes. Differences in the number of redundant and unspecific probes were also found among arrays. The database can be queried to compare specific genomic regions using a web interface. The software used to create, update and query the database is freely available as a toolbox named ArrayGene. Conclusion The software developed here allows researchers to create updated custom databases by using public or proprietary information on genes for any organisms. ArrayGene allows easy comparisons of gene coverage between microarray platforms for any region of the genome. The comparison presented here

  10. Gene expression profile analysis in astaxanthin-induced Haematococcus pluvialis using a cDNA microarray.

    Science.gov (United States)

    Eom, Hyunsuk; Lee, Choul-Gyun; Jin, EonSeon

    2006-05-01

    The unicellular green alga Haematococcus pluvialis (Volvocales) is known for the ketocarotenoid astaxanthin (3, 3'-dihydroxy-beta, beta-carotene-4, 4'-dione) accumulation, which is induced under unfavorable culture conditions. In this work, we used cDNA microarray analysis to screen differentially expressed genes in H. pluvialis under astaxanthin-inductive culture conditions, such as combination of cell exposure to high irradiance and nutrient deprivation. Among the 965 genes in the cDNA array, there are 144 genes exhibiting differential expression (twofold changes) under these conditions. A significant decrease in the expression of photosynthesis-related genes was shown in astaxanthin-accumulating cells (red cells). Defense- or stress-related genes and signal transduction genes were also induced in the red cells. A comparison of microarray and real-time PCR analysis showed good correlation between the differentially expressed genes by the two methods. Our results indicate that the cDNA microarray approach, as employed in this work, can be relied upon and used to monitor gene expression profiles in H. pluvialis. In addition, the genes that were differentially expressed during astaxanthin induction are suitable candidates for further study and can be used as tools for dissecting the molecular mechanism of this unique pigment accumulation process in the green alga H. pluvialis. PMID:16320067

  11. Evaluating historical candidate genes for schizophrenia

    DEFF Research Database (Denmark)

    Farrell, M S; Werge, T; Sklar, P;

    2015-01-01

    Prior to the genome-wide association era, candidate gene studies were a major approach in schizophrenia genetics. In this invited review, we consider the current status of 25 historical candidate genes for schizophrenia (for example, COMT, DISC1, DTNBP1 and NRG1). The initial study for 24 of these...... genes explicitly evaluated common variant hypotheses about schizophrenia. Our evaluation included a meta-analysis of the candidate gene literature, incorporation of the results of the largest genomic study yet published for schizophrenia, ratings from informed researchers who have published on these...... genes, and ratings from 24 schizophrenia geneticists. On the basis of current empirical evidence and mostly consensual assessments of informed opinion, it appears that the historical candidate gene literature did not yield clear insights into the genetic basis of schizophrenia. A likely reason why...

  12. Gene Expression Analysis Using Agilent DNA Microarrays

    DEFF Research Database (Denmark)

    Stangegaard, Michael

    2009-01-01

    Hybridization of labeled cDNA to microarrays is an intuitively simple and a vastly underestimated process. If it is not performed, optimized, and standardized with the same attention to detail as e.g., RNA amplification, information may be overlooked or even lost. Careful balancing of the amount of...... labeled cDNA added to each slide reduces dye-bias and slide to slide variation. Efficient mixing of the hybridization solution throughout the hybridization reaction increases signals several fold. The amount of near perfect target-probe hybrids may be reduced by efficient stringency washes of the...

  13. Identification of novel endogenous antisense transcripts by DNA microarray analysis targeting complementary strand of annotated genes

    Directory of Open Access Journals (Sweden)

    Kohama Chihiro

    2009-08-01

    Full Text Available Abstract Background Recent transcriptomic analyses in mammals have uncovered the widespread occurrence of endogenous antisense transcripts, termed natural antisense transcripts (NATs. NATs are transcribed from the opposite strand of the gene locus and are thought to control sense gene expression, but the mechanism of such regulation is as yet unknown. Although several thousand potential sense-antisense pairs have been identified in mammals, examples of functionally characterized NATs remain limited. To identify NAT candidates suitable for further functional analyses, we performed DNA microarray-based NAT screening using mouse adult normal tissues and mammary tumors to target not only the sense orientation but also the complementary strand of the annotated genes. Results First, we designed microarray probes to target the complementary strand of genes for which an antisense counterpart had been identified only in human public cDNA sources, but not in the mouse. We observed a prominent expression signal from 66.1% of 635 target genes, and 58 genes of these showed tissue-specific expression. Expression analyses of selected examples (Acaa1b and Aard confirmed their dynamic transcription in vivo. Although interspecies conservation of NAT expression was previously investigated by the presence of cDNA sources in both species, our results suggest that there are more examples of human-mouse conserved NATs that could not be identified by cDNA sources. We also designed probes to target the complementary strand of well-characterized genes, including oncogenes, and compared the expression of these genes between mammary cancerous tissues and non-pathological tissues. We found that antisense expression of 95 genes of 404 well-annotated genes was markedly altered in tumor tissue compared with that in normal tissue and that 19 of these genes also exhibited changes in sense gene expression. These results highlight the importance of NAT expression in the regulation

  14. A fisheye viewer for microarray-based gene expression data

    Directory of Open Access Journals (Sweden)

    Munson Ethan V

    2006-10-01

    Full Text Available Abstract Background Microarray has been widely used to measure the relative amounts of every mRNA transcript from the genome in a single scan. Biologists have been accustomed to reading their experimental data directly from tables. However, microarray data are quite large and are stored in a series of files in a machine-readable format, so direct reading of the full data set is not feasible. The challenge is to design a user interface that allows biologists to usefully view large tables of raw microarray-based gene expression data. This paper presents one such interface – an electronic table (E-table that uses fisheye distortion technology. Results The Fisheye Viewer for microarray-based gene expression data has been successfully developed to view MIAME data stored in the MAGE-ML format. The viewer can be downloaded from the project web site http://polaris.imt.uwm.edu:7777/fisheye/. The fisheye viewer was implemented in Java so that it could run on multiple platforms. We implemented the E-table by adapting JTable, a default table implementation in the Java Swing user interface library. Fisheye views use variable magnification to balance magnification for easy viewing and compression for maximizing the amount of data on the screen. Conclusion This Fisheye Viewer is a lightweight but useful tool for biologists to quickly overview the raw microarray-based gene expression data in an E-table.

  15. Regularized gene selection in cancer microarray meta-analysis

    OpenAIRE

    Huang Jian; Ma Shuangge

    2009-01-01

    Abstract Background In cancer studies, it is common that multiple microarray experiments are conducted to measure the same clinical outcome and expressions of the same set of genes. An important goal of such experiments is to identify a subset of genes that can potentially serve as predictive markers for cancer development and progression. Analyses of individual experiments may lead to unreliable gene selection results because of the small sample sizes. Meta analysis can be used to pool multi...

  16. Candidate genes for behavioural ecology

    NARCIS (Netherlands)

    Fitzpatrick, M.J.; Ben-Sahar, Y.; Smid, H.M.; Vet, L.E.M.; Robinson, G.E.; Sokolowski, M.B.

    2005-01-01

    In spite of millions of years of evolutionary divergence, the conservation of gene function is common across distant lineages. As such, genes that are known to influence behaviour in one organism are likely to influence similar behaviours in other organisms. Recent studies of the evolution of behavi

  17. Alcoholism and Alternative Splicing of Candidate Genes

    OpenAIRE

    Toshikazu Sasabe; Shoichi Ishiura

    2010-01-01

    Gene expression studies have shown that expression patterns of several genes have changed during the development of alcoholism. Gene expression is regulated not only at the level of transcription but also through alternative splicing of pre-mRNA. In this review, we discuss some of the evidence suggesting that alternative splicing of candidate genes such as DRD2 (encoding dopamine D2 receptor) may form the basis of the mechanisms underlying the pathophysiology of alcoholism. These reports sugg...

  18. Monitoring microarray-based gene expression profile changes in hepatocellular carcinoma

    Institute of Scientific and Technical Information of China (English)

    Hong-Ju Mao; Hong-Nian Li; Xiao-Mei Zhou; Jian-Long Zhao; Da-Fang Wan

    2005-01-01

    AIM: To find out key genes responsible for hepatocarc inogenesis and to further understand the underlying molecular mechanism through investigating the differential gene expression between human normal liver tissue and hepatocellular carcinoma (HCC).METHODS: DNA microarray was prepared by spotting PCR products of 1 000 human genes including 445 novel genes, 540 known genes as well as 12 positive (housekeeping) and 3 negative controls (plant gene) onto treated glass slides. cDNA probes were prepared by labeling normal liver tissue mRNA and cancer liver tissue mRNA with Cy3-dUTP and Cy5-dUTP separately through reverse transcription. The arrays were hybridized against the cDNA probe and the fluorescent signals were scanned. The dataobtained from repeated experiments were analyzed. RESULTS: Among the 20 couple samples investigated (from cancerous liver tissue and normal liver tissue), 38 genes including 21 novel genes and 17 known genes exhibited different expressions. CONCLUSION: cDNA microarray technique is powerful to identify candidate target genes that may play important roles in human carcinogenesis. Further analysis of the obtained genes is helpful to understand the molecular changes in HCC progression and ultimately may lead to the identification of new targets for HCC diagnosis and intervention.

  19. Gene networks from DNA microarray data: centrality and lethality

    OpenAIRE

    Provero, P.

    2002-01-01

    We construct a gene network based on expression data from DNA microarray experiments, by establishing a link between two genes whenever the Pearson's correlation coefficient between their expression profiles is higher than a certain cutoff. The resulting connectivity distribution is compatible with a power-law decay with exponent ~1, corrected by an exponential cutoff at large connectivity. The biological relevance of such network is demonstrated by showing that there is a strong statistical ...

  20. Meta-analysis of gene expression microarrays with missing replicates

    OpenAIRE

    Leckie Christopher; Abraham Gad; Shi Fan; Haviv Izhak; Kowalczyk Adam

    2011-01-01

    Abstract Background Many different microarray experiments are publicly available today. It is natural to ask whether different experiments for the same phenotypic conditions can be combined using meta-analysis, in order to increase the overall sample size. However, some genes are not measured in all experiments, hence they cannot be included or their statistical significance cannot be appropriately estimated in traditional meta-analysis. Nonetheless, these genes, which we refer to as incomple...

  1. Are Gene Expression Microarray Analyses Reliable? A Review of Studies of Retinoic Acid Responsive Genes

    Institute of Scientific and Technical Information of China (English)

    Peter J. van der Spek; Andreas Kremer; Lynn Murry; Michael G. Walker

    2003-01-01

    Microarray analyses of gene expression are widely used, but reports of the same analyses by different groups give widely divergent results, and raise questions regarding reproducibility and reliability. We take as an example recent published reports on microarray experiments that were designed to identify retinoic acid responsive genes. These reports show substantial differences in their results. In this article, we review the methodology, results, and potential causes of differences in these applications of microarrays. Finally, we suggest practices to improve the reliability and reproducibility of microarray experiments.

  2. Are Gene Expression Microarray Analyses Reliable? A Review of Studies of Retinoic Acid Responsive Genes

    Institute of Scientific and Technical Information of China (English)

    PeterJ.vanderSpek; AndreasKremer; LynnMurry; MichaelG.Walker

    2003-01-01

    Microarray analyses of gene expression are widely used,but reports of the same analyses by different groups give widely divergent results,and raise questions regarding reproducibility and reliability.We take as an example recent published reports on microarray experiments that were designed to identify retinoic acid responsive genes.These reports show substantial differences in their results.In this article,we review the methodology,results,and potential causes of differences in these applications of microarrays.Finally,we suggest practices to improve the reliability and reproducibility of microarray experiments.

  3. Evaluating historical candidate genes for schizophrenia.

    Science.gov (United States)

    Farrell, M S; Werge, T; Sklar, P; Owen, M J; Ophoff, R A; O'Donovan, M C; Corvin, A; Cichon, S; Sullivan, P F

    2015-05-01

    Prior to the genome-wide association era, candidate gene studies were a major approach in schizophrenia genetics. In this invited review, we consider the current status of 25 historical candidate genes for schizophrenia (for example, COMT, DISC1, DTNBP1 and NRG1). The initial study for 24 of these genes explicitly evaluated common variant hypotheses about schizophrenia. Our evaluation included a meta-analysis of the candidate gene literature, incorporation of the results of the largest genomic study yet published for schizophrenia, ratings from informed researchers who have published on these genes, and ratings from 24 schizophrenia geneticists. On the basis of current empirical evidence and mostly consensual assessments of informed opinion, it appears that the historical candidate gene literature did not yield clear insights into the genetic basis of schizophrenia. A likely reason why historical candidate gene studies did not achieve their primary aims is inadequate statistical power. However, the considerable efforts embodied in these early studies unquestionably set the stage for current successes in genomic approaches to schizophrenia. PMID:25754081

  4. Cattle Candidate Genes for Meat Production Traits

    OpenAIRE

    Bláhová, Alice

    2013-01-01

    The objective of this study was to compile a summary of the most important candidate genes for meat production. The studied genes were: GH, GHR, MSTN, MyoD family, leptin, IGF, TG5, SCD, DGAT and STAT5A. Growth hormone (GH) is involved in physiological processes of growth and metabolism. Growth hormone receptor (GHR) has been proposed as a candidate gene for meat production in cattle. Myostatin is a significant marker. It affects the amount of muscle, reduces marbling and elevate meat tendern...

  5. Coupled Two-Way Clustering Analysis of Gene Microarray Data

    CERN Document Server

    Getz, G; Domany, E

    2000-01-01

    We present a novel coupled two-way clustering approach to gene microarray data analysis. The main idea is to identify subsets of the genes and samples, such that when one of these is used to cluster the other, stable and significant partitions emerge. The search for such subsets is a computationally complex task: we present an algorithm, based on iterative clustering, which performs such a search. This analysis is especially suitable for gene microarray data, where the contributions of a variety of biological mechanisms to the gene expression levels are entangled in a large body of experimental data. The method was applied to two gene microarray data sets, on colon cancer and leukemia. By identifying relevant subsets of the data and focusing on them we were able to discover partitions and correlations that were masked and hidden when the full dataset was used in the analysis. Some of these partitions have clear biological interpretation; others can serve to identify possible directions for future research.

  6. Microarray analysis of gene expression profiles in ripening pineapple fruits

    Directory of Open Access Journals (Sweden)

    Koia Jonni H

    2012-12-01

    Full Text Available Abstract Background Pineapple (Ananas comosus is a tropical fruit crop of significant commercial importance. Although the physiological changes that occur during pineapple fruit development have been well characterized, little is known about the molecular events that occur during the fruit ripening process. Understanding the molecular basis of pineapple fruit ripening will aid the development of new varieties via molecular breeding or genetic modification. In this study we developed a 9277 element pineapple microarray and used it to profile gene expression changes that occur during pineapple fruit ripening. Results Microarray analyses identified 271 unique cDNAs differentially expressed at least 1.5-fold between the mature green and mature yellow stages of pineapple fruit ripening. Among these 271 sequences, 184 share significant homology with genes encoding proteins of known function, 53 share homology with genes encoding proteins of unknown function and 34 share no significant homology with any database accession. Of the 237 pineapple sequences with homologs, 160 were up-regulated and 77 were down-regulated during pineapple fruit ripening. DAVID Functional Annotation Cluster (FAC analysis of all 237 sequences with homologs revealed confident enrichment scores for redox activity, organic acid metabolism, metalloenzyme activity, glycolysis, vitamin C biosynthesis, antioxidant activity and cysteine peptidase activity, indicating the functional significance and importance of these processes and pathways during pineapple fruit development. Quantitative real-time PCR analysis validated the microarray expression results for nine out of ten genes tested. Conclusions This is the first report of a microarray based gene expression study undertaken in pineapple. Our bioinformatic analyses of the transcript profiles have identified a number of genes, processes and pathways with putative involvement in the pineapple fruit ripening process. This study

  7. ArrayExpress—a public repository for microarray gene expression data at the EBI

    OpenAIRE

    Brazma, Alvis; Parkinson, Helen; Sarkans, Ugis; Shojatalab, Mohammadreza; Vilo, Jaak; Abeygunawardena, Niran; Holloway, Ele; Kapushesky, Misha; Kemmeren, Patrick; Lara, Gonzalo Garcia; Oezcimen, Ahmet; Rocca-Serra, Philippe; Sansone, Susanna-Assunta

    2004-01-01

    ArrayExpress is a new public database of microarray gene expression data at the EBI, which is a generic gene expression database designed to hold data from all microarray platforms. ArrayExpress uses the annotation standard Minimum Information About a Microarray Experiment (MIAME) and the associated XML data exchange format Microarray Gene Expression Markup Language (MAGE-ML) and it is designed to store well annotated data in a structured way. The ArrayExpress infrastructure consists of the d...

  8. Assessment of gene set analysis methods based on microarray data.

    Science.gov (United States)

    Alavi-Majd, Hamid; Khodakarim, Soheila; Zayeri, Farid; Rezaei-Tavirani, Mostafa; Tabatabaei, Seyyed Mohammad; Heydarpour-Meymeh, Maryam

    2014-01-25

    Gene set analysis (GSA) incorporates biological information into statistical knowledge to identify gene sets differently expressed between two or more phenotypes. It allows us to gain an insight into the functional working mechanism of cells beyond the detection of differently expressed gene sets. In order to evaluate the competence of GSA approaches, three self-contained GSA approaches with different statistical methods were chosen; Category, Globaltest and Hotelling's T(2) together with their assayed power to identify the differences expressed via simulation and real microarray data. The Category does not take care of the correlation structure, while the other two deal with correlations. In order to perform these methods, R and Bioconductor were used. Furthermore, venous thromboembolism and acute lymphoblastic leukemia microarray data were applied. The results of three GSAs showed that the competence of these methods depends on the distribution of gene expression in a dataset. It is very important to assay the distribution of gene expression data before choosing the GSA method to identify gene sets differently expressed between phenotypes. On the other hand, assessment of common genes among significant gene sets indicated that there was a significant agreement between the result of GSA and the findings of biologists. PMID:24012817

  9. Ecologically relevant stress resistance: from microarrays and quantitative trait loci to candidate genes – A research plan and preliminary results using Drosophila as a model organism and climatic and genetic stress as model stresses

    Indian Academy of Sciences (India)

    Volker Loeschcke; Jesper G Sørensen; Torsten N Kristensen

    2004-12-01

    We aim at studying adaptation to genetic and environmental stress and its evolutionary implications at different levels of biological organization. Stress influences cellular processes, individual physiology, genetic variation at the population level, and the process of natural selection. To investigate these highly connected levels of stress effects, it is advisable – if not critical – to integrate approaches from ecology, evolution, physiology, molecular biology and genetics. To investigate the mechanisms of stress resistance, how resistance evolves, and what factors contribute to and constrain its evolution, we use the well-defined model systems of Drosophila species, representing both cosmopolitan species such as D. melanogaster with a known genome map, and more specialized and ecologically well described species such as the cactophilic D. buzzatii. Various climate-related stresses are used as model stresses including desiccation, starvation, cold and heat. Genetic stress or genetic load is modelled by studying the consequences of inbreeding, the accumulation of (slightly) deleterious mutations, hybridization or the loss of genetic variability. We present here a research plan and preliminary results combining various approaches: molecular techniques such as microarrays, quantitative trait loci (QTL) analyses, quantitative PCR, ELISA or Western blotting are combined with population studies of resistance to climatic and genetic stress in natural populations collected across climatic gradients as well as in selection lines maintained in the laboratory.

  10. Genome-wide prediction and analysis of human tissue-selective genes using microarray expression data

    Directory of Open Access Journals (Sweden)

    Teng Shaolei

    2013-01-01

    Full Text Available Abstract Background Understanding how genes are expressed specifically in particular tissues is a fundamental question in developmental biology. Many tissue-specific genes are involved in the pathogenesis of complex human diseases. However, experimental identification of tissue-specific genes is time consuming and difficult. The accurate predictions of tissue-specific gene targets could provide useful information for biomarker development and drug target identification. Results In this study, we have developed a machine learning approach for predicting the human tissue-specific genes using microarray expression data. The lists of known tissue-specific genes for different tissues were collected from UniProt database, and the expression data retrieved from the previously compiled dataset according to the lists were used for input vector encoding. Random Forests (RFs and Support Vector Machines (SVMs were used to construct accurate classifiers. The RF classifiers were found to outperform SVM models for tissue-specific gene prediction. The results suggest that the candidate genes for brain or liver specific expression can provide valuable information for further experimental studies. Our approach was also applied for identifying tissue-selective gene targets for different types of tissues. Conclusions A machine learning approach has been developed for accurately identifying the candidate genes for tissue specific/selective expression. The approach provides an efficient way to select some interesting genes for developing new biomedical markers and improve our knowledge of tissue-specific expression.

  11. Dimension Reduction for Classification with Gene Expression Microarray Data

    OpenAIRE

    Dai Jian J; Lieu Linh; Rocke David

    2006-01-01

    An important application of gene expression microarray data is classification of biological samples or prediction of clinical and other outcomes. One necessary part of multivariate statistical analysis in such applications is dimension reduction. This paper provides a comparison study of three dimension reduction techniques, namely partial least squares (PLS), sliced inverse regression (SIR) and principal component analysis (PCA), and evaluates the relative performance of classification proce...

  12. Data integration for microarrays: enhanced inference for gene regulatory networks

    OpenAIRE

    Alina Sîrbu; Martin Crane; Ruskin, Heather J

    2015-01-01

    Microarray technologies have been the basis of numerous important findings regarding gene expression in the few last decades. Studies have generated large amounts of data describing various processes, which, due to the existence of public databases, are widely available for further analysis. Given their lower cost and higher maturity compared to newer sequencing technologies, these data continue to be produced, even though data quality has been the subject of some debate. However, given the l...

  13. Gene expression profiling in peanut using high density oligonucleotide microarrays

    Directory of Open Access Journals (Sweden)

    Burow Mark

    2009-06-01

    Full Text Available Abstract Background Transcriptome expression analysis in peanut to date has been limited to a relatively small set of genes and only recently has a significant number of ESTs been released into the public domain. Utilization of these ESTs for oligonucleotide microarrays provides a means to investigate large-scale transcript responses to a variety of developmental and environmental signals, ultimately improving our understanding of plant biology. Results We have developed a high-density oligonucleotide microarray for peanut using 49,205 publicly available ESTs and tested the utility of this array for expression profiling in a variety of peanut tissues. To identify putatively tissue-specific genes and demonstrate the utility of this array for expression profiling in a variety of peanut tissues, we compared transcript levels in pod, peg, leaf, stem, and root tissues. Results from this experiment showed 108 putatively pod-specific/abundant genes, as well as transcripts whose expression was low or undetected in pod compared to peg, leaf, stem, or root. The transcripts significantly over-represented in pod include genes responsible for seed storage proteins and desiccation (e.g., late-embryogenesis abundant proteins, aquaporins, legumin B, oil production, and cellular defense. Additionally, almost half of the pod-abundant genes represent unknown genes allowing for the possibility of associating putative function to these previously uncharacterized genes. Conclusion The peanut oligonucleotide array represents the majority of publicly available peanut ESTs and can be used as a tool for expression profiling studies in diverse tissues.

  14. GenePublisher: automated analysis of DNA microarray data

    DEFF Research Database (Denmark)

    Knudsen, Steen; Workman, Christopher; Sicheritz-Ponten, T.;

    2003-01-01

    GenePublisher, a system for automatic analysis of data from DNA microarray experiments, has been implemented with a web interface at http://www.cbs.dtu.dk/services/GenePublisher. Raw data are uploaded to the server together with aspecification of the data. The server performs normalization......, statistical analysis and visualization of the data. The results are run against databases of signal transduction pathways, metabolic pathways and promoter sequences in order to extract more information. The results of the entire analysis are summarized in report form and returned to the user....

  15. Exhaustive Search for Fuzzy Gene Networks from Microarray Data

    Energy Technology Data Exchange (ETDEWEB)

    Sokhansanj, B A; Fitch, J P; Quong, J N; Quong, A A

    2003-07-07

    Recent technological advances in high-throughput data collection allow for the study of increasingly complex systems on the scale of the whole cellular genome and proteome. Gene network models are required to interpret large and complex data sets. Rationally designed system perturbations (e.g. gene knock-outs, metabolite removal, etc) can be used to iteratively refine hypothetical models, leading to a modeling-experiment cycle for high-throughput biological system analysis. We use fuzzy logic gene network models because they have greater resolution than Boolean logic models and do not require the precise parameter measurement needed for chemical kinetics-based modeling. The fuzzy gene network approach is tested by exhaustive search for network models describing cyclin gene interactions in yeast cell cycle microarray data, with preliminary success in recovering interactions predicted by previous biological knowledge and other analysis techniques. Our goal is to further develop this method in combination with experiments we are performing on bacterial regulatory networks.

  16. Sensitivity and fidelity of DNA microarray improved with integration of Amplified Differential Gene Expression (ADGE

    Directory of Open Access Journals (Sweden)

    Ile Kristina E

    2003-07-01

    Full Text Available Abstract Background The ADGE technique is a method designed to magnify the ratios of gene expression before detection. It improves the detection sensitivity to small change of gene expression and requires small amount of starting material. However, the throughput of ADGE is low. We integrated ADGE with DNA microarray (ADGE microarray and compared it with regular microarray. Results When ADGE was integrated with DNA microarray, a quantitative relationship of a power function between detected and input ratios was found. Because of ratio magnification, ADGE microarray was better able to detect small changes in gene expression in a drug resistant model cell line system. The PCR amplification of templates and efficient labeling reduced the requirement of starting material to as little as 125 ng of total RNA for one slide hybridization and enhanced the signal intensity. Integration of ratio magnification, template amplification and efficient labeling in ADGE microarray reduced artifacts in microarray data and improved detection fidelity. The results of ADGE microarray were less variable and more reproducible than those of regular microarray. A gene expression profile generated with ADGE microarray characterized the drug resistant phenotype, particularly with reference to glutathione, proliferation and kinase pathways. Conclusion ADGE microarray magnified the ratios of differential gene expression in a power function, improved the detection sensitivity and fidelity and reduced the requirement for starting material while maintaining high throughput. ADGE microarray generated a more informative expression pattern than regular microarray.

  17. Microarray data integration for genome-wide analysis of human tissue-selective gene expression

    OpenAIRE

    2010-01-01

    Background Microarray gene expression data are accumulating in public databases. The expression profiles contain valuable information for understanding human gene expression patterns. However, the effective use of public microarray data requires integrating the expression profiles from heterogeneous sources. Results In this study, we have compiled a compendium of microarray expression profiles of various human tissue samples. The microarray raw data generated in different research laboratorie...

  18. Transcriptome network analysis reveals potential candidate genes for squamous lung cancer.

    Science.gov (United States)

    Bai, Jing; Hu, Sheng

    2012-01-01

    Squamous lung cancer is a common type of lung cancer; however, its mechanism of oncogenesis is still unknown. The aim of this study was to screen candidate genes of squamous lung cancer using a bioinformatics strategy and elucidate the mechanism of squamous lung cancer. Published microarray data of the GSE3268 series was obtained from Gene Expression Omnibus (GEO). Significance analysis of microarrays was performed using the software R, and differentially expressed genes by R analysis were harvested. The relationship between transcription factors and target genes in cancer were collected from the Transcriptional regulatory element database. A transcriptome network analysis method was used to construct gene regulation networks and select the candidate genes for squamous lung cancer. SPI1, FLI1, FOS, ETS2, EGR1 and PPARG were defined as candidate genes for squamous lung cancer by the transcriptome network analysis method. Among them, 5 genes had been reported to be involved in lung cancer, except SPI1 and FLI1. Effective recall on previous knowledge conferred strong confidence in these methods. It is demonstrated that transcriptome network analysis is useful in the identification of candidate genes in disease. PMID:21922129

  19. DNA microarray analysis of genes differentially expressed in adipocyte differentiation

    Indian Academy of Sciences (India)

    Chunyan Yin; Yanfeng Xiao; Wei Zhang; Erdi Xu; Weihua Liu; Xiaoqing Yi; Ming Chang

    2014-06-01

    In the present study, the human liposarcoma cell line SW872 was used to identify global changes in gene expression profiles occurring during adipogenesis. We further explored some of the genes expressed during the late phase of adipocyte differentiation. These genes may play a major role in promoting excessive proliferation and accumulation of lipid droplets, which contribute to the development of obesity. By using microarray-based technology, we examined differential gene expression in early differentiated adipocytes and late differentiated adipocytes. Validated genes exhibited a ≥ 10-fold increase in the late phase of adipocyte differentiation by polymerase chain reaction (RT-PCR). Compared with undifferentiated preadipocytes, we found that 763 genes were increased in early differentiated adipocytes, and 667 genes were increased in later differentiated adipocytes. Furthermore, 21 genes were found being expressed 10-fold higher in the late phase of adipocyte differentiation. The results were in accordance with the RT-PCR test, which validated 11 genes, namely, CIDEC, PID1, LYRM1, ADD1, PPAR2, ANGPTL4, ADIPOQ, ACOX1, FIP1L1, MAP3K2 and PEX14. Most of these genes were found being expressed in the later phase of adipocyte differentiation involved in obesity-related diseases. The findings may help to better understand the mechanism of obesity and related diseases.

  20. Gene ordering in partitive clustering using microarray expressions

    Indian Academy of Sciences (India)

    Shubhra Sankar Ray; Sanghamitra Bandyopadhyay; Sankar K Pal

    2007-08-01

    A central step in the analysis of gene expression data is the identification of groups of genes that exhibit similar expression patterns. Clustering and ordering the genes using gene expression data into homogeneous groups was shown to be useful in functional annotation, tissue classification, regulatory motif identification, and other applications. Although there is a rich literature on gene ordering in hierarchical clustering framework for gene expression analysis, there is no work addressing and evaluating the importance of gene ordering in partitive clustering framework, to the best knowledge of the authors. Outside the framework of hierarchical clustering, different gene ordering algorithms are applied on the whole data set, and the domain of partitive clustering is still unexplored with gene ordering approaches. A new hybrid method is proposed for ordering genes in each of the clusters obtained from partitive clustering solution, using microarray gene expressions. Two existing algorithms for optimally ordering cities in travelling salesman problem (TSP), namely, FRAG_GALK and Concorde, are hybridized individually with self organizing MAP to show the importance of gene ordering in partitive clustering framework. We validated our hybrid approach using yeast and fibroblast data and showed that our approach improves the result quality of partitive clustering solution, by identifying subclusters within big clusters, grouping functionally correlated genes within clusters, minimization of summation of gene expression distances, and the maximization of biological gene ordering using MIPS categorization. Moreover, the new hybrid approach, finds comparable or sometimes superior biological gene order in less computation time than those obtained by optimal leaf ordering in hierarchical clustering solution.

  1. Conserved co-expression for candidate disease gene prioritization

    Directory of Open Access Journals (Sweden)

    Huynen Martijn A

    2008-04-01

    Full Text Available Abstract Background Genes that are co-expressed tend to be involved in the same biological process. However, co-expression is not a very reliable predictor of functional links between genes. The evolutionary conservation of co-expression between species can be used to predict protein function more reliably than co-expression in a single species. Here we examine whether co-expression across multiple species is also a better prioritizer of disease genes than is co-expression between human genes alone. Results We use co-expression data from yeast (S. cerevisiae, nematode worm (C. elegans, fruit fly (D. melanogaster, mouse and human and find that the use of evolutionary conservation can indeed improve the predictive value of co-expression. The effect that genes causing the same disease have higher co-expression than do other genes from their associated disease loci, is significantly enhanced when co-expression data are combined across evolutionarily distant species. We also find that performance can vary significantly depending on the co-expression datasets used, and just using more data does not necessarily lead to better prioritization. Instead, we find that dataset quality is more important than quantity, and using a consistent microarray platform per species leads to better performance than using more inclusive datasets pooled from various platforms. Conclusion We find that evolutionarily conserved gene co-expression prioritizes disease candidate genes better than human gene co-expression alone, and provide the integrated data as a new resource for disease gene prioritization tools.

  2. Meta-analysis of gene expression microarrays with missing replicates

    Directory of Open Access Journals (Sweden)

    Leckie Christopher

    2011-03-01

    Full Text Available Abstract Background Many different microarray experiments are publicly available today. It is natural to ask whether different experiments for the same phenotypic conditions can be combined using meta-analysis, in order to increase the overall sample size. However, some genes are not measured in all experiments, hence they cannot be included or their statistical significance cannot be appropriately estimated in traditional meta-analysis. Nonetheless, these genes, which we refer to as incomplete genes, may also be informative and useful. Results We propose a meta-analysis framework, called "Incomplete Gene Meta-analysis", which can include incomplete genes by imputing the significance of missing replicates, and computing a meta-score for every gene across all datasets. We demonstrate that the incomplete genes are worthy of being included and our method is able to appropriately estimate their significance in two groups of experiments. We first apply the Incomplete Gene Meta-analysis and several comparable methods to five breast cancer datasets with an identical set of probes. We simulate incomplete genes by randomly removing a subset of probes from each dataset and demonstrate that our method consistently outperforms two other methods in terms of their false discovery rate. We also apply the methods to three gastric cancer datasets for the purpose of discriminating diffuse and intestinal subtypes. Conclusions Meta-analysis is an effective approach that identifies more robust sets of differentially expressed genes from multiple studies. The incomplete genes that mainly arise from the use of different platforms may also have statistical and biological importance but are ignored or are not appropriately involved by previous studies. Our Incomplete Gene Meta-analysis is able to incorporate the incomplete genes by estimating their significance. The results on both breast and gastric cancer datasets suggest that the highly ranked genes and associated GO

  3. Data Integration for Microarrays: Enhanced Inference for Gene Regulatory Networks

    Directory of Open Access Journals (Sweden)

    Alina Sîrbu

    2015-05-01

    Full Text Available Microarray technologies have been the basis of numerous important findings regarding gene expression in the few last decades. Studies have generated large amounts of data describing various processes, which, due to the existence of public databases, are widely available for further analysis. Given their lower cost and higher maturity compared to newer sequencing technologies, these data continue to be produced, even though data quality has been the subject of some debate. However, given the large volume of data generated, integration can help overcome some issues related, e.g., to noise or reduced time resolution, while providing additional insight on features not directly addressed by sequencing methods. Here, we present an integration test case based on public Drosophila melanogaster datasets (gene expression, binding site affinities, known interactions. Using an evolutionary computation framework, we show how integration can enhance the ability to recover transcriptional gene regulatory networks from these data, as well as indicating which data types are more important for quantitative and qualitative network inference. Our results show a clear improvement in performance when multiple datasets are integrated, indicating that microarray data will remain a valuable and viable resource for some time to come.

  4. Fibrin-mediated lentivirus gene transfer: implications for lentivirus microarrays.

    Science.gov (United States)

    Raut, Shruti D; Lei, Pedro; Padmashali, Roshan M; Andreadis, Stelios T

    2010-06-01

    We employed fibrin hydrogel as a bioactive matrix for lentivirus mediated gene transfer. Fibrin-mediated gene transfer was highly efficient and exhibited strong dependence on fibrinogen concentration. Efficient gene transfer was achieved with fibrinogen concentration between 3.75 and 7.5mg/ml. Lower fibrinogen concentrations resulted in diffusion of virus out of the gel while higher concentrations led to ineffective fibrin degradation by target cells. Addition of fibrinolytic inhibitors decreased gene transfer in a dose-dependent manner suggesting that fibrin degradation by target cells may be necessary for successful gene delivery. Under these conditions transduction may be limited only to cells interacting with the matrix thereby providing a method for spatially-localized gene delivery. Indeed, when lentivirus-containing fibrin microgels were spotted in an array format gene transfer was confined to virus-containing fibrin spots with minimal cross-contamination between neighboring sites. Collectively, our data suggest that fibrin may provide an effective matrix for spatially-localized gene delivery with potential applications in high-throughput lentiviral microarrays and in regenerative medicine. PMID:20153386

  5. Candidate gene effects on beef quality

    OpenAIRE

    Ekerljung, Marie

    2012-01-01

    The contribution of five candidate genes to the variation in meat tenderness, pH, colour, marbling and water holding capacity (WHC) was analysed in muscle samples from 243 young bulls of Angus, Charolais, Hereford, Limousin, or Simmental breed, raised in Swedish commercial herds. The animals were genotyped for single nucleotide polymorphisms (SNPs) in the genes encoding calpain 1 (CAPN1:c.947G>C), calpastatin, (CAST:c.155C>T), diacylglycerol O-acyltransferase 1 (DGAT1), leptin (UASMS2C>T) a...

  6. Microarray Gene Expression Analysis to Evaluate Cell Type Specific Expression of Targets Relevant for Immunotherapy of Hematological Malignancies.

    Directory of Open Access Journals (Sweden)

    M J Pont

    Full Text Available Cellular immunotherapy has proven to be effective in the treatment of hematological cancers by donor lymphocyte infusion after allogeneic hematopoietic stem cell transplantation and more recently by targeted therapy with chimeric antigen or T-cell receptor-engineered T cells. However, dependent on the tissue distribution of the antigens that are targeted, anti-tumor responses can be accompanied by undesired side effects. Therefore, detailed tissue distribution analysis is essential to estimate potential efficacy and toxicity of candidate targets for immunotherapy of hematological malignancies. We performed microarray gene expression analysis of hematological malignancies of different origins, healthy hematopoietic cells and various non-hematopoietic cell types from organs that are often targeted in detrimental immune responses after allogeneic stem cell transplantation leading to graft-versus-host disease. Non-hematopoietic cells were also cultured in the presence of IFN-γ to analyze gene expression under inflammatory circumstances. Gene expression was investigated by Illumina HT12.0 microarrays and quality control analysis was performed to confirm the cell-type origin and exclude contamination of non-hematopoietic cell samples with peripheral blood cells. Microarray data were validated by quantitative RT-PCR showing strong correlations between both platforms. Detailed gene expression profiles were generated for various minor histocompatibility antigens and B-cell surface antigens to illustrate the value of the microarray dataset to estimate efficacy and toxicity of candidate targets for immunotherapy. In conclusion, our microarray database provides a relevant platform to analyze and select candidate antigens with hematopoietic (lineage-restricted expression as potential targets for immunotherapy of hematological cancers.

  7. Assessment of fusion gene status in sarcomas using a custom made fusion gene microarray.

    Directory of Open Access Journals (Sweden)

    Marthe Løvf

    Full Text Available Sarcomas are relatively rare malignancies and include a large number of histological subgroups. Based on morphology alone, the differential diagnoses of sarcoma subtypes can be challenging, but the identification of specific fusion genes aids correct diagnostication. The presence of individual fusion products are routinely investigated in Pathology labs. However, the methods used are time-consuming and based on prior knowledge about the expected fusion gene and often the most likely break-point. In this study, 16 sarcoma samples, representing seven different sarcoma subtypes with known fusion gene status from a diagnostic setting, were investigated using a fusion gene microarray. The microarray was designed to detect all possible exon-exon breakpoints between all known fusion genes in a single analysis. An automated scoring of the microarray data from the 38 known sarcoma-related fusion genes identified the correct fusion gene among the top-three hits in 11 of the samples. The analytical sensitivity may be further optimised, but we conclude that a sarcoma-fusion gene microarray is suitable as a time-saving screening tool to identify the majority of the correct fusion genes.

  8. Sensitive and robust gene expression changes in fish exposed to estrogen – a microarray approach

    Directory of Open Access Journals (Sweden)

    Nerman Olle

    2007-06-01

    Full Text Available Abstract Background Vitellogenin is a well established biomarker for estrogenic exposure in fish. However, effects on gonadal differentiation at concentrations of estrogen not sufficient to give rise to a measurable vitellogenin response suggest that more sensitive biomarkers would be useful. Induction of zona pellucida genes may be more sensitive but their specificities are not as clear. The objective of this study was to find additional sensitive and robust candidate biomarkers of estrogenic exposure. Results Hepatic mRNA expression profiles were characterized in juvenile rainbow trout exposed to a measured concentration of 0.87 and 10 ng ethinylestradiol/L using a salmonid cDNA microarray. The higher concentration was used to guide the subsequent identification of generally more subtle responses at the low concentration not sufficient to induce vitellogenin. A meta-analysis was performed with data from the present study and three similar microarray studies using different fish species and platforms. Within the generated list of presumably robust responses, several well-known estrogen-regulated genes were identified. Two genes, confirmed by quantitative RT-PCR (qPCR, fulfilled both the criteria of high sensitivity and robustness; the induction of the genes encoding zona pellucida protein 3 and a nucleoside diphosphate kinase (nm23. Conclusion The cross-species, cross-platform meta-analysis correctly identified several robust responses. This adds confidence to our approach used for identifying candidate biomarkers. Specifically, we propose that analyses of an nm23 gene together with zona pellucida genes may increase the possibilities to detect an exposure to low levels of estrogenic compounds in fish.

  9. A meta analysis of pancreatic microarray datasets yields new targets as cancer genes and biomarkers.

    Directory of Open Access Journals (Sweden)

    Nalin C W Goonesekere

    Full Text Available The lack of specific symptoms at early tumor stages, together with a high biological aggressiveness of the tumor contribute to the high mortality rate for pancreatic cancer (PC, which has a five year survival rate of less than 5%. Improved screening for earlier diagnosis, through the detection of diagnostic and prognostic biomarkers provides the best hope of increasing the rate of curatively resectable carcinomas. Though many serum markers have been reported to be elevated in patients with PC, so far, most of these markers have not been implemented into clinical routine due to low sensitivity or specificity. In this study, we have identified genes that are significantly upregulated in PC, through a meta-analysis of large number of microarray datasets. We demonstrate that the biological functions ascribed to these genes are clearly associated with PC and metastasis, and that that these genes exhibit a strong link to pathways involved with inflammation and the immune response. This investigation has yielded new targets for cancer genes, and potential biomarkers for pancreatic cancer. The candidate list of cancer genes includes protein kinase genes, new members of gene families currently associated with PC, as well as genes not previously linked to PC. In this study, we are also able to move towards developing a signature for hypomethylated genes, which could be useful for early detection of PC. We also show that the significantly upregulated 800+ genes in our analysis can serve as an enriched pool for tissue and serum protein biomarkers in pancreatic cancer.

  10. A salmonid EST genomic study: genes, duplications, phylogeny and microarrays

    Directory of Open Access Journals (Sweden)

    Brahmbhatt Sonal

    2008-11-01

    Full Text Available Abstract Background Salmonids are of interest because of their relatively recent genome duplication, and their extensive use in wild fisheries and aquaculture. A comprehensive gene list and a comparison of genes in some of the different species provide valuable genomic information for one of the most widely studied groups of fish. Results 298,304 expressed sequence tags (ESTs from Atlantic salmon (69% of the total, 11,664 chinook, 10,813 sockeye, 10,051 brook trout, 10,975 grayling, 8,630 lake whitefish, and 3,624 northern pike ESTs were obtained in this study and have been deposited into the public databases. Contigs were built and putative full-length Atlantic salmon clones have been identified. A database containing ESTs, assemblies, consensus sequences, open reading frames, gene predictions and putative annotation is available. The overall similarity between Atlantic salmon ESTs and those of rainbow trout, chinook, sockeye, brook trout, grayling, lake whitefish, northern pike and rainbow smelt is 93.4, 94.2, 94.6, 94.4, 92.5, 91.7, 89.6, and 86.2% respectively. An analysis of 78 transcript sets show Salmo as a sister group to Oncorhynchus and Salvelinus within Salmoninae, and Thymallinae as a sister group to Salmoninae and Coregoninae within Salmonidae. Extensive gene duplication is consistent with a genome duplication in the common ancestor of salmonids. Using all of the available EST data, a new expanded salmonid cDNA microarray of 32,000 features was created. Cross-species hybridizations to this cDNA microarray indicate that this resource will be useful for studies of all 68 salmonid species. Conclusion An extensive collection and analysis of salmonid RNA putative transcripts indicate that Pacific salmon, Atlantic salmon and charr are 94–96% similar while the more distant whitefish, grayling, pike and smelt are 93, 92, 89 and 86% similar to salmon. The salmonid transcriptome reveals a complex history of gene duplication that is

  11. Xylella fastidiosa gene expression analysis by DNA microarrays

    Directory of Open Access Journals (Sweden)

    Regiane F. Travensolo

    2009-01-01

    Full Text Available Xylella fastidiosa genome sequencing has generated valuable data by identifying genes acting either on metabolic pathways or in associated pathogenicity and virulence. Based on available information on these genes, new strategies for studying their expression patterns, such as microarray technology, were employed. A total of 2,600 primer pairs were synthesized and then used to generate fragments using the PCR technique. The arrays were hybridized against cDNAs labeled during reverse transcription reactions and which were obtained from bacteria grown under two different conditions (liquid XDM2 and liquid BCYE. All data were statistically analyzed to verify which genes were differentially expressed. In addition to exploring conditions for X. fastidiosa genome-wide transcriptome analysis, the present work observed the differential expression of several classes of genes (energy, protein, amino acid and nucleotide metabolism, transport, degradation of substances, toxins and hypothetical proteins, among others. The understanding of expressed genes in these two different media will be useful in comprehending the metabolic characteristics of X. fastidiosa, and in evaluating how important certain genes are for the functioning and survival of these bacteria in plants.

  12. Sample size for detecting differentially expressed genes in microarray experiments

    Directory of Open Access Journals (Sweden)

    Li Jiangning

    2004-11-01

    Full Text Available Abstract Background Microarray experiments are often performed with a small number of biological replicates, resulting in low statistical power for detecting differentially expressed genes and concomitant high false positive rates. While increasing sample size can increase statistical power and decrease error rates, with too many samples, valuable resources are not used efficiently. The issue of how many replicates are required in a typical experimental system needs to be addressed. Of particular interest is the difference in required sample sizes for similar experiments in inbred vs. outbred populations (e.g. mouse and rat vs. human. Results We hypothesize that if all other factors (assay protocol, microarray platform, data pre-processing were equal, fewer individuals would be needed for the same statistical power using inbred animals as opposed to unrelated human subjects, as genetic effects on gene expression will be removed in the inbred populations. We apply the same normalization algorithm and estimate the variance of gene expression for a variety of cDNA data sets (humans, inbred mice and rats comparing two conditions. Using one sample, paired sample or two independent sample t-tests, we calculate the sample sizes required to detect a 1.5-, 2-, and 4-fold changes in expression level as a function of false positive rate, power and percentage of genes that have a standard deviation below a given percentile. Conclusions Factors that affect power and sample size calculations include variability of the population, the desired detectable differences, the power to detect the differences, and an acceptable error rate. In addition, experimental design, technical variability and data pre-processing play a role in the power of the statistical tests in microarrays. We show that the number of samples required for detecting a 2-fold change with 90% probability and a p-value of 0.01 in humans is much larger than the number of samples commonly used in

  13. Probabilistic estimation of microarray data reliability and underlying gene expression

    Directory of Open Access Journals (Sweden)

    Sigvardsson Mikael

    2003-09-01

    Full Text Available Abstract Background The availability of high throughput methods for measurement of mRNA concentrations makes the reliability of conclusions drawn from the data and global quality control of samples and hybridization important issues. We address these issues by an information theoretic approach, applied to discretized expression values in replicated gene expression data. Results Our approach yields a quantitative measure of two important parameter classes: First, the probability P(σ|S that a gene is in the biological state σ in a certain variety, given its observed expression S in the samples of that variety. Second, sample specific error probabilities which serve as consistency indicators of the measured samples of each variety. The method and its limitations are tested on gene expression data for developing murine B-cells and a t-test is used as reference. On a set of known genes it performs better than the t-test despite the crude discretization into only two expression levels. The consistency indicators, i.e. the error probabilities, correlate well with variations in the biological material and thus prove efficient. Conclusions The proposed method is effective in determining differential gene expression and sample reliability in replicated microarray data. Already at two discrete expression levels in each sample, it gives a good explanation of the data and is comparable to standard techniques.

  14. Development of gene microarray in screening differently expressed genes in keloid and normal-control skin

    Institute of Scientific and Technical Information of China (English)

    陈伟; 付小兵; 葛世丽; 孙晓庆; 周岗; 赵志力; 盛志勇

    2004-01-01

    Background Keloid is an intricate lesion that is probably regulated by many genes. In this study, the authors used the technique of complementary DNA (cDNA) microarray to analyse abnormal gene expression in keloids and normal control skins. Methods The polymerase chain reaction (PCR) products of 8400 genes were spotted in an array on chemical-material-coated-glass plates. The DNAs were fixed on the glass plates. The total RNAs were isolated from freshly excised human keloid and normal control skins, and the mRNAs were then purified. The mRNA from both keloid and normal control skins were reversely transcribed to cDNAs, with the incorporation of fluorescent dUTP, for preparing the hybridisation probes. The mixed probes were then hybridised to the cDNA microarray. After thorough washing, the cDNA microarray was scanned for differing fluorescent signals from two types of tissues. Gene expression of tissue growth factor-β1 (TGF-β1) and of c-myc was detected with both RT-PCR and Northern blot hybridisation to confirm the effectiveness of cDNA microarray. Results Among the 8400 human genes, 402 were detected with different expression levels between keloid and normal control skins. Two hundred and fifty genes, including TGF-β1 and c-myc, were up-regulated and 152 genes were down-regulated. Higher expressions of TGF-β1 and c-myc in keloid were also revealed using RT-PCR and Northern blot methods. Conclusion cDNA microarray analysis provides a powerful tool for investigating differential gene expression in keloid and normal control skins. Keloid is a complicated lesion with many genes involved.

  15. Deletions and candidate genes in Williams syndrome

    Energy Technology Data Exchange (ETDEWEB)

    Perez Jurado, L.A.; Peoples, R.; Francke, U. [Stanford Univ. CA (United States)] [and others

    1994-09-01

    Hemizygosity at the elastin locus (ELN) on chromosome 7q11.23 has recently been reported in several familial and sporadic cases of the developmental disorder, Williams syndrome (WS). Because the deletion is greater than the span of the ELN gene, a contiguous gene deletion syndrome has been suggested as the probable molecular basis for this condition. Thus far, neither the size of the deletion(s), nor other genes within it are known. We have analyzed samples from 27 sporadic WS patients by genotyping two multiallelic ELN intragenic polymorphisms, detectable by PCR amplification, and by Southern blotting for ELN gene dosage. Twenty four patients were hemizygous at the ELN locus while 3 showed no deletion or detectable rearrangement. Genotype studies on parental DNA were informative in 12 of the deletions. All 12 were due to de novo events, 8 in the maternal and 4 in the paternal chromosome. In an attempt to identify genes involved in WS we are also using a candidate gene approach. Delayed clearance of an exogenous calcium load with normal or slightly increased calcitonin levels in serum has been documented in WS patients suggesting a defective calcitonin action or calcium sensing function. The calcitonin receptor (CTR) gene is, therefore, a good candidate since CTR has a dual role as a hormonal receptor for calcitonin and an extracellular calcium sensor. We have mapped the CTR gene to chromosome 7q21.1 by PCR-SSCA of somatic cell hybrids and FISH analysis. Using two color FISH with probes for ELN and CTR, both loci are located on 7q at a distance of {approximately}10 Mb, CTR being telomeric. Our CTR probe does not detect any genomic abnormality by FISH or Southern blot in the patients` samples analyzed. We have identified a diallelic polymorphism in the CTR cDNA and are currently testing the hypothesis of an impaired CTR expression as responsible for some of the clinical features of WS by analysing the CTR transcripts by RT-PCR.

  16. Detection bias in microarray and sequencing transcriptomic analysis identified by housekeeping genes

    OpenAIRE

    Yijuan Zhang; Oluwafemi S. Akintola; Liu, Ken J.A.; Bingyun Sun

    2015-01-01

    This work includes the original data used to discover the gene ontology bias in transcriptomic analysis conducted by microarray and high throughput sequencing (Zhang et al., 2015) [1]. In the analysis, housekeeping genes were used to examine the differential detection ability by microarray and sequencing because these genes are probably the most reliably detected. The genes included here were compiled from 15 human housekeeping gene studies. The provided tables here comprise of detailed chrom...

  17. Algorithm for Finding Optimal Gene Sets in Microarray Prediction

    CERN Document Server

    Deutsch, J M

    2001-01-01

    Motivation: Microarray data has been recently been shown to be efficacious in distinguishing closely related cell types that often appear in the diagnosis of cancer. It is useful to determine the minimum number of genes needed to do such a diagnosis both for clinical use and to determine the importance of specific genes for cancer. Here a replication algorithm is used for this purpose. It evolves an ensemble of predictors, all using different combinations of genes to generate a set of optimal predictors. Results: We apply this method to the leukemia data of the Whitehead/MIT group that attempts to differentially diagnose two kinds of leukemia, and also to data of Khan et. al. to distinguish four different kinds of childhood cancers. In the latter case we were able to reduce the number of genes needed from 96 down to 15, while at the same time being able to perfectly classify all of their test data. Availability: http://stravinsky.ucsc.edu/josh/gesses/ Contact: josh@physics.ucsc.edu

  18. Identification of new reference genes for the normalisation of canine osteoarthritic joint tissue transcripts from microarray data

    Directory of Open Access Journals (Sweden)

    Clements Dylan N

    2007-07-01

    Full Text Available Abstract Background Real-time reverse transcriptase quantitative polymerase chain reaction (real-time RT-qPCR is the most accurate measure of gene expression in biological systems. The comparison of different samples requires the transformation of data through a process called normalisation. Reference or housekeeping genes are candidate genes which are selected on the basis of constitutive expression across samples, and allow the quantification of changes in gene expression. At present, no reference gene has been identified for any organism which is universally optimal for use across different tissue types or disease situations. We used microarray data to identify new reference genes generated from total RNA isolated from normal and osteoarthritic canine articular tissues (bone, ligament, cartilage, synovium and fat. RT-qPCR assays were designed and applied to each different articular tissue. Reference gene expression stability and ranking was compared using three different mathematical algorithms. Results Twelve new potential reference genes were identified from microarray data. One gene (mitochondrial ribosomal protein S7 [MRPS7] was stably expressed in all five of the articular tissues evaluated. One gene HIRA interacting protein 5 isoform 2 [HIRP5] was stably expressed in four of the tissues evaluated. A commonly used reference gene glyceraldehyde-3-phosphate dehydrogenase (GAPDH was not stably expressed in any of the tissues evaluated. Most consistent agreement between rank ordering of reference genes was observed between Bestkeeper© and geNorm, although each method tended to agree on the identity of the most stably expressed genes and the least stably expressed genes for each tissue. New reference genes identified using microarray data normalised in a conventional manner were more stable than those identified by microarray data normalised by using a real-time RT-qPCR methodology. Conclusion Microarray data normalised by a conventional

  19. CRISPLD2: a novel NSCLP candidate gene.

    Science.gov (United States)

    Chiquet, Brett T; Lidral, Andrew C; Stal, Samuel; Mulliken, John B; Moreno, Lina M; Arcos-Burgos, Mauricio; Arco-Burgos, Mauricio; Valencia-Ramirez, Consuelo; Blanton, Susan H; Hecht, Jacqueline T

    2007-09-15

    Non-syndromic cleft lip with or without cleft palate (NSCLP) results from the complex interaction between genes and environmental factors. Candidate gene analysis and genome scans have been employed to identify the genes contributing to NSCLP. In this study, we evaluated the 16q24.1 chromosomal region, which has been identified by multiple genome scans as an NSCLP region of interest. Two candidate genes were found in the region: interferon regulatory factor 8 (IRF8) and cysteine-rich secretory protein LCCL domain containing 2 (CRISPLD2). Initially, Caucasian and Hispanic NSCLP multiplex families and simplex parent-child trios were genotyped for single nucleotide polymorphisms (SNPs) in both IRF8 and CRISPLD2. CRISPLD2 was subsequently genotyped in a data set comprised of NSCLP families from Colombia, South America. Linkage disequilibrium analysis identified a significant association between CRISPLD2 and NSCLP in both our Caucasian and Hispanic NSCLP cohorts. SNP rs1546124 and haplotypes between rs1546124 and either rs4783099 or rs16974880 were significant in the Caucasian multiplex population (P=0.01, P=0.002 and P=0.001, respectively). An altered transmission of CRISPLD2 SNPs rs8061351 (P=0.02) and rs2326398 (P=0.06) was detected in the Hispanic population. No association was found between CRISPLD2 and our Colombian population or IRF8 and NSCLP. In situ hybridization showed that CRISPLD2 is expressed in the mandible, palate and nasopharynx regions during craniofacial development at E13.5-E17.5, respectively. Altogether, these data suggest that genetic variation in CRISPLD2 has a role in the etiology of NSCLP. PMID:17616516

  20. DNA Microarray Detection of Antimicrobial Resistance Genes in Bacteria Co-Cultured from Swine Feces

    Science.gov (United States)

    One factor leading to the spread of antimicrobial resistance (AR) in bacteria is the horizontal transfer of resistance genes. To study this, a DNA microarray was recently developed to detect these genes. To maximize the capability of this microarray, probes were designed and added to detect all AR g...

  1. Can subtle changes in gene expression be consistently detected with different microarray platforms?

    NARCIS (Netherlands)

    P. Pedotti; P.A.C. 't Hoen (Peter); E. Vreugdenhil (Erno); G.J. Schenk (Geert); R. Vossen (Rolf); Y. Ariyurek (Yavuz); M. de Hollander (Mattias); R. Kuiper (Rowan); G.J. van Ommen (Gert); J.T. den Dunnen (Johan); J.M. Boer (Judith); R.X. de Menezes (Renee)

    2008-01-01

    textabstractBackground: The comparability of gene expression data generated with different microarray platforms is still a matter of concern. Here we address the performance and the overlap in the detection of differentially expressed genes for five different microarray platforms in a challenging bi

  2. Microarray analysis of radiation response genes in primary human fibroblasts

    International Nuclear Information System (INIS)

    Purpose: To identify radiation-induced early transcriptional responses in primary human fibroblasts and understand cellular pathways leading to damage correction. Methods and Materials: Primary human fibroblast cell lines were irradiated with 2 Gy γ-radiation and RNA isolated 2 h later. Radiation-induced transcriptional alterations were investigated with microarrays covering the entire human genome. Time- and dose dependent radiation responses were studied by quantitative real-time polymerase chain reaction (RT-PCR). Results: About 200 genes responded to ionizing radiation on the transcriptional level in primary human fibroblasts. The expression profile depended on individual genetic backgrounds. Thirty genes (28 up- and 2 down-regulated) responded to radiation in identical manner in all investigated cells. Twenty of these consensus radiation response genes were functionally categorized: most of them belong to the DNA damage response (GADD45A, BTG2, PCNA, IER5), regulation of cell cycle and cell proliferation (CDKN1A, PPM1D, SERTAD1, PLK2, PLK3, CYR61), programmed cell death (BBC3, TP53INP1) and signaling (SH2D2A, SLIC1, GDF15, THSD1) pathways. Four genes (SEL10, FDXR, CYP26B1, OR11A1) were annotated to other functional groups. Many of the consensus radiation response genes are regulated by, or regulate p53. Time- and dose-dependent expression profiles of selected consensus genes (CDKN1A, GADD45A, IER5, PLK3, CYR61) were investigated by quantitative RT-PCR. Transcriptional alterations depended on the applied dose, and on the time after irradiation. Conclusions: The data presented here could help in the better understanding of early radiation responses and the development of biomarkers to identify radiation susceptible individuals

  3. Blood-based gene expression signatures of medication-free outpatients with major depressive disorder: integrative genome-wide and candidate gene analyses

    OpenAIRE

    Hiroaki Hori; Daimei Sasayama; Toshiya Teraishi; Noriko Yamamoto; Seiji Nakamura; Miho Ota; Kotaro Hattori; Yoshiharu Kim; Teruhiko Higuchi; Hiroshi Kunugi

    2016-01-01

    Several microarray-based studies have investigated gene expression profiles in major depressive disorder (MDD), yet with highly variable findings. We examined blood-based genome-wide expression signatures of MDD, focusing on molecular pathways and networks underlying differentially expressed genes (DEGs) and behaviours of hypothesis-driven, evidence-based candidate genes for depression. Agilent human whole-genome arrays were used to measure gene expression in 14 medication-free outpatients wi...

  4. Microarray-Based Detection of 90 Antibiotic Resistance Genes of Gram-Positive Bacteria

    OpenAIRE

    Perreten, Vincent; Vorlet-Fawer, Lorianne; Slickers, Peter; Ehricht, Ralf; Kuhnert, Peter; Frey, Joachim

    2005-01-01

    A disposable microarray was developed for detection of up to 90 antibiotic resistance genes in gram-positive bacteria by hybridization. Each antibiotic resistance gene is represented by two specific oligonucleotides chosen from consensus sequences of gene families, except for nine genes for which only one specific oligonucleotide could be developed. A total of 137 oligonucleotides (26 to 33 nucleotides in length with similar physicochemical parameters) were spotted onto the microarray. The mi...

  5. A robust measure of correlation between two genes on a microarray

    OpenAIRE

    Hicks Leanne; Mitani Aya; Hardin Johanna; VanKoten Brian

    2007-01-01

    Abstract Background The underlying goal of microarray experiments is to identify gene expression patterns across different experimental conditions. Genes that are contained in a particular pathway or that respond similarly to experimental conditions could be co-expressed and show similar patterns of expression on a microarray. Using any of a variety of clustering methods or gene network analyses we can partition genes of interest into groups, clusters, or modules based on measures of similari...

  6. Can subtle changes in gene expression be consistently detected with different microarray platforms?

    OpenAIRE

    Kuiper Rowan; de Hollander Mattias; Ariyurek Yavuz; Vossen Rolf HAM; Schenk Geert J; Vreugdenhil Erno; 't Hoen Peter AC; Pedotti Paola; van Ommen Gertjan JB; den Dunnen Johan T; Boer Judith M; Menezes Renée X

    2008-01-01

    Abstract Background The comparability of gene expression data generated with different microarray platforms is still a matter of concern. Here we address the performance and the overlap in the detection of differentially expressed genes for five different microarray platforms in a challenging biological context where differences in gene expression are few and subtle. Results Gene expression profiles in the hippocampus of five wild-type and five transgenic δC-doublecortin-like kinase mice were...

  7. Information criterion-based clustering with order-restricted candidate profiles in short time-course microarray experiments

    Directory of Open Access Journals (Sweden)

    Zhang Baoxue

    2009-05-01

    Full Text Available Abstract Background Time-course microarray experiments produce vector gene expression profiles across a series of time points. Clustering genes based on these profiles is important in discovering functional related and co-regulated genes. Early developed clustering algorithms do not take advantage of the ordering in a time-course study, explicit use of which should allow more sensitive detection of genes that display a consistent pattern over time. Peddada et al. 1 proposed a clustering algorithm that can incorporate the temporal ordering using order-restricted statistical inference. This algorithm is, however, very time-consuming and hence inapplicable to most microarray experiments that contain a large number of genes. Its computational burden also imposes difficulty to assess the clustering reliability, which is a very important measure when clustering noisy microarray data. Results We propose a computationally efficient information criterion-based clustering algorithm, called ORICC, that also takes account of the ordering in time-course microarray experiments by embedding the order-restricted inference into a model selection framework. Genes are assigned to the profile which they best match determined by a newly proposed information criterion for order-restricted inference. In addition, we also developed a bootstrap procedure to assess ORICC's clustering reliability for every gene. Simulation studies show that the ORICC method is robust, always gives better clustering accuracy than Peddada's method and saves hundreds of times computational time. Under some scenarios, its accuracy is also better than some other existing clustering methods for short time-course microarray data, such as STEM 2 and Wang et al. 3. It is also computationally much faster than Wang et al. 3. Conclusion Our ORICC algorithm, which takes advantage of the temporal ordering in time-course microarray experiments, provides good clustering accuracy and is meanwhile much

  8. Transcriptomic Analysis Using Olive Varieties and Breeding Progenies Identifies Candidate Genes Involved in Plant Architecture

    Science.gov (United States)

    González-Plaza, Juan J.; Ortiz-Martín, Inmaculada; Muñoz-Mérida, Antonio; García-López, Carmen; Sánchez-Sevilla, José F.; Luque, Francisco; Trelles, Oswaldo; Bejarano, Eduardo R.; De La Rosa, Raúl; Valpuesta, Victoriano; Beuzón, Carmen R.

    2016-01-01

    Plant architecture is a critical trait in fruit crops that can significantly influence yield, pruning, planting density and harvesting. Little is known about how plant architecture is genetically determined in olive, were most of the existing varieties are traditional with an architecture poorly suited for modern growing and harvesting systems. In the present study, we have carried out microarray analysis of meristematic tissue to compare expression profiles of olive varieties displaying differences in architecture, as well as seedlings from their cross pooled on the basis of their sharing architecture-related phenotypes. The microarray used, previously developed by our group has already been applied to identify candidates genes involved in regulating juvenile to adult transition in the shoot apex of seedlings. Varieties with distinct architecture phenotypes and individuals from segregating progenies displaying opposite architecture features were used to link phenotype to expression. Here, we identify 2252 differentially expressed genes (DEGs) associated to differences in plant architecture. Microarray results were validated by quantitative RT-PCR carried out on genes with functional annotation likely related to plant architecture. Twelve of these genes were further analyzed in individual seedlings of the corresponding pool. We also examined Arabidopsis mutants in putative orthologs of these targeted candidate genes, finding altered architecture for most of them. This supports a functional conservation between species and potential biological relevance of the candidate genes identified. This study is the first to identify genes associated to plant architecture in olive, and the results obtained could be of great help in future programs aimed at selecting phenotypes adapted to modern cultivation practices in this species. PMID:26973682

  9. Relationship between gene co-expression and probe localization on microarray slides

    Directory of Open Access Journals (Sweden)

    Qian Jiang

    2003-12-01

    Full Text Available Abstract Background Microarray technology allows simultaneous measurement of thousands of genes in a single experiment. This is a potentially useful tool for evaluating co-expression of genes and extraction of useful functional and chromosomal structural information about genes. Results In this work we studied the association between the co-expression of genes, their location on the chromosome and their location on the microarray slides by analyzing a number of eukaryotic expression datasets, derived from the S. cerevisiae, C. elegans, and D. melanogaster. We find that in several different yeast microarray experiments the distribution of the number of gene pairs with correlated expression profiles as a function of chromosomal spacing is peaked at short separations and has two superimposed periodicities. The longer periodicity has a spacing of 22 genes (~42 Kb, and the shorter periodicity is 2 genes (~4 Kb. Conclusion The relative positioning of DNA probes on microarray slides and source plates introduces subtle but significant correlations between pairs of genes. Careful consideration of this spatial artifact is important for analysis of microarray expression data. It is particularly relevant to recent microarray analyses that suggest that co-expressed genes cluster along chromosomes or are spaced by multiples of a fixed number of genes along the chromosome.

  10. Estimating the False Discovery Rate Using Mixed Normal Distribution for Identifying Differentially Expressed Genes in Microarray Data Analysis

    Directory of Open Access Journals (Sweden)

    Chikuma Hamada

    2007-01-01

    Full Text Available The recent development of DNA microarray technology allows us to measure simultaneously the expression levels of thousands of genes and to identify truly correlated genes with anticancer drug response (differentially expressed genes from many candidate genes. Significance Analysis of Microarray (SAM is often used to estimate the false discovery rate (FDR, which is an index for optimizing the identifiability of differentially expressed genes, while the accuracy of the estimated FDR by SAM is not necessarily confirmed. We propose a new method for estimating the FDR assuming a mixed normal distribution on the test statistic and examine the performance of the proposed method and SAM using simulated data. The simulation results indicate that the accuracy of the estimated FDR by the proposed method and SAM, varied depending on the experimental conditions. We applied both methods to actual data comprised of expression levels of 12,625 genes of 10 responders and 14 non-responders to docetaxel for breast cancer. The proposed method identified 280 differentially expressed genes correlated with docetaxel response using a cut-off value for achieving FDR <0.01 to prevent false-positive genes, although 92 genes were previously thought to be correlated with docetaxel response ones.

  11. Complete gene expression profiling of Saccharopolyspora erythraea using GeneChip DNA microarrays

    Directory of Open Access Journals (Sweden)

    Bordoni Roberta

    2007-11-01

    Full Text Available Abstract Background The Saccharopolyspora erythraea genome sequence, recently published, presents considerable divergence from those of streptomycetes in gene organization and function, confirming the remarkable potential of S. erythraea for producing many other secondary metabolites in addition to erythromycin. In order to investigate, at whole transcriptome level, how S. erythraea genes are modulated, a DNA microarray was specifically designed and constructed on the S. erythraea strain NRRL 2338 genome sequence, and the expression profiles of 6494 ORFs were monitored during growth in complex liquid medium. Results The transcriptional analysis identified a set of 404 genes, whose transcriptional signals vary during growth and characterize three distinct phases: a rapid growth until 32 h (Phase A; a growth slowdown until 52 h (Phase B; and another rapid growth phase from 56 h to 72 h (Phase C before the cells enter the stationary phase. A non-parametric statistical method, that identifies chromosomal regions with transcriptional imbalances, determined regional organization of transcription along the chromosome, highlighting differences between core and non-core regions, and strand specific patterns of expression. Microarray data were used to characterize the temporal behaviour of major functional classes and of all the gene clusters for secondary metabolism. The results confirmed that the ery cluster is up-regulated during Phase A and identified six additional clusters (for terpenes and non-ribosomal peptides that are clearly regulated in later phases. Conclusion The use of a S. erythraea DNA microarray improved specificity and sensitivity of gene expression analysis, allowing a global and at the same time detailed picture of how S. erythraea genes are modulated. This work underlines the importance of using DNA microarrays, coupled with an exhaustive statistical and bioinformatic analysis of the results, to understand the transcriptional

  12. Cross-platform analysis of cancer microarray data improves gene expression based classification of phenotypes

    Directory of Open Access Journals (Sweden)

    Eils Roland

    2005-11-01

    Full Text Available Abstract Background The extensive use of DNA microarray technology in the characterization of the cell transcriptome is leading to an ever increasing amount of microarray data from cancer studies. Although similar questions for the same type of cancer are addressed in these different studies, a comparative analysis of their results is hampered by the use of heterogeneous microarray platforms and analysis methods. Results In contrast to a meta-analysis approach where results of different studies are combined on an interpretative level, we investigate here how to directly integrate raw microarray data from different studies for the purpose of supervised classification analysis. We use median rank scores and quantile discretization to derive numerically comparable measures of gene expression from different platforms. These transformed data are then used for training of classifiers based on support vector machines. We apply this approach to six publicly available cancer microarray gene expression data sets, which consist of three pairs of studies, each examining the same type of cancer, i.e. breast cancer, prostate cancer or acute myeloid leukemia. For each pair, one study was performed by means of cDNA microarrays and the other by means of oligonucleotide microarrays. In each pair, high classification accuracies (> 85% were achieved with training and testing on data instances randomly chosen from both data sets in a cross-validation analysis. To exemplify the potential of this cross-platform classification analysis, we use two leukemia microarray data sets to show that important genes with regard to the biology of leukemia are selected in an integrated analysis, which are missed in either single-set analysis. Conclusion Cross-platform classification of multiple cancer microarray data sets yields discriminative gene expression signatures that are found and validated on a large number of microarray samples, generated by different laboratories and

  13. Investigation of the molecular relationship between breast cancer and obesity by candidate gene prioritization methods

    Directory of Open Access Journals (Sweden)

    Saba Garshasbi

    2015-10-01

    Full Text Available Background: Cancer and obesity are two major public health concerns. More than 12 million cases of cancer are reported annually. Many reports confirmed obesity as a risk factor for cancer. The molecular relationship between obesity and breast cancer has not been clear yet. The purpose of this study was to investigate priorities of effective genes in the molecular relationship between obesity and breast cancer. Methods: In this study, computer simulation method was used for prioritizing the genes that involved in the molecular links between obesity and breast cancer in laboratory of systems biology and bioinformatics (LBB, Tehran University, Tehran, Iran, from March to July 2014. In this study, ENDEAVOUR software was used for prioritizing the genes and integrating multiple data sources was used for data analysis. Training genes were selected from effective genes in obesity and/or breast cancer. Two groups of candidate genes were selected. The first group was included the existential genes in 5 common region chromosomes (between obesity and breast cancer and the second group was included the results of genes microarray data analysis of research Creighton, et al (In 2012 on patients with breast cancer. The microarray data were analyzed with GER2 software (R online software on GEO website. Finally, both training and candidate genes were entered in ENDEAVOUR software package. Results: The candidate genes were prioritized to four style and five genes in ten of the first priorities were repeated twice. In other word, the outcome of prioritizing of 72 genes (Product of microarray data analysis and genes of 5 common chromosome regions (Between obesity and breast cancer showed, 5 genes (TNFRSF10B, F2, IGFALS, NTRK3 and HSP90B1 were the priorities in the molecular connection between obesity and breast cancer. Conclusion: There are some common genes between breast cancer and obesity. So, molecular relationship is confirmed. In this study the possible effect

  14. Radioactive cDNA microarray (II): Gene expression profiling of antidepressant treatment by human cDNA microarray

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Ji Hye; Kang, Rhee Hun; Ham, Byung Joo; Lee, Min Su; Shin, Kyung Ho; Choe, Jae Gol; Kim, Meyoung Kon [College of Medicine, Univ. of Korea, Seoul (Korea, Republic of)

    2003-07-01

    Major depressive disorder is a prevalent psychiatric disorder in primary care, associated with impaired patient functioning and well-being. Fluoxetine is a selective serotonin-reuptake inhibitors (SSRIs) and is a commonly prescribed antidepressant compound. Its action is primarily attributed to selective inhibition of the reuptake of serotonin (5-hydroxytryptamine) in the central nervous system. Objectives ; the aims of this study were two-fold: (1) to determine the usefulness for investigation of the transcription profiles in depression patients, and (2) to assess the differences in gene expression profiles between positive response group and negative response groups by fluoxetine treatment. This study included 53 patients with major depression (26 in positive response group with antidepressant treatment, 27 in negative response group with antidepressant treatment), and 53 healthy controls. To examine the difference of gene expression profile in depression patients, radioactive complementary DNA microarrays were used to evaluate changes in the expression of 1,152 genes in total. Using 33p-labeled probes, this method provided highly sensitive gene expression profiles including brain receptors, drug metabolism, and cellular signaling. Gene transcription profiles were classified into several categories in accordance with the antidepressant gene-regulation. The gene profiles were significantly up-(22 genes) and down-(16 genes) regulated in the positive response group when compared to the control group. Also, in the negative response group, 35 genes were up-regulated and 8 genes were down-regulated when compared to the control group. Consequently, we demonstrated that radioactive human cDNA microarray is highly likely to be an efficient technology for evaluating the gene regulation of antidepressants, such as selective serotonin-reuptake inhibitors (SSRIs), by using high-throughput biotechnology.

  15. Radioactive cDNA microarray (II): Gene expression profiling of antidepressant treatment by human cDNA microarray

    International Nuclear Information System (INIS)

    Major depressive disorder is a prevalent psychiatric disorder in primary care, associated with impaired patient functioning and well-being. Fluoxetine is a selective serotonin-reuptake inhibitors (SSRIs) and is a commonly prescribed antidepressant compound. Its action is primarily attributed to selective inhibition of the reuptake of serotonin (5-hydroxytryptamine) in the central nervous system. Objectives ; the aims of this study were two-fold: (1) to determine the usefulness for investigation of the transcription profiles in depression patients, and (2) to assess the differences in gene expression profiles between positive response group and negative response groups by fluoxetine treatment. This study included 53 patients with major depression (26 in positive response group with antidepressant treatment, 27 in negative response group with antidepressant treatment), and 53 healthy controls. To examine the difference of gene expression profile in depression patients, radioactive complementary DNA microarrays were used to evaluate changes in the expression of 1,152 genes in total. Using 33p-labeled probes, this method provided highly sensitive gene expression profiles including brain receptors, drug metabolism, and cellular signaling. Gene transcription profiles were classified into several categories in accordance with the antidepressant gene-regulation. The gene profiles were significantly up-(22 genes) and down-(16 genes) regulated in the positive response group when compared to the control group. Also, in the negative response group, 35 genes were up-regulated and 8 genes were down-regulated when compared to the control group. Consequently, we demonstrated that radioactive human cDNA microarray is highly likely to be an efficient technology for evaluating the gene regulation of antidepressants, such as selective serotonin-reuptake inhibitors (SSRIs), by using high-throughput biotechnology

  16. A genome-wide 20 K citrus microarray for gene expression analysis

    Directory of Open Access Journals (Sweden)

    Gadea Jose

    2008-07-01

    Full Text Available Abstract Background Understanding of genetic elements that contribute to key aspects of citrus biology will impact future improvements in this economically important crop. Global gene expression analysis demands microarray platforms with a high genome coverage. In the last years, genome-wide EST collections have been generated in citrus, opening the possibility to create new tools for functional genomics in this crop plant. Results We have designed and constructed a publicly available genome-wide cDNA microarray that include 21,081 putative unigenes of citrus. As a functional companion to the microarray, a web-browsable database 1 was created and populated with information about the unigenes represented in the microarray, including cDNA libraries, isolated clones, raw and processed nucleotide and protein sequences, and results of all the structural and functional annotation of the unigenes, like general description, BLAST hits, putative Arabidopsis orthologs, microsatellites, putative SNPs, GO classification and PFAM domains. We have performed a Gene Ontology comparison with the full set of Arabidopsis proteins to estimate the genome coverage of the microarray. We have also performed microarray hybridizations to check its usability. Conclusion This new cDNA microarray replaces the first 7K microarray generated two years ago and allows gene expression analysis at a more global scale. We have followed a rational design to minimize cross-hybridization while maintaining its utility for different citrus species. Furthermore, we also provide access to a website with full structural and functional annotation of the unigenes represented in the microarray, along with the ability to use this site to directly perform gene expression analysis using standard tools at different publicly available servers. Furthermore, we show how this microarray offers a good representation of the citrus genome and present the usefulness of this genomic tool for global

  17. Development and validation of a 2,000-gene microarray for the fathead minnow (Pimephales promelas)

    Energy Technology Data Exchange (ETDEWEB)

    Larkin, Patrick; Villeneuve, Daniel L.; Knoebl, Iris; Miracle, Ann L.; Carter, Barbara J.; Liu, Li; Denslow, Nancy D.; Ankley, Gerald T.

    2007-07-01

    Gene microarrays provide the field of ecotoxicology new tools to identify mechanisms of action of chemicals and chemical mixtures. Herein we describe the development and application of a 2,000-gene oligonucleotide microarray for the fathead minnow Pimephales promelas, a species commonly used in ecological risk assessments in North America. The microarrays were developed from various cDNA and subtraction libraries that we constructed. Consistency and reproducibility of the microarrays were documented by examining multiple technical replicates. To test application of the fathead minnow microarrays, gene expression profiles of fish exposed to 17-estradiol, a well-characterized estrogen receptor (ER) agonist, were examined. For these experiments, adult male fathead minnows were exposed for 24 h to waterborne 17-estradiol (40 or 100 ng/L) in a flow-through system, and gene expression in liver samples was characterized. Seventy-one genes were identified as differentially regulated by estradiol exposure. Examination of the gene ontology designations of these genes revealed patterns consistent with estradiol’s expected mechanisms of action and also provided novel insights as to molecular effects of the estrogen. Our studies indicate the feasibility and utility of microarrays as a basis for understanding biological responses to chemical exposure in a model ecotoxicology test species.

  18. Discovering gene expression patterns in time course microarray experiments by ANOVA-SCA

    NARCIS (Netherlands)

    Nueda, M.J.; Conesa, A.; Westerhuis, J.A.; Hoefsloot, H.C.J.; Smilde, A.K.; Talón, M.; Ferrer, A.

    2007-01-01

    Motivation: Designed microarray experiments are used to investigate the effects that controlled experimental factors have on gene expression and learn about the transcriptional responses associated with external variables. In these datasets, signals of interest coexist with varying sources of unwant

  19. Unifying Candidate Gene and GWAS Approaches in Asthma

    OpenAIRE

    Michel, Sven; Liang, Liming; Depner, Martin; Klopp, Norman; Ruether, Andreas; Kumar, Ashish; Schedel, Michaela; Vogelberg, Christian; Mutius, Erika von; Berg, Andrea von; Bufe, Albrecht; Rietschel, Ernst; Heinzmann, Andrea; Laub, Otto; Simma, Burkhard

    2010-01-01

    The first genome wide association study (GWAS) for childhood asthma identified a novel major susceptibility locus on chromosome 17q21 harboring the ORMDL3 gene, but the role of previous asthma candidate genes was not specifically analyzed in this GWAS. We systematically identified 89 SNPs in 14 candidate genes previously associated with asthma in >3 independent study populations. We re-genotyped 39 SNPs in these genes not covered by GWAS performed in 703 asthmatics and 658 reference children....

  20. Construction of citrus gene coexpression networks from microarray data using random matrix theory

    OpenAIRE

    Dongliang Du; Nidhi Rawat; Zhanao Deng; Gmitter Jr., Fred G.

    2015-01-01

    After the sequencing of citrus genomes, gene function annotation is becoming a new challenge. Gene coexpression analysis can be employed for function annotation using publicly available microarray data sets. In this study, 230 sweet orange (Citrus sinensis) microarrays were used to construct seven coexpression networks, including one condition-independent and six condition-dependent (Citrus canker, Huanglongbing, leaves, flavedo, albedo, and flesh) networks. In total, these networks contain 3...

  1. Strategy for multivariate Identification of diferentially expressed genes in microarray data

    OpenAIRE

    Acosta Rivera, Juan Pablo

    2015-01-01

    Abstract. Microarray technology has become one of the most important tools in understanding genetic expression in biological processes. As microarrays contain measurements of thousands of genes' expression levels across multiple conditions, identification of differentially expressed genes will necessarily involve data mining or large scale multiple testing procedures. To the date, advances in this regard have either been multivariate but descriptive, or inferential but univariate. In this...

  2. Jetset: selecting the optimal microarray probe set to represent a gene

    DEFF Research Database (Denmark)

    Li, Qiyuan; Birkbak, Nicolai Juul; Gyorffy, Balazs;

    2011-01-01

    Background: Interpretation of gene expression microarrays requires a mapping from probe set to gene. On many Affymetrix gene expression microarrays, a given gene may be detected by multiple probe sets, which may deliver inconsistent or even contradictory measurements. Therefore, obtaining an unam...... that were nominally detected by multiple probe sets, and we found that the probe set chosen by our method showed stronger concordance. Conclusions: This method provides a simple, unambiguous mapping to allow assessment of the expression levels of specific genes of interest....

  3. Identification of differentially expressed genes in microarray data in a principal component space.

    Science.gov (United States)

    Ospina, Luis; López-Kleine, Liliana

    2013-12-01

    Microarray experiments are often conducted in order to compare gene expression between two conditions. Tests to detected mean differential expression of genes between conditions are conducted applying correction for multiple testing. Seldom, relationships between gene expression and microarray conditions are investigated in a multivariate approach. Here we propose determining the relationship between genes and conditions using a Principal Component Analysis (PCA) space and classifying genes to one of two biological conditions based on their position relative to a direction on the PC space representing each condition. PMID:23539565

  4. Joint analysis of two microarray gene-expression data sets to select lung adenocarcinoma marker genes

    Directory of Open Access Journals (Sweden)

    Tsai Chung-Jui

    2004-06-01

    Full Text Available Abstract Background Due to the high cost and low reproducibility of many microarray experiments, it is not surprising to find a limited number of patient samples in each study, and very few common identified marker genes among different studies involving patients with the same disease. Therefore, it is of great interest and challenge to merge data sets from multiple studies to increase the sample size, which may in turn increase the power of statistical inferences. In this study, we combined two lung cancer studies using micorarray GeneChip®, employed two gene shaving methods and a two-step survival test to identify genes with expression patterns that can distinguish diseased from normal samples, and to indicate patient survival, respectively. Results In addition to common data transformation and normalization procedures, we applied a distribution transformation method to integrate the two data sets. Gene shaving (GS methods based on Random Forests (RF and Fisher's Linear Discrimination (FLD were then applied separately to the joint data set for cancer gene selection. The two methods discovered 13 and 10 marker genes (5 in common, respectively, with expression patterns differentiating diseased from normal samples. Among these marker genes, 8 and 7 were found to be cancer-related in other published reports. Furthermore, based on these marker genes, the classifiers we built from one data set predicted the other data set with more than 98% accuracy. Using the univariate Cox proportional hazard regression model, the expression patterns of 36 genes were found to be significantly correlated with patient survival (p Conclusion This study provided a valuable method of integrating microarray data sets with different origins, and new methods of selecting a minimum number of marker genes to aid in cancer diagnosis. After careful data integration, the classification method developed from one data set can be applied to the other with high prediction

  5. Microarray analysis of differentially expressed genes in ovarian and fallopian tube epithelium from risk-reducing salpingo-oophorectomies.

    Science.gov (United States)

    Veskimäe, Kristina; Staff, Synnöve; Tabaro, Francesco; Nykter, Matti; Isola, Jorma; Mäenpää, Johanna

    2015-05-01

    Mutations in the BRCA1 and BRCA2 genes confer an increased lifetime risk for breast and ovarian cancer. Ovarian cancer risk can be decreased by risk-reducing salpingo-oophorectomy (RRSO). Studies on RRSO material have altered the paradigm of serous ovarian cancer pathogenesis. The purpose of this study was to identify candidate genes possibly involved in the pathogenesis of serous ovarian cancer by carrying out a microarray analysis of differentially expressed genes in BRCA1/2- mutation positive ovarian and fallopian tube epithelium derived from RRSO surgery. Freshly frozen ovarian and fallopian tube samples from nine BRCA1/2 mutation carriers scheduled for RRSO were prospectively collected together with five mutation-negative control patients undergoing salpingo-oophorectomy for benign indications. Microarray analysis of genome-wide gene expression was performed on ovarian and fallopian tube samples from the BRCA1/2 and control patients. The validation of microarray data was performed by quantitative real-time polymerase chain reaction (qRT-PCR) in selected cases of RRSO samples and also in high grade serous carcinoma samples collected from patients with a BRCA phenotype. From 22,733 genes, 454 transcripts were identified that were differentially expressed in BRCA1/2 mutation carriers when compared with controls, pooling all ovarian and fallopian tube samples together. Of these, 299 genes were statistically significantly downregulated and 155 genes upregulated. Differentially expressed genes in BRCA1/2 samples reported here might be involved in serous ovarian carcinogenesis and provide interesting targets for further studies. PMID:25706666

  6. Evaluating gene × gene and gene × smoking interaction in rheumatoid arthritis using candidate genes in GAW15

    OpenAIRE

    Mei Ling; Li Xiaohui; Yang Kai; Cui Jinrui; Fang Belle; Guo Xiuqing; Rotter Jerome I

    2007-01-01

    Abstract We examined the potential gene × gene interactions and gene × smoking interactions in rheumatoid arthritis (RA) using the candidate gene data sets provided by Genetic Analysis Workshop 15 Problem 2. The multifactor dimensionality reduction (MDR) method was used to test gene × gene interactions among candidate genes. The case-only sample was used to test gene × smoking interactions. The best predictive model was the single-locus model with single-nucleotide polymorphism (SNP) rs247660...

  7. Quantitative multiplex quantum dot in-situ hybridisation based gene expression profiling in tissue microarrays identifies prognostic genes in acute myeloid leukaemia

    International Nuclear Information System (INIS)

    Highlights: ► Development of a quantitative high throughput in situ expression profiling method. ► Application to a tissue microarray of 242 AML bone marrow samples. ► Identification of HOXA4, HOXA9, Meis1 and DNMT3A as prognostic markers in AML. -- Abstract: Measurement and validation of microarray gene signatures in routine clinical samples is problematic and a rate limiting step in translational research. In order to facilitate measurement of microarray identified gene signatures in routine clinical tissue a novel method combining quantum dot based oligonucleotide in situ hybridisation (QD-ISH) and post-hybridisation spectral image analysis was used for multiplex in-situ transcript detection in archival bone marrow trephine samples from patients with acute myeloid leukaemia (AML). Tissue-microarrays were prepared into which white cell pellets were spiked as a standard. Tissue microarrays were made using routinely processed bone marrow trephines from 242 patients with AML. QD-ISH was performed for six candidate prognostic genes using triplex QD-ISH for DNMT1, DNMT3A, DNMT3B, and for HOXA4, HOXA9, Meis1. Scrambled oligonucleotides were used to correct for background staining followed by normalisation of expression against the expression values for the white cell pellet standard. Survival analysis demonstrated that low expression of HOXA4 was associated with poorer overall survival (p = 0.009), whilst high expression of HOXA9 (p < 0.0001), Meis1 (p = 0.005) and DNMT3A (p = 0.04) were associated with early treatment failure. These results demonstrate application of a standardised, quantitative multiplex QD-ISH method for identification of prognostic markers in formalin-fixed paraffin-embedded clinical samples, facilitating measurement of gene expression signatures in routine clinical samples.

  8. Quantitative multiplex quantum dot in-situ hybridisation based gene expression profiling in tissue microarrays identifies prognostic genes in acute myeloid leukaemia

    Energy Technology Data Exchange (ETDEWEB)

    Tholouli, Eleni [Department of Haematology, Manchester Royal Infirmary, Oxford Road, Manchester, M13 9WL (United Kingdom); MacDermott, Sarah [The Medical School, The University of Manchester, Oxford Road, M13 9PT Manchester (United Kingdom); Hoyland, Judith [School of Biomedicine, Faculty of Medical and Human Sciences, The University of Manchester, Oxford Road, M13 9PT Manchester (United Kingdom); Yin, John Liu [Department of Haematology, Manchester Royal Infirmary, Oxford Road, Manchester, M13 9WL (United Kingdom); Byers, Richard, E-mail: richard.byers@cmft.nhs.uk [School of Cancer and Enabling Sciences, Faculty of Medical and Human Sciences, The University of Manchester, Stopford Building, Oxford Road, M13 9PT Manchester (United Kingdom)

    2012-08-24

    Highlights: Black-Right-Pointing-Pointer Development of a quantitative high throughput in situ expression profiling method. Black-Right-Pointing-Pointer Application to a tissue microarray of 242 AML bone marrow samples. Black-Right-Pointing-Pointer Identification of HOXA4, HOXA9, Meis1 and DNMT3A as prognostic markers in AML. -- Abstract: Measurement and validation of microarray gene signatures in routine clinical samples is problematic and a rate limiting step in translational research. In order to facilitate measurement of microarray identified gene signatures in routine clinical tissue a novel method combining quantum dot based oligonucleotide in situ hybridisation (QD-ISH) and post-hybridisation spectral image analysis was used for multiplex in-situ transcript detection in archival bone marrow trephine samples from patients with acute myeloid leukaemia (AML). Tissue-microarrays were prepared into which white cell pellets were spiked as a standard. Tissue microarrays were made using routinely processed bone marrow trephines from 242 patients with AML. QD-ISH was performed for six candidate prognostic genes using triplex QD-ISH for DNMT1, DNMT3A, DNMT3B, and for HOXA4, HOXA9, Meis1. Scrambled oligonucleotides were used to correct for background staining followed by normalisation of expression against the expression values for the white cell pellet standard. Survival analysis demonstrated that low expression of HOXA4 was associated with poorer overall survival (p = 0.009), whilst high expression of HOXA9 (p < 0.0001), Meis1 (p = 0.005) and DNMT3A (p = 0.04) were associated with early treatment failure. These results demonstrate application of a standardised, quantitative multiplex QD-ISH method for identification of prognostic markers in formalin-fixed paraffin-embedded clinical samples, facilitating measurement of gene expression signatures in routine clinical samples.

  9. Construction of citrus gene coexpression networks from microarray data using random matrix theory.

    Science.gov (United States)

    Du, Dongliang; Rawat, Nidhi; Deng, Zhanao; Gmitter, Fred G

    2015-01-01

    After the sequencing of citrus genomes, gene function annotation is becoming a new challenge. Gene coexpression analysis can be employed for function annotation using publicly available microarray data sets. In this study, 230 sweet orange (Citrus sinensis) microarrays were used to construct seven coexpression networks, including one condition-independent and six condition-dependent (Citrus canker, Huanglongbing, leaves, flavedo, albedo, and flesh) networks. In total, these networks contain 37 633 edges among 6256 nodes (genes), which accounts for 52.11% measurable genes of the citrus microarray. Then, these networks were partitioned into functional modules using the Markov Cluster Algorithm. Significantly enriched Gene Ontology biological process terms and KEGG pathway terms were detected for 343 and 60 modules, respectively. Finally, independent verification of these networks was performed using another expression data of 371 genes. This study provides new targets for further functional analyses in citrus. PMID:26504573

  10. Discrimination of phytoplasmas using an oligonucleotide microarray targeting rps3, rpl22, and rps19 genes

    Czech Academy of Sciences Publication Activity Database

    Lenz, Ondřej; Marková, J.; Sarkisova, Tatiana; Fránová, Jana; Přibylová, Jaroslava

    2015-01-01

    Roč. 70, January 2015 (2015), s. 47-52. ISSN 0261-2194 Institutional support: RVO:60077344 Keywords : DNA microarray * rpl22 gene * rps19 gene * rps3 gene Subject RIV: EE - Microbiology, Virology Impact factor: 1.493, year: 2014

  11. Analysis of Gene Expression Profile in Lung Adenosquamous Carcinoma Using cDNA Microarray

    Institute of Scientific and Technical Information of China (English)

    YANG Fei; YANG Jiong; JIANG Man; YE Bo; ZHANG Yu-xia; CHEN Hong-lei; XIA Dong; LIU Ming-qiu

    2004-01-01

    Gene expression profile of the lung adenosquamous carcinoma was characterized by using cDNA microarray chip containing 4 096 human genes. Among target genes, 508 differentially expressed genes were identified in adenosquamous carcinoma of the lung, 232 genes were overexpressed and 276 genes were underexpressed. Among them, 92 genes are cell signals transduction genes, 34 genes are proto-oncogenes and tumor suppressor genes or cell cycle related genes or cell apoptosis related genes, 29 genes are cell skeleton genes, 28 genes are DNA synthesis, repair and recombination genes, 12 genes are DNA binding and transcription genes. These genes may be associated with the occurence and development of adenosquamous carinome of the lung.

  12. A fisheye viewer for microarray-based gene expression data

    OpenAIRE

    Munson Ethan V; Mu Xiangming; Thao Cheng; Wu Min

    2006-01-01

    Abstract Background Microarray has been widely used to measure the relative amounts of every mRNA transcript from the genome in a single scan. Biologists have been accustomed to reading their experimental data directly from tables. However, microarray data are quite large and are stored in a series of files in a machine-readable format, so direct reading of the full data set is not feasible. The challenge is to design a user interface that allows biologists to usefully view large tables of ra...

  13. Study on Wusan Granule Anti-tumor Related Target Gene Screened by Cdna Microarray

    Institute of Scientific and Technical Information of China (English)

    YOU Zi-li; SHI Jin-ping; CHEN Hai-hong

    2006-01-01

    To screen Wusan Granule anti-tumor related target gene using cDNA microarray technique, both mRNA from Lewis lung carcinoma tissues treated by Wusan Granule and untreated control are reversibly transcribed to prepare cDNA probes which are labeled by Cy5 and Cy3. Then, the probes are hybridized to the mice cDNA microarray type MGEC-20S. After hybridization, the cDNA microarray is scanned by ScanArray 3 000 scanner and the data is analyzed by ImaGene 3 software to screen the differentially expressed genes. There are 45 differentially expressed genes including 18 known genes and 27 unknown genes between the two groups, and among them, 20 elevated genes and 25 reduced genes are identified. Additionally, the genes related to invasion and metastasis of malignant carcinomas are down-regulated and the genes related to apoptosis are up-regulated. The cDNA microarray technique is a high-throughput approach to screen the Wusan Granule anti-tumor related target genes, which allow us to explore the molecular biological mechanism on a genomic scale.

  14. MIClique: An Algorithm to Identify Differentially Coexpressed Disease Gene Subset from Microarray Data

    Directory of Open Access Journals (Sweden)

    Huanping Zhang

    2009-01-01

    Full Text Available Computational analysis of microarray data has provided an effective way to identify disease-related genes. Traditional disease gene selection methods from microarray data such as statistical test always focus on differentially expressed genes in different samples by individual gene prioritization. These traditional methods might miss differentially coexpressed (DCE gene subsets because they ignore the interaction between genes. In this paper, MIClique algorithm is proposed to identify DEC gene subsets based on mutual information and clique analysis. Mutual information is used to measure the coexpression relationship between each pair of genes in two different kinds of samples. Clique analysis is a commonly used method in biological network, which generally represents biological module of similar function. By applying the MIClique algorithm to real gene expression data, some DEC gene subsets which correlated under one experimental condition but uncorrelated under another condition are detected from the graph of colon dataset and leukemia dataset.

  15. MIClique: An algorithm to identify differentially coexpressed disease gene subset from microarray data.

    Science.gov (United States)

    Zhang, Huanping; Song, Xiaofeng; Wang, Huinan; Zhang, Xiaobai

    2009-01-01

    Computational analysis of microarray data has provided an effective way to identify disease-related genes. Traditional disease gene selection methods from microarray data such as statistical test always focus on differentially expressed genes in different samples by individual gene prioritization. These traditional methods might miss differentially coexpressed (DCE) gene subsets because they ignore the interaction between genes. In this paper, MIClique algorithm is proposed to identify DEC gene subsets based on mutual information and clique analysis. Mutual information is used to measure the coexpression relationship between each pair of genes in two different kinds of samples. Clique analysis is a commonly used method in biological network, which generally represents biological module of similar function. By applying the MIClique algorithm to real gene expression data, some DEC gene subsets which correlated under one experimental condition but uncorrelated under another condition are detected from the graph of colon dataset and leukemia dataset. PMID:20169000

  16. Quality Control Usage in High-Density Microarrays Reveals Differential Gene Expression Profiles in Ovarian Cancer.

    Science.gov (United States)

    Villegas-Ruiz, Vanessa; Moreno, Jose; Jacome-Lopez, Karina; Zentella-Dehesa, Alejandro; Juarez-Mendez, Sergio

    2016-01-01

    There are several existing reports of microarray chip use for assessment of altered gene expression in different diseases. In fact, there have been over 1.5 million assays of this kind performed over the last twenty years, which have influenced clinical and translational research studies. The most commonly used DNA microarray platforms are Affymetrix GeneChip and Quality Control Software along with their GeneChip Probe Arrays. These chips are created using several quality controls to confirm the success of each assay, but their actual impact on gene expression profiles had not been previously analyzed until the appearance of several bioinformatics tools for this purpose. We here performed a data mining analysis, in this case specifically focused on ovarian cancer, as well as healthy ovarian tissue and ovarian cell lines, in order to confirm quality control results and associated variation in gene expression profiles. The microarray data used in our research were downloaded from ArrayExpress and Gene Expression Omnibus (GEO) and analyzed with Expression Console Software using RMA, MAS5 and Plier algorithms. The gene expression profiles were obtained using Partek Genomics Suite v6.6 and data were visualized using principal component analysis, heat map, and Venn diagrams. Microarray quality control analysis showed that roughly 40% of the microarray files were false negative, demonstrating over- and under-estimation of expressed genes. Additionally, we confirmed the results performing second analysis using independent samples. About 70% of the significant expressed genes were correlated in both analyses. These results demonstrate the importance of appropriate microarray processing to obtain a reliable gene expression profile. PMID:27268623

  17. Identification of genes differentially expressed in a resistant reaction to Mycosphaerella pinodes in pea using microarray technology

    Directory of Open Access Journals (Sweden)

    Cubero José I

    2011-01-01

    Full Text Available Abstract Background Ascochyta blight, caused by Mycosphaerella pinodes is one of the most important pea pathogens. However, little is known about the genes and mechanisms of resistance acting against M. pinodes in pea. Resistance identified so far to this pathogen is incomplete, polygenic and scarce in pea, being most common in Pisum relatives. The identification of the genes underlying resistance would increase our knowledge about M. pinodes-pea interaction and would facilitate the introgression of resistance into pea varieties. In the present study differentially expressed genes in the resistant P. sativum ssp. syriacum accession P665 comparing to the susceptible pea cv. Messire after inoculation with M. pinodes have been identified using a M. truncatula microarray. Results Of the 16,470 sequences analysed, 346 were differentially regulated. Differentially regulated genes belonged to almost all functional categories and included genes involved in defense such as genes involved in cell wall reinforcement, phenylpropanoid and phytoalexins metabolism, pathogenesis- related (PR proteins and detoxification processes. Genes associated with jasmonic acid (JA and ethylene signal transduction pathways were induced suggesting that the response to M. pinodes in pea is regulated via JA and ET pathways. Expression levels of ten differentially regulated genes were validated in inoculated and control plants using qRT-PCR showing that the P665 accession shows constitutively an increased expression of the defense related genes as peroxidases, disease resistance response protein 39 (DRR230-b, glutathione S-transferase (GST and 6a-hydroxymaackiain methyltransferase. Conclusions Through this study a global view of genes expressed during resistance to M. pinodes has been obtained, giving relevant information about the mechanisms and pathways conferring resistance to this important disease. In addition, the M. truncatula microarray represents an efficient tool to

  18. Development and application of the active surveillance of pathogens microarray to monitor bacterial gene flux

    Directory of Open Access Journals (Sweden)

    Hinds Jason

    2008-10-01

    Full Text Available Abstract Background Human and animal health is constantly under threat by emerging pathogens that have recently acquired genetic determinants that enhance their survival, transmissibility and virulence. We describe the construction and development of an Active Surveillance of Pathogens (ASP oligonucleotide microarray, designed to 'actively survey' the genome of a given bacterial pathogen for virulence-associated genes. Results The microarray consists of 4958 reporters from 151 bacterial species and include genes for the identification of individual bacterial species as well as mobile genetic elements (transposons, plasmid and phage, virulence genes and antibiotic resistance genes. The ASP microarray was validated with nineteen bacterial pathogens species, including Francisella tularensis, Clostridium difficile, Staphylococcus aureus, Enterococcus faecium and Stenotrophomonas maltophilia. The ASP microarray identified these bacteria, and provided information on potential antibiotic resistance (eg sufamethoxazole resistance and sulfonamide resistance and virulence determinants including genes likely to be acquired by horizontal gene transfer (e.g. an alpha-haemolysin. Conclusion The ASP microarray has potential in the clinic as a diagnostic tool, as a research tool for both known and emerging pathogens, and as an early warning system for pathogenic bacteria that have been recently modified either naturally or deliberately.

  19. Development, Characterization and Experimental Validation of a Cultivated Sunflower (Helianthus annuus L.) Gene Expression Oligonucleotide Microarray

    OpenAIRE

    Fernandez, Paula; Soria, Marcelo; Blesa, David; DiRienzo, Julio; Moschen, Sebastian; Rivarola, Maximo; Clavijo, Bernardo Jose; Gonzalez, Sergio; Peluffo, Lucila; Príncipi, Dario; Dosio, Guillermo; Aguirrezabal, Luis; García-García, Francisco; Conesa, Ana; Hopp, Esteban

    2012-01-01

    Oligonucleotide-based microarrays with accurate gene coverage represent a key strategy for transcriptional studies in orphan species such as sunflower, H. annuus L., which lacks full genome sequences. The goal of this study was the development and functional annotation of a comprehensive sunflower unigene collection and the design and validation of a custom sunflower oligonucleotide-based microarray. A large scale EST (>130,000 ESTs) curation, assembly and sequence annotation was performed us...

  20. Quality control in microarray assessment of gene expression in human airway epithelium

    OpenAIRE

    Attiyeh Marc A; Harvey Ben-Gary; Wang Wei; Hackett Neil R; O'Connor Timothy P; Raman Tina; Dang David T; Teater Matthew; Crystal Ronald G

    2009-01-01

    Abstract Background Microarray technology provides a powerful tool for defining gene expression profiles of airway epithelium that lend insight into the pathogenesis of human airway disorders. The focus of this study was to establish rigorous quality control parameters to ensure that microarray assessment of the airway epithelium is not confounded by experimental artifact. Samples (total n = 223) of trachea, large and small airway epithelium were collected by fiberoptic bronchoscopy of 144 in...

  1. Robust Microarray Meta-Analysis Identifies Differentially Expressed Genes for Clinical Prediction

    OpenAIRE

    Phan, John H.; Andrew N. Young; Wang, May D.

    2012-01-01

    Combining multiple microarray datasets increases sample size and leads to improved reproducibility in identification of informative genes and subsequent clinical prediction. Although microarrays have increased the rate of genomic data collection, sample size is still a major issue when identifying informative genetic biomarkers. Because of this, feature selection methods often suffer from false discoveries, resulting in poorly performing predictive models. We develop a simple meta-analysis-ba...

  2. Gene ARMADA: an integrated multi-analysis platform for microarray data implemented in MATLAB

    OpenAIRE

    Kolisis Fragiskos N; Moulos Panagiotis; Chatziioannou Aristotelis

    2009-01-01

    Abstract Background The microarray data analysis realm is ever growing through the development of various tools, open source and commercial. However there is absence of predefined rational algorithmic analysis workflows or batch standardized processing to incorporate all steps, from raw data import up to the derivation of significantly differentially expressed gene lists. This absence obfuscates the analytical procedure and obstructs the massive comparative processing of genomic microarray da...

  3. The Important Candidate Genes in Goats - A Review

    Directory of Open Access Journals (Sweden)

    China SUPAKORN

    2009-01-01

    Full Text Available A total of 271 candidate genes have been detected in goats. However, comprehensive investigations have been carried out on the polymorphism of some genes, involved in the control of economic traits. Candidate genes have an effect on the physiological pathway, metabolism and expression of phenotypes. For growth traits, growth hormone (GH, growth hormone receptor (GHR, insulin like growth factor I (IGF-I, leptin (LEP, caprine pituitary specific transcription factor-1 (POU1F1, caprine myostatin (MSTN and bone morphogenetic protein (BMP genes are necessary for bone formation, birth weight, weaning weight, body condition and muscle growth. For reproduction, forkhead box L 2 (FOXL2, melatonin receptor 1A (MTNR1A, sex determination region of Y chromosome (SRY and amelogenin (AMEL genes influence sex determination and proliferation. The major candidate genes for milk yield and milk composition traits are the casein gene and their family. Keratin associated protein (KAP and melanocortin 1 receptor (MC1R genes are candidate genes for wool traits. The major histocompatibility complex (MHC gene is considered important for the immune system and disease resistance traits. The functions of these genes on economically important traits are different. Some genes have synergistic or antagonistic effects in nature for expression of phenotypic traits. On the other hand, some genes could control more than one trait. Also, the producers should be concerned with these effects because selection of a single trait by using only a gene could affect other traits. Therefore, the identification of candidate genes and their mutations which cause variations of gene expression and phenotype of economic traits will help breeders to search some genetic markers for these economic traits. It may be used as an aid in the selection of parent stock at an early age in the future.

  4. Evaluation of gene importance in microarray data based upon probability of selection

    Directory of Open Access Journals (Sweden)

    Fu Li M

    2005-03-01

    Full Text Available Abstract Background Microarray devices permit a genome-scale evaluation of gene function. This technology has catalyzed biomedical research and development in recent years. As many important diseases can be traced down to the gene level, a long-standing research problem is to identify specific gene expression patterns linking to metabolic characteristics that contribute to disease development and progression. The microarray approach offers an expedited solution to this problem. However, it has posed a challenging issue to recognize disease-related genes expression patterns embedded in the microarray data. In selecting a small set of biologically significant genes for classifier design, the nature of high data dimensionality inherent in this problem creates substantial amount of uncertainty. Results Here we present a model for probability analysis of selected genes in order to determine their importance. Our contribution is that we show how to derive the P value of each selected gene in multiple gene selection trials based on different combinations of data samples and how to conduct a reliability analysis accordingly. The importance of a gene is indicated by its associated P value in that a smaller value implies higher information content from information theory. On the microarray data concerning the subtype classification of small round blue cell tumors, we demonstrate that the method is capable of finding the smallest set of genes (19 genes with optimal classification performance, compared with results reported in the literature. Conclusion In classifier design based on microarray data, the probability value derived from gene selection based on multiple combinations of data samples enables an effective mechanism for reducing the tendency of fitting local data particularities.

  5. Using a cDNA microarray to study cellular gene expression altered by Mycobacterium tuberculosis

    Institute of Scientific and Technical Information of China (English)

    徐永忠; 谢建平; 李瑶; 乐军; 陈建平; 淳于利娟; 王洪海

    2003-01-01

    Objective To examine the global effects of Mycobacterium tuberculosis (M.tuberculosis) infection on macrophages. Methods The gene expression profiling of macrophage U937, in response to infection with M.tuberculosis H37Ra, was monitored using a high-density cDNA microarray. Results M.tuberculosis infection caused 463 differentially expressed genes, of which 366 genes are known genes registered in the Gene Bank. These genes function in various cellular processes including intracellular signalling, cytoskeletal rearrangement, apoptosis, transcriptional regulation, cell surface receptors, cell-mediated immunity as well as a variety of cellular metabolic pathways, and may play key roles in M.tuberculosis infection and intracellular survival. Conclusions M.tuberculosis infection alters the expression of host-cell genes, and these genes will provide a foundation for understanding the infection process of M.tuberculosis. The cDNA microarray is a powerful tool for studying pathogen-host cell interaction.

  6. A Combinatory Approach for Selecting Prognostic Genes in Microarray Studies of Tumour Survivals

    Directory of Open Access Journals (Sweden)

    Qihua Tan

    2009-01-01

    Full Text Available Different from significant gene expression analysis which looks for genes that are differentially regulated, feature selection in the microarray-based prognostic gene expression analysis aims at finding a subset of marker genes that are not only differentially expressed but also informative for prediction. Unfortunately feature selection in literature of microarray study is predominated by the simple heuristic univariate gene filter paradigm that selects differentially expressed genes according to their statistical significances. We introduce a combinatory feature selection strategy that integrates differential gene expression analysis with the Gram-Schmidt process to identify prognostic genes that are both statistically significant and highly informative for predicting tumour survival outcomes. Empirical application to leukemia and ovarian cancer survival data through-within- and cross-study validations shows that the feature space can be largely reduced while achieving improved testing performances.

  7. Statistical Redundancy Testing for Improved Gene Selection in Cancer Classification Using Microarray Data

    Directory of Open Access Journals (Sweden)

    J. Sunil Rao

    2007-01-01

    Full Text Available In gene selection for cancer classifi cation using microarray data, we define an eigenvalue-ratio statistic to measure a gene’s contribution to the joint discriminability when this gene is included into a set of genes. Based on this eigenvalueratio statistic, we define a novel hypothesis testing for gene statistical redundancy and propose two gene selection methods. Simulation studies illustrate the agreement between statistical redundancy testing and gene selection methods. Real data examples show the proposed gene selection methods can select a compact gene subset which can not only be used to build high quality cancer classifiers but also show biological relevance.

  8. A novel time-course cDNA microarray analysis method identifies genes associated with the development of cisplatin resistance.

    Science.gov (United States)

    Whiteside, Martin A; Chen, Dung-Tsa; Desmond, Renee A; Abdulkadir, Sarki A; Johanning, Gary L

    2004-01-22

    In recent years, most cDNA microarray studies of chemotherapeutic drug resistance have not considered the temporal pattern of gene expression. The objective of this study was to examine systematically changes in gene expression of NCI-H226 and NCI-H2170 lung cancer cells treated weekly with IC10 doses of cisplatin. NCI-H226 lung cancer cells were treated weekly with an IC10 dose of cisplatin. Candidate genes with a fold change of 2.0 or more were identified from this study. A second experiment was conducted by exposing NCI-H2170 cells to cisplatin doses that were increased in week 4 and decreased in week 5. Overall, 44 genes were differentially expressed in both the NCI-H226 and NCI-H2170 cell lines. In the NCI-H2170 cell line, 24 genes had a twofold gene expression change from weeks 3 to 4. Real-time PCR found a significant correlation of the gene expression changes for seven genes of interest. This small time-ordered series identified novel genes associated with cisplatin resistance. This kind of analysis should be viewed as a first step towards building gene-regulatory networks. PMID:14737109

  9. Microarray analysis identified Puccinia striiformis f. sp. tritici genes involved in infection and sporulation.

    Science.gov (United States)

    Puccinia striiformis f. sp. tritici (Pst) causes stripe rust, one of the most important diseases of wheat worldwide. To identify Pst genes involved in infection and sporulation, a custom oligonucleotide Genechip was made using sequences of 442 genes selected from Pst cDNA libraries. Microarray analy...

  10. Development, Characterization and Experimental Validation of a Cultivated Sunflower (Helianthus annuus L.) Gene Expression Oligonucleotide Microarray

    Science.gov (United States)

    Fernandez, Paula; Soria, Marcelo; Blesa, David; DiRienzo, Julio; Moschen, Sebastian; Rivarola, Maximo; Clavijo, Bernardo Jose; Gonzalez, Sergio; Peluffo, Lucila; Príncipi, Dario; Dosio, Guillermo; Aguirrezabal, Luis; García-García, Francisco; Conesa, Ana; Hopp, Esteban; Dopazo, Joaquín; Heinz, Ruth Amelia; Paniego, Norma

    2012-01-01

    Oligonucleotide-based microarrays with accurate gene coverage represent a key strategy for transcriptional studies in orphan species such as sunflower, H. annuus L., which lacks full genome sequences. The goal of this study was the development and functional annotation of a comprehensive sunflower unigene collection and the design and validation of a custom sunflower oligonucleotide-based microarray. A large scale EST (>130,000 ESTs) curation, assembly and sequence annotation was performed using Blast2GO (www.blast2go.de). The EST assembly comprises 41,013 putative transcripts (12,924 contigs and 28,089 singletons). The resulting Sunflower Unigen Resource (SUR version 1.0) was used to design an oligonucleotide-based Agilent microarray for cultivated sunflower. This microarray includes a total of 42,326 features: 1,417 Agilent controls, 74 control probes for sunflower replicated 10 times (740 controls) and 40,169 different non-control probes. Microarray performance was validated using a model experiment examining the induction of senescence by water deficit. Pre-processing and differential expression analysis of Agilent microarrays was performed using the Bioconductor limma package. The analyses based on p-values calculated by eBayes (p<0.01) allowed the detection of 558 differentially expressed genes between water stress and control conditions; from these, ten genes were further validated by qPCR. Over-represented ontologies were identified using FatiScan in the Babelomics suite. This work generated a curated and trustable sunflower unigene collection, and a custom, validated sunflower oligonucleotide-based microarray using Agilent technology. Both the curated unigene collection and the validated oligonucleotide microarray provide key resources for sunflower genome analysis, transcriptional studies, and molecular breeding for crop improvement. PMID:23110046

  11. Development, characterization and experimental validation of a cultivated sunflower (Helianthus annuus L. gene expression oligonucleotide microarray.

    Directory of Open Access Journals (Sweden)

    Paula Fernandez

    Full Text Available Oligonucleotide-based microarrays with accurate gene coverage represent a key strategy for transcriptional studies in orphan species such as sunflower, H. annuus L., which lacks full genome sequences. The goal of this study was the development and functional annotation of a comprehensive sunflower unigene collection and the design and validation of a custom sunflower oligonucleotide-based microarray. A large scale EST (>130,000 ESTs curation, assembly and sequence annotation was performed using Blast2GO (www.blast2go.de. The EST assembly comprises 41,013 putative transcripts (12,924 contigs and 28,089 singletons. The resulting Sunflower Unigen Resource (SUR version 1.0 was used to design an oligonucleotide-based Agilent microarray for cultivated sunflower. This microarray includes a total of 42,326 features: 1,417 Agilent controls, 74 control probes for sunflower replicated 10 times (740 controls and 40,169 different non-control probes. Microarray performance was validated using a model experiment examining the induction of senescence by water deficit. Pre-processing and differential expression analysis of Agilent microarrays was performed using the Bioconductor limma package. The analyses based on p-values calculated by eBayes (p<0.01 allowed the detection of 558 differentially expressed genes between water stress and control conditions; from these, ten genes were further validated by qPCR. Over-represented ontologies were identified using FatiScan in the Babelomics suite. This work generated a curated and trustable sunflower unigene collection, and a custom, validated sunflower oligonucleotide-based microarray using Agilent technology. Both the curated unigene collection and the validated oligonucleotide microarray provide key resources for sunflower genome analysis, transcriptional studies, and molecular breeding for crop improvement.

  12. Integrative meta-analysis of differentially expressed genes in osteoarthritis using microarray technology

    OpenAIRE

    Wang, Xi; Ning, Yujie; Guo, Xiong

    2015-01-01

    The aim of the present study was to identify differentially expressed (DE) genes in patients with osteoarthritis (OA), and biological processes associated with changes in gene expression that occur in this disease. Using the INMEX (integrative meta-analysis of expression data) software tool, a meta-analysis of publicly available microarray Gene Expression Omnibus (GEO) datasets of OA was performed. Gene ontology (GO) enrichment analysis was performed in order to detect enriched functional att...

  13. Genome-wide screening for trait conferring genes using DNA microarrays

    OpenAIRE

    Gill, R. T.; S. Wildt; Yang, Y. T.; Ziesman, S.; Stephanopoulos, G.

    2002-01-01

    We report a DNA microarray-based method for genome-wide monitoring of competitively grown transformants to identify genes whose overexpression confers a specific cellular phenotype. Whereas transcriptional profiling identifies differentially expressed genes that are correlated with particular aspects of the cellular phenotype, this functional genomics approach determines genes that result in a specific physiology. This parallel gene-trait mapping method consists of transforming a strain with ...

  14. Unifying candidate gene and GWAS Approaches in Asthma.

    Directory of Open Access Journals (Sweden)

    Sven Michel

    Full Text Available The first genome wide association study (GWAS for childhood asthma identified a novel major susceptibility locus on chromosome 17q21 harboring the ORMDL3 gene, but the role of previous asthma candidate genes was not specifically analyzed in this GWAS. We systematically identified 89 SNPs in 14 candidate genes previously associated with asthma in >3 independent study populations. We re-genotyped 39 SNPs in these genes not covered by GWAS performed in 703 asthmatics and 658 reference children. Genotyping data were compared to imputation data derived from Illumina HumanHap300 chip genotyping. Results were combined to analyze 566 SNPs covering all 14 candidate gene loci. Genotyped polymorphisms in ADAM33, GSTP1 and VDR showed effects with p-values <0.0035 (corrected for multiple testing. Combining genotyping and imputation, polymorphisms in DPP10, EDN1, IL12B, IL13, IL4, IL4R and TNF showed associations at a significance level between p = 0.05 and p = 0.0035. These data indicate that (a GWAS coverage is insufficient for many asthma candidate genes, (b imputation based on these data is reliable but incomplete, and (c SNPs in three previously identified asthma candidate genes replicate in our GWAS population with significance after correction for multiple testing in 14 genes.

  15. Evaluation of a gene information summarization system by users during the analysis process of microarray datasets

    Directory of Open Access Journals (Sweden)

    Cohen Aaron

    2009-02-01

    Full Text Available Abstract Background Summarization of gene information in the literature has the potential to help genomics researchers translate basic research into clinical benefits. Gene expression microarrays have been used to study biomarkers for disease and discover novel types of therapeutics and the task of finding information in journal articles on sets of genes is common for translational researchers working with microarray data. However, manually searching and scanning the literature references returned from PubMed is a time-consuming task for scientists. We built and evaluated an automatic summarizer of information on genes studied in microarray experiments. The Gene Information Clustering and Summarization System (GICSS is a system that integrates two related steps of the microarray data analysis process: functional gene clustering and gene information gathering. The system evaluation was conducted during the process of genomic researchers analyzing their own experimental microarray datasets. Results The clusters generated by GICSS were validated by scientists during their microarray analysis process. In addition, presenting sentences in the abstract provided significantly more important information to the users than just showing the title in the default PubMed format. Conclusion The evaluation results suggest that GICSS can be useful for researchers in genomic area. In addition, the hybrid evaluation method, partway between intrinsic and extrinsic system evaluation, may enable researchers to gauge the true usefulness of the tool for the scientists in their natural analysis workflow and also elicit suggestions for future enhancements. Availability GICSS can be accessed online at: http://ir.ohsu.edu/jianji/index.html

  16. Microarray-based gene expression profiling of peripheral blood mononuclear cells in dairy cows with experimental hypocalcemia and milk fever.

    Science.gov (United States)

    Sasaki, K; Yamagishi, N; Kizaki, K; Sasaki, K; Devkota, B; Hashizume, K

    2014-01-01

    Although a molecular diagnostic assay using clinically accessible tissue, such as blood, would facilitate evaluation of disease conditions in humans and animals, little information exists on microarray-based gene expression profiling of circulating leukocytes from clinically hypocalcemic cows. Therefore, peripheral blood mononuclear cells from dairy cows with experimentally induced hypocalcemia or spontaneous milk fever were subjected to oligo-microarray analysis to identify specific biomarker genes. In experimental hypocalcemia induced by a 4-h infusion of 10% disodium EDTA (n=4), 32 genes were significantly up- or downregulated compared with control treatment (4-h infusion of 11% calcium EDTA; n=4). In cows with milk fever (n=8), 98 genes were expressed differentially (either up- or downregulated) compared with healthy parturient cows (n=5). From these data, the following 5 genes were selected as being strongly related to both experimental hypocalcemia and milk fever: protein kinase (cAMP-dependent, catalytic) inhibitor β (PKIB); DNA-damage-inducible transcript 4 (DDIT4); period homolog 1 (PER1); NUAK family, SNF1-like kinase, 1 (NUAK1); and expressed sequence tag (BI537947). Another gene (neuroendocrine secretory protein 55, NESP55) was also determined to be specific for milk fever, independently of hypocalcemia. The mRNA expression of these 6 genes in milk fever cases was verified by quantitative real-time reverse-transcription PCR and was significantly different compared with their expression in healthy parturient cows. In the present study, the selected genes appeared to be candidate biomarkers of milk fever because the continuous interactions between blood cells and the entire body suggest that subtle intracellular changes occur in association with disease. However, before any genomic biomarkers are incorporated into clinical evaluation of the disease, the effect of hypocalcemia on the mRNA expression of these genes in the tissues that regulate calcium

  17. Asymmetric microarray data produces gene lists highly predictive of research literature on multiple cancer types

    Directory of Open Access Journals (Sweden)

    Tozeren Aydin

    2010-09-01

    Full Text Available Abstract Background Much of the public access cancer microarray data is asymmetric, belonging to datasets containing no samples from normal tissue. Asymmetric data cannot be used in standard meta-analysis approaches (such as the inverse variance method to obtain large sample sizes for statistical power enrichment. Noting that plenty of normal tissue microarray samples exist in studies not involving cancer, we investigated the viability and accuracy of an integrated microarray analysis approach based on significance analysis of microarrays (merged SAM using a collection of data from separate diseased and normal samples. Results We focused on five solid cancer types (colon, kidney, liver, lung, and pancreas, where available microarray data allowed us to compare meta-analysis and integrated approaches. Our results from the merged SAM significantly overlapped gene lists from the validated inverse-variance method. Both meta-analysis and merged SAM approaches successfully captured the aberrances in the cell cycle that commonly occur in the different cancer types. However, the integrated SAM analysis replicated the known cancer literature (excluding microarray studies with much more accuracy than the meta-analysis. Conclusion The merged SAM test is a powerful, robust approach for combining data from similar platforms and for analyzing asymmetric datasets, including those with only normal or only cancer samples that cannot be utilized by meta-analysis methods. The integrated SAM approach can also be used in comparing global gene expression between various subtypes of cancer arising from the same tissue.

  18. Oral tongue cancer gene expression profiling: Identification of novel potential prognosticators by oligonucleotide microarray analysis

    International Nuclear Information System (INIS)

    The present study is aimed at identifying potential candidate genes as prognostic markers in human oral tongue squamous cell carcinoma (SCC) by large scale gene expression profiling. The gene expression profile of patients (n=37) with oral tongue SCC were analyzed using Affymetrix HG-U95Av2 high-density oligonucleotide arrays. Patients (n=20) from which there were available tumor and matched normal mucosa were grouped into stage (early vs. late) and nodal disease (node positive vs. node negative) subgroups and genes differentially expressed in tumor vs. normal and between the subgroups were identified. Three genes, GLUT3, HSAL2, and PACE4, were selected for their potential biological significance in a larger cohort of 49 patients via quantitative real-time RT-PCR. Hierarchical clustering analyses failed to show significant segregation of patients. In patients (n=20) with available tumor and matched normal mucosa, 77 genes were found to be differentially expressed (P< 0.05) in the tongue tumor samples compared to their matched normal controls. Among the 45 over-expressed genes, MMP-1 encoding interstitial collagenase showed the highest level of increase (average: 34.18 folds). Using the criterion of two-fold or greater as overexpression, 30.6%, 24.5% and 26.5% of patients showed high levels of GLUT3, HSAL2 and PACE4, respectively. Univariate analyses demonstrated that GLUT3 over-expression correlated with depth of invasion (P<0.0001), tumor size (P=0.024), pathological stage (P=0.009) and recurrence (P=0.038). HSAL2 was positively associated with depth of invasion (P=0.015) and advanced T stage (P=0.047). In survival studies, only GLUT3 showed a prognostic value with disease-free (P=0.049), relapse-free (P=0.002) and overall survival (P=0.003). PACE4 mRNA expression failed to show correlation with any of the relevant parameters. The characterization of genes identified to be significant predictors of prognosis by oligonucleotide microarray and further validation by

  19. Predicting gene ontology from a global meta-analysis of 1-color microarray experiments

    OpenAIRE

    Wren Jonathan D; Giles Cory B; Dozmorov Mikhail G

    2011-01-01

    Abstract Background Global meta-analysis (GMA) of microarray data to identify genes with highly similar co-expression profiles is emerging as an accurate method to predict gene function and phenotype, even in the absence of published data on the gene(s) being analyzed. With a third of human genes still uncharacterized, this approach is a promising way to direct experiments and rapidly understand the biological roles of genes. To predict function for genes of interest, GMA relies on a guilt-by...

  20. Sediment denitrifier community composition and nirS gene expression investigated with functional gene microarrays

    DEFF Research Database (Denmark)

    Francis, C.A.; Jackson, G.A.; Ward, B.B.; Bülow, Steffen

    2008-01-01

    A functional gene microarray was used to investigate denitrifier community composition and nitrite reductase (nirS) gene expression in sediments along the estuarine gradient in Chesapeake Bay, USA. The nirS oligonucleotide probe set was designed to represent a sequence database containing 539...... Chesapeake Bay clones, as well as sequences from many other environments. Greatest nirS diversity was detected at the freshwater station at the head of the bay and least diversity at the higher salinity station near the mouth of the Bay. The most common OTUs from the sequence database were detected on the......RNA level. These results suggest that the most actively denitrifying groups are responsible for most nirS expression as well Udgivelsesdato: 2008/11...

  1. A direct molecular link between the autism candidate gene RORa and the schizophrenia candidate MIR137

    Science.gov (United States)

    Devanna, Paolo; Vernes, Sonja C.

    2014-02-01

    Retinoic acid-related orphan receptor alpha gene (RORa) and the microRNA MIR137 have both recently been identified as novel candidate genes for neuropsychiatric disorders. RORa encodes a ligand-dependent orphan nuclear receptor that acts as a transcriptional regulator and miR-137 is a brain enriched small non-coding RNA that interacts with gene transcripts to control protein levels. Given the mounting evidence for RORa in autism spectrum disorders (ASD) and MIR137 in schizophrenia and ASD, we investigated if there was a functional biological relationship between these two genes. Herein, we demonstrate that miR-137 targets the 3'UTR of RORa in a site specific manner. We also provide further support for MIR137 as an autism candidate by showing that a large number of previously implicated autism genes are also putatively targeted by miR-137. This work supports the role of MIR137 as an ASD candidate and demonstrates a direct biological link between these previously unrelated autism candidate genes.

  2. Identification of human prolactinoma related genes by DNA microarray

    Directory of Open Access Journals (Sweden)

    Lin Zhao

    2014-01-01

    Conclusion: Several DEGs between prolactinoma and normal samples were identified in our study and candidate agents such as LHB and FSHB may provide the groundwork for a targeted therapy approach for prolactinomas.

  3. A robust measure of correlation between two genes on a microarray

    Directory of Open Access Journals (Sweden)

    Hicks Leanne

    2007-06-01

    Full Text Available Abstract Background The underlying goal of microarray experiments is to identify gene expression patterns across different experimental conditions. Genes that are contained in a particular pathway or that respond similarly to experimental conditions could be co-expressed and show similar patterns of expression on a microarray. Using any of a variety of clustering methods or gene network analyses we can partition genes of interest into groups, clusters, or modules based on measures of similarity. Typically, Pearson correlation is used to measure distance (or similarity before implementing a clustering algorithm. Pearson correlation is quite susceptible to outliers, however, an unfortunate characteristic when dealing with microarray data (well known to be typically quite noisy. Results We propose a resistant similarity metric based on Tukey's biweight estimate of multivariate scale and location. The resistant metric is simply the correlation obtained from a resistant covariance matrix of scale. We give results which demonstrate that our correlation metric is much more resistant than the Pearson correlation while being more efficient than other nonparametric measures of correlation (e.g., Spearman correlation. Additionally, our method gives a systematic gene flagging procedure which is useful when dealing with large amounts of noisy data. Conclusion When dealing with microarray data, which are known to be quite noisy, robust methods should be used. Specifically, robust distances, including the biweight correlation, should be used in clustering and gene network analysis.

  4. Fish and chips: Various methodologies demonstrate utility of a 16,006-gene salmonid microarray

    Directory of Open Access Journals (Sweden)

    Nelson Colleen C

    2005-09-01

    Full Text Available Abstract Background We have developed and fabricated a salmonid microarray containing cDNAs representing 16,006 genes. The genes spotted on the array have been stringently selected from Atlantic salmon and rainbow trout expressed sequence tag (EST databases. The EST databases presently contain over 300,000 sequences from over 175 salmonid cDNA libraries derived from a wide variety of tissues and different developmental stages. In order to evaluate the utility of the microarray, a number of hybridization techniques and screening methods have been developed and tested. Results We have analyzed and evaluated the utility of a microarray containing 16,006 (16K salmonid cDNAs in a variety of potential experimental settings. We quantified the amount of transcriptome binding that occurred in cross-species, organ complexity and intraspecific variation hybridization studies. We also developed a methodology to rapidly identify and confirm the contents of a bacterial artificial chromosome (BAC library containing Atlantic salmon genomic DNA. Conclusion We validate and demonstrate the usefulness of the 16K microarray over a wide range of teleosts, even for transcriptome targets from species distantly related to salmonids. We show the potential of the use of the microarray in a variety of experimental settings through hybridization studies that examine the binding of targets derived from different organs and tissues. Intraspecific variation in transcriptome expression is evaluated and discussed. Finally, BAC hybridizations are demonstrated as a rapid and accurate means to identify gene content.

  5. Generating Genome-Scale Candidate Gene Lists for Pharmacogenomics

    DEFF Research Database (Denmark)

    Hansen, Niclas Tue; Brunak, Søren; Altman, R. B.

    2009-01-01

    A critical task in pharmacogenomics is identifying genes that may be important modulators of drug response. High-throughput experimental methods are often plagued by false positives and do not take advantage of existing knowledge. Candidate gene lists can usefully summarize existing knowledge, bu...

  6. Identification of Genes Expressed in Hyperpigmented Skin using Meta-Analysis of Microarray Datasets

    OpenAIRE

    Yin, Lanlan; Coelho, Sergio G.; Valencia, Julio C.; Ebsen, Dominik; Mahns, Andre; Smuda, Christoph; Miller, Sharon A.; Beer, Janusz Z.; Kolbe, Ludger; Hearing, Vincent J.

    2015-01-01

    More than 375 genes have been identified that are involved in regulating skin pigmentation, and those act during development, survival, differentiation and/or responses of melanocytes to the environment. Many of those genes have been cloned and disruptions of their functions are associated with various pigmentary diseases, however many remain to be identified. We have performed a series of microarray analyses of hyperpigmented compared to less pigmented skin to identify genes responsible for ...

  7. High-Resolution Analysis of Gene Copy Number Alterations in Human Prostate Cancer Using CGH on cDNA Microarrays: Impact of Copy Number on Gene Expression

    Directory of Open Access Journals (Sweden)

    Maija Wolf

    2004-05-01

    Full Text Available Identification of target genes for genetic rearrangements in prostate cancer and the impact of copy number changes on gene expression are currently not well understood. Here, we applied high-resolution comparative genomic hybridization (CGH on cDNA microarrays for analysis of prostate cancer cell lines. CGH microarrays identified most of the alterations detected by classical chromosomal CGH, as well as a number of previously unreported alterations. Specific recurrent regions of gain (28 and loss (18 were found, their boundaries defined with sub-megabasepair accuracy. The most common changes included copy number decreases at 13% and gains at iq and 5p. Refined mapping identified several sites, such as at 13q (33-44, 49-51, 74-76 Mbp from the p-telomere, which matched with minimal regions of loss seen in extensive loss of heterozygosity mapping studies of large numbers of tumors. Previously unreported recurrent changes were found at 2p, 2q, 3p, 17q (losses, at 3q, 5p, 6p (gains. Integration of genomic and transcriptomic data revealed the role of individual candidate target genes for genomic alterations as well as a highly significant (P < .0001 overall association between copy number levels and the percentage of differentially expressed genes. Across the genome, the overall impact of copy number on gene expression levels was, to a large extent, attributable to low-level gains and losses of copy number, corresponding to common deletions and gains of often large chromosomal regions.

  8. Candidate gene studies in human anxiety disorders

    OpenAIRE

    Donner, Jonas

    2012-01-01

    Anxiety disorders, such as panic disorder (PD), obsessive-compulsive disorder, post-traumatic stress disorder, generalized anxiety disorder, and phobias are common psychiatric disorders, characterized by exaggerated, prolonged and debilitating levels of anxiety. They are complex diseases with onset influenced by both environmental and genetic factors, but so far little progress has been made in identifying solid susceptibility genes. The aim of this study was to shed light on the genetic basi...

  9. Array2BIO: from microarray expression data to functional annotation of co-regulated genes

    Directory of Open Access Journals (Sweden)

    Rasley Amy

    2006-06-01

    Full Text Available Abstract Background There are several isolated tools for partial analysis of microarray expression data. To provide an integrative, easy-to-use and automated toolkit for the analysis of Affymetrix microarray expression data we have developed Array2BIO, an application that couples several analytical methods into a single web based utility. Results Array2BIO converts raw intensities into probe expression values, automatically maps those to genes, and subsequently identifies groups of co-expressed genes using two complementary approaches: (1 comparative analysis of signal versus control and (2 clustering analysis of gene expression across different conditions. The identified genes are assigned to functional categories based on Gene Ontology classification and KEGG protein interaction pathways. Array2BIO reliably handles low-expressor genes and provides a set of statistical methods for quantifying expression levels, including Benjamini-Hochberg and Bonferroni multiple testing corrections. An automated interface with the ECR Browser provides evolutionary conservation analysis for the identified gene loci while the interconnection with Crème allows prediction of gene regulatory elements that underlie observed expression patterns. Conclusion We have developed Array2BIO – a web based tool for rapid comprehensive analysis of Affymetrix microarray expression data, which also allows users to link expression data to Dcode.org comparative genomics tools and integrates a system for translating co-expression data into mechanisms of gene co-regulation. Array2BIO is publicly available at http://array2bio.dcode.org.

  10. Use of non-amplified RNA samples for microarray analysis of gene expression.

    Directory of Open Access Journals (Sweden)

    Hiroko Sudo

    Full Text Available Demand for high quality gene expression data has driven the development of revolutionary microarray technologies. The quality of the data is affected by the performance of the microarray platform as well as how the nucleic acid targets are prepared. The most common method for target nucleic acid preparation includes in vitro transcription amplification of the sample RNA. Although this method requires a small amount of starting material and is reported to have high reproducibility, there are also technical disadvantages such as amplification bias and the long, laborious protocol. Using RNA derived from human brain, breast and colon, we demonstrate that a non-amplification method, which was previously shown to be inferior, could be transformed to a highly quantitative method with a dynamic range of five orders of magnitude. Furthermore, the correlation coefficient calculated by comparing microarray assays using non-amplified samples with qRT-PCR assays was approximately 0.9, a value much higher than when samples were prepared using amplification methods. Our results were also compared with data from various microarray platforms studied in the MicroArray Quality Control (MAQC project. In combination with micro-columnar 3D-Gene™ microarray, this non-amplification method is applicable to a variety of genetic analyses, including biomarker screening and diagnostic tests for cancer.

  11. Identification of human prolactinoma related genes by DNA microarray

    OpenAIRE

    Lin Zhao; Min Lin; Shousen Wang

    2014-01-01

    Objective: To identify the genes involved in prolactinoma by bioinformatics methods and provide new potential biomarkers for prolactinoma. Materials and Methods: The gene-expression profile data, GSE36314, including 4 prolactinoma samples and 3 controls, was downloaded from Gene Expression Omnibus (GEO) database. Differentially expressed genes (DEGs) were identified using the limma package in R and were then classified into different functional groups by COG (Clusters of Orthologous Group...

  12. Spectral Biclustering of Microarray Data: Coclustering Genes and Conditions

    OpenAIRE

    Kluger, Yuval; Basri, Ronen; Chang, Joseph T; Gerstein, Mark

    2003-01-01

    Global analyses of RNA expression levels are useful for classifying genes and overall phenotypes. Often these classification problems are linked, and one wants to find “marker genes” that are differentially expressed in particular sets of “conditions.” We have developed a method that simultaneously clusters genes and conditions, finding distinctive “checkerboard” patterns in matrices of gene expression data, if they exist. In a cancer context, these checkerboards correspond to genes that are ...

  13. Microarray expression profiles of 20.000 genes across 23 healthy porcine tissues.

    Directory of Open Access Journals (Sweden)

    Henrik Hornshøj

    Full Text Available BACKGROUND: Gene expression microarrays have been intensively applied to screen for genes involved in specific biological processes of interest such as diseases or responses to environmental stimuli. For mammalian species, cataloging of the global gene expression profiles in large tissue collections under normal conditions have been focusing on human and mouse genomes but is lacking for the pig genome. METHODOLOGY/PRINCIPAL FINDINGS: Here we present the results from a large-scale porcine study establishing microarray cDNA expression profiles of approximately 20.000 genes across 23 healthy tissues. As expected, a large portion of the genes show tissue specific expression in agreement with mappings to gene descriptions, Gene Ontology terms and KEGG pathways. Two-way hierarchical clustering identified expected tissue clusters in accordance with tissue type and a number of cDNA clusters having similar gene expression patterns across tissues. For one of these cDNA clusters, we demonstrate that possible tissue associated gene function can be inferred for previously uncharacterized genes based on their shared expression patterns with functionally annotated genes. We show that gene expression in common porcine tissues is similar to the expression in homologous tissues of human. CONCLUSIONS/SIGNIFICANCE: The results from this study constitute a valuable and publicly available resource of basic gene expression profiles in normal porcine tissues and will contribute to the identification and functional annotation of porcine genes.

  14. Production of DNA microarray and expression analysis of genes from Xylella fastidiosa in different culture media

    Directory of Open Access Journals (Sweden)

    Regiane de Fátima Travensolo

    2009-06-01

    Full Text Available DNA Microarray was developed to monitor the expression of many genes from Xylella fastidiosa, allowing the side by-side comparison of two situations in a single experiment. The experiments were performed using X. fastidiosa cells grown in two culture media: BCYE and XDM2. The primers were synthesized, spotted onto glass slides and the array was hybridized against fluorescently labeled cDNAs. The emitted signals were quantified, normalized and the data were statistically analyzed to verify the differentially expressed genes. According to the data, 104 genes were differentially expressed in XDM2 and 30 genes in BCYE media. The present study showed that DNA microarray technique efficiently differentiate the expressed genes under different conditions.DNA Microarray foi desenvolvida para monitorar a expressão de muitos genes de Xylella fastidiosa, permitindo a comparação de duas situações distintas em um único experimento. Os experimentos foram feitos utilizando células de X. fastidiosa cultivada em dois meios de cultura: BCYE e XDM2. Pares de oligonucleotídeos iniciadores foram sintetizados, depositados em lâminas de vidro e o arranjo foi hibridizado contra cDNAs marcados fluorescentemente. Os sinais emitidos foram quantificados, normalizados e os dados foram estatisticamente analisados para verificar os genes diferencialmente expressos. De acordo com nossos dados, 104 genes foram diferencialmente expressos para o meio de cultura XDM2 e 30 genes para o BCYE. No presente estudo, nós demonstramos que a técnica de DNA microarrays eficientemente diferencia genes expressos sob diferentes condições de cultivo.

  15. Microarray gene expression profiling and analysis in renal cell carcinoma

    Directory of Open Access Journals (Sweden)

    Sadhukhan Provash

    2004-06-01

    Full Text Available Abstract Background Renal cell carcinoma (RCC is the most common cancer in adult kidney. The accuracy of current diagnosis and prognosis of the disease and the effectiveness of the treatment for the disease are limited by the poor understanding of the disease at the molecular level. To better understand the genetics and biology of RCC, we profiled the expression of 7,129 genes in both clear cell RCC tissue and cell lines using oligonucleotide arrays. Methods Total RNAs isolated from renal cell tumors, adjacent normal tissue and metastatic RCC cell lines were hybridized to affymatrix HuFL oligonucleotide arrays. Genes were categorized into different functional groups based on the description of the Gene Ontology Consortium and analyzed based on the gene expression levels. Gene expression profiles of the tissue and cell line samples were visualized and classified by singular value decomposition. Reverse transcription polymerase chain reaction was performed to confirm the expression alterations of selected genes in RCC. Results Selected genes were annotated based on biological processes and clustered into functional groups. The expression levels of genes in each group were also analyzed. Seventy-four commonly differentially expressed genes with more than five-fold changes in RCC tissues were identified. The expression alterations of selected genes from these seventy-four genes were further verified using reverse transcription polymerase chain reaction (RT-PCR. Detailed comparison of gene expression patterns in RCC tissue and RCC cell lines shows significant differences between the two types of samples, but many important expression patterns were preserved. Conclusions This is one of the initial studies that examine the functional ontology of a large number of genes in RCC. Extensive annotation, clustering and analysis of a large number of genes based on the gene functional ontology revealed many interesting gene expression patterns in RCC. Most

  16. Optimization of gene expression microarray protocol for formalin-fixed paraffin-embedded tissues

    Directory of Open Access Journals (Sweden)

    Nevin Belder

    2016-03-01

    Full Text Available Formalin-fixed paraffin-embedded (FFPE tissue is a widely available clinical specimen for retrospective studies. The possibility of long-term clinical follow-up of FFPE samples makes them a valuable source to evaluate links between molecular and clinical information. Working with FFPE samples in the molecular research area, especially using high-throughput molecular techniques such as microarray gene expression profiling, has come into prominence. Because of the harmful effects of formalin fixation process such as degradation of nucleic acids, cross-linking with proteins, and chemical modifications on DNA and RNA, there are some limitations in gene expression profiling studies using FFPE samples. To date many studies have been conducted to evaluate gene expression profiling using microarrays (Thomas et al., Thomas et al. (2013 [1]; Scicchitano et al., Scicchitano et al. (2006 [2]; Frank et al., Frank et al. (2007 [3]; Fedorowicz et al., Fedorowicz et al. (2009 [4]. However, there is still no generally accepted, efficient and standardized procedure for microarray analysis of FFPE samples. This paper describes the microarray data presented in our recently accepted to be published article showing a standard protocol from deparaffinization of FFPE tissue sections and RNA extraction to microarray gene expression analysis. Here we represent our data in detail, deposited in the gene expression omnibus (GEO database with the accession number GSE73883. Four combinations of two different cRNA/cDNA preparation and labeling protocols with two different array platforms (Affymetrix Human Genome U133 Plus 2.0 and U133_X3P were evaluated to determine which combination gives the best percentage of present call. The study presents a dataset for comparative analysis which has a potential in terms of providing a robust protocol for gene expression profiling with FFPE tissue samples.

  17. Optimization of gene expression microarray protocol for formalin-fixed paraffin-embedded tissues.

    Science.gov (United States)

    Belder, Nevin; Coşkun, Öznur; Erdoğan, Beyza Doğanay; Savaş, Berna; Ensari, Arzu; Özdağ, Hilal

    2016-03-01

    Formalin-fixed paraffin-embedded (FFPE) tissue is a widely available clinical specimen for retrospective studies. The possibility of long-term clinical follow-up of FFPE samples makes them a valuable source to evaluate links between molecular and clinical information. Working with FFPE samples in the molecular research area, especially using high-throughput molecular techniques such as microarray gene expression profiling, has come into prominence. Because of the harmful effects of formalin fixation process such as degradation of nucleic acids, cross-linking with proteins, and chemical modifications on DNA and RNA, there are some limitations in gene expression profiling studies using FFPE samples. To date many studies have been conducted to evaluate gene expression profiling using microarrays (Thomas et al., Thomas et al. (2013) [1]; Scicchitano et al., Scicchitano et al. (2006) [2]; Frank et al., Frank et al. (2007) [3]; Fedorowicz et al., Fedorowicz et al. (2009) [4]). However, there is still no generally accepted, efficient and standardized procedure for microarray analysis of FFPE samples. This paper describes the microarray data presented in our recently accepted to be published article showing a standard protocol from deparaffinization of FFPE tissue sections and RNA extraction to microarray gene expression analysis. Here we represent our data in detail, deposited in the gene expression omnibus (GEO) database with the accession number GSE73883. Four combinations of two different cRNA/cDNA preparation and labeling protocols with two different array platforms (Affymetrix Human Genome U133 Plus 2.0 and U133_X3P) were evaluated to determine which combination gives the best percentage of present call. The study presents a dataset for comparative analysis which has a potential in terms of providing a robust protocol for gene expression profiling with FFPE tissue samples. PMID:26981433

  18. GENE EXPRESSION IN THE TESTES OF NORMOSPERMIC VERSUS TERATOSPERMIC DOMESTIC CATS USING HUMAN CDNA MICROARRAY ANALYSES

    Science.gov (United States)

    GENE EXPRESSION IN THE TESTES OF NORMOSPERMIC VERSUS TERATOSPERMIC DOMESTIC CATS USING HUMAN cDNA MICROARRAY ANALYSESB.S. Pukazhenthi1, J. C. Rockett2, M. Ouyang3, D.J. Dix2, J.G. Howard1, P. Georgopoulos4, W.J. J. Welsh3 and D. E. Wildt11Department of Reproductiv...

  19. Gene expression analysis of strawberry achene and receptacle maturation using DNA microarrays

    NARCIS (Netherlands)

    Aharoni, A.; O'Connell, A.P.

    2002-01-01

    Large-scale, single pass sequencing and parallel gene expression analysis using DNA microarrays were employed for the comprehensive investigation of ripening in strawberry fruit. A total of 1701 cDNA clones (comprising 1100 strawberry ESTs and 601 unsequenced cDNAs) obtained from a strawberry (Fraga

  20. Density based pruning for identification of differentially expressed genes from microarray data

    Directory of Open Access Journals (Sweden)

    Xu Jia

    2010-11-01

    Full Text Available Abstract Motivation Identification of differentially expressed genes from microarray datasets is one of the most important analyses for microarray data mining. Popular algorithms such as statistical t-test rank genes based on a single statistics. The false positive rate of these methods can be improved by considering other features of differentially expressed genes. Results We proposed a pattern recognition strategy for identifying differentially expressed genes. Genes are mapped to a two dimension feature space composed of average difference of gene expression and average expression levels. A density based pruning algorithm (DB Pruning is developed to screen out potential differentially expressed genes usually located in the sparse boundary region. Biases of popular algorithms for identifying differentially expressed genes are visually characterized. Experiments on 17 datasets from Gene Omnibus Database (GEO with experimentally verified differentially expressed genes showed that DB pruning can significantly improve the prediction accuracy of popular identification algorithms such as t-test, rank product, and fold change. Conclusions Density based pruning of non-differentially expressed genes is an effective method for enhancing statistical testing based algorithms for identifying differentially expressed genes. It improves t-test, rank product, and fold change by 11% to 50% in the numbers of identified true differentially expressed genes. The source code of DB pruning is freely available on our website http://mleg.cse.sc.edu/degprune

  1. Fibrin-mediated lentivirus gene transfer: implications for lentivirus microarrays

    OpenAIRE

    Raut, Shruti; Lei, Pedro; Padmashali, Roshan; Andreadis, Stelios T.

    2010-01-01

    We employed fibrin hydrogel as bioactive matrix for lentivirus mediated gene transfer. Fibrin-mediated gene transfer was highly efficient and exhibited strong dependence on fibrinogen concentration. Efficient gene transfer was achieved with fibrinogen concentration between 3.75 – 7.5 mg/mL. Lower fibrinogen concentrations resulted in diffusion of virus out of the gel while higher concentrations led to ineffective fibrin degradation by target cells. Addition of fibrinolytic inhibitors decrease...

  2. Differential expression and prognostic significance of SOX genes in pediatric medulloblastoma and ependymoma identified by microarray analysis.

    NARCIS (Netherlands)

    J.M. de Bont (Judith Maria); J.M. Kros (Johan); M.M. Passier (Monique); R.E. Reddingius (Roel); P.A.E. Sillevis Smitt (Peter); T.M. Luider (Theo); M.L. den Boer (Monique); R. Pieters (Rob)

    2008-01-01

    textabstractThe objective of this study was to identify differentially expressed and prognostically important genes in pediatric medulloblastoma and pediatric ependymoma by Affymetrix microarray analysis. Among the most discriminative genes, three members of the SOX transcription factor family were

  3. Oligonucleotide conjugates - Candidates for gene silencing therapeutics.

    Science.gov (United States)

    Gooding, Matt; Malhotra, Meenakshi; Evans, James C; Darcy, Raphael; O'Driscoll, Caitriona M

    2016-10-01

    The potential therapeutic and diagnostic applications of oligonucleotides (ONs) have attracted great attention in recent years. The capability of ONs to selectively inhibit target genes through antisense and RNA interference mechanisms, without causing un-intended sideeffects has led them to be investigated for various biomedical applications, especially for the treatment of viral diseases and cancer. In recent years, many researchers have focused on enhancing the stability and target specificity of ONs by encapsulating/complexing them with polymers or lipid chains to formulate nanoparticles/nanocomplexes/micelles. Also, chemical modification of nucleic acids has emerged as an alternative to impart stability to ONs against nucleases and other degrading enzymes and proteins found in blood. In addition to chemically modifying the nucleic acids directly, another strategy that has emerged, involves conjugating polymers/peptide/aptamers/antibodies/proteins, preferably to the sense strand (3'end) of siRNAs. Conjugation to the siRNA not only enhances the stability and targeting specificity of the siRNA, but also allows for the development of self-administering siRNA formulations, with a much smaller size than what is usually observed for nanoparticle (∼200nm). This review concentrates mainly on approaches and studies involving ON-conjugates for biomedical applications. PMID:27521696

  4. Identification of Genes Expressed in Hyperpigmented Skin Using Meta-Analysis of Microarray Data Sets.

    Science.gov (United States)

    Yin, Lanlan; Coelho, Sergio G; Valencia, Julio C; Ebsen, Dominik; Mahns, Andre; Smuda, Christoph; Miller, Sharon A; Beer, Janusz Z; Kolbe, Ludger; Hearing, Vincent J

    2015-10-01

    More than 375 genes have been identified that are involved in regulating skin pigmentation and these act during development, survival, differentiation, and/or responses of melanocytes to the environment. Many of these genes have been cloned, and disruptions of their functions are associated with various pigmentary diseases; however, many remain to be identified. We have performed a series of microarray analyses of hyperpigmented compared with less pigmented skin to identify genes responsible for these differences. The rationale and goal for this study was to perform a meta-analysis on these microarray databases to identify genes that may be significantly involved in regulating skin phenotype either directly or indirectly that might not have been identified due to subtle differences by any of these individual studies alone. The meta-analysis demonstrates that 1,271 probes representing 921 genes are differentially expressed at significant levels in the 5 microarray data sets compared, providing new insights into the variety of genes involved in determining skin phenotype. Immunohistochemistry was used to validate two of these markers at the protein level (TRIM63 and QPCT), and we discuss the possible functions of these genes in regulating skin physiology. PMID:25950827

  5. Gene selection and classification for cancer microarray data based on machine learning and similarity measures

    Directory of Open Access Journals (Sweden)

    Liu Qingzhong

    2011-12-01

    Full Text Available Abstract Background Microarray data have a high dimension of variables and a small sample size. In microarray data analyses, two important issues are how to choose genes, which provide reliable and good prediction for disease status, and how to determine the final gene set that is best for classification. Associations among genetic markers mean one can exploit information redundancy to potentially reduce classification cost in terms of time and money. Results To deal with redundant information and improve classification, we propose a gene selection method, Recursive Feature Addition, which combines supervised learning and statistical similarity measures. To determine the final optimal gene set for prediction and classification, we propose an algorithm, Lagging Prediction Peephole Optimization. By using six benchmark microarray gene expression data sets, we compared Recursive Feature Addition with recently developed gene selection methods: Support Vector Machine Recursive Feature Elimination, Leave-One-Out Calculation Sequential Forward Selection and several others. Conclusions On average, with the use of popular learning machines including Nearest Mean Scaled Classifier, Support Vector Machine, Naive Bayes Classifier and Random Forest, Recursive Feature Addition outperformed other methods. Our studies also showed that Lagging Prediction Peephole Optimization is superior to random strategy; Recursive Feature Addition with Lagging Prediction Peephole Optimization obtained better testing accuracies than the gene selection method varSelRF.

  6. Combining mouse mammary gland gene expression and comparative mapping for the identification of candidate genes for QTL of milk production traits in cattle

    Directory of Open Access Journals (Sweden)

    Shani Moshe

    2007-06-01

    Full Text Available Abstract Background Many studies have found segregating quantitative trait loci (QTL for milk production traits in different dairy cattle populations. However, even for relatively large effects with a saturated marker map the confidence interval for QTL location by linkage analysis spans tens of map units, or hundreds of genes. Combining mapping and arraying has been suggested as an approach to identify candidate genes. Thus, gene expression analysis in the mammary gland of genes positioned in the confidence interval of the QTL can bridge the gap between fine mapping and quantitative trait nucleotide (QTN determination. Results We hybridized Affymetrix microarray (MG-U74v2, containing 12,488 murine probes, with RNA derived from mammary gland of virgin, pregnant, lactating and involuting C57BL/6J mice in a total of nine biological replicates. We combined microarray data from two additional studies that used the same design in mice with a total of 75 biological replicates. The same filtering and normalization was applied to each microarray data using GeneSpring software. Analysis of variance identified 249 differentially expressed probe sets common to the three experiments along the four developmental stages of puberty, pregnancy, lactation and involution. 212 genes were assigned to their bovine map positions through comparative mapping, and thus form a list of candidate genes for previously identified QTLs for milk production traits. A total of 82 of the genes showed mammary gland-specific expression with at least 3-fold expression over the median representing all tissues tested in GeneAtlas. Conclusion This work presents a web tool for candidate genes for QTL (cgQTL that allows navigation between the map of bovine milk production QTL, potential candidate genes and their level of expression in mammary gland arrays and in GeneAtlas. Three out of four confirmed genes that affect QTL in livestock (ABCG2, DGAT1, GDF8, IGF2 were over expressed in the

  7. Genes transactivated by hepatitis C virus core protein, a microarray assay

    Institute of Scientific and Technical Information of China (English)

    Min Liu; Shu-Lin Zhang; Jun Cheng; Yan Liu; Lin Wang; Qing Shao; Jian Zhang; Shu-Mei Lin

    2005-01-01

    AIM: To explore the new target genes transactivated by hepatitis C virus (HCV) core protein and to elucidate the pathogenesis of HCV infection.METHODS: Reverse transcribed cDNA was subjected tomicroarray assay. The coding gene transactivated by HCV core protein was cloned and analyzed with bioinformatics methods.RESULTS: The expressive vector of pcDNA3.1(-)-core was constructed and confirmed by restriction enzyme digestion and DNA sequencing and approved correct. mRNA was purified from HepG2 and HepG2 cells transfected with pcDNA3.1(-)-core, respectively. The cDNA derived was subjected to microarray assay. A new gene namedHCTP4 was cloned with molecular biological method in combination with bioinformatics method.CONCLUSION: HCV core is a potential transactivator.Microarray is an efficient and convenient method for analysis of differentially expressed genes.

  8. Kernel-imbedded Gaussian processes for disease classification using microarray gene expression data

    OpenAIRE

    Cheung Leo; Zhao Xin

    2007-01-01

    Abstract Background Designing appropriate machine learning methods for identifying genes that have a significant discriminating power for disease outcomes has become more and more important for our understanding of diseases at genomic level. Although many machine learning methods have been developed and applied to the area of microarray gene expression data analysis, the majority of them are based on linear models, which however are not necessarily appropriate for the underlying connection be...

  9. Microarray analysis of potential genes in the pathogenesis of recurrent oral ulcer

    OpenAIRE

    HAN, JINGYING; He, Zhiwei; Li, Kun; Hou, Lu

    2015-01-01

    Recurrent oral ulcer seriously threatens patients’ daily life and health. This study investigated potential genes and pathways that participate in the pathogenesis of recurrent oral ulcer by high throughput bioinformatic analysis. RT-PCR and Western blot were applied to further verify screened interleukins effect. Recurrent oral ulcer related genes were collected from websites and papers, and further found out from Human Genome 280 6.0 microarray data. Each pathway of recurrent oral ulcer rel...

  10. Integrating Microarray Gene Expression Object Model and Clinical Document Architecture for Cancer Genomics Research

    OpenAIRE

    Park, Yu Rang; Lee, Hye Won; Kim, Ju Han

    2005-01-01

    Systematic integration of gene expression profiling with clinical information may facilitate cancer genomics research. MAGE-OM (MicroArray Gene Expression Object Model) defines standard objects for genomic but not for clinical data. HL7 CDA (Clinical Document Architecture) is a document model for clinical information, describing syntax but not semantics. We designed a document template and common data elements in XML Schema with additional constraints for CDA to define conte...

  11. Profound effect of normalization on detection of differentially expressed genes in oligonucleotide microarray data analysis

    OpenAIRE

    Hoffmann, Reinhard; Seidl, Thomas; Dugas, Martin

    2002-01-01

    Background Oligonucleotide microarrays measure the relative transcript abundance of thousands of mRNAs in parallel. A large number of procedures for normalization and detection of differentially expressed genes have been proposed. However, the relative impact of these methods on the detection of differentially expressed genes remains to be determined. Results We have employed four different normalization methods and all possible combinations with three different statistical algorithms for det...

  12. GeneRank: Using search engine technology for the analysis of microarray experiments

    OpenAIRE

    Breitling Rainer; Morrison Julie L; Higham Desmond J; Gilbert David R

    2005-01-01

    Abstract Background Interpretation of simple microarray experiments is usually based on the fold-change of gene expression between a reference and a "treated" sample where the treatment can be of many types from drug exposure to genetic variation. Interpretation of the results usually combines lists of differentially expressed genes with previous knowledge about their biological function. Here we evaluate a method – based on the PageRank algorithm employed by the popular search engine Google ...

  13. OLIGONUCLEOTIDE MICROARRAY FOR THE IDENTIFICATION OF CARBAPENEMASE GENES OF MOLECULAR CLASSES A, B, AND D

    OpenAIRE

    Ulyashova, M.; Khalilova, Yu; Rubtsova, M.; Edelstein, M.; Alexandrova, I; Egorov, A.

    2010-01-01

    This work is a report on the development of a method of hybridization analysis on DNA microarrays for the simultaneous identification and typing of carbapenemase-encoding genes. These enzymes are produced by the microorganisms that are responsible for causing infectious diseases. The method involves several steps, including DNA extraction from clinical samples and amplification of carbapenemase genes by multiplex PCR with simultaneous labelling by biotin. Following that, hybridization of the ...

  14. Candidate genes of idiopathic pulmonary fibrosis: current evidence and research

    Directory of Open Access Journals (Sweden)

    Zhou W

    2016-02-01

    Full Text Available Wei Zhou,1,2 Yaping Wang1,2 1Department of Medical Genetics, 2Jiangsu Key Laboratory of Molecular Medicine, Nanjing University School of Medicine, Nanjing, People's Republic of China Abstract: Idiopathic pulmonary fibrosis (IPF is a group of common and lethal forms of idiopathic interstitial pulmonary disease. IPF is characterized by a progressive decline in lung function with a median survival of 2–3 years after diagnosis. Although the pathogenesis of the disease remains unknown, genetic predisposition could play a causal role in IPF. A set of genes have been identified as candidate genes of IPF in the past 20 years. However, the recent technological advances that allow for the analysis of millions of polymorphisms in different subjects have deepened the understanding of the genetic complexity of IPF susceptibility. Genome-wide association studies and whole-genome sequencing continue to reveal the genetic loci associated with IPF risk. In this review, we describe candidate genes on the basis of their functions and aim to gain a better understanding of the genetic basis of IPF. The discovered candidate genes may help to clarify pivotal aspects in the diagnosis, prognosis, and therapies of IPF. Keywords: idiopathic pulmonary fibrosis, candidate genes, susceptibility 

  15. Microarray analysis of adipose tissue gene expression profiles between two chicken breeds

    Indian Academy of Sciences (India)

    Hongbao Wang; Hui Li; Qigui Wang; Yuxiang Wang; Huabin Han; Hui Shi

    2006-12-01

    The chicken is an important model organism that bridges the evolutionary gap between mammals and other vertebrates and provides a major protein source from meat and eggs throughout the world. Excessive accumulation of lipids in the adipose tissue is one of the main problems faced by the broiler industry nowadays. In order to visualize the mechanisms involved in the gene expression and regulation of lipid metabolism in adipose tissue, cDNA microarray containing 9 024 cDNA was used to construct gene expression profile and screen differentially expressed genes in adipose tissue between broilers and layers of 10 wk of age. Sixty-seven differentially expressed sequences were screened out, and 42 genes were found when blasted with the GenBank database. These genes are mainly related to lipid metabolism, energy metabolism, transcription and splicing factor, protein synthesis and degradation. The remained 25 sequences had no annotation available in the GenBank database. Furthermore, Northern blot and semi-quantitative RT-PCR were developed to confirm 4 differentially expressed genes screened by cDNA microarray, and it showed great consistency between the microarray data and Northern blot results or semi-quantitative RT-PCR results. The present study will be helpful for clarifying the molecular mechanism of obesity in chickens.

  16. DNA Microarray Assay Helps to Identify Functional Genes Specific for Leukemia Stem Cells

    Directory of Open Access Journals (Sweden)

    Haojian Zhang

    2013-01-01

    Full Text Available Chronic myeloid leukemia (CML is a myeloproliferative disease derived from an abnormal hematopoietic stem cell (HSC and is consistently associated with the formation of Philadelphia (Ph chromosome. Tyrosine kinase inhibitors (TKIs are highly effective in treating chronic phase CML but do not eliminate leukemia stem cells (LSCs, which are believed to be related to disease relapse. Therefore, one major challenge in the current CML research is to understand the biology of LSCs and to identify the molecular difference between LSCs and its normal stem cell counterparts. Comparing the gene expression profiles between LSCs and normal HSCs by DNA microarray assay is a systematic and unbiased approach to address this issue. In this paper, we present a DNA microarray dataset for CML LSCs and normal HSCs to show that the microarray assay will benefit the current and future studies of the biology of CML stem cells.

  17. Biclustering using Parallel Fuzzy Approach for Analysis of Microarray Gene Expression Data

    Directory of Open Access Journals (Sweden)

    Dwitiya Tyagi-Tiwari

    2015-09-01

    Full Text Available Biclusters are required to analyzing gene expression patterns of genes comparing rows in expression profiles and analyzing expression profiles of samples by comparing columns in gene expression matrix. In the process of biclustering we need to cluster genes and samples. The algorithm presented in this paper is based upon the two-way clustering approach in which the genes and samples are clustered using parallel fuzzy C-means clustering using message passing interface, we call it MFCM. MFCM applied for clustering on genes and samples which maximize membership function values of the data set. It is a parallelized rework of a parallel fuzzy two-way clustering algorithm for microarray gene expression data [9], to study the efficiency and parallelization improvement of the algorithm. The algorithm uses gene entropy measure to filter the clustered data to find biclusters. The method is able to get highly correlated biclusters of the gene expression dataset.

  18. Exploring matrix factorization techniques for significant genes identification of Alzheimer’s disease microarray gene expression data

    Directory of Open Access Journals (Sweden)

    Hu Xiaohua

    2011-07-01

    Full Text Available Abstract Background The wide use of high-throughput DNA microarray technology provide an increasingly detailed view of human transcriptome from hundreds to thousands of genes. Although biomedical researchers typically design microarray experiments to explore specific biological contexts, the relationships between genes are hard to identified because they are complex and noisy high-dimensional data and are often hindered by low statistical power. The main challenge now is to extract valuable biological information from the colossal amount of data to gain insight into biological processes and the mechanisms of human disease. To overcome the challenge requires mathematical and computational methods that are versatile enough to capture the underlying biological features and simple enough to be applied efficiently to large datasets. Methods Unsupervised machine learning approaches provide new and efficient analysis of gene expression profiles. In our study, two unsupervised knowledge-based matrix factorization methods, independent component analysis (ICA and nonnegative matrix factorization (NMF are integrated to identify significant genes and related pathways in microarray gene expression dataset of Alzheimer’s disease. The advantage of these two approaches is they can be performed as a biclustering method by which genes and conditions can be clustered simultaneously. Furthermore, they can group genes into different categories for identifying related diagnostic pathways and regulatory networks. The difference between these two method lies in ICA assume statistical independence of the expression modes, while NMF need positivity constrains to generate localized gene expression profiles. Results In our work, we performed FastICA and non-smooth NMF methods on DNA microarray gene expression data of Alzheimer’s disease respectively. The simulation results shows that both of the methods can clearly classify severe AD samples from control samples, and

  19. Identification of quantitative trait loci and candidate genes for cadmium tolerance in Populus

    Energy Technology Data Exchange (ETDEWEB)

    Induri, Brahma R [West Virginia University; Ellis, Danielle R [West Virginia University; Slavov, Goncho T. [West Virginia University; Yin, Tongming [ORNL; Zhang, Xinye [ORNL; Tuskan, Gerald A [ORNL; DiFazio, Steven P [West Virginia University

    2012-01-01

    Understanding genetic variation for the response of Populus to heavy metals like cadmium (Cd) is an important step in elucidating the underlying mechanisms of tolerance. In this study, a pseudo-backcross pedigree of Populus trichocarpa Torr. & Gray and Populus deltoides Bart. was characterized for growth and performance traits after Cd exposure. A total of 16 quantitative trait loci (QTL) at logarithm of odds (LOD) ratio 2.5 were detected for total dry weight, its components and root volume. Major QTL for Cd responses were mapped to two different linkage groups and the relative allelic effects were in opposing directions on the two chromosomes, suggesting differential mechanisms at these two loci. The phenotypic variance explained by Cd QTL ranged from 5.9 to 11.6% and averaged 8.2% across all QTL. A whole-genome microarray study led to the identification of nine Cd-responsive genes from these QTL. Promising candidates for Cd tolerance include an NHL repeat membrane-spanning protein, a metal transporter and a putative transcription factor. Additional candidates in the QTL intervals include a putative homolog of a glutamate cysteine ligase, and a glutathione-S-transferase. Functional characterization of these candidate genes should enhance our understanding of Cd metabolism and transport and phytoremediation capabilities of Populus.

  20. Multi-gene detection and identification of mosquito-borne RNA viruses using an oligonucleotide microarray.

    Directory of Open Access Journals (Sweden)

    Nathan D Grubaugh

    Full Text Available BACKGROUND: Arthropod-borne viruses are important emerging pathogens world-wide. Viruses transmitted by mosquitoes, such as dengue, yellow fever, and Japanese encephalitis viruses, infect hundreds of millions of people and animals each year. Global surveillance of these viruses in mosquito vectors using molecular based assays is critical for prevention and control of the associated diseases. Here, we report an oligonucleotide DNA microarray design, termed ArboChip5.1, for multi-gene detection and identification of mosquito-borne RNA viruses from the genera Flavivirus (family Flaviviridae, Alphavirus (Togaviridae, Orthobunyavirus (Bunyaviridae, and Phlebovirus (Bunyaviridae. METHODOLOGY/PRINCIPAL FINDINGS: The assay utilizes targeted PCR amplification of three genes from each virus genus for electrochemical detection on a portable, field-tested microarray platform. Fifty-two viruses propagated in cell-culture were used to evaluate the specificity of the PCR primer sets and the ArboChip5.1 microarray capture probes. The microarray detected all of the tested viruses and differentiated between many closely related viruses such as members of the dengue, Japanese encephalitis, and Semliki Forest virus clades. Laboratory infected mosquitoes were used to simulate field samples and to determine the limits of detection. Additionally, we identified dengue virus type 3, Japanese encephalitis virus, Tembusu virus, Culex flavivirus, and a Quang Binh-like virus from mosquitoes collected in Thailand in 2011 and 2012. CONCLUSIONS/SIGNIFICANCE: We demonstrated that the described assay can be utilized in a comprehensive field surveillance program by the broad-range amplification and specific identification of arboviruses from infected mosquitoes. Furthermore, the microarray platform can be deployed in the field and viral RNA extraction to data analysis can occur in as little as 12 h. The information derived from the ArboChip5.1 microarray can help to establish

  1. STARNET 2: a web-based tool for accelerating discovery of gene regulatory networks using microarray co-expression data

    OpenAIRE

    Jupiter, Daniel; Chen, Hailin; VanBuren, Vincent

    2009-01-01

    Background Although expression microarrays have become a standard tool used by biologists, analysis of data produced by microarray experiments may still present challenges. Comparison of data from different platforms, organisms, and labs may involve complicated data processing, and inferring relationships between genes remains difficult. Results STARNET 2 is a new web-based tool that allows post hoc visual analysis of correlations that are derived from expression microarray data. STARNET 2 fa...

  2. Identification of Quantitative Trait Loci (QTL) and Candidate Genes for Cadmium Tolerance in Populus

    Energy Technology Data Exchange (ETDEWEB)

    Induri, Brahma R [West Virginia University; Ellis, Danielle R [West Virginia University; Slavov, Gancho [West Virginia University; Yin, Tongming [ORNL; Muchero, Wellington [ORNL; Tuskan, Gerald A [ORNL; DiFazio, Stephen P [West Virginia University

    2012-01-01

    Knowledge of genetic variation in response of Populus to heavy metals like cadmium (Cd) is an important step in understanding the underlying mechanisms of tolerance. In this study, a pseudo-backcross pedigree of Populus trichocarpa and Populus deltoides was characterized for Cd exposure. The pedigree showed significant variation for Cd tolerance thus enabling the identification of relatively tolerant and susceptible genotypes for intensive characterization. A total of 16 QTLs at logarithm of odds (LOD) ratio > 2.5, were found to be associated with total dry weight, its components, and root volume. Four major QTLs for total dry weight were mapped to different linkage groups in control (LG III) and Cd conditions (LG XVI) and had opposite allelic effects on Cd tolerance, suggesting that these genomic regions were differentially controlled. The phenotypic variation explained by Cd QTL for all traits under study varied from 5.9% to 11.6% and averaged 8.2% across all QTL. Leaf Cd contents also showed significant variation suggesting the phytoextraction potential of Populus genotypes, though heritability of this trait was low (0.22). A whole-genome microarray study was conducted by using two genotypes with extreme responses for Cd tolerance in the above study and differentially expressed genes were identified. Candidate genes including CAD2 (CADMIUM SENSITIVE 2), HMA5 (HEAVY METAL ATPase5), ATGTST1 (Arabidopsis thaliana Glutathione S-Transferase1), ATGPX6 (Glutathione peroxidase 6), and ATMRP 14 (Arabidopsis thaliana Multidrug Resistance associated Protein 14) were identified from QTL intervals and microarray study. Functional characterization of these candidate genes could enhance phytoremediation capabilities of Populus.

  3. GeneMesh: a web-based microarray analysis tool for relating differentially expressed genes to MeSH terms

    Directory of Open Access Journals (Sweden)

    Argraves W Scott

    2010-04-01

    Full Text Available Abstract Background An important objective of DNA microarray-based gene expression experimentation is determining inter-relationships that exist between differentially expressed genes and biological processes, molecular functions, cellular components, signaling pathways, physiologic processes and diseases. Results Here we describe GeneMesh, a web-based program that facilitates analysis of DNA microarray gene expression data. GeneMesh relates genes in a query set to categories available in the Medical Subject Headings (MeSH hierarchical index. The interface enables hypothesis driven relational analysis to a specific MeSH subcategory (e.g., Cardiovascular System, Genetic Processes, Immune System Diseases etc. or unbiased relational analysis to broader MeSH categories (e.g., Anatomy, Biological Sciences, Disease etc.. Genes found associated with a given MeSH category are dynamically linked to facilitate tabular and graphical depiction of Entrez Gene information, Gene Ontology information, KEGG metabolic pathway diagrams and intermolecular interaction information. Expression intensity values of groups of genes that cluster in relation to a given MeSH category, gene ontology or pathway can be displayed as heat maps of Z score-normalized values. GeneMesh operates on gene expression data derived from a number of commercial microarray platforms including Affymetrix, Agilent and Illumina. Conclusions GeneMesh is a versatile web-based tool for testing and developing new hypotheses through relating genes in a query set (e.g., differentially expressed genes from a DNA microarray experiment to descriptors making up the hierarchical structure of the National Library of Medicine controlled vocabulary thesaurus, MeSH. The system further enhances the discovery process by providing links between sets of genes associated with a given MeSH category to a rich set of html linked tabular and graphic information including Entrez Gene summaries, gene ontologies

  4. GeneRank: Using search engine technology for the analysis of microarray experiments

    Directory of Open Access Journals (Sweden)

    Breitling Rainer

    2005-09-01

    Full Text Available Abstract Background Interpretation of simple microarray experiments is usually based on the fold-change of gene expression between a reference and a "treated" sample where the treatment can be of many types from drug exposure to genetic variation. Interpretation of the results usually combines lists of differentially expressed genes with previous knowledge about their biological function. Here we evaluate a method – based on the PageRank algorithm employed by the popular search engine Google – that tries to automate some of this procedure to generate prioritized gene lists by exploiting biological background information. Results GeneRank is an intuitive modification of PageRank that maintains many of its mathematical properties. It combines gene expression information with a network structure derived from gene annotations (gene ontologies or expression profile correlations. Using both simulated and real data we find that the algorithm offers an improved ranking of genes compared to pure expression change rankings. Conclusion Our modification of the PageRank algorithm provides an alternative method of evaluating microarray experimental results which combines prior knowledge about the underlying network. GeneRank offers an improvement compared to assessing the importance of a gene based on its experimentally observed fold-change alone and may be used as a basis for further analytical developments.

  5. Effects of aspirin on metastasis-associated gene expression detected by cDNA microarray

    Institute of Scientific and Technical Information of China (English)

    Xue-qin GAO; Jin-xiang HAN; Hai-yan HUANG; Shi YAN; Chang-zheng SONG; Hai-nan HUANG

    2004-01-01

    AIM: To investigate the effect of aspirin on the metastasis-associated gene expression in 3AO ovarian cancer cells.METHODS: 3AO cells were treated with aspirin at the concentration of 1.2 mmol/L for 16 and 48 h, respectively.The total RNA was extracted with Trizol reagents and reverse transcribed with Superscript II and hybridized with cDNA microarray (containing oncogenes, tumor suppressor genes, signal transduction pathway molecules, adhesive molecules, growth factors and ESTs) fabricated in our lab. After normalization, the ratio of gene expression of aspirin treated to untreated 3AO cells being either 2 fold up higher or 0.5 fold down (lower) were defined as differential expression. Semi-quantitative RT-PCR was used to validate the microarray results. RESULTS: Among the 447 metastasis-associated genes, 4 genes were up-regulated and 14 genes were down-regulated in 3AO cells treated with aspirin for 16 h compared with untreated cells. While 24 genes were up-regulated and 10 genes were down-regulated in cells treated with aspirin for 48 h. Several up or down-regulated gene expression changes continued from 16 h to 48 h. CONCLUSION: Aspirin might exert its anti-metastasis effects on ovarian cancer by affecting metastasis-associated gene expression.

  6. DNA Microarray Analysis of Gene Expression in Antifungal Bacterium of Bacillus lenthmorbus WJ5

    International Nuclear Information System (INIS)

    This simultaneous expression levels of antifungal activity related was analyzed by DNA microarray. We constructured DNA chips contained 2,000 randomly digested genome spots of the antifungal bacterium of Bacillus lentimorbus WJ5 and compared it squantitative aspect with 7 antifungal activity deficient mutants induced by gamma radiation . From the analysis of microarray hybridization by the Gene Cluster, totally 408 genes were expressed and 20 genes among them were significantly suppressed in mutants. pbuX, ywbA, ptsG,yufO, and ftsY were simultaneously down-regulated in all muatants. It suggested that they were supposed to be related to the antifungal activity of B. lentimorbus WJ5

  7. Microarray and Proteomic Analysis of Brassinosteroid- and Gibberellin-Regulated Gene and Protein Expression in Rice

    Institute of Scientific and Technical Information of China (English)

    Guangxiao Yang; Setsuko Komatsu

    2004-01-01

    Brassinosteroid (BR) and gibberellin (GA) are two groups of plant growth regulators essential for normal plant growth and development. To gain insight into the molecular mechanism by which BR and GA regulate the growth and development of plants, especially the monocot plant rice, it is necessary to identify and analyze more genes and proteins that are regulated by them. With the availability of draft sequences of two major types, japonica and indica rice, it has become possible to analyze expression changes of genes and proteins at genome scale. In this review, we summarize rice functional genomic research by using microarray and proteomic approaches and our recent research results focusing on the comparison of cDNA microarray and proteomic analyses of BR- and GA-regulated gene and protein expression in rice. We believe our findings have important implications for understanding the mechanism by which BR and GA regulate the growth and development of rice.

  8. Gene expression profile analysis of genes in rat hippocampus from antidepressant treated rats using DNA microarray

    Directory of Open Access Journals (Sweden)

    Shin Minkyu

    2010-11-01

    Full Text Available Abstract Background The molecular and biological mechanisms by which many antidepressants function are based on the monoamine depletion hypothesis. However, the entire cascade of mechanisms responsible for the therapeutic effect of antidepressants has not yet been elucidated. Results We used a genome-wide microarray system containing 30,000 clones to evaluate total RNA that had been isolated from the brains of treated rats to identify the genes involved in the therapeutic mechanisms of various antidepressants, a tricyclic antidepressant (imipramine. a selective serotonin reuptake inhibitor (fluoxetine, a monoamine oxidase inhibitor (phenelzine and psychoactive herbal extracts of Nelumbinis Semen (NS. To confirm the differential expression of the identified genes, we analyzed the amount of mRNA that was isolated from the hippocampus of rats that had been treated with antidepressants by real-time RT-PCR using primers specific for selected genes of interest. These data demonstrate that antidepressants interfere with the expression of a large array of genes involved in signaling, survival and protein metabolism, suggesting that the therapeutic effect of these antidepressants is very complex. Surprisingly, unlike other antidepressants, we found that the standardized herbal medicine, Nelumbinis Semen, is free of factors that can induce neurodegenerative diseases such as caspase 8, α-synuclein, and amyloid precursor protein. In addition, the production of the inflammatory cytokine, IFNγ, was significantly decreased in rat hippocampus in response to treatment with antidepressants, while the inhibitory cytokine, TGFβ, was significantly enhanced. Conclusions These results suggest that antidepressants function by regulating neurotransmission as well as suppressing immunoreactivity in the central nervous system.

  9. Consistent Differential Expression Pattern (CDEP on microarray to identify genes related to metastatic behavior

    Directory of Open Access Journals (Sweden)

    Tsoi Lam C

    2011-11-01

    Full Text Available Abstract Background To utilize the large volume of gene expression information generated from different microarray experiments, several meta-analysis techniques have been developed. Despite these efforts, there remain significant challenges to effectively increasing the statistical power and decreasing the Type I error rate while pooling the heterogeneous datasets from public resources. The objective of this study is to develop a novel meta-analysis approach, Consistent Differential Expression Pattern (CDEP, to identify genes with common differential expression patterns across different datasets. Results We combined False Discovery Rate (FDR estimation and the non-parametric RankProd approach to estimate the Type I error rate in each microarray dataset of the meta-analysis. These Type I error rates from all datasets were then used to identify genes with common differential expression patterns. Our simulation study showed that CDEP achieved higher statistical power and maintained low Type I error rate when compared with two recently proposed meta-analysis approaches. We applied CDEP to analyze microarray data from different laboratories that compared transcription profiles between metastatic and primary cancer of different types. Many genes identified as differentially expressed consistently across different cancer types are in pathways related to metastatic behavior, such as ECM-receptor interaction, focal adhesion, and blood vessel development. We also identified novel genes such as AMIGO2, Gem, and CXCL11 that have not been shown to associate with, but may play roles in, metastasis. Conclusions CDEP is a flexible approach that borrows information from each dataset in a meta-analysis in order to identify genes being differentially expressed consistently. We have shown that CDEP can gain higher statistical power than other existing approaches under a variety of settings considered in the simulation study, suggesting its robustness and

  10. Analysis of gene expression in resynthesized Brassica napus Allopolyploids using arabidopsis 70mer oligo microarrays.

    Directory of Open Access Journals (Sweden)

    Robert T Gaeta

    Full Text Available BACKGROUND: Studies in resynthesized Brassica napus allopolyploids indicate that homoeologous chromosome exchanges in advanced generations (S(5ratio6 alter gene expression through the loss and doubling of homoeologous genes within the rearrangements. Rearrangements may also indirectly affect global gene expression if homoeologous copies of gene regulators within rearrangements have differential affects on the transcription of genes in networks. METHODOLOGY/PRINCIPAL FINDINGS: We utilized Arabidopsis 70mer oligonucleotide microarrays for exploring gene expression in three resynthesized B. napus lineages at the S(0ratio1 and S(5ratio6 generations as well as their diploid progenitors B. rapa and B. oleracea. Differential gene expression between the progenitors and additive (midparent expression in the allopolyploids were tested. The S(5ratio6 lines differed in the number of genetic rearrangements, allowing us to test if the number of genes displaying nonadditive expression was related to the number of rearrangements. Estimates using per-gene and common variance ANOVA models indicated that 6-15% of 26,107 genes were differentially expressed between the progenitors. Individual allopolyploids showed nonadditive expression for 1.6-32% of all genes. Less than 0.3% of genes displayed nonadditive expression in all S(0ratio1 lines and 0.1-0.2% were nonadditive among all S(5ratio6 lines. Differentially expressed genes in the polyploids were over-represented by genes differential between the progenitors. The total number of differentially expressed genes was correlated with the number of genetic changes in S(5ratio6 lines under the common variance model; however, there was no relationship using a per-gene variance model, and many genes showed nonadditive expression in S(0ratio1 lines. CONCLUSIONS/SIGNIFICANCE: Few genes reproducibly demonstrated nonadditive expression among lineages, suggesting few changes resulted from a general response to polyploidization

  11. Rasch-based high-dimensionality data reduction and class prediction with applications to microarray gene expression data

    CERN Document Server

    Kastrin, Andrej

    2010-01-01

    Class prediction is an important application of microarray gene expression data analysis. The high-dimensionality of microarray data, where number of genes (variables) is very large compared to the number of samples (obser- vations), makes the application of many prediction techniques (e.g., logistic regression, discriminant analysis) difficult. An efficient way to solve this prob- lem is by using dimension reduction statistical techniques. Increasingly used in psychology-related applications, Rasch model (RM) provides an appealing framework for handling high-dimensional microarray data. In this paper, we study the potential of RM-based modeling in dimensionality reduction with binarized microarray gene expression data and investigate its prediction ac- curacy in the context of class prediction using linear discriminant analysis. Two different publicly available microarray data sets are used to illustrate a general framework of the approach. Performance of the proposed method is assessed by re-randomization s...

  12. Genome-wide linkage analysis of global gene expression in loin muscle tissue identifies candidate genes in pigs.

    Directory of Open Access Journals (Sweden)

    Juan Pedro Steibel

    Full Text Available BACKGROUND: Nearly 6,000 QTL have been reported for 588 different traits in pigs, more than in any other livestock species. However, this effort has translated into only a few confirmed causative variants. A powerful strategy for revealing candidate genes involves expression QTL (eQTL mapping, where the mRNA abundance of a set of transcripts is used as the response variable for a QTL scan. METHODOLOGY/PRINCIPAL FINDINGS: We utilized a whole genome expression microarray and an F(2 pig resource population to conduct a global eQTL analysis in loin muscle tissue, and compared results to previously inferred phenotypic QTL (pQTL from the same experimental cross. We found 62 unique eQTL (FDR <10% and identified 3 gene networks enriched with genes subject to genetic control involved in lipid metabolism, DNA replication, and cell cycle regulation. We observed strong evidence of local regulation (40 out of 59 eQTL with known genomic position and compared these eQTL to pQTL to help identify potential candidate genes. Among the interesting associations, we found aldo-keto reductase 7A2 (AKR7A2 and thioredoxin domain containing 12 (TXNDC12 eQTL that are part of a network associated with lipid metabolism and in turn overlap with pQTL regions for marbling, % intramuscular fat (% fat and loin muscle area on Sus scrofa (SSC chromosome 6. Additionally, we report 13 genomic regions with overlapping eQTL and pQTL involving 14 local eQTL. CONCLUSIONS/SIGNIFICANCE: Results of this analysis provide novel candidate genes for important complex pig phenotypes.

  13. Identification of candidate genes for dyslexia susceptibility on chromosome 18.

    Directory of Open Access Journals (Sweden)

    Thomas S Scerri

    Full Text Available Six independent studies have identified linkage to chromosome 18 for developmental dyslexia or general reading ability. Until now, no candidate genes have been identified to explain this linkage. Here, we set out to identify the gene(s conferring susceptibility by a two stage strategy of linkage and association analysis.Linkage analysis: 264 UK families and 155 US families each containing at least one child diagnosed with dyslexia were genotyped with a dense set of microsatellite markers on chromosome 18. Association analysis: Using a discovery sample of 187 UK families, nearly 3000 SNPs were genotyped across the chromosome 18 dyslexia susceptibility candidate region. Following association analysis, the top ranking SNPs were then genotyped in the remaining samples. The linkage analysis revealed a broad signal that spans approximately 40 Mb from 18p11.2 to 18q12.2. Following the association analysis and subsequent replication attempts, we observed consistent association with the same SNPs in three genes; melanocortin 5 receptor (MC5R, dymeclin (DYM and neural precursor cell expressed, developmentally down-regulated 4-like (NEDD4L.Along with already published biological evidence, MC5R, DYM and NEDD4L make attractive candidates for dyslexia susceptibility genes. However, further replication and functional studies are still required.

  14. Reranking candidate gene models with cross-species comparison for improved gene prediction

    Directory of Open Access Journals (Sweden)

    Pereira Fernando CN

    2008-10-01

    Full Text Available Abstract Background Most gene finders score candidate gene models with state-based methods, typically HMMs, by combining local properties (coding potential, splice donor and acceptor patterns, etc. Competing models with similar state-based scores may be distinguishable with additional information. In particular, functional and comparative genomics datasets may help to select among competing models of comparable probability by exploiting features likely to be associated with the correct gene models, such as conserved exon/intron structure or protein sequence features. Results We have investigated the utility of a simple post-processing step for selecting among a set of alternative gene models, using global scoring rules to rerank competing models for more accurate prediction. For each gene locus, we first generate the K best candidate gene models using the gene finder Evigan, and then rerank these models using comparisons with putative orthologous genes from closely-related species. Candidate gene models with lower scores in the original gene finder may be selected if they exhibit strong similarity to probable orthologs in coding sequence, splice site location, or signal peptide occurrence. Experiments on Drosophila melanogaster demonstrate that reranking based on cross-species comparison outperforms the best gene models identified by Evigan alone, and also outperforms the comparative gene finders GeneWise and Augustus+. Conclusion Reranking gene models with cross-species comparison improves gene prediction accuracy. This straightforward method can be readily adapted to incorporate additional lines of evidence, as it requires only a ranked source of candidate gene models.

  15. Are TMEM genes potential candidate genes for panic disorder?

    DEFF Research Database (Denmark)

    Gregersen, Noomi O; Buttenschøn, Henriette Nørmølle; Hedemand, Anne;

    2014-01-01

    We analysed single nucleotide polymorphisms in two transmembrane genes (TMEM98 and TMEM132E) in panic disorder (PD) patients and control individuals from the Faroe Islands, Denmark and Germany. The genes encode single-pass membrane proteins and are located within chromosome 17q11.2-q12, a...

  16. Gene Expression Profile Differences in Gastric Cancer and Normal Gastric Mucosa by Oligonucleotide Microarrays

    Institute of Scientific and Technical Information of China (English)

    Chuanding Yu; Shenhua Xu; HangZhou Mou; Zhiming Jiang; Chihong Zhu; Xianglin Liu

    2006-01-01

    OBJECTIVE To study the difference of gene expression in gastric cancer (T) and normal tissue of gastric mucosa (C), and to screen for associated novel genes in gastric cancers by oligonucleotide microarrays.METHODS U133A (Affymetrix, Santa Clara, CA) gene chip was used to detect the gene expression profile difference in T and C. Bioinformatics was used to analyze the detected results.RESULTS When gastric cancers were compared with normal gastric mucosa, a total of 270 genes were found with a difference of more than 9times in expression levels. Of the 270 genes, 157 were up-regulated (Signal Log Ratio [SLR] ≥3), and 113 were down-regulated (SLR ≤-3).Using a classification of function, the highest number of gene expression differences related to enzymes and their regulatory genes (67, 24.8%),followed by signal-transduction genes (43,15.9%). The third were nucleic acid binding genes (17, 6.3%), fourth were transporter genes (15, 5.5%)and fifth were protein binding genes (12, 4.4%). In addition there were 50genes of unknown function, accounting for 18.5%. The five above mentioned groups made up 56.9% of the total gene number.CONCLUSION The 5 gene groups (enzymes and their regulatory proteins, signal transduction proteins, nucleic acid binding proteins, transporter and protein binding) were abnormally expressed and are important genes for further study in gastric cancers.

  17. No Evidence for Association between Amelogenesis Imperfecta and Candidate Genes

    Directory of Open Access Journals (Sweden)

    M Ghandehari Motlagh

    2009-03-01

    Full Text Available "nBackground: Amelogenesis imperfecta (AI is an inherited tooth disorder. Despite the fact that up to now, several gene muta­tions in MMP20, ENAM, AMELX and KLK4 genes have been reported to be associated with AI, many other genes sug­gested to be involved. The main objective of this study was to find the mutations in three major candidate genes including MMP20, ENAM and KLK4 responsible for AI from three Iranian families with generalized hypoplastic phenotype in all teeth. "nMethods: All exon/intron boundaries of subjected genes were amplified by polymerase chain reaction and subjected to direct sequencing."nResults: One polymorphisms was identified in KLK4 exon 2, in one family a homozygous mutation was found in the third base of codon 22 for serine (TCG>TCT, but not in other families. Although these base substitutions have been occurred in the signaling domain, they do not seem to influence the activity of KLK4 protein."nConclusion: Our results might support the further evidence for genetic heterogeneity; at least, in some AI cases are not caused by a gene in these reported candidate genes.

  18. CANDIDATE GENE ANALYSIS IN ISRAELI SOLDIERS WITH STRESS FRACTURES

    Directory of Open Access Journals (Sweden)

    Ran Yanovich

    2012-03-01

    Full Text Available To investigate the association of polymorphisms within candidate genes which we hypothesized may contribute to stress fracture predisposition, a case-control, cross- sectional study design was employed. Genotyping 268 Single Nucleotide Polymorphisms- SNPs within 17 genes in 385 Israeli young male and female recruits (182 with and 203 without stress fractures. Twenty-five polymorphisms within 9 genes (NR3C1, ANKH, VDR, ROR2, CALCR, IL6, COL1A2, CBG, and LRP4 showed statistically significant differences (p < 0.05 in the distribution between stress fracture cases and non stress fracture controls. Seventeen genetic variants were associated with an increased stress fracture risk, and eight variants with a decreased stress fracture risk. None of the SNP associations remained significant after correcting for multiple comparisons (false discovery rate- FDR. Our findings suggest that genes may be involved in stress fracture pathogenesis. Specifically, the CALCR and the VDR genes are intriguing candidates. The putative involvement of these genes in stress fracture predisposition requires analysis of more cases and controls and sequencing the relevant genomic regions, in order to define the specific gene mutations

  19. mRMR-ABC: A Hybrid Gene Selection Algorithm for Cancer Classification Using Microarray Gene Expression Profiling

    Directory of Open Access Journals (Sweden)

    Hala Alshamlan

    2015-01-01

    Full Text Available An artificial bee colony (ABC is a relatively recent swarm intelligence optimization approach. In this paper, we propose the first attempt at applying ABC algorithm in analyzing a microarray gene expression profile. In addition, we propose an innovative feature selection algorithm, minimum redundancy maximum relevance (mRMR, and combine it with an ABC algorithm, mRMR-ABC, to select informative genes from microarray profile. The new approach is based on a support vector machine (SVM algorithm to measure the classification accuracy for selected genes. We evaluate the performance of the proposed mRMR-ABC algorithm by conducting extensive experiments on six binary and multiclass gene expression microarray datasets. Furthermore, we compare our proposed mRMR-ABC algorithm with previously known techniques. We reimplemented two of these techniques for the sake of a fair comparison using the same parameters. These two techniques are mRMR when combined with a genetic algorithm (mRMR-GA and mRMR when combined with a particle swarm optimization algorithm (mRMR-PSO. The experimental results prove that the proposed mRMR-ABC algorithm achieves accurate classification performance using small number of predictive genes when tested using both datasets and compared to previously suggested methods. This shows that mRMR-ABC is a promising approach for solving gene selection and cancer classification problems.

  20. mRMR-ABC: A Hybrid Gene Selection Algorithm for Cancer Classification Using Microarray Gene Expression Profiling.

    Science.gov (United States)

    Alshamlan, Hala; Badr, Ghada; Alohali, Yousef

    2015-01-01

    An artificial bee colony (ABC) is a relatively recent swarm intelligence optimization approach. In this paper, we propose the first attempt at applying ABC algorithm in analyzing a microarray gene expression profile. In addition, we propose an innovative feature selection algorithm, minimum redundancy maximum relevance (mRMR), and combine it with an ABC algorithm, mRMR-ABC, to select informative genes from microarray profile. The new approach is based on a support vector machine (SVM) algorithm to measure the classification accuracy for selected genes. We evaluate the performance of the proposed mRMR-ABC algorithm by conducting extensive experiments on six binary and multiclass gene expression microarray datasets. Furthermore, we compare our proposed mRMR-ABC algorithm with previously known techniques. We reimplemented two of these techniques for the sake of a fair comparison using the same parameters. These two techniques are mRMR when combined with a genetic algorithm (mRMR-GA) and mRMR when combined with a particle swarm optimization algorithm (mRMR-PSO). The experimental results prove that the proposed mRMR-ABC algorithm achieves accurate classification performance using small number of predictive genes when tested using both datasets and compared to previously suggested methods. This shows that mRMR-ABC is a promising approach for solving gene selection and cancer classification problems. PMID:25961028

  1. Age-Specific Gene Expression Profiles of Rhesus Monkey Ovaries Detected by Microarray Analysis.

    Science.gov (United States)

    Wei, Hengxi; Liu, Xiangjie; Yuan, Jihong; Li, Li; Zhang, Dongdong; Guo, Xinzheng; Liu, Lin; Zhang, Shouquan

    2015-01-01

    The biological function of human ovaries declines with age. To identify the potential molecular changes in ovarian aging, we performed genome-wide gene expression analysis by microarray of ovaries from young, middle-aged, and old rhesus monkeys. Microarray data was validated by quantitative real-time PCR. Results showed that a total of 503 (60 upregulated, 443 downregulated) and 84 (downregulated) genes were differentially expressed in old ovaries compared to young and middle-aged groups, respectively. No difference in gene expression was found between middle-aged and young groups. Differentially expressed genes were mainly enriched in cell and organelle, cellular and physiological process, binding, and catalytic activity. These genes were primarily associated with KEGG pathways of cell cycle, DNA replication and repair, oocyte meiosis and maturation, MAPK, TGF-beta, and p53 signaling pathway. Genes upregulated were involved in aging, defense response, oxidation reduction, and negative regulation of cellular process; genes downregulated have functions in reproduction, cell cycle, DNA and RNA process, macromolecular complex assembly, and positive regulation of macromolecule metabolic process. These findings show that monkey ovary undergoes substantial change in global transcription with age. Gene expression profiles are useful in understanding the mechanisms underlying ovarian aging and age-associated infertility in primates. PMID:26421297

  2. Comparison and evaluation of methods for generating differentially expressed gene lists from microarray data

    Directory of Open Access Journals (Sweden)

    Culhane Aedín C

    2006-07-01

    Full Text Available Abstract Background Numerous feature selection methods have been applied to the identification of differentially expressed genes in microarray data. These include simple fold change, classical t-statistic and moderated t-statistics. Even though these methods return gene lists that are often dissimilar, few direct comparisons of these exist. We present an empirical study in which we compare some of the most commonly used feature selection methods. We apply these to 9 publicly available datasets, and compare, both the gene lists produced and how these perform in class prediction of test datasets. Results In this study, we compared the efficiency of the feature selection methods; significance analysis of microarrays (SAM, analysis of variance (ANOVA, empirical bayes t-statistic, template matching, maxT, between group analysis (BGA, Area under the receiver operating characteristic (ROC curve, the Welch t-statistic, fold change, rank products, and sets of randomly selected genes. In each case these methods were applied to 9 different binary (two class microarray datasets. Firstly we found little agreement in gene lists produced by the different methods. Only 8 to 21% of genes were in common across all 10 feature selection methods. Secondly, we evaluated the class prediction efficiency of each gene list in training and test cross-validation using four supervised classifiers. Conclusion We report that the choice of feature selection method, the number of genes in the genelist, the number of cases (samples and the noise in the dataset, substantially influence classification success. Recommendations are made for choice of feature selection. Area under a ROC curve performed well with datasets that had low levels of noise and large sample size. Rank products performs well when datasets had low numbers of samples or high levels of noise. The Empirical bayes t-statistic performed well across a range of sample sizes.

  3. Development of a Pacific oyster (Crassostrea gigas 31,918-feature microarray: identification of reference genes and tissue-enriched expression patterns

    Directory of Open Access Journals (Sweden)

    Huvet Arnaud

    2011-09-01

    Full Text Available Abstract Background Research using the Pacific oyster Crassostrea gigas as a model organism has experienced rapid growth in recent years due to the development of high-throughput molecular technologies. As many as 56,268 EST sequences have been sequenced to date, representing a genome-wide resource that can be used for transcriptomic investigations. Results In this paper, we developed a Pacific oyster microarray containing oligonucleotides representing 31,918 transcribed sequences selected from the publicly accessible GigasDatabase. This newly designed microarray was used to study the transcriptome of male and female gonads, mantle, gills, posterior adductor muscle, visceral ganglia, hemocytes, labial palps and digestive gland. Statistical analyses identified genes differentially expressed among tissues and clusters of tissue-enriched genes. These genes reflect major tissue-specific functions at the molecular level, such as tissue formation in the mantle, filtering in the gills and labial palps, and reproduction in the gonads. Hierarchical clustering predicted the involvement of unannotated genes in specific functional pathways such as the insulin/NPY pathway, an important pathway under study in our model species. Microarray data also accurately identified reference genes whose mRNA level appeared stable across all the analyzed tissues. Adp-ribosylation factor 1 (arf1 appeared to be the most robust reference for normalizing gene expression data across different tissues and is therefore proposed as a relevant reference gene for further gene expression analysis in the Pacific oyster. Conclusions This study provides a new transcriptomic tool for studies of oyster biology, which will help in the annotation of its genome and which identifies candidate reference genes for gene expression analysis.

  4. Candidate genes associated with bud dormancy release in blackcurrant (Ribes nigrum L.

    Directory of Open Access Journals (Sweden)

    Hedley Peter E

    2010-09-01

    Full Text Available Abstract Background The detrimental effects of mild winter temperatures on the consistency of cropping of blackcurrant (Ribes nigrum L. in parts of Europe have led to increasing interest in the genetic control of dormancy release in this species. This study examined patterns of gene expression in leaf buds of blackcurrant to identify key differential changes in these profiles around the time of budbreak. Results Using leaf bud tissue of blackcurrant, a cDNA library was generated as a source of blackcurrant ESTs for construction of a custom microarray, which was used to identify differential gene expression during dormancy release. Gene activity was lowest in early stages of dormancy, increasing to reach a maximum around the time of budbreak. Genes with significantly changing expression profiles were clustered and evidence is provided for the transient activity of genes previously associated with dormancy processes in other species. Expression profiling identified candidate genes which were mapped onto a blackcurrant genetic linkage map containing budbreak-related QTL. Three genes, which putatively encode calmodulin-binding protein, beta tubulin and acetyl CoA carboxylase respectively, were found to co-localise with budbreak QTL. Conclusions This study provides insight into the genetic control of dormancy transition in blackcurrant, identifying key changes in gene expression around budbreak. Genetic mapping of ESTs enabled the identification of genes which co-localise with previously-characterised blackcurrant QTL, and it is concluded that these genes have probable roles in release of dormancy and can therefore provide a basis for the development of genetic markers for future breeding deployment.

  5. A genome-wide 20 K citrus microarray for gene expression analysis

    OpenAIRE

    Gadea Jose; Forment Javier; Santiago Julia; Marques M Carmen; Juarez Jose; Mauri Nuria; Martinez-Godoy M Angeles

    2008-01-01

    Abstract Background Understanding of genetic elements that contribute to key aspects of citrus biology will impact future improvements in this economically important crop. Global gene expression analysis demands microarray platforms with a high genome coverage. In the last years, genome-wide EST collections have been generated in citrus, opening the possibility to create new tools for functional genomics in this crop plant. Results We have designed and constructed a publicly available genome-...

  6. A genome-wide 20 K citrus microarray for gene expression analysis

    OpenAIRE

    Martínez-Godoy, M. Ángeles; Mauri, Nuria; Juárez, José; Marqués, M.Carmen; Santiago, Julia; Forment, Javier; Gadea Vacas, José

    2008-01-01

    Background: Understanding of genetic elements that contribute to key aspects of citrus biology will impact future improvements in this economically important crop. Global gene expression analysis demands microarray platforms with a high genome coverage. In the last years, genomewide EST collections have been generated in citrus, opening the possibility to create new tools for functional genomics in this crop plant. Results: We have designed and constructed a publicly available ...

  7. A genome-wide 20 K citrus microarray for gene expression analysis

    OpenAIRE

    Martinez-Godoy, M Angeles; Mauri, Nuria; Juarez, Jose; Marques, M Carmen; Santiago, Julia; Forment, Javier; Gadea, Jose

    2008-01-01

    Background Understanding of genetic elements that contribute to key aspects of citrus biology will impact future improvements in this economically important crop. Global gene expression analysis demands microarray platforms with a high genome coverage. In the last years, genome-wide EST collections have been generated in citrus, opening the possibility to create new tools for functional genomics in this crop plant. Results We have designed and constructed a publicly available genome-wide cDNA...

  8. Methods for interpreting lists of affected genes obtained in a DNA microarray experiment

    Directory of Open Access Journals (Sweden)

    Hedegaard Jakob

    2009-07-01

    Full Text Available Abstract Background The aim of this paper was to describe and compare the methods used and the results obtained by the participants in a joint EADGENE (European Animal Disease Genomic Network of Excellence and SABRE (Cutting Edge Genomics for Sustainable Animal Breeding workshop focusing on post analysis of microarray data. The participating groups were provided with identical lists of microarray probes, including test statistics for three different contrasts, and the normalised log-ratios for each array, to be used as the starting point for interpreting the affected probes. The data originated from a microarray experiment conducted to study the host reactions in broilers occurring shortly after a secondary challenge with either a homologous or heterologous species of Eimeria. Results Several conceptually different analytical approaches, using both commercial and public available software, were applied by the participating groups. The following tools were used: Ingenuity Pathway Analysis, MAPPFinder, LIMMA, GOstats, GOEAST, GOTM, Globaltest, TopGO, ArrayUnlock, Pathway Studio, GIST and AnnotationDbi. The main focus of the approaches was to utilise the relation between probes/genes and their gene ontology and pathways to interpret the affected probes/genes. The lack of a well-annotated chicken genome did though limit the possibilities to fully explore the tools. The main results from these analyses showed that the biological interpretation is highly dependent on the statistical method used but that some common biological conclusions could be reached. Conclusion It is highly recommended to test different analytical methods on the same data set and compare the results to obtain a reliable biological interpretation of the affected genes in a DNA microarray experiment.

  9. Association Study between BDNF Gene Polymorphisms and Autism by Three-Dimensional Gel-Based Microarray

    OpenAIRE

    Zuhong Lu; Yunfei Bai; Xiaoyan Ke; Beili Sun; Lu Cheng; Pengfeng Xiao; Qinyu Ge

    2009-01-01

    Single nucleotide polymorphisms (SNPs) are important markers which can be used in association studies searching for susceptible genes of complex diseases. High-throughput methods are needed for SNP genotyping in a large number of samples. In this study, we applied polyacrylamide gel-based microarray combined with dual-color hybridization for association study of four BDNF polymorphisms with autism. All the SNPs in both patients and controls could be analyzed quickly and correctly. Among four ...

  10. Are females more variable than males in gene expression? Meta-analysis of microarray datasets

    OpenAIRE

    Itoh, Y.; Arnold, AP

    2015-01-01

    Background The majority of preclinical biomedical research involves studies of males rather than females. It is thought that researchers have avoided females based on the idea that female traits are more variable than those of males because of cyclic variation in effects of ovarian hormones. Methods To test the assumption of inherently greater female variability, we analyzed 293 microarray datasets measuring gene expression in various tissues of mice and humans, comprising analysis of more th...

  11. Consistent Differential Expression Pattern (CDEP) on microarray to identify genes related to metastatic behavior

    OpenAIRE

    Tsoi Lam C; Qin Tingting; Slate Elizabeth H; Zheng W Jim

    2011-01-01

    Abstract Background To utilize the large volume of gene expression information generated from different microarray experiments, several meta-analysis techniques have been developed. Despite these efforts, there remain significant challenges to effectively increasing the statistical power and decreasing the Type I error rate while pooling the heterogeneous datasets from public resources. The objective of this study is to develop a novel meta-analysis approach, Consistent Differential Expressio...

  12. Oligonucleotide microarray identifies genes differentially expressed during tumorigenesis of DMBA-induced pancreatic cancer in rats.

    Directory of Open Access Journals (Sweden)

    Jun-Chao Guo

    Full Text Available The extremely dismal prognosis of pancreatic cancer (PC is attributed, at least in part, to lack of early diagnosis. Therefore, identifying differentially expressed genes in multiple steps of tumorigenesis of PC is of great interest. In the present study, a 7,12-dimethylbenzanthraene (DMBA-induced PC model was established in male Sprague-Dawley rats. The gene expression profile was screened using an oligonucleotide microarray, followed by real-time quantitative polymerase chain reaction (qRT-PCR and immunohistochemical staining validation. A total of 661 differentially expressed genes were identified in stages of pancreatic carcinogenesis. According to GO classification, these genes were involved in multiple molecular pathways. Using two-way hierarchical clustering analysis, normal pancreas, acute and chronic pancreatitis, PanIN, early and advanced pancreatic cancer were completely discriminated. Furthermore, 11 upregulated and 142 downregulated genes (probes were found by Mann-Kendall trend Monotone test, indicating homologous genes of rat and human. The qRT-PCR and immunohistochemistry analysis of CXCR7 and UBe2c, two of the identified genes, confirmed the microarray results. In human PC cell lines, knockdown of CXCR7 resulted in decreased migration and invasion. Collectively, our data identified several promising markers and therapeutic targets of PC based on a comprehensive screening and systemic validation.

  13. Microarray data on gene modulation by HIV-1 in immune cells: 2000-2006.

    Science.gov (United States)

    Giri, Malavika S; Nebozhyn, Michael; Showe, Louise; Montaner, Luis J

    2006-11-01

    Here, we review 34 HIV microarray studies in human immune cells over the period of 2000-March 2006 with emphasis on analytical approaches used and conceptual advances on HIV modulation of target cells (CD4 T cell, macrophage) and nontargets such as NK cell, B cell, and dendritic cell subsets. Results to date address advances on gene modulation associated with immune dysregulation, susceptibility to apoptosis, virus replication, and viral persistence following in vitro or in vivo infection/exposure to HIV-1 virus or HIV-1 accessory proteins. In addition to gene modulation associated with known functional correlates of HIV infection and replication (e.g., T cell apoptosis), microarray data have yielded novel, potential mechanisms of HIV-mediated pathogenesis such as modulation of cholesterol biosynthetic genes in CD4 T cells (relevant to virus replication and infectivity) and modulation of proteasomes and histone deacetylases in chronically infected cell lines (relevant to virus latency). Intrinsic challenges in summarizing gene modulation studies remain in development of sound approaches for comparing data obtained using different platforms and analytical tools, deriving unifying concepts to distil the large volumes of data collected, and the necessity to impose a focus for validation on a small fraction of genes. Notwithstanding these challenges, the field overall continues to demonstrate progress in expanding the pool of target genes validated to date in in vitro and in vivo datasets and understanding the functional correlates of gene modulation to HIV-1 pathogenesis in vivo. PMID:16940334

  14. Microarray-Based Differential Expression Monitoring of 79 Novel Genes in Human Fetal Tissues

    Institute of Scientific and Technical Information of China (English)

    Ma; Shu-hua; Wang; Dun-cheng; 等

    2003-01-01

    79 ESTs fragments with represents corresponding novel genes were obtained by sequencing and bioinformatics analysis of human fetal kidney cDNA library. Microarray was prepared by using these novel EST fragments by automatic spotting. Expression patters of 79 ESTs of novel genes from human fetal kidney were analyzed in fetal brain and fetal heart tissues of 20-week-and 26-week-age fetus by performing of cDNA chip hybridization. This provides clues for studying exact functions of the novel genes. 8 genes were obtained which were expressed differentially in the fetal brain and heart of 20-week-and 26-week-age respectively. Then differentially expressed genes were identified by Northern analysis. The more exact function of the novel genes is under study.

  15. Microarray gene expression analysis of tumorigenesis and regional lymph node metastasis in laryngeal squamous cell carcinoma.

    Directory of Open Access Journals (Sweden)

    Meng Lian

    Full Text Available BACKGROUND: Laryngeal squamous cell carcinoma (LSCC is the most common type in head and neck squamous cell carcinoma (HNSCC, and the development and progression of LSCC are multistep processes accompanied by changes of molecular biology. OBJECTIVE: The purpose of this study was to investigate the molecular basis of tumorigenesis and regional lymph node metastasis in LSCC, and provide a set of genes that may be useful for the development of novel diagnostic markers and/or more effective therapeutic strategies. METHODS: A total number of 10 patients who underwent surgery for primary laryngeal squamous cell carcinoma were recruited for microarray analysis. LSCC tissues compared with corresponding adjacent non-neoplastic tissues were analysed by Illumina mRNA microarrays, and LSCC tissues with regional lymph node metastasis and LSCC tissues without regional lymph node metastasis were analyzed in the same manner. The most frequently differently expressed genes screened by microarrays were also validated by qRT-PCR in another 42 patients diagnosed for LSCC. RESULTS: Analysed by Illumina mRNA microarrays, there were 361 genes significantly related to tumorigenesis while 246 genes significantly related to regional lymph node metastasis in LSCC. We found that the six genes (CDK1, CDK2, CDK4, MCM2, MCM3, MCM4 were most frequently differently expressed functional genes related to tumorigenesis while eIF3a and RPN2 were most frequently differently expressed functional genes related to regional lymph node metastasis in LSCC. The expressions of these genes were also validated by qRT-PCR. CONCLUSIONS: The research revealed a gene expression signature of tumorigenesis and regional lymph node metastasis in laryngeal squamous cell carcinoma. Of the total, the deregulation of several genes (CDK1, CDK2, CDK4, MCM2, MCM3, MCM4, EIF3a and RPN2 were potentially associated with disease development and progression. The result will contribute to the understanding of the

  16. Investigating the effect of paralogs on microarray gene-set analysis

    LENUS (Irish Health Repository)

    Faure, Andre J

    2011-01-24

    Abstract Background In order to interpret the results obtained from a microarray experiment, researchers often shift focus from analysis of individual differentially expressed genes to analyses of sets of genes. These gene-set analysis (GSA) methods use previously accumulated biological knowledge to group genes into sets and then aim to rank these gene sets in a way that reflects their relative importance in the experimental situation in question. We suspect that the presence of paralogs affects the ability of GSA methods to accurately identify the most important sets of genes for subsequent research. Results We show that paralogs, which typically have high sequence identity and similar molecular functions, also exhibit high correlation in their expression patterns. We investigate this correlation as a potential confounding factor common to current GSA methods using Indygene http:\\/\\/www.cbio.uct.ac.za\\/indygene, a web tool that reduces a supplied list of genes so that it includes no pairwise paralogy relationships above a specified sequence similarity threshold. We use the tool to reanalyse previously published microarray datasets and determine the potential utility of accounting for the presence of paralogs. Conclusions The Indygene tool efficiently removes paralogy relationships from a given dataset and we found that such a reduction, performed prior to GSA, has the ability to generate significantly different results that often represent novel and plausible biological hypotheses. This was demonstrated for three different GSA approaches when applied to the reanalysis of previously published microarray datasets and suggests that the redundancy and non-independence of paralogs is an important consideration when dealing with GSA methodologies.

  17. Genome-Wide Screening of Genes Showing Altered Expression in Liver Metastases of Human Colorectal Cancers by cDNA Microarray

    Directory of Open Access Journals (Sweden)

    Rempei Yanagawa

    2001-01-01

    Full Text Available In spite of intensive and increasingly successful attempts to determine the multiple steps involved in colorectal carcinogenesis, the mechanisms responsible for metastasis of colorectal tumors to the liver remain to be clarified. To identify genes that are candidates for involvement in the metastatic process, we analyzed genome-wide expression profiles of 10 primary colorectal cancers and their corresponding metastatic lesions by means of a cDNA microarray consisting of 9121 human genes. This analysis identified 40 genes whose expression was commonly upregulated in metastatic lesions, and 7 that were commonly downregulated. The upregulated genes encoded proteins involved in cell adhesion, or remodeling of the actin cytoskeleton. Investigation of the functions of more of the altered genes should improve our understanding of metastasis and may identify diagnostic markers and/or novel molecular targets for prevention or therapy of metastatic lesions.

  18. The KCNE genes in hypertrophic cardiomyopathy: a candidate gene study

    DEFF Research Database (Denmark)

    Hedley, Paula L; Haundrup, Ole; Andersen, Paal S;

    2011-01-01

    The gene family KCNE1-5, which encode modulating β-subunits of several repolarising K+-ion channels, has been associated with genetic cardiac diseases such as long QT syndrome, atrial fibrillation and Brugada syndrome. The minK peptide, encoded by KCNE1, is attached to the Z-disc of the sarcomere...... as well as the T-tubules of the sarcolemma. It has been suggested that minK forms part of an "electro-mechanical feed-back" which links cardiomyocyte stretching to changes in ion channel function. We examined whether mutations in KCNE genes were associated with hypertrophic cardiomyopathy (HCM), a...

  19. Slitrks as emerging candidate genes involved in neuropsychiatric disorders

    OpenAIRE

    Proenca, Catia C.; Gao, Kate P.; Shmelkov, Sergey V.; Rafii, Shahin; Lee, Francis S

    2011-01-01

    Slitrks are a family of structurally-related transmembrane proteins belonging to the leucine-rich repeat (LRR) superfamily. Six family members exist (Slitrk1–Slitrk6), and all are highly expressed in the central nervous system (CNS). Slitrks have been implicated in mediating basic neuronal processes ranging from neurite outgrowth and dendritic elaboration to neuronal survival. Recent studies in humans and genetic mouse models have led to the identification of Slitrks as candidate genes that m...

  20. Genetics of intracerebral hemorrhage: Insights from candidate gene approaches

    OpenAIRE

    Baoqiong Liu; Le Zhang; Qidong Yang

    2012-01-01

    Intracerebral hemorrhage (ICH) is a heterogeneous disease with genetic factors playing an important role. Association studies on a wide range of candidate pathways suggest a weak but significant effect for several alleles with ICH risk. Among the most widely investigated genes are those involved in the renin-angiotensin-aldosterone system (e.g., angiotensin-converting enzyme), coagulation pathway (e.g., Factor XIII, Factor VII, platelet-activating factor acetylhydrolase, Factor V Leiden, and ...

  1. Association of candidate genes with antisocial drug dependence in adolescents

    OpenAIRE

    Corley, Robin P.; Zeiger, Joanna S.; Crowley, Thomas; Ehringer, Marissa A.; Hewitt, John K.; Christian J Hopfer; Lessem, Jeffrey; McQueen, Matthew B.; Rhee, Soo Hyun; Smolen, Andrew; Stallings, Michael C.; Young, Susan E.; Krauter, Kenneth

    2008-01-01

    The Colorado Center for Antisocial Drug Dependence (CADD) is using several research designs and strategies in its study of the genetic basis for antisocial drug dependence in adolescents. This study reports Single Nucleotide Polymorphism (SNP) association results from a Targeted Gene Assay (SNP chip) of 231 Caucasian male probands in treatment with antisocial drug dependence and a matched set of community controls. The SNP chip was designed to assay 1500 SNPs distributed across 50 candidate g...

  2. Comparative analysis of gene expression by microarray analysis of male and female flowers of Asparagus officinalis.

    Science.gov (United States)

    Gao, Wu-Jun; Li, Shu-Fen; Zhang, Guo-Jun; Wang, Ning-Na; Deng, Chuan-Liang; Lu, Long-Dou

    2013-01-01

    To identify rapidly a number of genes probably involved in sex determination and differentiation of the dioecious plant Asparagus officinalis, gene expression profiles in early flower development for male and female plants were investigated by microarray assay with 8,665 probes. In total, 638 male-biased and 543 female-biased genes were identified. These genes with biased-expression for male and female were involved in a variety of processes associated with molecular functions, cellular components, and biological processes, suggesting that a complex mechanism underlies the sex development of asparagus. Among the differentially expressed genes involved in the reproductive process, a number of genes associated with floral development were identified. Reverse transcription-PCR was performed for validation, and the results were largely consistent with those obtained by microarray analysis. The findings of this study might contribute to understanding of the molecular mechanisms of sex determination and differentiation in dioecious asparagus and provide a foundation for further studies of this plant. PMID:23748756

  3. Annual Killifish Transcriptomics and Candidate Genes for Metazoan Diapause.

    Science.gov (United States)

    Thompson, Andrew W; Ortí, Guillermo

    2016-09-01

    Dormancy has evolved in all major metazoan lineages. It is critical for survival when environmental stresses are not conducive to growth, maturation, or reproduction. Embryonic diapause is a form of dormancy where development is reversibly delayed and metabolism is depressed. We report the diapause transcriptome of the annual killifish Nematolebias whitei, and compare gene expression between diapause embryos and free-living larvae to identify a candidate set of 945 differentially expressed "diapause" genes for this species. Similarity of transcriptional patterns among N. whitei and other diapausing animals is striking for a small set of genes associated with stress resistance, circadian rhythm, and metabolism, while other genes show discordant patterns. Although convergent evolution of diapause may require shared molecular mechanisms for fundamental processes, similar physiological phenotypes also may arise through modification of alternative pathways. Annual killifishes are a tractable model system for comparative transcriptomic studies on the evolution of diapause. PMID:27297470

  4. Building gene co-expression networks using transcriptomics data for systems biology investigations: Comparison of methods using microarray data

    OpenAIRE

    Kadarmideen, Haja N; Watson-Haigh, Nathan S

    2012-01-01

    Gene co-expression networks (GCN), built using high-throughput gene expression data are fundamental aspects of systems biology. The main aims of this study were to compare two popular approaches to building and analysing GCN. We use real ovine microarray transcriptomics datasets representing four different treatments with Metyrapone, an inhibitor of cortisol biosynthesis. We conducted several microarray quality control checks before applying GCN methods to filtered datasets. Then we compared ...

  5. Gene expression profiling of gastric cancer by microarray combined with laser capture microdissection

    Institute of Scientific and Technical Information of China (English)

    Ming-Shiang Wu; Yi-Shing Lin; Yu-Ting Chang; Chia-Tung Shun; Ming-Tsan Lin; Jaw-Town Lin

    2005-01-01

    AIM: To examine the gene expression profile of gastric cancer (GC) by combination of laser capture microdissection (LCM) and microarray and to correlate the profiling with histological subtypes. METHODS: Using LCM, pure cancer cells were procured from 45 cancerous tissues. After procurement of about 5 000 cells, total RNA was extracted and the quality of RNA was determined before further amplification and hybridization. One microgram of amplified RNA was converted to cDNA and hybridized to cDNA microarray. RESULTS: Among 45 cases, only 21 were qualified for their RNAs. A total of 62 arrays were performed. These included 42 arrays for cancer (21 cases with dyeswab duplication) and 20 arrays for non-tumorous cells (10 cases with dye-swab duplication) with universal reference. Analyzed data showed 504 genes were differentially expressed and could distinguish cancerous and non-cancerous groups with more than 99% accuracy. Of the 504 genes, trefoil factors 1, 2, and 3 were in the list and their expression patterns were consistent with previous reports. Immunohistochemical staining of trefoil factor 1 was also consistent with the array data. Analyses of the tumor group with these 504 genes showed that there were 3 subgroups of GC that did not correspond to any current classification system, including Lauren's classification. CONCLUSION: By using LCM, linear amplification of RNA, and cDNA microarray, we have identified a panel of genes that have the power to discriminate between GC and non-cancer groups. The new molecular classification and the identified novel genes in gastric carcinogenesis deserve further investigations to elucidate their dinicopathological significance.

  6. Candidate genes responsible for common and different pathology of infected muscle tissues between Trichinella spiralis and T. pseudospiralis infection.

    Science.gov (United States)

    Wu, Zhiliang; Nagano, Isao; Takahashi, Yuzo

    2008-09-01

    The gene expression profiles were compared between Trichinella spiralis- and T. pseudospiralis-infected muscle tissues by means of a cDNA microarray. Out of 30,000 genes, the expressions of 55 genes were up-regulated in both T. spiralis and T. pseudospiralis infections, 24 genes were down-regulated in both Trichinella infections, 30 genes were up-regulated only in T. spiralis infection, 23 genes were down-regulated only in T. spiralis infection, 25 genes were up-regulated only in T. pseudospiralis infection, and 21 genes were down-regulated only in T. pseudospiralis infection. Many of these differentially expressed genes were associated with satellite cell activation and proliferation (paired box gene 7, Pax7; Pax3; desmin; M-cadherin), myogenesis and muscle development (eyes absent 2 homolog, Eya2; myocyte enhancer factor 2C, MEF2C; pre B-cell leukemia transcription factor 1, Pbx1; chordin-like 2, Chrdl2), cell differentiation (galectin 1; insulin like growth factors, IGFs; c-ski; msh-like 1, Msx1; Numb), cell proliferation and cycle regulation (retinoblastoma 1, Rb1; granulin; p21, CDK4, cyclin A2), and apoptosis (tumor necrosis factor receptor 1, TNF-R1; programmed cell death protein 11, Pdcd11; Pdcd1; nuclear protein 1, Nuprl; clusterin, CLU). The differential expression of 17 genes was validated by quantitative real time PCR and 15 genes showed identical results with the microarray analysis. The present study listed the candidate genes that were commonly and differentially expressed between T. spiralis and/or T. pseudospiralis infection, thus suggesting that these genes need to be further investigated to reveal the mechanism of the common and/or different pathological changes induced by the two species Trichinella. PMID:18501667

  7. Genetic Variation in Candidate Genes Like the HMGA2 Gene in the Extremely Tall

    NARCIS (Netherlands)

    Hendriks, A. E. J.; Brown, M. R.; Boot, A. M.; Oostra, B. A.; Drop, S. L. S.; Parks, J. S.

    2011-01-01

    Background/Aims: Genetic variation in several candidate genes has been associated with short stature. Recently, a high-mobility group A2 (HMGA2) gene SNP has been robustly associated with height in the general population. Only few have attempted to study these genes in extremely tall stature. We the

  8. PAX3 gene deletion detected by microarray analysis in a girl with hearing loss

    OpenAIRE

    Drozniewska, Malgorzata; Haus, Olga

    2014-01-01

    Deletions of the PAX3 gene have been rarely reported in the literature. Mutations of this gene are a common cause of Waardenburg syndrome type 1 and 3. We report a 16 year old female presenting hearing loss and normal intellectual development, without major features of Waardenburg syndrome type 1, and without family history of the syndrome. Her phenotype, however, overlaps with features of craniofacial-deafness-hand syndrome. Microarray analysis showed ~862 kb de novo deletion at 2q36.1 inclu...

  9. Monitoring Gene Expression in Mixed Microbial Communities by Using DNA Microarrays

    OpenAIRE

    Dennis, Philip; Edwards, Elizabeth A.; Liss, Steven N; Fulthorpe, Roberta

    2003-01-01

    A DNA microarray to monitor the expression of bacterial metabolic genes within mixed microbial communities was designed and tested. Total RNA was extracted from pure and mixed cultures containing the 2,4-dichlorophenoxyacetic acid (2,4-D)-degrading bacterium Ralstonia eutropha JMP134, and the inducing agent 2,4-D. Induction of the 2,4-D catabolic genes present in this organism was readily detected 4, 7, and 24 h after the addition of 2,4-D. This strain was diluted into a constructed mixed mic...

  10. An ensemble method for gene discovery based on DNA microarray data

    Institute of Scientific and Technical Information of China (English)

    LI Xia; RAO Shaoqi; ZHANG Tianwen; GUO Zheng; ZHANG Qingpu; Kathy L. MOSER; Eric J. TOPOL

    2004-01-01

    The advent of DNA microarray technology has offered the promise of casting new insights onto deciphering secrets of life by monitoring activities of thousands of genes simultaneously.Current analyses of microarray data focus on precise classification of biological types,for example,tumor versus normal tissues.A further scientific challenging task is to extract disease-relevant genes from the bewildering amounts of raw data,which is one of the most critical themes in the post-genomic era,but it is generally ignored due to lack of an efficient approach.In this paper,we present a novel ensemble method for gene extraction that can be tailored to fulfill multiple biological tasks including(i)precise classification of biological types;(ii)disease gene mining; and(iii)target-driven gene networking.We also give a numerical application for(i)and(ii)using a public microarrary data set and set aside a separate paper to address(iii).

  11. Genetic Bee Colony (GBC) algorithm: A new gene selection method for microarray cancer classification.

    Science.gov (United States)

    Alshamlan, Hala M; Badr, Ghada H; Alohali, Yousef A

    2015-06-01

    Naturally inspired evolutionary algorithms prove effectiveness when used for solving feature selection and classification problems. Artificial Bee Colony (ABC) is a relatively new swarm intelligence method. In this paper, we propose a new hybrid gene selection method, namely Genetic Bee Colony (GBC) algorithm. The proposed algorithm combines the used of a Genetic Algorithm (GA) along with Artificial Bee Colony (ABC) algorithm. The goal is to integrate the advantages of both algorithms. The proposed algorithm is applied to a microarray gene expression profile in order to select the most predictive and informative genes for cancer classification. In order to test the accuracy performance of the proposed algorithm, extensive experiments were conducted. Three binary microarray datasets are use, which include: colon, leukemia, and lung. In addition, another three multi-class microarray datasets are used, which are: SRBCT, lymphoma, and leukemia. Results of the GBC algorithm are compared with our recently proposed technique: mRMR when combined with the Artificial Bee Colony algorithm (mRMR-ABC). We also compared the combination of mRMR with GA (mRMR-GA) and Particle Swarm Optimization (mRMR-PSO) algorithms. In addition, we compared the GBC algorithm with other related algorithms that have been recently published in the literature, using all benchmark datasets. The GBC algorithm shows superior performance as it achieved the highest classification accuracy along with the lowest average number of selected genes. This proves that the GBC algorithm is a promising approach for solving the gene selection problem in both binary and multi-class cancer classification. PMID:25880524

  12. Normal uniform mixture differential gene expression detection for cDNA microarrays

    Directory of Open Access Journals (Sweden)

    Raftery Adrian E

    2005-07-01

    Full Text Available Abstract Background One of the primary tasks in analysing gene expression data is finding genes that are differentially expressed in different samples. Multiple testing issues due to the thousands of tests run make some of the more popular methods for doing this problematic. Results We propose a simple method, Normal Uniform Differential Gene Expression (NUDGE detection for finding differentially expressed genes in cDNA microarrays. The method uses a simple univariate normal-uniform mixture model, in combination with new normalization methods for spread as well as mean that extend the lowess normalization of Dudoit, Yang, Callow and Speed (2002 1. It takes account of multiple testing, and gives probabilities of differential expression as part of its output. It can be applied to either single-slide or replicated experiments, and it is very fast. Three datasets are analyzed using NUDGE, and the results are compared to those given by other popular methods: unadjusted and Bonferroni-adjusted t tests, Significance Analysis of Microarrays (SAM, and Empirical Bayes for microarrays (EBarrays with both Gamma-Gamma and Lognormal-Normal models. Conclusion The method gives a high probability of differential expression to genes known/suspected a priori to be differentially expressed and a low probability to the others. In terms of known false positives and false negatives, the method outperforms all multiple-replicate methods except for the Gamma-Gamma EBarrays method to which it offers comparable results with the added advantages of greater simplicity, speed, fewer assumptions and applicability to the single replicate case. An R package called nudge to implement the methods in this paper will be made available soon at http://www.bioconductor.org.

  13. Uncovering Gene Regulatory Networks from Time-Series Microarray Data with Variational Bayesian Structural Expectation Maximization

    Directory of Open Access Journals (Sweden)

    Huang Yufei

    2007-01-01

    Full Text Available We investigate in this paper reverse engineering of gene regulatory networks from time-series microarray data. We apply dynamic Bayesian networks (DBNs for modeling cell cycle regulations. In developing a network inference algorithm, we focus on soft solutions that can provide a posteriori probability (APP of network topology. In particular, we propose a variational Bayesian structural expectation maximization algorithm that can learn the posterior distribution of the network model parameters and topology jointly. We also show how the obtained APPs of the network topology can be used in a Bayesian data integration strategy to integrate two different microarray data sets. The proposed VBSEM algorithm has been tested on yeast cell cycle data sets. To evaluate the confidence of the inferred networks, we apply a moving block bootstrap method. The inferred network is validated by comparing it to the KEGG pathway map.

  14. Uncovering Gene Regulatory Networks from Time-Series Microarray Data with Variational Bayesian Structural Expectation Maximization

    Directory of Open Access Journals (Sweden)

    Isabel Tienda Luna

    2007-06-01

    Full Text Available We investigate in this paper reverse engineering of gene regulatory networks from time-series microarray data. We apply dynamic Bayesian networks (DBNs for modeling cell cycle regulations. In developing a network inference algorithm, we focus on soft solutions that can provide a posteriori probability (APP of network topology. In particular, we propose a variational Bayesian structural expectation maximization algorithm that can learn the posterior distribution of the network model parameters and topology jointly. We also show how the obtained APPs of the network topology can be used in a Bayesian data integration strategy to integrate two different microarray data sets. The proposed VBSEM algorithm has been tested on yeast cell cycle data sets. To evaluate the confidence of the inferred networks, we apply a moving block bootstrap method. The inferred network is validated by comparing it to the KEGG pathway map.

  15. Validation and characterization of DNA microarray gene expression data distribution and associated moments

    Directory of Open Access Journals (Sweden)

    Chang Xiaoqing

    2010-11-01

    Full Text Available Abstract Background The data from DNA microarrays are increasingly being used in order to understand effects of different conditions, exposures or diseases on the modulation of the expression of various genes in a biological system. This knowledge is then further used in order to generate molecular mechanistic hypotheses for an organism when it is exposed to different conditions. Several different methods have been proposed to analyze these data under different distributional assumptions on gene expression. However, the empirical validation of these assumptions is lacking. Results Best fit hypotheses tests, moment-ratio diagrams and relationships between the different moments of the distribution of the gene expression was used to characterize the observed distributions. The data are obtained from the publicly available gene expression database, Gene Expression Omnibus (GEO to characterize the empirical distributions of gene expressions obtained under varying experimental situations each of which providing relatively large number of samples for hypothesis testing. All data were obtained from either of two microarray platforms - the commercial Affymetrix mouse 430.2 platform and a non-commercial Rosetta/Merck one. The data from each platform were preprocessed in the same manner. Conclusions The null hypotheses for goodness of fit for all considered univariate theoretical probability distributions (including the Normal distribution are rejected for more than 50% of probe sets on the Affymetrix microarray platform at a 95% confidence level, suggesting that under the tested conditions a priori assumption of any of these distributions across all probe sets is not valid. The pattern of null hypotheses rejection was different for the data from Rosetta/Merck platform with only around 20% of the probe sets failing the logistic distribution goodness-of-fit test. We find that there are statistically significant (at 95% confidence level based on the F

  16. Sleeping Beauty Mouse Models Identify Candidate Genes Involved in Gliomagenesis

    Science.gov (United States)

    Vyazunova, Irina; Maklakova, Vilena I.; Berman, Samuel; De, Ishani; Steffen, Megan D.; Hong, Won; Lincoln, Hayley; Morrissy, A. Sorana; Taylor, Michael D.; Akagi, Keiko; Brennan, Cameron W.; Rodriguez, Fausto J.; Collier, Lara S.

    2014-01-01

    Genomic studies of human high-grade gliomas have discovered known and candidate tumor drivers. Studies in both cell culture and mouse models have complemented these approaches and have identified additional genes and processes important for gliomagenesis. Previously, we found that mobilization of Sleeping Beauty transposons in mice ubiquitously throughout the body from the Rosa26 locus led to gliomagenesis with low penetrance. Here we report the characterization of mice in which transposons are mobilized in the Glial Fibrillary Acidic Protein (GFAP) compartment. Glioma formation in these mice did not occur on an otherwise wild-type genetic background, but rare gliomas were observed when mobilization occurred in a p19Arf heterozygous background. Through cloning insertions from additional gliomas generated by transposon mobilization in the Rosa26 compartment, several candidate glioma genes were identified. Comparisons to genetic, epigenetic and mRNA expression data from human gliomas implicates several of these genes as tumor suppressor genes and oncogenes in human glioblastoma. PMID:25423036

  17. Exploring Mycobacterium tuberculosis infection-induced alterations in gene expression in macrophage by microarray hybridization

    Institute of Scientific and Technical Information of China (English)

    谢建平; 李瑶; 乐军; 徐永忠; 黄达蔷; 梁莉; 王洪海

    2003-01-01

    Tuberculosis remains a serious threat to public health. Its causative agent Mycobacte- rium tuberculosis is an intracellular pathogen which survives and replicates within cells of the host immune system, primarily macrophages. Knowledge of the bacteria-macrophage interaction can help to develop novel measures to combat the disease. The global gene expression of macro- phage following invasion by and growth of M. tuberculosis was studied by cDNA microarray. Of the 12800 human genes analyzed, totally 473 (3.7%) macrophage genes were differentially expressed after being infected by M. tuberculosis, among which, only 25 (5.2%, corresponding to less than 0.2% of the 12800 genes) genes were up-regulated, while others (94.8%) were down-regulated against the control. Of the 473 genes, 376 genes are registered in the GenBank, and 97 are novel genes. Expression of 5 up-regulated genes has been induced by more than 3-fold. 25 genes were down-regulated by more than 3-fold. Syndecan binding protein has been down-regu- lated up to 12.5-fold. The data gave an insight into the early gene expression in macrophage ensuing M. tuberculosis infection and a basis for further study.

  18. Gene-expression profiling of human mononuclear cells from welders using cDNA microarray.

    Science.gov (United States)

    Rim, Kyung Taek; Park, Kun Koo; Kim, Yang Ho; Lee, Yong Hwan; Han, Jeong Hee; Chung, Yong Hyun; Yu, Il Je

    2007-08-01

    A toxicogenomic chip developed to detect welding-related diseases was tested and validated for field trials. To verify the suitability of the microarray, white blood cells (WBC) or whole blood was purified and characterized from 20 subjects in the control group (average work experience of 7 yr) and 20 welders in the welding-fume exposed group (welders with an average work experience of 23 yr). Two hundred and fifty-three rat genes homologous to human genes were obtained and spotted on the chip slide. Meanwhile, a human cDNA chip spotted with 8600 human genes was also used to detect any increased or decreased levels of gene expression among the welders. After comparing the levels of gene expression between the control and welder groups using the toxicogenomic chips, 103 genes were identified as likely to be specifically changed by welding-fume exposure. Eighteen of the 253 rat genes were specifically changed in the welders, while 103 genes from the human cDNA chip were specifically changed. The genes specifically expressed by the welders were associated with inflammatory responses, toxic chemical metabolism, stress proteins, transcription factors, and signal transduction. In contrast, there was no significant change in the genes related to short-term welding-fume exposure, such as tumor necrosis factor (TNF)-alpha and interleukin. In conclusion, if further validation studies are conducted, the present toxicogenomic gene chips could be used for the effective monitoring of welding-fume-exposure-related diseases among welders. PMID:17654244

  19. ANALYSIS OF GENES ASSOCIATED WITH LYMPHATIC METASTASIS IN PANCREATIC CARCINOMA USING cDNA MICROARRAY

    Institute of Scientific and Technical Information of China (English)

    谭志军; 胡先贵; 曹贵松; 唐岩

    2003-01-01

    Objective: To identify new markers for prediction of lymph node metastasis. Methods: cDNA probes were prepared by labeling mRNA from samples of four pancreatic carcinoma tissues with Cy5-dUTP and mRNA from adjacent normal tissues with Cy3-dUTP respectively through reverse transcription. The mixed probes of each sample were then hybridized with 4,096 cDNA arrays (4,000 unique human cDNA sequences), and the fluorescent signals were scanned by ScanArray 3000 scanner (General Scanning, Inc.). The values of Cy5-dUTP and Cy3-dUTP on each spot were analyzed and calculated by ImaGene 3.0 software (BioDiscovery, Inc.). Genes that differentially expresses in each cancerous tissue were sought out according to the standard that the absolute value of natural logarithm of the ratio of Cy5 to Cy3 is greater than 0.69, i. e., more than 2 times change of gene expression, and the signal value of either Cy3 and Cy5 need to be greater than 600. Then, the genes differently expressed in cancer with and without lymphatic metastasis were screened out for further analysis. Results: Among 2 samples with lymphatic metastasis and 2 samples without metastasis, 56 genes, which accounted for 1.40% of genes on the microarray slides, exhibited differentially expression in cancerous tissues with lymphatic metastasis. There were 32 over-expressed genes including 11 having been registered in Genebank, and 24 under-expressed genes including 3 in Genebank. Conclusion: Microarray analysis may provide invaluable information to identify specific gene expression profile of lymphatic metastasis in pancreatic cancer.

  20. Functional Insight From Fruit Flies on Human ADHD Candidate Genes

    DEFF Research Database (Denmark)

    Rohde, Palle Duun; Demontis, Ditte; Arvidson, Sandra Marie Neumann;

    2015-01-01

    of developing ADHD. We use Minos mutants, where target genes have been disrupted by the Minos transposable element, to test the effect on locomotor activity. By measuring the distance traveled, we find disparity in locomotor activity between control and Minos mutants. Impaired dopamine system...... underlies the majority of ADHD symptoms, and effective treatment is achieved with amphetamines. We fed flies with either 1.5 mg/ml dexamphetamine dissolved in 5% w/w sucrose or a 5% w/w sucrose solution. Treatment with dexamphetamine increased activity of controls and some Minos lines, and decreased...... activity levels for other mutants. Decreased activity level, when treated with dexamphetamine, is seen when using other ADHD animal models. Our findings suggest involvement of the proposed candidate genes Genes, Brain, and Behavior 2015 36 Talk Abstracts in hyperactivity in D. melanogaster, providing...

  1. Microarray analysis identifies a common set of cellular genes modulated by different HCV replicon clones

    Directory of Open Access Journals (Sweden)

    Gerosolimo Germano

    2008-06-01

    Full Text Available Abstract Background Hepatitis C virus (HCV RNA synthesis and protein expression affect cell homeostasis by modulation of gene expression. The impact of HCV replication on global cell transcription has not been fully evaluated. Thus, we analysed the expression profiles of different clones of human hepatoma-derived Huh-7 cells carrying a self-replicating HCV RNA which express all viral proteins (HCV replicon system. Results First, we compared the expression profile of HCV replicon clone 21-5 with both the Huh-7 parental cells and the 21-5 cured (21-5c cells. In these latter, the HCV RNA has been eliminated by IFN-α treatment. To confirm data, we also analyzed microarray results from both the 21-5 and two other HCV replicon clones, 22-6 and 21-7, compared to the Huh-7 cells. The study was carried out by using the Applied Biosystems (AB Human Genome Survey Microarray v1.0 which provides 31,700 probes that correspond to 27,868 human genes. Microarray analysis revealed a specific transcriptional program induced by HCV in replicon cells respect to both IFN-α-cured and Huh-7 cells. From the original datasets of differentially expressed genes, we selected by Venn diagrams a final list of 38 genes modulated by HCV in all clones. Most of the 38 genes have never been described before and showed high fold-change associated with significant p-value, strongly supporting data reliability. Classification of the 38 genes by Panther System identified functional categories that were significantly enriched in this gene set, such as histones and ribosomal proteins as well as extracellular matrix and intracellular protein traffic. The dataset also included new genes involved in lipid metabolism, extracellular matrix and cytoskeletal network, which may be critical for HCV replication and pathogenesis. Conclusion Our data provide a comprehensive analysis of alterations in gene expression induced by HCV replication and reveal modulation of new genes potentially useful

  2. Microarray Analysis on Gene Regulation by Estrogen, Progesterone and Tamoxifen in Human Endometrial Stromal Cells

    Directory of Open Access Journals (Sweden)

    Chun-E Ren

    2015-03-01

    Full Text Available Epithelial stromal cells represent a major cellular component of human uterine endometrium that is subject to tight hormonal regulation. Through cell-cell contacts and/or paracrine mechanisms, stromal cells play a significant role in the malignant transformation of epithelial cells. We isolated stromal cells from normal human endometrium and investigated the morphological and transcriptional changes induced by estrogen, progesterone and tamoxifen. We demonstrated that stromal cells express appreciable levels of estrogen and progesterone receptors and undergo different morphological changes upon hormonal stimulation. Microarray analysis indicated that both estrogen and progesterone induced dramatic alterations in a variety of genes associated with cell structure, transcription, cell cycle, and signaling. However, divergent patterns of changes, and in some genes opposite effects, were observed for the two hormones. A large number of genes are identified as novel targets for hormonal regulation. These hormone-responsive genes may be involved in normal uterine function and the development of endometrial malignancies.

  3. Microarray analysis of gene expression profiles of Schistosoma japonicum derived from less-susceptible host water buffalo and susceptible host goat.

    Directory of Open Access Journals (Sweden)

    Jianmei Yang

    Full Text Available BACKGROUND: Water buffalo and goats are natural hosts for S. japonicum in endemic areas of China. The susceptibility of these two hosts to schistosome infection is different, as water buffalo are less conducive to S. japonicum growth and development. To identify genes that may affect schistosome development and survival, we compared gene expression profiles of schistosomes derived from these two natural hosts using high-throughput microarray technology. RESULTS: The worm recovery rate was lower and the length and width of worms from water buffalo were smaller compared to those from goats following S. japonicum infection for 7 weeks. Besides obvious morphological difference between the schistosomes derived from the two hosts, differences were also observed by scanning and transmission electron microscopy. Microarray analysis showed differentially expressed gene patterns for parasites from the two hosts, which revealed that genes related to lipid and nucleotide metabolism, as well as protein folding, sorting, and degradation were upregulated, while others associated with signal transduction, endocrine function, development, immune function, endocytosis, and amino acid/carbohydrate/glycan metabolism were downregulated in schistosomes from water buffalo. KEGG pathway analysis deduced that the differentially expressed genes mainly involved lipid metabolism, the MAPK and ErbB signaling pathways, progesterone-mediated oocyte maturation, dorso-ventral axis formation, reproduction, and endocytosis, etc. CONCLUSION: The microarray gene analysis in schistosomes derived from water buffalo and goats provide a useful platform to disclose differences determining S. japonicum host compatibility to better understand the interplay between natural hosts and parasites, and identify schistosome target genes associated with susceptibility to screen vaccine candidates.

  4. Improving PLS-RFE based gene selection for microarray data classification.

    Science.gov (United States)

    Wang, Aiguo; An, Ning; Chen, Guilin; Li, Lian; Alterovitz, Gil

    2015-07-01

    Gene selection plays a crucial role in constructing efficient classifiers for microarray data classification, since microarray data is characterized by high dimensionality and small sample sizes and contains irrelevant and redundant genes. In practical use, partial least squares-based gene selection approaches can obtain gene subsets of good qualities, but are considerably time-consuming. In this paper, we propose to integrate partial least squares based recursive feature elimination (PLS-RFE) with two feature elimination schemes: simulated annealing and square root, respectively, to speed up the feature selection process. Inspired from the strategy of annealing schedule, the two proposed approaches eliminate a number of features rather than one least informative feature during each iteration and the number of removed features decreases as the iteration proceeds. To verify the effectiveness and efficiency of the proposed approaches, we perform extensive experiments on six publicly available microarray data with three typical classifiers, including Naïve Bayes, K-Nearest-Neighbor and Support Vector Machine, and compare our approaches with ReliefF, PLS and PLS-RFE feature selectors in terms of classification accuracy and running time. Experimental results demonstrate that the two proposed approaches accelerate the feature selection process impressively without degrading the classification accuracy and obtain more compact feature subsets for both two-category and multi-category problems. Further experimental comparisons in feature subset consistency show that the proposed approach with simulated annealing scheme not only has better time performance, but also obtains slightly better feature subset consistency than the one with square root scheme. PMID:25912984

  5. Comparison of threshold selection methods for microarray gene co-expression matrices

    Directory of Open Access Journals (Sweden)

    Saxton Arnold M

    2009-12-01

    Full Text Available Abstract Background Network and clustering analyses of microarray co-expression correlation data often require application of a threshold to discard small correlations, thus reducing computational demands and decreasing the number of uninformative correlations. This study investigated threshold selection in the context of combinatorial network analysis of transcriptome data. Findings Six conceptually diverse methods - based on number of maximal cliques, correlation of control spots with expressed genes, top 1% of correlations, spectral graph clustering, Bonferroni correction of p-values, and statistical power - were used to estimate a correlation threshold for three time-series microarray datasets. The validity of thresholds was tested by comparison to thresholds derived from Gene Ontology information. Stability and reliability of the best methods were evaluated with block bootstrapping. Two threshold methods, number of maximal cliques and spectral graph, used information in the correlation matrix structure and performed well in terms of stability. Comparison to Gene Ontology found thresholds from number of maximal cliques extracted from a co-expression matrix were the most biologically valid. Approaches to improve both methods were suggested. Conclusion Threshold selection approaches based on network structure of gene relationships gave thresholds with greater relevance to curated biological relationships than approaches based on statistical pair-wise relationships.

  6. OpWise: Operons aid the identification of differentially expressed genes in bacterial microarray experiments

    Directory of Open Access Journals (Sweden)

    Arkin Adam P

    2006-01-01

    Full Text Available Abstract Background Differentially expressed genes are typically identified by analyzing the variation between replicate measurements. These procedures implicitly assume that there are no systematic errors in the data even though several sources of systematic error are known. Results OpWise estimates the amount of systematic error in bacterial microarray data by assuming that genes in the same operon have matching expression patterns. OpWise then performs a Bayesian analysis of a linear model to estimate significance. In simulations, OpWise corrects for systematic error and is robust to deviations from its assumptions. In several bacterial data sets, significant amounts of systematic error are present, and replicate-based approaches overstate the confidence of the changers dramatically, while OpWise does not. Finally, OpWise can identify additional changers by assigning genes higher confidence if they are consistent with other genes in the same operon. Conclusion Although microarray data can contain large amounts of systematic error, operons provide an external standard and allow for reasonable estimates of significance. OpWise is available at http://microbesonline.org/OpWise.

  7. The unique genomic properties of sex-biased genes: Insights from avian microarray data

    Directory of Open Access Journals (Sweden)

    Webster Matthew T

    2008-03-01

    Full Text Available Abstract Background In order to develop a framework for the analysis of sex-biased genes, we present a characterization of microarray data comparing male and female gene expression in 18 day chicken embryos for brain, gonad, and heart tissue. Results From the 15982 significantly expressed coding regions that have been assigned to either the autosomes or the Z chromosome (12979 in brain, 13301 in gonad, and 12372 in heart, roughly 18% were significantly sex-biased in any one tissue, though only 4 gene targets were biased in all tissues. The gonad was the most sex-biased tissue, followed by the brain. Sex-biased autosomal genes tended to be expressed at lower levels and in fewer tissues than unbiased gene targets, and autosomal somatic sex-biased genes had more expression noise than similar unbiased genes. Sex-biased genes linked to the Z-chromosome showed reduced expression in females, but not in males, when compared to unbiased Z-linked genes, and sex-biased Z-linked genes were also expressed in fewer tissues than unbiased Z coding regions. Third position GC content, and codon usage bias showed some sex-biased effects, primarily for autosomal genes expressed in the gonad. Finally, there were several over-represented Gene Ontology terms in the sex-biased gene sets. Conclusion On the whole, this analysis suggests that sex-biased genes have unique genomic and organismal properties that delineate them from genes that are expressed equally in males and females.

  8. Microarray analysis of the AHR system: Tissue-specific flexibility in signal and target genes

    International Nuclear Information System (INIS)

    Data mining published microarray experiments require that expression profiles are directly comparable. We performed linear global normalization on the data of 1967 Affymetrix U74av2 microarrays, i.e. the transcriptomes of > 100 murine tissues or cell types. The mathematical transformation effectively nullifies inter-experimental or inter-laboratory differences between microarrays. The correctness of expression values was validated by quantitative RT-PCR. Using the database we analyze components of the aryl hydrocarbon receptor (AHR) signaling pathway in various tissues. We identified lineage and differentiation specific variant expression of AHR, ARNT, and HIF1α in the T-cell lineage and high expression of CYP1A1 in immature B cells and dendritic cells. Performing co-expression analysis we found unorthodox expression of the AHR in the absence of ARNT, particularly in stem cell populations, and can reject the hypothesis that ARNT2 takes over and is highly expressed when ARNT expression is low or absent. Furthermore the AHR shows no co-expression with any other transcript present on the chip. Analysis of differential gene expression under 308 conditions revealed 53 conditions under which the AHR is regulated, numerous conditions under which an intrinsic AHR action is modified as well as conditions activating the AHR even in the absence of known AHR ligands. Thus meta-analysis of published expression profiles is a powerful tool to gain novel insights into known and unknown systems

  9. A Generally Applicable Translational Strategy Identifies S100A4 as a Candidate Gene in Allergy

    DEFF Research Database (Denmark)

    Bruhn, Sören; Fang, Yu; Barrenäs, Fredrik;

    2014-01-01

    The identification of diagnostic markers and therapeutic candidate genes in common diseases is complicated by the involvement of thousands of genes. We hypothesized that genes co-regulated with a key gene in allergy, IL13, would form a module that could help to identify candidate genes. We identi...

  10. Monitoring the Expression of Maize Genes in Developing Kernels under Drought Stress using Oligo-microarray

    Institute of Scientific and Technical Information of China (English)

    Meng Luo; Jia Liu; R. Dewey Lee; Brian T. Scully; Baozhu Guo

    2010-01-01

    Preharvest aflatoxin contamination of grain grown on the US southeastern Coast Plain is provoked and aggravated by abiotic stress. The primary abiotic stress is drought along with high temperatures. The objectives of the present study were to monitor gene expression in developing kernels in response to drought stress and to identify drought-responsive genes for possible use in germplasm assessment. The maize breeding line Tex6 was used, and gene expression profiles were analyzed in developing kernels under drought stress verses well-watered conditions at the stages of 25, 30, 35, 40, 45 d after pollination (DAP) using the 70 mer maize oligo-arrays. A total of 9 573 positive array spots were detected with unique gene IDs, and 7 988 were common in both stressed and well-watered samples. Expression patterns of some genes in several stress response-associated pathways, including abscisic acid, jasmonic acid and phenylalanine ammonia-lyase, were examined, and these specific genes were responsive to drought stress positively. Real-time quantitative polymerase chain reaction validated microarray expression data.The comparison between Tex6 and B73 revealed that there were significant differences in specific gene expression, patterns and levels. Several defense-related genes had been downregulated, even though some defense-related or drought responsive genes were upregulated at the later stages.

  11. Analysis of gene expression profile of pancreatic carcinoma using CDNA microarray

    Institute of Scientific and Technical Information of China (English)

    ZhiJun Tan; Xian-Gui Hu; Gui-Song Cao; Yan Tang

    2003-01-01

    AIM: To identify new diagnostic markers and drug targets,the gene expression profiles of pancreatic cancer were compared with that of adjacent normal tissues utilizing cDNA microarray analysis.METHODS: cDNA probes were prepared by labeling mRNA from samples of six pancreatic carcinoma tissues with Cy5dUTP and mRNA from adjacent normal tissues with Cy3dUTP respectively through reverse transcription. The mixed probes of each sample were then hybridized with 12 800cDNA arrays (12 648 unique human cDNA sequences), and the fluorescent signals were scanned by ScanArray 3 000scanner (General Scanning, Inc.). The values of CyS-dUTP and Cy3-dUTP on each spot were analyzed and calculated by ImaGene 3.0 software (BioDiscovery, Inc.). Differentially expressed genes were screened according to the criterion that the absolute value of natural logarithm of the ratio of Cy5-dUTP to Cy3-dUTP was greater-than 0.69.RESETS: Among 6 samples investigated, 301 genes, which accounted for 2.38% of genes on the microarry slides,exhibited differentially expression at least in 5. There were 166 over-expressed genes including 136 having been registered in Genebank, and 135 under-expressed genes including 79 in Genebank in cancerous tissues.CONCLUSION: Microarray analysis may provide invaluable information on disease pathology, progression, resistance to treatment, and response to cellular microenvironments of pancreatic carcinoma and ultimately may lead to improving early diagnosis and discovering innovative therapeutic approaches for cancer.

  12. Analysis of differences of gene expressions in keloid and normal skin with the aid of cDNA microarray

    Institute of Scientific and Technical Information of China (English)

    Chen Wei; Fu Xiaobing; Sun Xiaoqing; Sun Tongzhu; Zhao Zhili; Yang Yinhui; Sheng Zhiyong

    2003-01-01

    Background: Microarray analysis is a popular tool to investigate the function of genes that are responsible for the phenotype of the disease. Keloid is a intricate lesion which is probably modulated by interplay of many genes. We ventured to study the differences of gene expressions between keloids and normal skins with the aid of cDNA microarray in order to explore the molecular mechanism underlying keloid formation. Methods: The PCR products of 8400 human genes were spotted on a chip in array. The DNAs were then fixed on the glass plate by a series of treatments. Total RNAs was isolated from freshly excised human keloids and normal skin, and then was purified to mRNA by Oligotex. Both the mRNA from keloids and normal skin was reversely transcribed to cDNAs with the incorporations of fluorescent dUTP, for preparing the hybridization probes. The mixed probes were then hybridized to the cDNA microarray. After highly stringent washing, the cDNA microarray was scanned for the fluorescent signals to display the differences between two kinds of tissues. Results: Among 8400 human genes, there were 402 genes (4.79%) with different expression levels between the keloids and normal skins in all cases, 250were up-regulated (2.98%) and 152 down-regulated (1.81%). Analyses of collagen, fibronectin, proteoglycan,growth factors and apoptosis related molecule gene expression confirmed that our molecular data obtained by cDNA microarray were consistent with published biochemical and clinical observations of keloids. Conclusions: DNA microarray technology is an effective technique in screening for differences in gene expression between keloid and normal skin. Many genes are involved in the formation of keloids. Further analysis of the obtained genes will help understand the molecular mechanism of keloid formation.

  13. Identification of methylated genes in salivary gland adenoid cystic carcinoma xenografts using global demethylation and methylation microarray screening

    Science.gov (United States)

    LING, SHIZHANG; RETTIG, ELENI M.; TAN, MARIETTA; CHANG, XIAOFEI; WANG, ZHIMING; BRAIT, MARIANA; BISHOP, JUSTIN A.; FERTIG, ELANA J.; CONSIDINE, MICHAEL; WICK, MICHAEL J.; HA, PATRICK K.

    2016-01-01

    Salivary gland adenoid cystic carcinoma (ACC) is a rare head and neck malignancy without molecular biomarkers that can be used to predict the chemotherapeutic response or prognosis of ACC. The regulation of gene expression of oncogenes and tumor suppressor genes (TSGs) through DNA promoter methylation may play a role in the carcinogenesis of ACC. To identify differentially methylated genes in ACC, a global demethylating agent, 5-aza-2′-deoxycytidine (5-AZA) was utilized to unmask putative TSG silencing in ACC xenograft models in mice. Fresh xenografts were passaged, implanted in triplicate in mice that were treated with 5-AZA daily for 28 days. These xenografts were then evaluated for genome-wide DNA methylation patterns using the Illumina Infinium HumanMethylation27 BeadChip array. Validation of the 32 candidate genes was performed by bisulfite sequencing (BS-seq) in a separate cohort of 6 ACC primary tumors and 6 normal control salivary gland tissues. Hypermethylation was identified in the HCN2 gene promoter in all 6 control tissues, but hypomethylation was found in all 6 ACC tumor tissues. Quantitative validation of HCN2 promoter methylation level in the region detected by BS-seq was performed in a larger cohort of primary tumors (n=32) confirming significant HCN2 hypomethylation in ACCs compared with normal samples (n=10; P=0.04). HCN2 immunohistochemical staining was performed on an ACC tissue microarray. HCN2 staining intensity and H-score, but not percentage of the positively stained cells, were significantly stronger in normal tissues than those of ACC tissues. With our novel screening and sequencing methods, we identified several gene candidates that were methylated. The most significant of these genes, HCN2, was actually hypomethylated in tumors. However, promoter methylation status does not appear to be a major determinant of HCN2 expression in normal and ACC tissues. HCN2 hypomethylation is a biomarker of ACC and may play an important role in the

  14. A meta-analysis of kidney microarray datasets: investigation of cytokine gene detection and correlation with rt-PCR and detection thresholds

    Directory of Open Access Journals (Sweden)

    Stegall Mark D

    2007-03-01

    Full Text Available Abstract Background Microarrays provide a means to simultaneously examine the gene expression of the entire transcriptome in a single sample. Many studies have highlighted the need for novel software and statistical approaches to assess the measured gene expression. Less attention has been directed toward whether genes considered undetectable by microarray can be detected by other strategies or whether these genes can provide accurate gene expression determinations. In the kidney this is a concern for genes such as cytokines which dramatically influence the immune response but are often considered low abundance genes produced by a small number of cells. Results Using both publicly available and our own microarray datasets we analyzed the detection p-value and detection call values for 81 human kidney samples run on the U133A or U133Plus2.0 Affymetrix microarrays (Affymetrix, Santa Clara, CA. For the cytokine genes, the frequency of detection in each sample group (normal, transplant and renal cell carcinoma was examined and revealed that a majority of cytokine related genes are not detectable in human kidney by microarray. Using a subset of 29 Mayo transplant samples, a group of seven transplant-related cytokines and eight non-cytokine genes were evaluated by real-time PCR (rt-PCR. For these 15 genes we compared the impact of decreasing microarray detection frequency with the changes in gene expression observed by both microarray and rt-PCR. We found that as microarray detection frequency decreased the correlation between microarray and rt-PCR data also decreased. Conclusion We conclude that, when analyzing microarray data from human kidney samples, genes generally expressed at low abundance (i.e. cytokines should be evaluated with more sensitive approaches such as rt-PCR. In addition, our data suggest that the use of detection frequency cutoffs for inclusion or exclusion of microarray data may be appropriate when comparing microarray and rt

  15. A combination of transcriptome and methylation analyses reveals embryologically-relevant candidate genes in MRKH patients

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    Riess Olaf

    2011-05-01

    Full Text Available Abstract Background The Mayer-Rokitansky-Küster-Hauser (MRKH syndrome is present in at least 1 out of 4,500 female live births and is the second most common cause for primary amenorrhea. It is characterized by vaginal and uterine aplasia in an XX individual with normal secondary characteristics. It has long been considered a sporadic anomaly, but familial clustering occurs. Several candidate genes have been studied although no single factor has yet been identified. Cases of discordant monozygotic twins suggest that the involvement of epigenetic factors is more likely. Methods Differences in gene expression and methylation patterns of uterine tissue between eight MRKH patients and eight controls were identified using whole-genome microarray analyses. Results obtained by expression and methylation arrays were confirmed by qRT-PCR and pyrosequencing. Results We delineated 293 differentially expressed and 194 differentially methylated genes of which nine overlap in both groups. These nine genes are mainly embryologically relevant for the development of the female genital tract. Conclusion Our study used, for the first time, a combined whole-genome expression and methylation approach to reveal the etiology of the MRKH syndrome. The findings suggest that either deficient estrogen receptors or the ectopic expression of certain HOXA genes might lead to abnormal development of the female reproductive tract. In utero exposure to endocrine disruptors or abnormally high maternal hormone levels might cause ectopic expression or anterior transformation of HOXA genes. It is, however, also possible that different factors influence the anti-Mullerian hormone promoter activity during embryological development causing regression of the Müllerian ducts. Thus, our data stimulate new research directions to decipher the pathogenic basis of MRKH syndrome.

  16. Gene expression signature analysis identifies vorinostat as a candidate therapy for gastric cancer.

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    Sofie Claerhout

    Full Text Available BACKGROUND: Gastric cancer continues to be one of the deadliest cancers in the world and therefore identification of new drugs targeting this type of cancer is thus of significant importance. The purpose of this study was to identify and validate a therapeutic agent which might improve the outcomes for gastric cancer patients in the future. METHODOLOGY/PRINCIPAL FINDINGS: Using microarray technology, we generated a gene expression profile of human gastric cancer-specific genes from human gastric cancer tissue samples. We used this profile in the Broad Institute's Connectivity Map analysis to identify candidate therapeutic compounds for gastric cancer. We found the histone deacetylase inhibitor vorinostat as the lead compound and thus a potential therapeutic drug for gastric cancer. Vorinostat induced both apoptosis and autophagy in gastric cancer cell lines. Pharmacological and genetic inhibition of autophagy however, increased the therapeutic efficacy of vorinostat, indicating that a combination of vorinostat with autophagy inhibitors may therapeutically be more beneficial. Moreover, gene expression analysis of gastric cancer identified a collection of genes (ITGB5, TYMS, MYB, APOC1, CBX5, PLA2G2A, and KIF20A whose expression was elevated in gastric tumor tissue and downregulated more than 2-fold by vorinostat treatment in gastric cancer cell lines. In contrast, SCGB2A1, TCN1, CFD, APLP1, and NQO1 manifested a reversed pattern. CONCLUSIONS/SIGNIFICANCE: We showed that analysis of gene expression signature may represent an emerging approach to discover therapeutic agents for gastric cancer, such as vorinostat. The observation of altered gene expression after vorinostat treatment may provide the clue to identify the molecular mechanism of vorinostat and those patients likely to benefit from vorinostat treatment.

  17. Integrating microarray gene expression object model and clinical document architecture for cancer genomics research.

    Science.gov (United States)

    Park, Yu Rang; Lee, Hye Won; Kim, Ju Han

    2005-01-01

    Systematic integration of genomic-scale expression profiles with clinical information may facilitate cancer genomics research. MAGE-OM (Microarray Gene Expression Object Model) defines standard objects for genomic but not for clinical data. HL7 CDA (Clinical Document Architecture) is a document model for clinical information, describing syntax (generic structure) but not semantics. We designed a document template in XML Schema with additional constraints for CDA to define content semantics, enabling data model-level integration of MAGE-OM and CDA for cancer genomics research. PMID:16779360

  18. Herpesvirus of turkeys: microarray analysis of host gene responses to infection

    International Nuclear Information System (INIS)

    Herpesvirus of turkeys (HVT) provides an economically important live vaccine for prevention of Marek's disease (MD) of chickens. MD, characterized by both immunosuppression and T-cell lymphoma, is caused by another herpesvirus termed Marek's disease virus (MDV). Microarrays were used to investigate the response of chicken embryonic fibroblasts (CEF) to infection with HVT. Genes responding to HVT infection include several induced by interferon along with others modulating signal transduction, transcription, scaffolding proteins, and the cytoskeleton. Results are compared with earlier studies examining the responses of CEF cells to infection with MDV

  19. A multi-resource data integration approach: Identification of candidate genes regulating cell proliferation during neocortical development

    Directory of Open Access Journals (Sweden)

    Cynthia M Vied

    2014-08-01

    Full Text Available Neurons of the mammalian neocortex are produced by proliferating cells located in the ventricular zone (VZ lining the lateral ventricles. This is a complex and sequential process, requiring precise control of cell cycle progression, fate commitment and differentiation. We have analyzed publicly available databases from mouse and human to identify candidate genes that are potentially involved in regulating early neocortical development and neurogenesis. We used a mouse in situ hybridization dataset (The Allen Institute for Brain Science to identify 13 genes (Cdon, Celsr1, Dbi, E2f5, Eomes, Hmgn2, Neurog2, Notch1, Pcnt, Sox3, Ssrp1, Tead2, Tgif2 with high correlation of expression in the proliferating cells of the VZ of the neocortex at early stages of development (E15.5. We generated a similar human brain network using microarray and RNA-seq data (BrainSpan Atlas and identified 407 genes with high expression in the developing human VZ and subventricular zone (SVZ at 8-9 post-conception weeks. Seven of the human genes were also present in the mouse VZ network. The human and mouse networks were extended using available genetic and proteomic datasets through GeneMANIA. A gene ontology search of the mouse and human networks indicated that many of the genes are involved in the cell cycle, DNA replication, mitosis and transcriptional regulation. The reported involvement of Cdon, Celsr1, Dbi, Eomes, Neurog2, Notch1, Pcnt, Sox3, Tead2 and Tgif2 in neural development or diseases resulting from the disruption of neurogenesis validates these candidate genes. Taken together, our knowledge-based discovery method has validated the involvement of many genes already known to be involved in neocortical development and extended the potential number of genes by 100's, many of which are involved in functions related to cell proliferation but others of which are potential candidates for involvement in the regulation of neocortical development.

  20. Meta-Analysis of Multiple Sclerosis Microarray Data Reveals Dysregulation in RNA Splicing Regulatory Genes

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    Elvezia Maria Paraboschi

    2015-09-01

    Full Text Available Abnormalities in RNA metabolism and alternative splicing (AS are emerging as important players in complex disease phenotypes. In particular, accumulating evidence suggests the existence of pathogenic links between multiple sclerosis (MS and altered AS, including functional studies showing that an imbalance in alternatively-spliced isoforms may contribute to disease etiology. Here, we tested whether the altered expression of AS-related genes represents a MS-specific signature. A comprehensive comparative analysis of gene expression profiles of publicly-available microarray datasets (190 MS cases, 182 controls, followed by gene-ontology enrichment analysis, highlighted a significant enrichment for differentially-expressed genes involved in RNA metabolism/AS. In detail, a total of 17 genes were found to be differentially expressed in MS in multiple datasets, with CELF1 being dysregulated in five out of seven studies. We confirmed CELF1 downregulation in MS (p = 0.0015 by real-time RT-PCRs on RNA extracted from blood cells of 30 cases and 30 controls. As a proof of concept, we experimentally verified the unbalance in alternatively-spliced isoforms in MS of the NFAT5 gene, a putative CELF1 target. In conclusion, for the first time we provide evidence of a consistent dysregulation of splicing-related genes in MS and we discuss its possible implications in modulating specific AS events in MS susceptibility genes.

  1. Meta-Analysis of Multiple Sclerosis Microarray Data Reveals Dysregulation in RNA Splicing Regulatory Genes.

    Science.gov (United States)

    Paraboschi, Elvezia Maria; Cardamone, Giulia; Rimoldi, Valeria; Gemmati, Donato; Spreafico, Marta; Duga, Stefano; Soldà, Giulia; Asselta, Rosanna

    2015-01-01

    Abnormalities in RNA metabolism and alternative splicing (AS) are emerging as important players in complex disease phenotypes. In particular, accumulating evidence suggests the existence of pathogenic links between multiple sclerosis (MS) and altered AS, including functional studies showing that an imbalance in alternatively-spliced isoforms may contribute to disease etiology. Here, we tested whether the altered expression of AS-related genes represents a MS-specific signature. A comprehensive comparative analysis of gene expression profiles of publicly-available microarray datasets (190 MS cases, 182 controls), followed by gene-ontology enrichment analysis, highlighted a significant enrichment for differentially-expressed genes involved in RNA metabolism/AS. In detail, a total of 17 genes were found to be differentially expressed in MS in multiple datasets, with CELF1 being dysregulated in five out of seven studies. We confirmed CELF1 downregulation in MS (p=0.0015) by real-time RT-PCRs on RNA extracted from blood cells of 30 cases and 30 controls. As a proof of concept, we experimentally verified the unbalance in alternatively-spliced isoforms in MS of the NFAT5 gene, a putative CELF1 target. In conclusion, for the first time we provide evidence of a consistent dysregulation of splicing-related genes in MS and we discuss its possible implications in modulating specific AS events in MS susceptibility genes. PMID:26437396

  2. Dorsal horn-enriched genes identified by DNA microarray, in situ hybridization and immunohistochemistry

    Directory of Open Access Journals (Sweden)

    Koblan Kenneth S

    2002-08-01

    Full Text Available Abstract Background Neurons in the dorsal spinal cord play important roles in nociception and pain. These neurons receive input from peripheral sensory neurons and then transmit the signals to the brain, as well as receive and integrate descending control signals from the brain. Many molecules important for pain transmission have been demonstrated to be localized to the dorsal horn of the spinal cord. Further understanding of the molecular interactions and signaling pathways in the dorsal horn neurons will require a better knowledge of the molecular neuroanatomy in the dorsal spinal cord. Results A large scale screening was conducted for genes with enriched expression in the dorsal spinal cord using DNA microarray and quantitative real-time PCR. In addition to genes known to be specifically expressed in the dorsal spinal cord, other neuropeptides, receptors, ion channels, and signaling molecules were also found enriched in the dorsal spinal cord. In situ hybridization and immunohistochemistry revealed the cellular expression of a subset of these genes. The regulation of a subset of the genes was also studied in the spinal nerve ligation (SNL neuropathic pain model. In general, we found that the genes that are enriched in the dorsal spinal cord were not among those found to be up-regulated in the spinal nerve ligation model of neuropathic pain. This study also provides a level of validation of the use of DNA microarrays in conjunction with our novel analysis algorithm (SAFER for the identification of differences in gene expression. Conclusion This study identified molecules that are enriched in the dorsal horn of the spinal cord and provided a molecular neuroanatomy in the spinal cord, which will aid in the understanding of the molecular mechanisms important in nociception and pain.

  3. Novel primary immunodeficiency candidate genes predicted by the human gene connectome

    Directory of Open Access Journals (Sweden)

    Yuval eItan

    2015-04-01

    Full Text Available Germline genetic mutations underlie various primary immunodeficiency (PID diseases. Patients with rare PID diseases (like most non-PID patients and healthy individuals carry, on average, 20,000 rare and common coding variants detected by high throughput sequencing. It is thus a major challenge to select only a few candidate disease-causing variants for experimental testing. One of the tools commonly used in the pipeline for estimating a potential PID candidate gene is to test whether the specific gene is included in the list of genes that were already experimentally validated as PID-causing in previous studies. However, this approach is limited because it cannot detect the PID-causing mutation(s in the many PID patients carrying causal mutations of as yet unidentified PID-causing genes. In this study, we expanded in silico the list of potential PID-causing candidate genes from 229 to 3,110. We first identified the top 1% of human genes predicted by the human genes connectome to be biologically close to the 229 known PID genes. We then further narrowed down the list of genes by retaining only the most biologically relevant genes, with functionally enriched gene ontology biological categories similar to those for the known PID genes. We validated this prediction by showing that 17 of the 21 novel PID genes published since the last IUIS classification fall into this group of 3,110 genes (p<10-7. The resulting new extended list of 3,110 predicted PID genes should be useful for the discovery of novel PID genes in patients.

  4. FiRe and microarrays: a fast answer to burning questions

    OpenAIRE

    Garcion, Christophe; ApplimathFRI; Métraux, Jean-Pierre

    2006-01-01

    FiRe is a user-friendly Excel® macro designed to survey microarray data rapidly. This software interactively assembles data from different experiments and produces lists of candidate genes according to patterns of gene expression. Furthermore, macros bundled with FiRe can compare lists of genes, merge information from different spreadsheets, link candidates to information available from web-based databases, and produce heat-maps for easy visualization of microarray data. FiRe is freely availa...

  5. Identifying disease candidate genes via large-scale gene network analysis.

    Science.gov (United States)

    Kim, Haseong; Park, Taesung; Gelenbe, Erol

    2014-01-01

    Gene Regulatory Networks (GRN) provide systematic views of complex living systems, offering reliable and large-scale GRNs to identify disease candidate genes. A reverse engineering technique, Bayesian Model Averaging-based Networks (BMAnet), which ensembles all appropriate linear models to tackle uncertainty in model selection that integrates heterogeneous biological data sets is introduced. Using network evaluation metrics, we compare the networks that are thus identified. The metric 'Random walk with restart (Rwr)' is utilised to search for disease genes. In a simulation our method shows better performance than elastic-net and Gaussian graphical models, but topological quantities vary among the three methods. Using real-data, brain tumour gene expression samples consisting of non-tumour, grade III and grade IV are analysed to estimate networks with a total of 4422 genes. Based on these networks, 169 brain tumour-related candidate genes were identified and some were found to relate to 'wound', 'apoptosis', and 'cell death' processes. PMID:25796737

  6. Analysis of microarray-identified genes and microRNAs associated with drug resistance in ovarian cancer

    OpenAIRE

    Zou, Jing; Yin, Fuqiang; Wang, Qi; Zhang, Wei; Li, Li

    2015-01-01

    The aim of this study was to identify potential microRNAs and genes associated with drug resistance in ovarian cancer through web-available microarrays. The drug resistant-related microRNA microarray dataset GS54665 and mRNA dataset GSE33482, GSE28646, and GSE15372 were downloaded from the Gene Expression Omnibus database. Dysregulated microRNAs/genes were screened with GEO2R and were further identified in SKOV3 (SKOV3/DDP) and A2780 (A2780/DDP) cells by real-time quantitative PCR (qRT-PCR), ...

  7. Integrative meta-analysis of differentially expressed genes in osteoarthritis using microarray technology.

    Science.gov (United States)

    Wang, Xi; Ning, Yujie; Guo, Xiong

    2015-09-01

    The aim of the present study was to identify differentially expressed (DE) genes in patients with osteoarthritis (OA), and biological processes associated with changes in gene expression that occur in this disease. Using the INMEX (integrative meta‑analysis of expression data) software tool, a meta‑analysis of publicly available microarray Gene Expression Omnibus (GEO) datasets of OA was performed. Gene ontology (GO) enrichment analysis was performed in order to detect enriched functional attributes based on gene‑associated GO terms. Three GEO datasets, containing 137 patients with OA and 52 healthy controls, were included in the meta‑analysis. The analysis identified 85 genes that were consistently differentially expressed in OA (30 genes were upregulated and 55 genes were downregulated). The upregulated gene with the lowest P‑value (P=5.36E‑07) was S‑phase kinase‑associated protein 2, E3 ubiquitin protein ligase (SKP2). The downregulated gene with the lowest P‑value (P=4.42E‑09) was Proline rich 5 like (PRR5L). Among the 210 GO terms that were associated with the set of DE genes, the most significant two enrichments were observed in the GO categories of 'Immune response', with a P‑value of 0.000129438, and 'Immune effectors process', with a P‑value of 0.000288619. The current meta‑analysis identified genes that were consistently DE in OA, in addition to biological pathways associated with changes in gene expression that occur during OA, which may provide insight into the molecular mechanisms underlying the pathogenesis of this disease. PMID:25975828

  8. DNA-microarrays identification of Streptococcus mutans genes associated with biofilm thickness

    Directory of Open Access Journals (Sweden)

    Feldman Mark

    2008-12-01

    Full Text Available Abstract Background A biofilm is a complex community of microorganisms that develop on surfaces in diverse environments. The thickness of the biofilm plays a crucial role in the physiology of the immobilized bacteria. The most cariogenic bacteria, mutans streptococci, are common inhabitants of a dental biofilm community. In this study, DNA-microarray analysis was used to identify differentially expressed genes associated with the thickness of S. mutans biofilms. Results Comparative transcriptome analyses indicated that expression of 29 genes was differentially altered in 400- vs. 100-microns depth and 39 genes in 200- vs. 100-microns biofilms. Only 10 S. mutans genes showed differential expression in both 400- vs. 100-microns and 200- vs. 100-microns biofilms. All of these genes were upregulated. As sucrose is a predominant factor in oral biofilm development, its influence was evaluated on selected genes expression in the various depths of biofilms. The presence of sucrose did not noticeably change the regulation of these genes in 400- vs. 100-microns and/or 200- vs. 100-microns biofilms tested by real-time RT-PCR. Furthermore, we analyzed the expression profile of selected biofilm thickness associated genes in the luxS- mutant strain. The expression of those genes was not radically changed in the mutant strain compared to wild-type bacteria in planktonic condition. Only slight downregulation was recorded in SMU.2146c, SMU.574, SMU.609, and SMU.987 genes expression in luxS- bacteria in biofilm vs. planktonic environments. Conclusion These findings reveal genes associated with the thickness of biofilms of S. mutans. Expression of these genes is apparently not regulated directly by luxS and is not necessarily influenced by the presence of sucrose in the growth media.

  9. Meta-analysis of microarray data using a pathway-based approach identifies a 37-gene expression signature for systemic lupus erythematosus in human peripheral blood mononuclear cells

    OpenAIRE

    Arasappan, Dhivya; Tong, Weida; Mummaneni, Padmaja; Fang, Hong; Amur, Shashi

    2011-01-01

    Background A number of publications have reported the use of microarray technology to identify gene expression signatures to infer mechanisms and pathways associated with systemic lupus erythematosus (SLE) in human peripheral blood mononuclear cells. However, meta-analysis approaches with microarray data have not been well-explored in SLE. Methods In this study, a pathway-based meta-analysis was applied to four independent gene expression oligonucleotide microarray data sets to identify gene ...

  10. Investigation of two candidate genes for Hailey-Hailey disease

    Energy Technology Data Exchange (ETDEWEB)

    Peluso, A.M.; Ikeda, S.; Bonifas, J.M. [Univ. of California, San Francisco, CA (United States)] [and others

    1994-09-01

    Hailey-Hailey disease (familial benign chronic pemphigus) is an autosomal dominant skin disease characterized by impaired keratinocyte cohesion and consequent blister formation. Recently we have used linkage to map the gene for this disease to a region of chromosome 3q between D3S1589 and D3S1316. The maximum combined two point lod score in four families studied was 14.60 at {theta} = 0 at the D3S1290 microsatellite repeat. Several genes have been mapped to chromosome 3q21-24, including cellular retinol binding protein (RBP1) and rhodopsin (RHO). Using microsatellite repeat for RHO we have found a recombinant with the RHO gene and Hailey-Hailey disease in one patient. Because of the profound effects of retinoids on epidermal differentiation, RBP1 could be considered as a possible candidate gene. We have amplified genomic DNA from patients from 14 individual families with Hailey-Hailey disease and 10 different control samples for each of the 4 exons of RBP1. Thus far, SSCP analysis has failed to detect different banding patterns in patients versus controls. We are now attempting to extend this RBP1 analysis and are collecting new families to use linkage analysis to narrow this still rather large (approximately 14 cM) interval.

  11. Differentially expressed genes identified by microarray analysis following leptin treatment of hepatic stellate cells

    Institute of Scientific and Technical Information of China (English)

    ZHONG Li-hua; CHENG Jun; ZHU Li-ying

    2010-01-01

    Background Liver fibrosis is the process through which numerous chronic liver diseases develop into liver cirrhosis. Leptin can activate hepatic stellate cells (HSCs) and play an important role in the formation of liver fibrosis. However, the process by which leptin activates HSCs is complicated, and research on this process is limited. The aim of this study was to explore the related changes in gene expression and the control mechanisms involved in leptin activated HSCs to understand the overall mechanism of liver fibrosis development. Methods We cultivate rat HSCs, with and without stimulation by leptin, and extracted mRNA. Differentially expressed genes were detected by microarray analysis. Results The differentially expressed genes identified included six upregulated genes and six downregulated genes. The representative upregulated genes included short chain dehydrogenase (CY5/CY3=2.265) and pulmonary surfactant protein A1 (CY5/CY3=2.036). The significant downregulated gene encoded hepatic stearoyl coenzyme A desaturase 1 (SCD-1) (CY5/CY3=0.351).Conclusion Leptin might mediate the molecular biological mechanisms of liver fibrosis.

  12. Microarray analysis of New Green Cocoon associated genes in silkworm, Bombyx mori.

    Science.gov (United States)

    Lu, Ya-Ru; He, Song-Zhen; Tong, Xiao-Ling; Han, Min-Jin; Li, Chun-Lin; Li, Zhi-Quan; Dai, Fang-Yin

    2016-06-01

    Green cocoons in silkworm, Bombyx mori, are caused by flavonoids accumulation in the silk proteins, fibroin and sericin. Despite the economic value of natural green cocoon and medical value of flavonoids, there is limited understanding of the molecular mechanism regulating flavonoids uptake in silkworm, which is tightly associated with the trait of green cocoon. The purpose of this study is to perform a comprehensive analysis to understand the molecular mechanisms of flavonoids uptake in silkworm based on microarray analyses. The study subject was the New Green Cocoon from the silkworm strains, G200 and N100, a new spontaneous dominant green cocoon trait identified in the 2000s. The genes regulating this trait are independent of other green cocoon genes previously reported. Genome-wide gene expression was compared between the New Green Cocoon producing silkworm strains, G200 and N100, and the control sample, which is the white cocoon producing strain 872B. Among these strains, N100 and 872B are near-isogenic lines. The results showed that 130 genes have consistently changing expression patterns in the green cocoon strains when compared with the white cocoon strain. Among these, we focused on the genes related to flavonoids metabolism and absorption, such as sugar transporter genes and UDP-glucosyltransferase genes. Based on our findings, we propose the potential mechanisms for flavonoids absorption and metabolism in silkworm. Our results imply that silkworm might be used as an underlying model for flavonoids in pharmaceutical research. PMID:26936509

  13. Tissue-Based Microarray Expression of Genes Predictive of Metastasis in Uveal Melanoma and Differentially Expressed in Metastatic Uveal Melanoma

    Directory of Open Access Journals (Sweden)

    Hakan Demirci

    2013-01-01

    Full Text Available Purpose: To screen the microarray expression of CDH1, ECM1, EIF1B, FXR1, HTR2B, ID2, LMCD1, LTA4H, MTUS1, RAB31, ROBO1, and SATB1 genes which are predictive of primary uveal melanoma metastasis, and NFKB2, PTPN18, MTSS1, GADD45B, SNCG, HHIP, IL12B, CDK4, RPLP0, RPS17, RPS12 genes that are differentially expressed in metastatic uveal melanoma in normal whole human blood and tissues prone to metastatic involvement by uveal melanoma. Methods: We screened the GeneNote and GNF BioGPS databases for microarray analysis of genes predictive of primary uveal melanoma metastasis and those differentially expressed in metastatic uveal melanoma in normal whole blood, liver, lung and skin. Results: Microarray analysis showed expression of all 22 genes in normal whole blood, liver, lung and skin, which are the most common sites of metastases. In the GNF BioGPS database, data for expression of the HHIP gene in normal whole blood and skin was not complete. Conclusions: Microarray analysis of genes predicting systemic metastasis of uveal melanoma and genes differentially expressed in metastatic uveal melanoma may not be used as a biomarker for metastasis in whole blood, liver, lung, and skin. Their expression in tissues prone to metastasis may suggest that they play a role in tropism of uveal melanoma metastasis to these tissues.

  14. Development of a miniaturized DNA microarray for identification of 66 virulence genes of Legionella pneumophila

    Directory of Open Access Journals (Sweden)

    Mariusz Żak

    2011-12-01

    Full Text Available Introduction:For the last five years, Legionella sp. infections and legionnaire’s disease in Poland have been receiving a lot of attention, because of the new regulations concerning microbiological quality of drinking water. This was the inspiration to search for and develop a new assay to identify many virulence genes of Legionella pneumophila to better understand their distribution in environmental and clinical strains. The method might be an invaluable help in infection risk assessment and in epidemiological investigations.Material/Methods:The microarray is based on Array Tube technology. It contains 3 positive and 1 negative control. Target genes encode structural elements of T4SS, effector proteins and factors not related to T4SS. Probes were designed using OligoWiz software and data analyzed using IconoClust software. To isolate environmental and clinical strains, BAL samples and samples of hot water from different and independent hot water distribution systems of public utility buildings were collected.Results.We have developed a miniaturized DNA microarray for identification of 66 virulence genes of L. pneumophila. The assay is specific to L. pneumophila sg 1 with sensitivity sufficient to perform the assay using DNA isolated from a single L. pneumophila colony. Seven environmental strains were analyzed. Two exhibited a hybridization pattern distinct from the reference strain.Discussion:The method is time- and cost-effective. Initial studies have shown that genes encoding effector proteins may vary among environmental strains. Further studies might help to identify set of genes increasing the risk of clinical disease and to determine the pathogenic potential of environmental strains.

  15. Identification of Reference Genes across Physiological States for qRT-PCR through Microarray Meta-Analysis

    OpenAIRE

    Cheng, Wei-Chung; Chang, Cheng-Wei; Chen, Chaang-Ray; Tsai, Min-Lung; Shu, Wun-Yi; Li, Chia-Yang; Hsu, Ian C.

    2011-01-01

    Background The accuracy of quantitative real-time PCR (qRT-PCR) is highly dependent on reliable reference gene(s). Some housekeeping genes which are commonly used for normalization are widely recognized as inappropriate in many experimental conditions. This study aimed to identify reference genes for clinical studies through microarray meta-analysis of human clinical samples. Methodology/Principal Findings After uniform data preprocessing and data quality control, 4,804 Affymetrix HU-133A arr...

  16. Association Study between BDNF Gene Polymorphisms and Autism by Three-Dimensional Gel-Based Microarray

    Directory of Open Access Journals (Sweden)

    Zuhong Lu

    2009-06-01

    Full Text Available Single nucleotide polymorphisms (SNPs are important markers which can be used in association studies searching for susceptible genes of complex diseases. High-throughput methods are needed for SNP genotyping in a large number of samples. In this study, we applied polyacrylamide gel-based microarray combined with dual-color hybridization for association study of four BDNF polymorphisms with autism. All the SNPs in both patients and controls could be analyzed quickly and correctly. Among four SNPs, only C270T polymorphism showed significant differences in the frequency of the allele (χ2 = 7.809, p = 0.005 and genotype (χ2 = 7.800, p = 0.020. In the haplotype association analysis, there was significant difference in global haplotype distribution between the groups (χ2 = 28.19,p = 3.44e-005. We suggest that BDNF has a possible role in the pathogenesis of autism. The study also show that the polyacrylamide gel-based microarray combined with dual-color hybridization is a rapid, simple and high-throughput method for SNPs genotyping, and can be used for association study of susceptible gene with disorders in large samples.

  17. The microarray analysis for gene expression in haploids and diploids derived from twin-seedling rice

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    In this study, microarray technique was employed to analyze the gene expression at the RNA level between haploids and corresponding diploids derived from a rice twin-seedling line SARII-628. Differ- ent degrees of expression variations were observed in the plant after haploidization. The main results are as follows: (1) after haploidization, the ratio of the sensitive loci was 2.47% of the total loci designed on chip. Those loci were randomly distributed on the 12 pairs of rice chromosomes and the activated loci were more than the silenced ones. (2) Gene clusters on chromosome were observed for 33 se- quences. (3) GoPipe function classification for 575 sensitive loci revealed an involvement in the bio- logical process, cell component and molecular function. (4) RT-PCR generally validated the result from microarray with a coincidence rate of 83.78%. And for the randomly-selected activated or silenced loci in chip analysis, the coincidence rate was up to 91.86%.

  18. Microarray analysis of gene expression profile of multidrug resistance in pancreatic cancer

    Institute of Scientific and Technical Information of China (English)

    ZHAO Yu-pei; CHEN Ge; FENG Bin; ZHANG Tai-ping; MA En-ling; WU Yuan-de

    2007-01-01

    Background Chemotherapy is the most frequently adopted adjuvant therapy of pancreatic ductal adenocarcinoma (PDAC), but the development of drug resistance reduces its effectiveness. Clarification of the mechanism of multidrug resistance (MDR) development in PDAC is needed to improve the therapeutic effect of chemotherapy. This study was aimed to investigate the molecular mechanism of MDR of PDAC and to identify genes associated with MDR development.Methods The gene expression profiles of cell line SW1990 and three drug-selected pancreatic chemoresistant sub-lines, SW1990/5-Fu, SW1990/ADM and SW1990/GEM, were obtained using an oligonucleotide microarray (Affymetrix HG U133 2.0 plus) that contained approximately 38 000 human genes. The microarray results were validated by real-time quantitative polymerase chain reaction and Western blot analysis.Results There were 165 genes and expressed sequence tags, some of which have never been linked to drug resistance, that were up- or down-regulated at least 2-fold in all resistant sub-lines when compared with SW1990.According to Gene Ontology annotation, differentially expressed genes related to MDR in pancreatic cancer belong to many functional families and with diverse biological processes. Genes related to antioxidant activity, apoptosis, the cell cycle, signal transduction and intracellular adhesion may undergo epigenetic changes preceding MDR development. A hierarchical clustering was conducted and several interesting clusters were discovered that may be primarily related to cell cycle and developmental regulation. A prediction rule was built from the expression profiles of 117 genes after support vector machine (SVM) analysis, and the prediction result was examined by cytotoxic testing. As a result, a differential gene expression pattern was constructed in multidrug resistant pancreatic cancer cells.Conclusions The findings of this study prove that construction of a chemoresistance prediction rule, based on gene

  19. Swarm Intelligence Approach Based on Adaptive ELM Classifier with ICGA Selection for Microarray Gene Expression and Cancer Classification

    Directory of Open Access Journals (Sweden)

    T. Karthikeyan

    2014-05-01

    Full Text Available The aim of this research study is based on efficient gene selection and classification of microarray data analysis using hybrid machine learning algorithms. The beginning of microarray technology has enabled the researchers to quickly measure the position of thousands of genes expressed in an organic/biological tissue samples in a solitary experiment. One of the important applications of this microarray technology is to classify the tissue samples using their gene expression representation, identify numerous type of cancer. Cancer is a group of diseases in which a set of cells shows uncontrolled growth, instance that interrupts upon and destroys nearby tissues and spreading to other locations in the body via lymph or blood. Cancer has becomes a one of the major important disease in current scenario. DNA microarrays turn out to be an effectual tool utilized in molecular biology and cancer diagnosis. Microarrays can be measured to establish the relative quantity of mRNAs in two or additional organic/biological tissue samples for thousands/several thousands of genes at the same time. As the superiority of this technique become exactly analysis/identifying the suitable assessment of microarray data in various open issues. In the field of medical sciences multi-category cancer classification play a major important role to classify the cancer types according to the gene expression. The need of the cancer classification has been become indispensible, because the numbers of cancer victims are increasing steadily identified by recent years. To perform this proposed a combination of Integer-Coded Genetic Algorithm (ICGA and Artificial Bee Colony algorithm (ABC, coupled with an Adaptive Extreme Learning Machine (AELM, is used for gene selection and cancer classification. ICGA is used with ABC based AELM classifier to chose an optimal set of genes which results in an efficient hybrid algorithm that can handle sparse data and sample imbalance. The

  20. Ultrafiltration and Microarray for Detection of Microbial Source Tracking Marker and Pathogen Genes in Riverine and Marine Systems.

    Science.gov (United States)

    Li, Xiang; Harwood, Valerie J; Nayak, Bina; Weidhaas, Jennifer L

    2016-03-01

    Pathogen identification and microbial source tracking (MST) to identify sources of fecal pollution improve evaluation of water quality. They contribute to improved assessment of human health risks and remediation of pollution sources. An MST microarray was used to simultaneously detect genes for multiple pathogens and indicators of fecal pollution in freshwater, marine water, sewage-contaminated freshwater and marine water, and treated wastewater. Dead-end ultrafiltration (DEUF) was used to concentrate organisms from water samples, yielding a recovery efficiency of >95% for Escherichia coli and human polyomavirus. Whole-genome amplification (WGA) increased gene copies from ultrafiltered samples and increased the sensitivity of the microarray. Viruses (adenovirus, bocavirus, hepatitis A virus, and human polyomaviruses) were detected in sewage-contaminated samples. Pathogens such as Legionella pneumophila, Shigella flexneri, and Campylobacter fetus were detected along with genes conferring resistance to aminoglycosides, beta-lactams, and tetracycline. Nonmetric dimensional analysis of MST marker genes grouped sewage-spiked freshwater and marine samples with sewage and apart from other fecal sources. The sensitivity (percent true positives) of the microarray probes for gene targets anticipated in sewage was 51 to 57% and was lower than the specificity (percent true negatives; 79 to 81%). A linear relationship between gene copies determined by quantitative PCR and microarray fluorescence was found, indicating the semiquantitative nature of the MST microarray. These results indicate that ultrafiltration coupled with WGA provides sufficient nucleic acids for detection of viruses, bacteria, protozoa, and antibiotic resistance genes by the microarray in applications ranging from beach monitoring to risk assessment. PMID:26729716

  1. PAX3 gene deletion detected by microarray analysis in a girl with hearing loss.

    Science.gov (United States)

    Drozniewska, Malgorzata; Haus, Olga

    2014-01-01

    Deletions of the PAX3 gene have been rarely reported in the literature. Mutations of this gene are a common cause of Waardenburg syndrome type 1 and 3. We report a 16 year old female presenting hearing loss and normal intellectual development, without major features of Waardenburg syndrome type 1, and without family history of the syndrome. Her phenotype, however, overlaps with features of craniofacial-deafness-hand syndrome. Microarray analysis showed ~862 kb de novo deletion at 2q36.1 including PAX3. The above findings suggest that the rearrangement found in our patient appeared de novo and with high probability is a cause of her phenotype. PMID:24839464

  2. Bayesian Hierarchical Model for Estimating Gene Expression Intensity Using Multiple Scanned Microarrays

    Directory of Open Access Journals (Sweden)

    Auvinen Petri

    2008-01-01

    Full Text Available We propose a method for improving the quality of signal from DNA microarrays by using several scans at varying scanner sen-sitivities. A Bayesian latent intensity model is introduced for the analysis of such data. The method improves the accuracy at which expressions can be measured in all ranges and extends the dynamic range of measured gene expression at the high end. Our method is generic and can be applied to data from any organism, for imaging with any scanner that allows varying the laser power, and for extraction with any image analysis software. Results from a self-self hybridization data set illustrate an improved precision in the estimation of the expression of genes compared to what can be achieved by applying standard methods and using only a single scan.

  3. Knowledge-based analysis of microarray gene expression data by using support vector machines

    Energy Technology Data Exchange (ETDEWEB)

    William Grundy; Manuel Ares, Jr.; David Haussler

    2001-06-18

    The authors introduce a method of functionally classifying genes by using gene expression data from DNA microarray hybridization experiments. The method is based on the theory of support vector machines (SVMs). SVMs are considered a supervised computer learning method because they exploit prior knowledge of gene function to identify unknown genes of similar function from expression data. SVMs avoid several problems associated with unsupervised clustering methods, such as hierarchical clustering and self-organizing maps. SVMs have many mathematical features that make them attractive for gene expression analysis, including their flexibility in choosing a similarity function, sparseness of solution when dealing with large data sets, the ability to handle large feature spaces, and the ability to identify outliers. They test several SVMs that use different similarity metrics, as well as some other supervised learning methods, and find that the SVMs best identify sets of genes with a common function using expression data. Finally, they use SVMs to predict functional roles for uncharacterized yeast ORFs based on their expression data.

  4. GeneAnalytics: An Integrative Gene Set Analysis Tool for Next Generation Sequencing, RNAseq and Microarray Data.

    Science.gov (United States)

    Ben-Ari Fuchs, Shani; Lieder, Iris; Stelzer, Gil; Mazor, Yaron; Buzhor, Ella; Kaplan, Sergey; Bogoch, Yoel; Plaschkes, Inbar; Shitrit, Alina; Rappaport, Noa; Kohn, Asher; Edgar, Ron; Shenhav, Liraz; Safran, Marilyn; Lancet, Doron; Guan-Golan, Yaron; Warshawsky, David; Shtrichman, Ronit

    2016-03-01

    Postgenomics data are produced in large volumes by life sciences and clinical applications of novel omics diagnostics and therapeutics for precision medicine. To move from "data-to-knowledge-to-innovation," a crucial missing step in the current era is, however, our limited understanding of biological and clinical contexts associated with data. Prominent among the emerging remedies to this challenge are the gene set enrichment tools. This study reports on GeneAnalytics™ ( geneanalytics.genecards.org ), a comprehensive and easy-to-apply gene set analysis tool for rapid contextualization of expression patterns and functional signatures embedded in the postgenomics Big Data domains, such as Next Generation Sequencing (NGS), RNAseq, and microarray experiments. GeneAnalytics' differentiating features include in-depth evidence-based scoring algorithms, an intuitive user interface and proprietary unified data. GeneAnalytics employs the LifeMap Science's GeneCards suite, including the GeneCards®--the human gene database; the MalaCards-the human diseases database; and the PathCards--the biological pathways database. Expression-based analysis in GeneAnalytics relies on the LifeMap Discovery®--the embryonic development and stem cells database, which includes manually curated expression data for normal and diseased tissues, enabling advanced matching algorithm for gene-tissue association. This assists in evaluating differentiation protocols and discovering biomarkers for tissues and cells. Results are directly linked to gene, disease, or cell "cards" in the GeneCards suite. Future developments aim to enhance the GeneAnalytics algorithm as well as visualizations, employing varied graphical display items. Such attributes make GeneAnalytics a broadly applicable postgenomics data analyses and interpretation tool for translation of data to knowledge-based innovation in various Big Data fields such as precision medicine, ecogenomics, nutrigenomics, pharmacogenomics, vaccinomics

  5. Identification of novel cholesteatoma-related gene expression signatures using full-genome microarrays.

    Directory of Open Access Journals (Sweden)

    Christin Klenke

    Full Text Available BACKGROUND: Cholesteatoma is a gradually expanding destructive epithelial lesion within the middle ear. It can cause extensive local tissue destruction in the temporal bone and can initially lead to the development of conductive hearing loss via ossicular erosion. As the disease progresses, sensorineural hearing loss, vertigo or facial palsy may occur. Cholesteatoma may promote the spread of infection through the tegmen of the middle ear and cause meningitis or intracranial infections with abscess formation. It must, therefore, be considered as a potentially life-threatening middle ear disease. METHODS AND FINDINGS: In this study, we investigated differentially expressed genes in human cholesteatomas in comparison to regular auditory canal skin using Whole Human Genome Microarrays containing 19,596 human genes. In addition to already described up-regulated mRNAs in cholesteatoma, such as MMP9, DEFB2 and KRT19, we identified 3558 new cholesteatoma-related transcripts. 811 genes appear to be significantly differentially up-regulated in cholesteatoma. 334 genes were down-regulated more than 2-fold. Significantly regulated genes with protein metabolism activity include matrix metalloproteinases as well as PI3, SERPINB3 and SERPINB4. Genes like SPP1, KRT6B, PRPH, SPRR1B and LAMC2 are known as genes with cell growth and/or maintenance activity. Transport activity genes and signal transduction genes are LCN2, GJB2 and CEACAM6. Three cell communication genes were identified; one CDH19 and two from the S100 family. CONCLUSIONS: This study demonstrates that the expression profile of cholesteatoma is similar to a metastatic tumour and chronically inflamed tissue. Based on the investigated profiles we present novel protein-protein interaction and signal transduction networks, which include cholesteatoma-regulated transcripts and may be of great value for drug targeting and therapy development.

  6. Microarray analysis of tumor necrosis factor α induced gene expression in U373 human glioblastoma cells

    Directory of Open Access Journals (Sweden)

    Prüllage Maria

    2003-11-01

    Full Text Available Abstract Background Tumor necrosis factor α (TNF is able to induce a variety of biological responses in the nervous system including inflammation and neuroprotection. Human astrocytoma cells U373 have been widely used as a model for inflammatory cytokine actions in the nervous system. Here we used cDNA microarrays to analyze the time course of the transcriptional response from 1 h up to 12 h post TNF treatment in comparison to untreated U373 cells. TNF activated strongly the NF-κB transcriptional pathway and is linked to other pathways via the NF-κB target genes JUNB and IRF-1. Part of the TNF-induced gene expression could be inhibited by pharmacological inhibition of NF-κB with pyrrolidine-dithiocarbamate (PDTC. NF-κB comprises a family of transcription factors which are involved in the inducible expression of genes regulating neuronal survival, inflammatory response, cancer and innate immunity. Results In this study we show that numerous genes responded to TNF (> 880 from 7500 tested with a more than two-fold induction rate. Several novel TNF-responsive genes (about 60% of the genes regulated by a factor ≥ 3 were detected. A comparison of our TNF-induced gene expression profiles of U373, with profiles from 3T3 and Hela cells revealed a striking cell-type specificity. SCYA2 (MCP-1, CCL2, MCAF was induced in U373 cells in a sustained manner and at the highest level of all analyzed genes. MCP-1 protein expression, as monitored with immunofluorescence and ELISA, correlated exactly with microarray data. Based on these data and on evidence from literature we suggest a model for the potential neurodegenerative effect of NF-κB in astroglia: Activation of NF-κB via TNF results in a strongly increased production of MCP-1. This leads to a exacerbation of neurodegeneration in stoke or Multiple Sclerosis, presumably via infiltration of macrophages. Conclusions The vast majority of genes regulated more than 3-fold were previously not linked to

  7. Expression cloning of a candidate gene for Mucolipidosis type IV

    Energy Technology Data Exchange (ETDEWEB)

    Gama Sosa, M.A.; De Gasperi, R.; Battistini, S. [New York Univ. School of Medicine, NY (United States)] [and others

    1994-09-01

    Mucolipidosis IV is an autosomal recessive lysosomal storage disease characterized by progressive psychomotor retardation and opthalmological abnormalities, namely corneal opacity and retinal degeneration. Biochemically, it is characterized by the lysosomal accumulation of diverse compounds such as gangliosides, phospholipids and acidic mucopolysaccharides. To date, the basic biochemical defect causing this storage disease is still unknown and the relevant gene has also not been identified. An expression cloning strategy was used to identify human kidney cDNA clones capable of reverting in transient gene expression assays the PAS+ phenotype typical of Mucolipidosis IV cells to the normal PAS- phenotype. By this method, a candidate cDNA clone (Mu cDNA) capable of clearing Mucolipidosis IV fibroblasts of their PAS+ positive storage material was isolated. Nucleotide sequence analysis indicated the presence of 2 open reading frames. In vitro translation of T7 transcribed Mu RNA showed protein products of 7,000 and 6,000 mw. Altered expression of the Mu gene may result in the onset of Mucolipidosis type IV.

  8. Missing value imputation for microarray gene expression data using histone acetylation information

    Directory of Open Access Journals (Sweden)

    Feng Jihua

    2008-05-01

    Full Text Available Abstract Background It is an important pre-processing step to accurately estimate missing values in microarray data, because complete datasets are required in numerous expression profile analysis in bioinformatics. Although several methods have been suggested, their performances are not satisfactory for datasets with high missing percentages. Results The paper explores the feasibility of doing missing value imputation with the help of gene regulatory mechanism. An imputation framework called histone acetylation information aided imputation method (HAIimpute method is presented. It incorporates the histone acetylation information into the conventional KNN(k-nearest neighbor and LLS(local least square imputation algorithms for final prediction of the missing values. The experimental results indicated that the use of acetylation information can provide significant improvements in microarray imputation accuracy. The HAIimpute methods consistently improve the widely used methods such as KNN and LLS in terms of normalized root mean squared error (NRMSE. Meanwhile, the genes imputed by HAIimpute methods are more correlated with the original complete genes in terms of Pearson correlation coefficients. Furthermore, the proposed methods also outperform GOimpute, which is one of the existing related methods that use the functional similarity as the external information. Conclusion We demonstrated that the using of histone acetylation information could greatly improve the performance of the imputation especially at high missing percentages. This idea can be generalized to various imputation methods to facilitate the performance. Moreover, with more knowledge accumulated on gene regulatory mechanism in addition to histone acetylation, the performance of our approach can be further improved and verified.

  9. Length of Selection Around Candidate Genes for Artificial Selection During Domestication and Crop Improvement in Maize

    Science.gov (United States)

    Genomic screens for artificial selection have been successful in identifying candidate genes for agronomic traits in maize (Zea mays L). However, the validity of the candidates identified requires that selection sweeps are very short, only containing the candidate gene with the nearest neighboring g...

  10. Candidate Genes Detected in Transcriptome Studies are Strongly Dependent on Genetic Background

    DEFF Research Database (Denmark)

    Sarup, Pernille Merete; Sørensen, Jesper Givskov; Kristensen, Torsten Nygård; Hoffmann, Ary Anthony; Loeschcke, Volker; Paige, Ken N; Sørensen, Peter

    2011-01-01

    Whole genome transcriptomic studies can point to potential candidate genes for organismal traits. However, the importance of potential candidates is rarely followed up through functional studies and/or by comparing results across independent studies. We have analysed the overlap of candidate gene...

  11. Computational selection and prioritization of candidate genes for Fetal Alcohol Syndrome

    Directory of Open Access Journals (Sweden)

    Hide Winston

    2007-10-01

    Full Text Available Abstract Background Fetal alcohol syndrome (FAS is a serious global health problem and is observed at high frequencies in certain South African communities. Although in utero alcohol exposure is the primary trigger, there is evidence for genetic- and other susceptibility factors in FAS development. No genome-wide association or linkage studies have been performed for FAS, making computational selection and -prioritization of candidate disease genes an attractive approach. Results 10174 Candidate genes were initially selected from the whole genome using a previously described method, which selects candidate genes according to their expression in disease-affected tissues. Hereafter candidates were prioritized for experimental investigation by investigating criteria pertinent to FAS and binary filtering. 29 Criteria were assessed by mining various database sources to populate criteria-specific gene lists. Candidate genes were then prioritized for experimental investigation using a binary system that assessed the criteria gene lists against the candidate list, and candidate genes were scored accordingly. A group of 87 genes was prioritized as candidates and for future experimental validation. The validity of the binary prioritization method was assessed by investigating the protein-protein interactions, functional enrichment and common promoter element binding sites of the top-ranked genes. Conclusion This analysis highlighted a list of strong candidate genes from the TGF-β, MAPK and Hedgehog signalling pathways, which are all integral to fetal development and potential targets for alcohol's teratogenic effect. We conclude that this novel bioinformatics approach effectively prioritizes credible candidate genes for further experimental analysis.

  12. Genetics of intracerebral hemorrhage: Insights from candidate gene approaches

    Directory of Open Access Journals (Sweden)

    Baoqiong Liu

    2012-01-01

    Full Text Available Intracerebral hemorrhage (ICH is a heterogeneous disease with genetic factors playing an important role. Association studies on a wide range of candidate pathways suggest a weak but significant effect for several alleles with ICH risk. Among the most widely investigated genes are those involved in the renin-angiotensin-aldosterone system (e.g., angiotensin-converting enzyme, coagulation pathway (e.g., Factor XIII, Factor VII, platelet-activating factor acetylhydrolase, Factor V Leiden, and beta1-tubulin, lipid metabolism (e.g., apolipoproteins (ApoE, Apo(a, ApoH, homocysteine metabolism (e.g., methylenetetrahydrofolate reductase, inflammation (e.g., interleukin-6 and tumor necrosis-alpha and other candidate pathways. To identify the robustness of the above associations with ICH, a search of Pubmed (1988 through December 2011 was performed, with searches limited to English-language studies conducted among adult human subjects. This article presents a review of the examined literature on the genetics of ICH.

  13. Kernel-imbedded Gaussian processes for disease classification using microarray gene expression data

    Directory of Open Access Journals (Sweden)

    Cheung Leo

    2007-02-01

    Full Text Available Abstract Background Designing appropriate machine learning methods for identifying genes that have a significant discriminating power for disease outcomes has become more and more important for our understanding of diseases at genomic level. Although many machine learning methods have been developed and applied to the area of microarray gene expression data analysis, the majority of them are based on linear models, which however are not necessarily appropriate for the underlying connection between the target disease and its associated explanatory genes. Linear model based methods usually also bring in false positive significant features more easily. Furthermore, linear model based algorithms often involve calculating the inverse of a matrix that is possibly singular when the number of potentially important genes is relatively large. This leads to problems of numerical instability. To overcome these limitations, a few non-linear methods have recently been introduced to the area. Many of the existing non-linear methods have a couple of critical problems, the model selection problem and the model parameter tuning problem, that remain unsolved or even untouched. In general, a unified framework that allows model parameters of both linear and non-linear models to be easily tuned is always preferred in real-world applications. Kernel-induced learning methods form a class of approaches that show promising potentials to achieve this goal. Results A hierarchical statistical model named kernel-imbedded Gaussian process (KIGP is developed under a unified Bayesian framework for binary disease classification problems using microarray gene expression data. In particular, based on a probit regression setting, an adaptive algorithm with a cascading structure is designed to find the appropriate kernel, to discover the potentially significant genes, and to make the optimal class prediction accordingly. A Gibbs sampler is built as the core of the algorithm to make

  14. GeneAnalytics: An Integrative Gene Set Analysis Tool for Next Generation Sequencing, RNAseq and Microarray Data

    Science.gov (United States)

    Ben-Ari Fuchs, Shani; Lieder, Iris; Mazor, Yaron; Buzhor, Ella; Kaplan, Sergey; Bogoch, Yoel; Plaschkes, Inbar; Shitrit, Alina; Rappaport, Noa; Kohn, Asher; Edgar, Ron; Shenhav, Liraz; Safran, Marilyn; Lancet, Doron; Guan-Golan, Yaron; Warshawsky, David; Shtrichman, Ronit

    2016-01-01

    Abstract Postgenomics data are produced in large volumes by life sciences and clinical applications of novel omics diagnostics and therapeutics for precision medicine. To move from “data-to-knowledge-to-innovation,” a crucial missing step in the current era is, however, our limited understanding of biological and clinical contexts associated with data. Prominent among the emerging remedies to this challenge are the gene set enrichment tools. This study reports on GeneAnalytics™ (geneanalytics.genecards.org), a comprehensive and easy-to-apply gene set analysis tool for rapid contextualization of expression patterns and functional signatures embedded in the postgenomics Big Data domains, such as Next Generation Sequencing (NGS), RNAseq, and microarray experiments. GeneAnalytics' differentiating features include in-depth evidence-based scoring algorithms, an intuitive user interface and proprietary unified data. GeneAnalytics employs the LifeMap Science's GeneCards suite, including the GeneCards®—the human gene database; the MalaCards—the human diseases database; and the PathCards—the biological pathways database. Expression-based analysis in GeneAnalytics relies on the LifeMap Discovery®—the embryonic development and stem cells database, which includes manually curated expression data for normal and diseased tissues, enabling advanced matching algorithm for gene–tissue association. This assists in evaluating differentiation protocols and discovering biomarkers for tissues and cells. Results are directly linked to gene, disease, or cell “cards” in the GeneCards suite. Future developments aim to enhance the GeneAnalytics algorithm as well as visualizations, employing varied graphical display items. Such attributes make GeneAnalytics a broadly applicable postgenomics data analyses and interpretation tool for translation of data to knowledge-based innovation in various Big Data fields such as precision medicine, ecogenomics, nutrigenomics

  15. Quadratic regression analysis for gene discovery and pattern recognition for non-cyclic short time-course microarray experiments

    Directory of Open Access Journals (Sweden)

    Getchell Thomas V

    2005-04-01

    Full Text Available Abstract Background Cluster analyses are used to analyze microarray time-course data for gene discovery and pattern recognition. However, in general, these methods do not take advantage of the fact that time is a continuous variable, and existing clustering methods often group biologically unrelated genes together. Results We propose a quadratic regression method for identification of differentially expressed genes and classification of genes based on their temporal expression profiles for non-cyclic short time-course microarray data. This method treats time as a continuous variable, therefore preserves actual time information. We applied this method to a microarray time-course study of gene expression at short time intervals following deafferentation of olfactory receptor neurons. Nine regression patterns have been identified and shown to fit gene expression profiles better than k-means clusters. EASE analysis identified over-represented functional groups in each regression pattern and each k-means cluster, which further demonstrated that the regression method provided more biologically meaningful classifications of gene expression profiles than the k-means clustering method. Comparison with Peddada et al.'s order-restricted inference method showed that our method provides a different perspective on the temporal gene profiles. Reliability study indicates that regression patterns have the highest reliabilities. Conclusion Our results demonstrate that the proposed quadratic regression method improves gene discovery and pattern recognition for non-cyclic short time-course microarray data. With a freely accessible Excel macro, investigators can readily apply this method to their microarray data.

  16. An improved procedure for gene selection from microarray experiments using false discovery rate criterion

    Directory of Open Access Journals (Sweden)

    Yang Mark CK

    2006-01-01

    Full Text Available Abstract Background A large number of genes usually show differential expressions in a microarray experiment with two types of tissues, and the p-values of a proper statistical test are often used to quantify the significance of these differences. The genes with small p-values are then picked as the genes responsible for the differences in the tissue RNA expressions. One key question is what should be the threshold to consider the p-values small. There is always a trade off between this threshold and the rate of false claims. Recent statistical literature shows that the false discovery rate (FDR criterion is a powerful and reasonable criterion to pick those genes with differential expression. Moreover, the power of detection can be increased by knowing the number of non-differential expression genes. While this number is unknown in practice, there are methods to estimate it from data. The purpose of this paper is to present a new method of estimating this number and use it for the FDR procedure construction. Results A combination of test functions is used to estimate the number of differentially expressed genes. Simulation study shows that the proposed method has a higher power to detect these genes than other existing methods, while still keeping the FDR under control. The improvement can be substantial if the proportion of true differentially expressed genes is large. This procedure has also been tested with good results using a real dataset. Conclusion For a given expected FDR, the method proposed in this paper has better power to pick genes that show differentiation in their expression than two other well known methods.

  17. Gene expression microarray analysis of the sciatic nerve of mice with diabetic neuropathy.

    Science.gov (United States)

    Zhang, Lei; Qu, Shen; Liang, Aibin; Jiang, Hong; Wang, Hao

    2015-02-01

    The present study aimed to explore novel target genes that regulate the development of diabetic neuropathy (DN) by analyzing gene expression profiles in the sciatic nerve of infected mice. The GSE11343 microarray dataset, which was downloaded from Gene Expression Omnibus, included data on 4 control samples and 5 samples from mice with diabetes induced by streptozotocin (STZ), 5 samples from normal mice treated with rosiglitazone (Rosi) and 5 samples from mice with diabetes induced by STZ and treated with Rosi. Differentially expressed genes (DEGs) between the different groups were identified using the substitution augmentation modification redefinition (SAMR) model. The Gene Ontology (GO) term and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses were performed using the Database for Annotation, Visualization and Integrated Discovery (DAVID). Regulatory and protein‑protein interaction networks were searched using BioCarta and STRING, respectively. The protein structures of potential regulatory genes were predicted using the SYBYL program. Compared with the controls, 1,384 DEGs were identified in the mice with STZ-induced diabetes and 7 DEGs were identified in the mice treated with Rosi. There were 518 DEGs identified between the mice in the STZ + Rosi and STZ groups. We identified 45 GO items, and the calmodulin nerve phosphatase and chemokine signaling pathways were identified as the main pathways. Three genes [myristoylated alanine-rich protein kinase C substrate (Marcks), GLI pathogenesis-related 2 (Glipr2) and centrosomal protein 170 kDa (Cep170)] were found to be co-regulated by both STZ and Rosi, the protein structure of which was predicted and certain binding activity to Rosi was docked. Our study demonstrates that the Marcks, Glipr2 and Cep170 genes may be underlying drug targets in the treatment of DN. PMID:25435094

  18. Principal components analysis based methodology to identify differentially expressed genes in time-course microarray data

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    Srinivasan Rajagopalan

    2008-06-01

    Full Text Available Abstract Background Time-course microarray experiments are being increasingly used to characterize dynamic biological processes. In these experiments, the goal is to identify genes differentially expressed in time-course data, measured between different biological conditions. These differentially expressed genes can reveal the changes in biological process due to the change in condition which is essential to understand differences in dynamics. Results In this paper, we propose a novel method for finding differentially expressed genes in time-course data and across biological conditions (say C1 and C2. We model the expression at C1 using Principal Component Analysis and represent the expression profile of each gene as a linear combination of the dominant Principal Components (PCs. Then the expression data from C2 is projected on the developed PCA model and scores are extracted. The difference between the scores is evaluated using a hypothesis test to quantify the significance of differential expression. We evaluate the proposed method to understand differences in two case studies (1 the heat shock response of wild-type and HSF1 knockout mice, and (2 cell-cycle between wild-type and Fkh1/Fkh2 knockout Yeast strains. Conclusion In both cases, the proposed method identified biologically significant genes.

  19. Microarray gene expression profiling of developmental transitions in Sitka spruce (Picea sitchensis) apical shoots.

    Science.gov (United States)

    Friedmann, Michael; Ralph, Steven G; Aeschliman, Dana; Zhuang, Jun; Ritland, Kermit; Ellis, Brian E; Bohlmann, Joerg; Douglas, Carl J

    2007-01-01

    The apical shoot drives the yearly new stem growth of conifer trees, is the primary site for the establishment of chemical and physical defences, and is important in establishing subsequent perennial growth. This organ presents an interesting developmental system, with growth and development progressing from a meristematic tip through development of a primary vascular system, to a base with fully differentiated and lignified secondary xylem on the inside and bark tissue with constitutive defence structures such as resin, polyphenolic phloem parenchyma cells, and sclereids on the outside. A spruce (Picea spp.) microarray containing approximately 16.7K unique cDNAs was used to study transcript profiles that characterize the developmental transition in apical shoots of Sitka spruce (Picea sitchensis) from their vegetative tips to their woody bases. Along with genes involved in cell-wall modification and lignin biosynthesis, a number of differentially regulated genes encoding protein kinases and transcription factors with base-preferred expression patterns were identified, which could play roles in the formation of woody tissues inside the apical shoot, as well as in regulating other developmental transitions associated with organ maturation. Preferential expression of known conifer defence genes, genes encoding defence-related proteins, and genes encoding regulatory proteins was observed at the apical shoot tip and in the green bark tissues at the apical shoot base, suggesting a commitment to constitutive defence in the apical shoot that is co-ordinated with rapid development of secondary xylem. PMID:17220514

  20. Protective Effect of Gwakhyangjeonggisan Herbal Acupuncture Solution in Glioblastoma Cells: Microarray Analysis of Gene Expression

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    Hong-Seok Lee

    2005-12-01

    Full Text Available Objectives : Neurological disorders have been one of main therapeutic targets of acupuncture. The present study investigated the protective effects of Gwakhyangjeonggisan herbal acupuncture solution (GHAS. Methods : We performed 3-(4,5-dimethylthiazol-2-yl-2,5-diphenyltetrazolium bromide (MTT assay in glioblastoma cells, and did microarray analysis with cells exposed to reactive oxigen species (ROS of hydrogen peroxide by 8.0 k Human cDNA, with cut-off level of 2-fold changes in gene expression. Results : MTT assay showed protective effect of GHAS on the glioblastoma cells exposed to hydrogen peroxide. When glioblastoma cells were exposed to hydrogen peroxide, 24 genes were downregulated. When the cells were pretreated with GHAS before exposure to hydrogen peroxide, 46 genes were downregulated. Many of the genes downregulated by hydrogen peroxide stimulation were decreased in the amount of downregulation or reversed to upregulation. Conclusions : The gene expression changes observed in the present study are supposed to be related to the protective molecular mechanism of GHAS in the glioblastoma cells exposed to ROS stress.

  1. Genomic Interspecies Microarray Hybridization: Rapid Discovery of Three Thousand Genes in the Maize Endophyte, Klebsiella pneumoniae 342, by Microarray Hybridization with Escherichia coli K-12 Open Reading Frames

    OpenAIRE

    Dong, Yuemei; Glasner, Jeremy D.; Blattner, Frederick R.; Triplett, Eric W.

    2001-01-01

    In an effort to efficiently discover genes in the diazotrophic endophyte of maize, Klebsiella pneumoniae 342, DNA from strain 342 was hybridized to a microarray containing 96% (n = 4,098) of the annotated open reading frames from Escherichia coli K-12. Using a criterion of 55% identity or greater, 3,000 (70%) of the E. coli K-12 open reading frames were also found to be present in strain 342. Approximately 24% (n = 1,030) of the E. coli K-12 open reading frames are absent in strain 342. For 1...

  2. Estimation of false discovery rates in multiple testing: application to gene microarray data.

    Science.gov (United States)

    Tsai, Chen-An; Hsueh, Huey-miin; Chen, James J

    2003-12-01

    Testing for significance with gene expression data from DNA microarray experiments involves simultaneous comparisons of hundreds or thousands of genes. If R denotes the number of rejections (declared significant genes) and V denotes the number of false rejections, then V/R, if R > 0, is the proportion of false rejected hypotheses. This paper proposes a model for the distribution of the number of rejections and the conditional distribution of V given R, V / R. Under the independence assumption, the distribution of R is a convolution of two binomials and the distribution of V / R has a noncentral hypergeometric distribution. Under an equicorrelated model, the distributions are more complex and are also derived. Five false discovery rate probability error measures are considered: FDR = E(V/R), pFDR = E(V/R / R > 0) (positive FDR), cFDR = E(V/R / R = r) (conditional FDR), mFDR = E(V)/E(R) (marginal FDR), and eFDR = E(V)/r (empirical FDR). The pFDR, cFDR, and mFDR are shown to be equivalent under the Bayesian framework, in which the number of true null hypotheses is modeled as a random variable. We present a parametric and a bootstrap procedure to estimate the FDRs. Monte Carlo simulations were conducted to evaluate the performance of these two methods. The bootstrap procedure appears to perform reasonably well, even when the alternative hypotheses are correlated (rho = .25). An example from a toxicogenomic microarray experiment is presented for illustration. PMID:14969487

  3. The Local Maximum Clustering Method and Its Application in Microarray Gene Expression Data Analysis

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    Chen Yidong

    2004-01-01

    Full Text Available An unsupervised data clustering method, called the local maximum clustering (LMC method, is proposed for identifying clusters in experiment data sets based on research interest. A magnitude property is defined according to research purposes, and data sets are clustered around each local maximum of the magnitude property. By properly defining a magnitude property, this method can overcome many difficulties in microarray data clustering such as reduced projection in similarities, noises, and arbitrary gene distribution. To critically evaluate the performance of this clustering method in comparison with other methods, we designed three model data sets with known cluster distributions and applied the LMC method as well as the hierarchic clustering method, the -mean clustering method, and the self-organized map method to these model data sets. The results show that the LMC method produces the most accurate clustering results. As an example of application, we applied the method to cluster the leukemia samples reported in the microarray study of Golub et al. (1999.

  4. Differences in gene expression between first and third trimester human placenta: a microarray study.

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    Vasilis Sitras

    Full Text Available BACKGROUND: The human placenta is a rapidly developing organ that undergoes structural and functional changes throughout the pregnancy. Our objectives were to investigate the differences in global gene expression profile, the expression of imprinted genes and the effect of smoking in first and third trimester normal human placentas. MATERIALS AND METHODS: Placental samples were collected from 21 women with uncomplicated pregnancies delivered at term and 16 healthy women undergoing termination of pregnancy at 9-12 weeks gestation. Placental gene expression profile was evaluated by Human Genome Survey Microarray v.2.0 (Applied Biosystems and real-time polymerase chain reaction. RESULTS: Almost 25% of the genes spotted on the array (n = 7519 were differentially expressed between first and third trimester placentas. Genes regulating biological processes involved in cell proliferation, cell differentiation and angiogenesis were up-regulated in the first trimester; whereas cell surface receptor mediated signal transduction, G-protein mediated signalling, ion transport, neuronal activities and chemosensory perception were up-regulated in the third trimester. Pathway analysis showed that brain and placenta might share common developmental routes. Principal component analysis based on the expression of 17 imprinted genes showed a clear separation of first and third trimester placentas, indicating that epigenetic modifications occur throughout pregnancy. In smokers, a set of genes encoding oxidoreductases were differentially expressed in both trimesters. CONCLUSIONS: Differences in global gene expression profile between first and third trimester human placenta reflect temporal changes in placental structure and function. Epigenetic rearrangements in the human placenta seem to occur across gestation, indicating the importance of environmental influence in the developing feto-placental unit.

  5. Meta-analysis of microarray data using a pathway-based approach identifies a 37-gene expression signature for systemic lupus erythematosus in human peripheral blood mononuclear cells

    OpenAIRE

    Fang Hong; Mummaneni Padmaja; Tong Weida; Arasappan Dhivya; Amur Shashi

    2011-01-01

    Abstract Background A number of publications have reported the use of microarray technology to identify gene expression signatures to infer mechanisms and pathways associated with systemic lupus erythematosus (SLE) in human peripheral blood mononuclear cells. However, meta-analysis approaches with microarray data have not been well-explored in SLE. Methods In this study, a pathway-based meta-analysis was applied to four independent gene expression oligonucleotide microarray data sets to ident...

  6. Gene set enrichment analysis of microarray data from Pimephales promelas (Rafinesque, a non-mammalian model organism

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    Klaper Rebecca D

    2011-01-01

    Full Text Available Abstract Background Methods for gene-class testing, such as Gene Set Enrichment Analysis (GSEA, incorporate biological knowledge into the analysis and interpretation of microarray data by comparing gene expression patterns to pathways, systems and emergent phenotypes. However, to use GSEA to its full capability with non-mammalian model organisms, a microarray platform must be annotated with human gene symbols. Doing so enables the ability to relate a model organism's gene expression, in response to a given treatment, to potential human health consequences of that treatment. We enhanced the annotation of a microarray platform from a non-mammalian model organism, and then used the GSEA approach in a reanalysis of a study examining the biological significance of acute and chronic methylmercury exposure on liver tissue of fathead minnow (Pimephales promelas. Using GSEA, we tested the hypothesis that fathead livers, in response to methylmercury exposure, would exhibit gene expression patterns similar to diseased human livers. Results We describe an enhanced annotation of the fathead minnow microarray platform with human gene symbols. This resource is now compatible with the GSEA approach for gene-class testing. We confirmed that GSEA, using this enhanced microarray platform, is able to recover results consistent with a previous analysis of fathead minnow exposure to methylmercury using standard analytical approaches. Using GSEA to compare fathead gene expression profiles to human phenotypes, we also found that fathead methylmercury-treated livers exhibited expression profiles that are homologous to human systems & pathways and results in damage that is similar to those of human liver damage associated with hepatocellular carcinoma and hepatitis B. Conclusions This study describes a powerful resource for enabling the use of non-mammalian model organisms in the study of human health significance. Results of microarray gene expression studies involving

  7. Integration of genomic and proteomic data to identify candidate genes in HT-29 cells after incubation with Bifidobacterium bifidum ATCC 29521.

    Science.gov (United States)

    Wang, Bao-Gui; Wu, Yaoping; Qiu, Liang; Shah, Nagendra P; Xu, Feng; Wei, Hua

    2016-09-01

    As the predominant group inhabiting the human gastrointestinal tract, bifidobacteria play a vital role in human nutrition, therapeutics, and health by shaping and maintaining the gut ecosystem, reducing blood cholesterol, and promoting the supply of nutrients. The interaction between bacterial cells and human intestinal epithelial cell lines has been studied for decades in an attempt to understand the mechanisms of action. These studies, however, have been limited by lack of genomic and proteomic database to aid in achieving comprehensive understanding of these mechanisms at molecular levels. Microarray data (GSE: 74119) coupled with isobaric tags for relative and absolute quantitation (iTRAQ) were performed to detect differentially expressed genes and proteins in HT-29 cells after incubation with Bifidobacterium bifidum. Real-time quantitative PCR, gene ontology, and Kyoto Encyclopedia of Genes and Genomes analyses were further conducted for mRNA validation, functional annotation, and pathway identification, respectively. According to the results of microarray, 1,717 differentially expressed genes, including 1,693 upregulated and 24 downregulated genes, were selected and classified by the gene ontology database. The iTRAQ analysis identified 43 differentially expressed proteins, where 29 proteins were upregulated and 14 proteins were downregulated. Eighty-two candidate genes showing consistent differences with microarray and iTRAQ were further validated in HT-29 and Caco-2 cells by real-time quantitative PCR. Nine of the top genes showing interesting results with high confidence were further investigated in vivo in mice intestine samples. Integration of genomic and proteomic data provides an approach to identify candidate genes that are more likely to function in ubiquitin-mediated proteolysis, positive regulation of apoptosis, membrane proteins, and transferase catalysis. These findings might contribute to our understanding of molecular mechanisms regulating the

  8. A meta-analysis of kidney microarray datasets: investigation of cytokine gene detection and correlation with rt-PCR and detection thresholds

    OpenAIRE

    Stegall Mark D; Park Walter D

    2007-01-01

    Abstract Background Microarrays provide a means to simultaneously examine the gene expression of the entire transcriptome in a single sample. Many studies have highlighted the need for novel software and statistical approaches to assess the measured gene expression. Less attention has been directed toward whether genes considered undetectable by microarray can be detected by other strategies or whether these genes can provide accurate gene expression determinations. In the kidney this is a co...

  9. Resolution of large and small differences in gene expression using models for the Bayesian analysis of gene expression levels and spotted DNA microarrays

    OpenAIRE

    Townsend Jeffrey P

    2004-01-01

    Abstract Background The detection of small yet statistically significant differences in gene expression in spotted DNA microarray studies is an ongoing challenge. Meeting this challenge requires careful examination of the performance of a range of statistical models, as well as empirical examination of the effect of replication on the power to resolve these differences. Results New models are derived and software is developed for the analysis of microarray ratio data. These models incorporate...

  10. Association of single nucleotide polymorphisms in candidate genes residing under quantitative trait loci in beef cattle

    Science.gov (United States)

    The objective was to assess the association of single nucleotide polymorphisms (SNP) developed on candidate genes residing under previously identified quantitative trait loci for marbling score and meat tenderness. Two hundred five SNP were identified on twenty candidate genes. Genes selected under ...

  11. Effect of Thyrotropin Releasing Hormone (TRH on Gene Expressions in Rat Pancreas: Approach by Microarray Hybridization

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    Luo LG

    2004-07-01

    Full Text Available CONTEXT: Thyrotropin releasing hormone (TRH, originally identified as a hypothalamic hormone, expresses in the pancreas. The effects of TRH such as, inhibiting amylase secretion in rats through a direct effect on acinar cells, enhancing basal glucagon secretion from isolated perfused rat pancreas, and potentiating glucose-stimulated insulin secretion in perfused rat islets and insulin-secreting clonal beta-cell lines, suggest that TRH may play a role in pancreas. TRH also enlarged pancreas and increased pancreatic DNA content but deletion of TRH gene expression caused hyperglycemia in mice, suggesting that TRH may play a critical role in pancreatic development; however, the biological mechanisms of TRH in the adult pancreas remains unclear. OBJECTIVES: This study explored the effect of TRH on rat pancreas. SUBJECTS: Four male-Sprague-Dawley-rats (200-250 g were given 10 microg/kg BW of TRH intraperitoneally on 1st and 3rd day and sacrificed on 7th day. Four same-strain rats without TRH injection served as controls. MAIN OUTCOME MEASURES: Wet pancreatic weights were measured. Pancreatic tissues were homogenized and extracted. The insulin levels of the extracts were measured by ELISA. Total RNA from the pancreases were fluorescently labeled and hybridized to microarray with 1,081 spot genes. RESULTS: TRH increased pancreatic wet weight and insulin contents. About 75% of the 1,081 genes were detected in the pancreas. TRH regulated up 99 genes and down 76 genes. The administration of TRH induced various types of gene expressions, such as G-protein coupled receptors (GPCR and signal transduction related genes (GPCR kinase 4, transducin beta subunit 5, arrestin beta1MAPK3, MAPK5, c-Src kinase, PKCs, PI3 kinase, growth factors (PDGF-B, IGF-2, IL-18, IGF-1, IL-2, IL-6, endothelin-1 and apoptotic factors (Bcl2, BAD, Bax. CONCLUSION: Reprogramming of transcriptome may be a way for TRH-regulation of pancreatic cellular functions.

  12. Feasibility of subcutaneously implanted magnetic microarrays for site specific drug and gene targeting

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    M. Babincová

    2010-01-01

    Full Text Available The magnetic nanoparticles play a crucial role as a drug carriers in the human body. The wedge like magnetic arrays creatinga strongly non-homogeneous magnetic field are considered as a useful way to focus magnetic nanoparticles functionalizedwith various drugs or genes to desired sites. The goal of this study is to develop a numerical model of drug targetingusing subcutaneously implanted magnetic microarrays. The Finite Element Method is applied to solve partial differentialequations describing electromagnetic field (Maxwell equations and motion of these particles in a given magnetic field isobtained solving set of ordinary differential equations expressed by Newton law of motion. The results are encouragingshowing the potential to target drug to the tumour cell locally, without unwanted side effects.

  13. Microarrays, Integrated Analytical Systems

    Science.gov (United States)

    Combinatorial chemistry is used to find materials that form sensor microarrays. This book discusses the fundamentals, and then proceeds to the many applications of microarrays, from measuring gene expression (DNA microarrays) to protein-protein interactions, peptide chemistry, carbodhydrate chemistry, electrochemical detection, and microfluidics.

  14. Genomic interspecies microarray hybridization: rapid discovery of three thousand genes in the maize endophyte, Klebsiella pneumoniae 342, by microarray hybridization with Escherichia coli K-12 open reading frames.

    Science.gov (United States)

    Dong, Y; Glasner, J D; Blattner, F R; Triplett, E W

    2001-04-01

    In an effort to efficiently discover genes in the diazotrophic endophyte of maize, Klebsiella pneumoniae 342, DNA from strain 342 was hybridized to a microarray containing 96% (n = 4,098) of the annotated open reading frames from Escherichia coli K-12. Using a criterion of 55% identity or greater, 3,000 (70%) of the E. coli K-12 open reading frames were also found to be present in strain 342. Approximately 24% (n = 1,030) of the E. coli K-12 open reading frames are absent in strain 342. For 1.6% (n = 68) of the open reading frames, the signal was too low to make a determination regarding the presence or absence of the gene. Genes with high identity between the two organisms are those involved in energy metabolism, amino acid metabolism, fatty acid metabolism, cofactor synthesis, cell division, DNA replication, transcription, translation, transport, and regulatory proteins. Functions that were less highly conserved included carbon compound metabolism, membrane proteins, structural proteins, putative transport proteins, cell processes such as adaptation and protection, and central intermediary metabolism. Open reading frames of E. coli K-12 with little or no identity in strain 342 included putative regulatory proteins, putative chaperones, surface structure proteins, mobility proteins, putative enzymes, hypothetical proteins, and proteins of unknown function, as well as genes presumed to have been acquired by lateral transfer from sources such as phage, plasmids, or transposons. The results were in agreement with the physiological properties of the two strains. Whole genome comparisons by genomic interspecies microarray hybridization are shown to rapidly identify thousands of genes in a previously uncharacterized bacterial genome provided that the genome of a close relative has been fully sequenced. This approach will become increasingly more useful as more full genome sequences become available. PMID:11282649

  15. Challenges in microarray class discovery: a comprehensive examination of normalization, gene selection and clustering

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    Landfors Mattias

    2010-10-01

    Full Text Available Abstract Background Cluster analysis, and in particular hierarchical clustering, is widely used to extract information from gene expression data. The aim is to discover new classes, or sub-classes, of either individuals or genes. Performing a cluster analysis commonly involve decisions on how to; handle missing values, standardize the data and select genes. In addition, pre-processing, involving various types of filtration and normalization procedures, can have an effect on the ability to discover biologically relevant classes. Here we consider cluster analysis in a broad sense and perform a comprehensive evaluation that covers several aspects of cluster analyses, including normalization. Result We evaluated 2780 cluster analysis methods on seven publicly available 2-channel microarray data sets with common reference designs. Each cluster analysis method differed in data normalization (5 normalizations were considered, missing value imputation (2, standardization of data (2, gene selection (19 or clustering method (11. The cluster analyses are evaluated using known classes, such as cancer types, and the adjusted Rand index. The performances of the different analyses vary between the data sets and it is difficult to give general recommendations. However, normalization, gene selection and clustering method are all variables that have a significant impact on the performance. In particular, gene selection is important and it is generally necessary to include a relatively large number of genes in order to get good performance. Selecting genes with high standard deviation or using principal component analysis are shown to be the preferred gene selection methods. Hierarchical clustering using Ward's method, k-means clustering and Mclust are the clustering methods considered in this paper that achieves the highest adjusted Rand. Normalization can have a significant positive impact on the ability to cluster individuals, and there are indications that

  16. Analysis of dyslexia candidate genes in the Raine cohort representing the general Australian population

    OpenAIRE

    Paracchini, S; Ang, Q W; Stanley, F J; Monaco, A. P.; Pennell, C E; Whitehouse, A J O

    2011-01-01

    Several genes have been suggested as dyslexia candidates. Some of these candidate genes have been recently shown to be associated with literacy measures in sample cohorts derived from the general population. Here, we have conducted an association study in a novel sample derived from the Australian population (the Raine cohort) to further investigate the role of dyslexia candidate genes. We analysed markers, previously reported to be associated with dyslexia, located within the MRPL19/C2ORF3, ...

  17. DNA microarray analysis of Staphylococcus aureus causing bloodstream infection: bacterial genes associated with mortality?

    Science.gov (United States)

    Blomfeldt, A; Aamot, H V; Eskesen, A N; Monecke, S; White, R A; Leegaard, T M; Bjørnholt, J V

    2016-08-01

    Providing evidence for microbial genetic determinants' impact on outcome in Staphylococcus aureus bloodstream infections (SABSI) is challenging due to the complex and dynamic microbe-host interaction. Our recent population-based prospective study reported an association between the S. aureus clonal complex (CC) 30 genotype and mortality in SABSI patients. This follow-up investigation aimed to examine the genetic profiles of the SABSI isolates and test the hypothesis that specific genetic characteristics in S. aureus are associated with mortality. SABSI isolates (n = 305) and S. aureus CC30 isolates from asymptomatic nasal carriers (n = 38) were characterised by DNA microarray analysis and spa typing. Fisher's exact test, least absolute shrinkage and selection operator (LASSO) and elastic net regressions were performed to discern within four groups defined by patient outcome and characteristics. No specific S. aureus genetic determinants were found to be associated with mortality in SABSI patients. By applying LASSO and elastic net regressions, we found evidence suggesting that agrIII and cna were positively and setC (=selX) and seh were negatively associated with S. aureus CC30 versus non-CC30 isolates. The genes chp and sak, encoding immune evasion molecules, were found in higher frequencies in CC30 SABSI isolates compared to CC30 carrier isolates, indicating a higher virulence potential. In conclusion, no specific S. aureus genes were found to be associated with mortality by DNA microarray analysis and state-of-the-art statistical analyses. The next natural step is to test the hypothesis in larger samples with higher resolution methods, like whole genome sequencing. PMID:27177754

  18. Cross-platform comparison of SYBR® Green real-time PCR with TaqMan PCR, microarrays and other gene expression measurement technologies evaluated in the MicroArray Quality Control (MAQC study

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    Dial Stacey L

    2008-07-01

    Full Text Available Abstract Background The MicroArray Quality Control (MAQC project evaluated the inter- and intra-platform reproducibility of seven microarray platforms and three quantitative gene expression assays in profiling the expression of two commercially available Reference RNA samples (Nat Biotechnol 24:1115-22, 2006. The tested microarrays were the platforms from Affymetrix, Agilent Technologies, Applied Biosystems, GE Healthcare, Illumina, Eppendorf and the National Cancer Institute, and quantitative gene expression assays included TaqMan® Gene Expression PCR Assay, Standardized (Sta RT-PCR™ and QuantiGene®. The data showed great consistency in gene expression measurements across different microarray platforms, different technologies and test sites. However, SYBR® Green real-time PCR, another common technique utilized by half of all real-time PCR users for gene expression measurement, was not addressed in the MAQC study. In the present study, we compared the performance of SYBR Green PCR with TaqMan PCR, microarrays and other quantitative technologies using the same two Reference RNA samples as the MAQC project. We assessed SYBR Green real-time PCR using commercially available RT2 Profiler™ PCR Arrays from SuperArray, containing primer pairs that have been experimentally validated to ensure gene-specificity and high amplification efficiency. Results The SYBR Green PCR Arrays exhibit good reproducibility among different users, PCR instruments and test sites. In addition, the SYBR Green PCR Arrays have the highest concordance with TaqMan PCR, and a high level of concordance with other quantitative methods and microarrays that were evaluated in this study in terms of fold-change correlation and overlap of lists of differentially expressed genes. Conclusion These data demonstrate that SYBR Green real-time PCR delivers highly comparable results in gene expression measurement with TaqMan PCR and other high-density microarrays.

  19. Comparison of molecular mechanisms of rheumatoid arthritis and osteoarthritis using gene microarrays.

    Science.gov (United States)

    Li, Hongqiang; Hao, Zhenyong; Zhao, Liqiang; Liu, Wei; Han, Yanlong; Bai, Yunxing; Wang, Jian

    2016-06-01

    The present study aimed to compare the molecular mechanisms of rheumatoid arthritis (RA) and osteoarthritis (OA). The microarray dataset no. GSE29746 was downloaded from Gene Expression Omnibus. After data pre‑processing, differential expression analysis between the RA group and the control, as well as between the OA group and the control was performed using the LIMMA package in R and differentially expressed transcripts (DETs) with |log2fold change (FC)|>1 and P<0.01 were identified. DETs screened from each disease group were then subjected to functional annotation using DAVID. Next, DETs from each group were used to construct individual interaction networks using the BIND database, followed by sub‑network mining using clusterONE. Significant functions of nodes in each sub‑network were also investigated. In total, 19 and 281 DETs were screened from the RA and OA groups, respectively, with only six common DETs. DETs from the RA and OA groups were enriched in 8 and 130 gene ontology (GO) terms, respectively, with four common GO terms, of which to were associated with phospholipase C (PLC) activity. In addition, DETs screened from the OA group were enriched in immune response‑associated GO terms, and those screened from the RA group were largely associated with biological processes linked with the cell cycle and chromosomes. Genes involved in PLC activity and its regulation were indicated to be altered in RA as well as in OA. Alterations in the expression of cell cycle‑associated genes were indicated to be linked with the occurrence of OA, while genes participating in the immune response were involved in the occurrence of RA. PMID:27082252

  20. Unique gene expression profile in osteoarthritis synovium compared with cartilage: analysis of publicly accessible microarray datasets.

    Science.gov (United States)

    Park, Robin; Ji, Jong Dae

    2016-06-01

    The purpose of this study was to identify a gene expression signature in osteoarthritis (OA) synovium and genomic pathways likely to be involved in the pathogenesis of OA. Four publicly accessible microarray studies from synovium of OA patients were integrated, and a transcriptomic and network-based meta-analysis was performed. Based on pathways according to the Kyoto Encyclopedia of Genes and Genomes, functional enrichment analysis was performed. Meta-analysis results of OA synovium were compared to two previously published studies of OA cartilage to determine the relative number of common and specific DEGs of the cartilage and synovium. According to our meta-analysis, a total of 1350 genes were found to be differentially expressed in the synovium of OA patients as compared to that of healthy controls. Pathway analysis found 41 significant pathways in the total DEGs, and 22 and 16 pathways in the upregulated and downregulated DEGs, respectively. Cell adhesion molecules and cytokine-cytokine receptor interaction were the most significant pathway in the upregulated and downregulated DEGs, respectively. Comparison of meta-analysis results of OA synovium with results of two previous studies of OA cartilage identified 85 common genes and 1632 cartilage-specific DEGs and 1265 synovium-specific DEGs in the first study; and 142 common genes, and 856 cartilage-specific DEGs and 1208 synovium-specific DEGs in the second study. Our results show a small overlap between the DEGs of the synovium compared to DEGs of the cartilage, suggesting different pathogenic mechanisms that are specific to the synovium. PMID:26942917

  1. Quantitative profiling of housekeeping and Epstein-Barr virus gene transcription in Burkitt lymphoma cell lines using an oligonucleotide microarray

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    Niggli Felix K

    2006-06-01

    Full Text Available Abstract Background The Epstein-Barr virus (EBV is associated with lymphoid malignancies, including Burkitt's lymphoma (BL, and can transform human B cells in vitro. EBV-harboring cell lines are widely used to investigate lymphocyte transformation and oncogenesis. Qualitative EBV gene expression has been extensively described, but knowledge of quantitative transcription is lacking. We hypothesized that transcription levels of EBNA1, the gene essential for EBV persistence within an infected cell, are similar in BL cell lines. Results To compare quantitative gene transcription in the BL cell lines Namalwa, Raji, Akata, Jijoye, and P3HR1, we developed an oligonucleotide microarray chip, including 17 housekeeping genes, six latent EBV genes (EBNA1, EBNA2, EBNA3A, EBNA3C, LMP1, LMP2, and four lytic EBV genes (BZLF1, BXLF2, BKRF2, BZLF2, and used the cell line B95.8 as a reference for EBV gene transcription. Quantitative polymerase chain reaction assays were used to validate microarray results. We found that transcription levels of housekeeping genes differed considerably among BL cell lines. Using a selection of housekeeping genes with similar quantitative transcription in the tested cell lines to normalize EBV gene transcription data, we showed that transcription levels of EBNA1 were quite similar in very different BL cell lines, in contrast to transcription levels of other EBV genes. As demonstrated with Akata cells, the chip allowed us to accurately measure EBV gene transcription changes triggered by treatment interventions. Conclusion Our results suggest uniform EBNA1 transcription levels in BL and that microarray profiling can reveal novel insights on quantitative EBV gene transcription and its impact on lymphocyte biology.

  2. Analysis of gene expression profile induced by EMP-1 in esophageal cancer cells using cDNA Microarray

    Institute of Scientific and Technical Information of China (English)

    Hai-Tao Wang; Jian-Ping Kong; Fang Ding; Xiu-Qin Wang; Ming-Rong Wang; Lian-Xin Liu; Min Wu; Zhi-Hua Liu

    2003-01-01

    AIM: To obtain human esophageal cancer cell EC9706 stably expressed epithelial membrane protein-1 (EMP-1) with integrated eukaryotic plasmid harboring the open reading frame (ORF) of human EMP-1, and then to study the mechanism by which EMP-1 exerts its diverse cellular action on cell proliferation and altered gene profile by exploring the effect of EMP-1.METHODS: The authors first constructed pcDNA3.1/mychis expression vector harboring the ORF of EMP-1 and then transfected it into human esophageal carcinoma cell line EC9706. The positive clones were analyzed by Western blot and RT-PCR. Moreover, the cell growth curve was observed and the cell cycle was checked by FACS technique. Using cDNA microarray technology, the authors compared the gene expression pattern in positive clones with control. To confirm the gene expression profile, semi-quantitative RT-PCR was carried out for 4 of the randomly picked differentially expressed genes. For those differentially expressed genes,classification was performed according to their function and cellular component.RESULTS: Human EMP-1 gene can be stably expressed in ECg706 cell line transfected with human EMP-1. The authors found the cell growth decreased, among which S phase was arrested and G1 phase was prolonged in the transfected positive clones. By cDNA microarray analysis, 35 genes showed an over 2.0 fold change in expression level after transfection, with 28 genes being consistently up-regulated and 7 genes being down-regulated. Among the classified genes, almost half of the induced genes (13 out of 28 genes) were related to cell signaling, cell communication and particularly to adhesion.CONCLUSION: Overexpression of human EMP-1 gene can inhibit the proliferation of EC9706 cell with S phase arrested and G1 phase prolonged. The cDNA microarray analysis suggested that EMP-1 may be one of regulators involved incell signaling, cell communication and adhesion regulators.

  3. Rapid Identification of Carbapenemase Genes in Gram-Negative Bacteria with an Oligonucleotide Microarray-Based Assay

    OpenAIRE

    Braun, Sascha D.; Monecke, Stefan; Thürmer, Alexander; Ruppelt, Antje; Makarewicz, Oliwia; Pletz, Mathias; Reißig, Annett; Slickers, Peter; Ehricht, Ralf

    2014-01-01

    Rapid molecular identification of carbapenemase genes in Gram-negative bacteria is crucial for infection control and prevention, surveillance and for epidemiological purposes. Furthermore, it may have a significant impact upon determining the appropriate initial treatment and greatly benefit for critically ill patients. A novel oligonucleotide microarray-based assay was developed to simultaneously detect genes encoding clinically important carbapenemases as well as selected extended (ESBL) an...

  4. Differential expression and prognostic significance of SOX genes in pediatric medulloblastoma and ependymoma identified by microarray analysis

    OpenAIRE

    de Bont, Judith M.; Kros, Johan M.; Passier, Monique M.C.J.; Reddingius, Roel E.; Sillevis Smitt, Peter A.E.; Luider, Theo M.; Den Boer, Monique L.; Pieters, Rob

    2008-01-01

    The objective of this study was to identify differentially expressed and prognostically important genes in pediatric medulloblastoma and pediatric ependymoma by Affymetrix microarray analysis. Among the most discriminative genes, three members of the SOX transcription factor family were differentially expressed. Both SOX4 and SOX11 were significantly overexpressed in medulloblastoma (median, 11-fold and 5-fold, respectively) compared with ependymoma and normal cerebellum. SOX9 had greater exp...

  5. Candidate genes for drought tolerance and improved productivity in rice (Oryza sativa L.)

    Indian Academy of Sciences (India)

    M S Vinod; Naveen Sharma; K Manjunatha; Adnan Kanbar; N B Prakash; H E Shashidhar

    2006-03-01

    Candidate genes are sequenced genes of known biological action involved in the development or physiology of a trait. Twenty-one putative candidate genes were designed after an exhaustive search in the public databases along with an elaborate literature survey for candidate gene products and/or regulatory sequences associated with enhanced drought resistance. The downloaded sequences were then used to design primers considering the flanking sequences as well. Polymerase chain reaction (PCR) performed on 10 diverse cultivars that involved Japonica, Indica and local accessions, revealed 12 polymorphic candidate genes. Seven polymorphic candidate genes were then utilized to genotype 148 individuals of CT9993 × IR62266 doubled haploid (DH) mapping population. The segregation data were tested for deviation from the expected Mendelian ratio (1:1) using a Chi-square test (<1%). Based on this, four candidate genes were assessed to be significant and the remaining three, as non-significant. All the significant candidate genes were biased towards CT9993, the female parent in the DH mapping population. Single-marker analysis strongly associated ( < 1%) them to different traits under both well-watered and low-moisture stress conditions. Two candidate genes, EXP15 and EXP13, were found to be associated with root number and silicon content in the stem respectively, under both well-watered and low-moisture stress conditions.

  6. Predicting the response to preoperative radiation or chemoradiation by a microarray analysis of the gene expression profiles in rectal cancer

    International Nuclear Information System (INIS)

    Preoperative radiotherapy or chemoradiotherapy (CRT) has become a standard treatment for patients with locally advanced rectal cancer. However, there is a wide spectrum of responses to preoperative CRT, ranging from none to complete. There has been intense interest in the identification of molecular biomarkers to predict the response to preoperative CRT, in order to spare potentially non-responsive patients from unnecessary treatment. However, no specific molecular biomarkers have yet been definitively proven to be predictive of the response to CRT. Instead of focusing on specific factors, microarray-based gene expression profiling technology enables the simultaneous analysis of large numbers of genes, and might therefore have immense potential for predicting the response to preoperative CRT. We herein review published studies using a microarray-based analysis to identify gene expression profiles associated with the response of rectal cancer to radiation or CRT. Although some studies have reported gene expression signatures capable of high predictive accuracy, the compositions of these signatures have differed considerably, with little gene overlap. However, considering the promising data regarding gene profiling in breast cancer, the microarray analysis could still have potential to improve the management of locally advanced rectal cancer. Increasing the number of patients analyzed for more accurate prediction and the extensive validation of predictive classifiers in prospective clinical trials are necessary before such profiling can be incorporated into future clinical practice. (author)

  7. Supplementing High-Density SNP Microarrays for Additional Coverage of Disease-Related Genes: Addiction as a Paradigm

    Energy Technology Data Exchange (ETDEWEB)

    SacconePhD, Scott F [Washington University, St. Louis; Chesler, Elissa J [ORNL; Bierut, Laura J [Washington University, St. Louis; Kalivas, Peter J [Medical College of South Carolina, Charleston; Lerman, Caryn [University of Pennsylvania; Saccone, Nancy L [Washington University, St. Louis; Uhl, George R [Johns Hopkins University; Li, Chuan-Yun [Peking University; Philip, Vivek M [ORNL; Edenberg, Howard [Indiana University; Sherry, Steven [National Center for Biotechnology Information; Feolo, Michael [National Center for Biotechnology Information; Moyzis, Robert K [Johns Hopkins University; Rutter, Joni L [National Institute of Drug Abuse

    2009-01-01

    Commercial SNP microarrays now provide comprehensive and affordable coverage of the human genome. However, some diseases have biologically relevant genomic regions that may require additional coverage. Addiction, for example, is thought to be influenced by complex interactions among many relevant genes and pathways. We have assembled a list of 486 biologically relevant genes nominated by a panel of experts on addiction. We then added 424 genes that showed evidence of association with addiction phenotypes through mouse QTL mappings and gene co-expression analysis. We demonstrate that there are a substantial number of SNPs in these genes that are not well represented by commercial SNP platforms. We address this problem by introducing a publicly available SNP database for addiction. The database is annotated using numeric prioritization scores indicating the extent of biological relevance. The scores incorporate a number of factors such as SNP/gene functional properties (including synonymy and promoter regions), data from mouse systems genetics and measures of human/mouse evolutionary conservation. We then used HapMap genotyping data to determine if a SNP is tagged by a commercial microarray through linkage disequilibrium. This combination of biological prioritization scores and LD tagging annotation will enable addiction researchers to supplement commercial SNP microarrays to ensure comprehensive coverage of biologically relevant regions.

  8. Identification of genes regulated by Wnt/β-catenin pathway and involved in apoptosis via microarray analysis

    International Nuclear Information System (INIS)

    Wnt/β-catenin pathway has critical roles in development and oncogenesis. Although significant progress has been made in understanding the downstream signaling cascade of this pathway, little is known regarding Wnt/β-catenin pathway modification of the cellular apoptosis. To identify potential genes regulated by Wnt/β-catenin pathway and involved in apoptosis, we used a stably integrated, inducible RNA interference (RNAi) vector to specific inhibit the expression and the transcriptional activity of β-catenin in HeLa cells. Meanwhile, we designed an oligonucleotide microarray covering 1384 apoptosis-related genes. Using oligonucleotide microarrays, a series of differential expression of genes was identified and further confirmed by RT-PCR. Stably integrated inducible RNAi vector could effectively suppress β-catenin expression and the transcriptional activity of β-catenin/TCF. Meanwhile, depletion of β-catenin in this manner made the cells more sensitive to apoptosis. 130 genes involved in some important cell-apoptotic pathways, such as PTEN-PI3K-AKT pathway, NF-κB pathway and p53 pathway, showed significant alteration in their expression level after the knockdown of β-catenin. Coupling RNAi knockdown with microarray and RT-PCR analyses proves to be a versatile strategy for identifying genes regulated by Wnt/β-catenin pathway and for a better understanding the role of this pathway in apoptosis. Some of the identified β-catenin/TCF directed or indirected target genes may represent excellent targets to limit tumor growth

  9. Identification of differentially-expressed genes potentially implicated in drought response in pitaya (Hylocereus undatus) by suppression subtractive hybridization and cDNA microarray analysis.

    Science.gov (United States)

    Fan, Qing-Jie; Yan, Feng-Xia; Qiao, Guang; Zhang, Bing-Xue; Wen, Xiao-Peng

    2014-01-01

    Drought is one of the most severe threats to the growth, development and yield of plant. In order to unravel the molecular basis underlying the high tolerance of pitaya (Hylocereus undatus) to drought stress, suppression subtractive hybridization (SSH) and cDNA microarray approaches were firstly combined to identify the potential important or novel genes involved in the plant responses to drought stress. The forward (drought over drought-free) and reverse (drought-free over drought) suppression subtractive cDNA libraries were constructed using in vitro shoots of cultivar 'Zihonglong' exposed to drought stress and drought-free (control). A total of 2112 clones, among which half were from either forward or reverse SSH library, were randomly picked up to construct a pitaya cDNA microarray. Microarray analysis was carried out to verify the expression fluctuations of this set of clones upon drought treatment compared with the controls. A total of 309 expressed sequence tags (ESTs), 153 from forward library and 156 from reverse library, were obtained, and 138 unique ESTs were identified after sequencing by clustering and blast analyses, which included genes that had been previously reported as responsive to water stress as well as some functionally unknown genes. Thirty six genes were mapped to 47 KEGG pathways, including carbohydrate metabolism, lipid metabolism, energy metabolism, nucleotide metabolism, and amino acid metabolism of pitaya. Expression analysis of the selected ESTs by reverse transcriptase polymerase chain reaction (RT-PCR) corroborated the results of differential screening. Moreover, time-course expression patterns of these selected ESTs further confirmed that they were closely responsive to drought treatment. Among the differentially expressed genes (DEGs), many are related to stress tolerances including drought tolerance. Thereby, the mechanism of drought tolerance of this pitaya genotype is a very complex physiological and biochemical process, in

  10. Asymmetric microarray data produces gene lists highly predictive of research literature on multiple cancer types

    OpenAIRE

    2010-01-01

    Background Much of the public access cancer microarray data is asymmetric, belonging to datasets containing no samples from normal tissue. Asymmetric data cannot be used in standard meta-analysis approaches (such as the inverse variance method) to obtain large sample sizes for statistical power enrichment. Noting that plenty of normal tissue microarray samples exist in studies not involving cancer, we investigated the viability and accuracy of an integrated microarray analysis approach based ...

  11. DNA microarray global gene expression analysis of influenza virus-infected chicken and duck cells

    Directory of Open Access Journals (Sweden)

    Suresh V. Kuchipudi

    2015-06-01

    Full Text Available The data described in this article pertain to the article by Kuchipudi et al. (2014 titled “Highly Pathogenic Avian Influenza Virus Infection in Chickens But Not Ducks Is Associated with Elevated Host Immune and Pro-inflammatory Responses” [1]. While infection of chickens with highly pathogenic avian influenza (HPAI H5N1 virus subtypes often leads to 100% mortality within 1 to 2 days, infection of ducks in contrast causes mild or no clinical signs. The rapid onset of fatal disease in chickens, but with no evidence of severe clinical symptoms in ducks, suggests underlying differences in their innate immune mechanisms. We used Chicken Genechip microarrays (Affymetrix to analyse the gene expression profiles of primary chicken and duck lung cells infected with a low pathogenic avian influenza (LPAI H2N3 virus and two HPAI H5N1 virus subtypes to understand the molecular basis of host susceptibility and resistance in chickens and ducks. Here, we described the experimental design, quality control and analysis that were performed on the data set. The data are publicly available through the Gene Expression Omnibus (GEOdatabase with accession number GSE33389, and the analysis and interpretation of these data are included in Kuchipudi et al. (2014 [1].

  12. Analyzing Multiple-Probe Microarray: Estimation and Application of Gene Expression Indexes

    KAUST Repository

    Maadooliat, Mehdi

    2012-07-26

    Gene expression index estimation is an essential step in analyzing multiple probe microarray data. Various modeling methods have been proposed in this area. Amidst all, a popular method proposed in Li and Wong (2001) is based on a multiplicative model, which is similar to the additive model discussed in Irizarry et al. (2003a) at the logarithm scale. Along this line, Hu et al. (2006) proposed data transformation to improve expression index estimation based on an ad hoc entropy criteria and naive grid search approach. In this work, we re-examined this problem using a new profile likelihood-based transformation estimation approach that is more statistically elegant and computationally efficient. We demonstrate the applicability of the proposed method using a benchmark Affymetrix U95A spiked-in experiment. Moreover, We introduced a new multivariate expression index and used the empirical study to shows its promise in terms of improving model fitting and power of detecting differential expression over the commonly used univariate expression index. As the other important content of the work, we discussed two generally encountered practical issues in application of gene expression index: normalization and summary statistic used for detecting differential expression. Our empirical study shows somewhat different findings from the MAQC project (MAQC, 2006).

  13. Characterization of ovine hepatic gene expression profiles in response to Escherichia coli lipopolysaccharide using a bovine cDNA microarray

    Directory of Open Access Journals (Sweden)

    Boermans Herman J

    2006-11-01

    Full Text Available Abstract Background During systemic gram-negative bacterial infections, lipopolysaccharide (LPS ligation to the hepatic Toll-like receptor-4 complex induces the production of hepatic acute phase proteins that are involved in the host response to infection and limit the associated inflammatory process. Identifying the genes that regulate this hepatic response to LPS in ruminants may provide insight into the pathogenesis of bacterial diseases and eventually facilitate breeding of more disease resistant animals. The objective of this research was to profile the expression of ovine hepatic genes in response to Escherichia coli LPS challenge (0, 200, 400 ng/kg using a bovine cDNA microarray and quantitative real-time PCR (qRT-PCR. Results Twelve yearling ewes were challenged iv with E. coli LPS (0, 200, 400 ng/kg and liver biopsies were collected 4–5 hours post-challenge to assess hepatic gene expression profiles by bovine cDNA microarray and qRT-PCR analyses. The expression of CD14, C3, IL12R, NRAMP1, SOD and IGFBP3 genes was down regulated, whereas the expression of ACTHR, IFNαR, CD1, MCP-1 and GH was increased during LPS challenge. With the exception of C3, qRT-PCR analysis of 7 of these genes confirmed the microarray results and demonstrated that GAPDH is not a suitable housekeeping gene in LPS challenged sheep. Conclusion We have identified several potentially important genes by bovine cDNA microarray and qRT-PCR analyses that are differentially expressed during the ovine hepatic response to systemic LPS challenge. Their potential role in regulating the inflammatory response to LPS warrants further investigation.

  14. Differential Gene Expression Reveals Candidate Genes for Drought Stress Response in Abies alba (Pinaceae)

    OpenAIRE

    David Behringer; Heike Zimmermann; Birgit Ziegenhagen; Sascha Liepelt

    2015-01-01

    Increasing drought periods as a result of global climate change pose a threat to many tree species by possibly outpacing their adaptive capabilities. Revealing the genetic basis of drought stress response is therefore implemental for future conservation strategies and risk assessment. Access to informative genomic regions is however challenging, especially for conifers, partially due to their large genomes, which puts constraints on the feasibility of whole genome scans. Candidate genes offer...

  15. Characterization of fetal cells from the maternal circulation by microarray gene expression analysis - Could the extravillous trophoblasts be a target for future cell-based non-invasive prenatal diagnosis?

    DEFF Research Database (Denmark)

    Hatt, Lotte; Brinch, Marie; Singh, Ripudaman;

    2014-01-01

    stem cell microarray analysis. Results: 39 genes were identified as candidates for unique fetal cell markers. More than half of these are genes known to be expressed in the placenta, especially in extravillous trophoblasts (EVTs). Immunohistochemical staining of placental tissue confirmed CD105...... staining in EVTs and 76% of fetal cells enriched by CD105 were found to be cytokeratin-positive. Discussion: The unique combination of mesodermal (CD105) and ectodermal (cytokeratin) markers in EVTs could be a potential marker set for cell enrichment of this cell type in maternal blood and could be the...

  16. Database of cattle candidate genes and genetic markers for milk production and mastitis

    OpenAIRE

    Ogorevc, J; Kunej, T; Razpet, A; Dovc, P

    2009-01-01

    A cattle database of candidate genes and genetic markers for milk production and mastitis has been developed to provide an integrated research tool incorporating different types of information supporting a genomic approach to study lactation, udder development and health. The database contains 943 genes and genetic markers involved in mammary gland development and function, representing candidates for further functional studies. The candidate loci were drawn on a genetic map to reveal positio...

  17. Differential expression of 114 oxidative stressrelated genes in peripheral blood mononuclear cells of acute cerebral infarction patients A gene microarray experiment

    Institute of Scientific and Technical Information of China (English)

    Jing Yang; Fei Zhong; Mingshan Ren; Jiangming Zhao

    2010-01-01

    Previous studies have focused on the analysis of single or several function-related genes in oxidative stress;however,little information is available regarding altered expression of oxidative stress-related genes in the process of ischemia-reperfusion injury from microarray experiments.The aim of the present study was to investigate the changes in cell oxidative stress-and toxicity-related gene expression utilizing microarray screening in patients with acute cerebral infarction during cerebral ischemia-reperfusion injury.Of the included 114 genes,expression was significantly upregulated in eight genes,including three heat shock protein-related genes,one oxidative and metabolic stress-related gene,one cell growth arrest/senescence related gene,two apoptosis signal-related genes,and one DNA damage and repair related gene.Expression was significantly downregulated in four genes,including one cell proliferation/cancer related gene,two oxidative and metabolic stress-related genes and one DNA damage and repair related gene.The results demonstrated that cerebral ischemia-reperfusion injury in patients with acute cerebral infarction was affected by many genes including oxidative stress-,heat shock-,DNA damage and repair-,and apoptosis signal-related genes.Therefore,it could be suggested that cerebral ischemia-reperfusion injury may be subjected to complex genetic regulation mechanisms.

  18. A hybrid gene selection approach for microarray data classification using cellular learning automata and ant colony optimization.

    Science.gov (United States)

    Vafaee Sharbaf, Fatemeh; Mosafer, Sara; Moattar, Mohammad Hossein

    2016-06-01

    This paper proposes an approach for gene selection in microarray data. The proposed approach consists of a primary filter approach using Fisher criterion which reduces the initial genes and hence the search space and time complexity. Then, a wrapper approach which is based on cellular learning automata (CLA) optimized with ant colony method (ACO) is used to find the set of features which improve the classification accuracy. CLA is applied due to its capability to learn and model complicated relationships. The selected features from the last phase are evaluated using ROC curve and the most effective while smallest feature subset is determined. The classifiers which are evaluated in the proposed framework are K-nearest neighbor; support vector machine and naïve Bayes. The proposed approach is evaluated on 4 microarray datasets. The evaluations confirm that the proposed approach can find the smallest subset of genes while approaching the maximum accuracy. PMID:27154739

  19. Microarray studies on effects of Pneumocystis carinii infection on global gene expression in alveolar macrophages

    Directory of Open Access Journals (Sweden)

    Liao Chung-Ping

    2010-04-01

    Full Text Available Abstract Background Pneumocystis pneumonia is a common opportunistic disease in AIDS patients. The alveolar macrophage is an important effector cell in the clearance of Pneumocystis organisms by phagocytosis. However, both the number and phagocytic activity of alveolar macrophages are decreased in Pneumocystis infected hosts. To understand how Pneumocystis inactivates alveolar macrophages, Affymetrix GeneChip® RG-U34A DNA microarrays were used to study the difference in global gene expression in alveolar macrophages from uninfected and Pneumocystis carinii-infected Sprague-Dawley rats. Results Analyses of genes that were affected by Pneumocystis infection showed that many functions in the cells were affected. Antigen presentation, cell-mediated immune response, humoral immune response, and inflammatory response were most severely affected, followed by cellular movement, immune cell trafficking, immunological disease, cell-to-cell signaling and interaction, cell death, organ injury and abnormality, cell signaling, infectious disease, small molecular biochemistry, antimicrobial response, and free radical scavenging. Since rats must be immunosuppressed in order to develop Pneumocystis infection, alveolar macrophages from four rats of the same sex and age that were treated with dexamethasone for the entire eight weeks of the study period were also examined. With a filter of false-discovery rate less than 0.1 and fold change greater than 1.5, 200 genes were found to be up-regulated, and 144 genes were down-regulated by dexamethasone treatment. During Pneumocystis pneumonia, 115 genes were found to be up- and 137 were down-regulated with the same filtering criteria. The top ten genes up-regulated by Pneumocystis infection were Cxcl10, Spp1, S100A9, Rsad2, S100A8, Nos2, RT1-Bb, Lcn2, RT1-Db1, and Srgn with fold changes ranging between 12.33 and 5.34; and the top ten down-regulated ones were Lgals1, Psat1, Tbc1d23, Gsta1, Car5b, Xrcc5, Pdlim1, Alcam

  20. Dickkopf-1 is an epigenetically silenced candidate tumor suppressor gene in medulloblastoma1

    OpenAIRE

    Vibhakar, Rajeev; Foltz, Greg; Yoon, Jae-Geun; Field, Lorie; Lee, Hwahyung; Ryu, Gi-Yung; Pierson, Jessica; Davidson, Beverly; Madan, Anup

    2007-01-01

    Medulloblastoma is a heterogeneous pediatric brain tumor with significant therapy-related morbidity, its five-year survival rates ranging from 30% to 70%. Improvement in diagnosis and therapy requires better understanding of medulloblastoma pathology. We used whole-genome microarray analysis to identify putative tumor suppressor genes silenced by epigenetic mechanisms in medulloblastoma. This analysis yielded 714 up-regulated genes in immortalized medulloblastoma cell line D283 on treatment w...

  1. Molecular classification of melanomas and nevi using gene expression microarray signatures and formalin-fixed and paraffin-embedded tissue.

    Science.gov (United States)

    Koh, Stephen S; Opel, Michael L; Wei, Jia-Perng J; Yau, Kenneth; Shah, Rashmi; Gorre, Mercedes E; Whitman, Eric; Shitabata, Paul K; Tao, Yong; Cochran, Alistair J; Abrishami, Payam; Binder, Scott W

    2009-04-01

    Melanoma may be difficult to identify histologically and relatively high rates of misdiagnosis leads to many malpractice claims. Currently separation of melanomas from nevi is based primarily on light microscopic interpretation of hematoxylin and eosin stained sections with limited assistance from immunohistology. To increase the accuracy of discrimination of benign and malignant melanocytic lesions we identified DNA microarray-derived gene expression profiles of different melanocytic lesions and evaluated the performance of these gene signatures as molecular diagnostic tools in the molecular classification and separation of melanomas and nevi. Melanocyte-derived cells were isolated by laser capture microdissection from 165 formalin-fixed and paraffin-embedded melanocytic nevi and melanoma tissue sections. RNA was isolated, amplified, labeled, and hybridized to a custom DNA microarray. In all 120 samples were used to identify differentially expressed genes and generate a gene expression classifier capable of distinguishing between melanomas and nevi. These classifiers were tested by the leave-one-out method and in a blinded study. RT-PCR verified the results. Unsupervised hierarchical clustering identified two distinct lesional groups that closely correlated with the histopathologically identified melanomas and nevi. Analysis of gene expression levels identified 36 significant differentially expressed genes. In comparison with nevi, melanomas expressed higher levels of genes promoting signal transduction, transcription, and cell growth. In contrast, expression of L1CAM (homolog) was reduced in melanomas relative to nevi. Genes differentially expressed in melanomas and nevi, on the basis of molecular signal, sub classified a group of unknown melanocytic lesions as melanomas or nevi and had high concordance rates with histopathology. Gene signatures established using DNA microarray gene expression profiling can distinguish melanomas from nevi, indicating the

  2. Microarray Analysis in a Cell Death Resistant Glioma Cell Line to Identify Signaling Pathways and Novel Genes Controlling Resistance and Malignancy

    International Nuclear Information System (INIS)

    Glioblastoma multiforme (GBM) is a lethal type of cancer mainly resistant to radio- and chemotherapy. Since the tumor suppressor p53 functions as a transcription factor regulating the expression of genes involved in growth inhibition, DNA repair and apoptosis, we previously assessed whether specific differences in the modulation of gene expression are responsible for the anti-tumor properties of a dominant positive p53, chimeric tumor suppressor (CTS)-1. CTS-1 is based on the sequence of p53 and designed to resist various mechanisms of inactivation which limit the activity of p53. To identify CTS-1-regulated cell death-inducing genes, we generated a CTS-1-resistant glioma cell line (229R). We used Affymetrix whole-genome microarray expression analysis to analyze alterations in gene expression and identified a variety of CTS-1 regulated genes involved in cancer-linked processes. 313 genes were differentially expressed in Adeno-CTS-1 (Ad-CTS-1)-infected and 700 genes in uninfected 229R cells compared to matching parental cells. Ingenuity Pathway Analysis (IPA) determined a variety of differentially expressed genes in Ad-CTS-1-infected cells that were members of the intracellular networks with central tumor-involved players such as nuclear factor kappa B (NF-κB), protein kinase B (PKB/AKT) or transforming growth factor beta (TGF-β). Differentially regulated genes include secreted factors as well as intracellular proteins and transcription factors regulating not only cell death, but also processes such as tumor cell motility and immunity. This work gives an overview of the pathways differentially regulated in the resistant versus parental glioma cells and might be helpful to identify candidate genes which could serve as targets to develop novel glioma specific therapy strategies

  3. Microarray Analysis in a Cell Death Resistant Glioma Cell Line to Identify Signaling Pathways and Novel Genes Controlling Resistance and Malignancy

    Energy Technology Data Exchange (ETDEWEB)

    Seznec, Janina; Naumann, Ulrike, E-mail: ulrike.naumann@uni-tuebingen.de [Laboratory of Molecular Neuro-Oncology, Department of General Neurology, Hertie-Institute for Clinical Brain Research and Center Neurology, University of Tuebingen, Otfried-Mueller-Str. 27, Tuebingen 72076 (Germany)

    2011-06-27

    Glioblastoma multiforme (GBM) is a lethal type of cancer mainly resistant to radio- and chemotherapy. Since the tumor suppressor p53 functions as a transcription factor regulating the expression of genes involved in growth inhibition, DNA repair and apoptosis, we previously assessed whether specific differences in the modulation of gene expression are responsible for the anti-tumor properties of a dominant positive p53, chimeric tumor suppressor (CTS)-1. CTS-1 is based on the sequence of p53 and designed to resist various mechanisms of inactivation which limit the activity of p53. To identify CTS-1-regulated cell death-inducing genes, we generated a CTS-1-resistant glioma cell line (229R). We used Affymetrix whole-genome microarray expression analysis to analyze alterations in gene expression and identified a variety of CTS-1 regulated genes involved in cancer-linked processes. 313 genes were differentially expressed in Adeno-CTS-1 (Ad-CTS-1)-infected and 700 genes in uninfected 229R cells compared to matching parental cells. Ingenuity Pathway Analysis (IPA) determined a variety of differentially expressed genes in Ad-CTS-1-infected cells that were members of the intracellular networks with central tumor-involved players such as nuclear factor kappa B (NF-κB), protein kinase B (PKB/AKT) or transforming growth factor beta (TGF-β). Differentially regulated genes include secreted factors as well as intracellular proteins and transcription factors regulating not only cell death, but also processes such as tumor cell motility and immunity. This work gives an overview of the pathways differentially regulated in the resistant versus parental glioma cells and might be helpful to identify candidate genes which could serve as targets to develop novel glioma specific therapy strategies.

  4. Exclusion of the PAX2 gene as a candidate gene for Crouzon craniofacial dysostosis

    Energy Technology Data Exchange (ETDEWEB)

    Preston, R.A.; Gorry, M.C. [Univ. of Pittsburgh, PA (United States); Warman, M. [Harvard Univ., Boston, MA (United States)] [and others

    1994-09-01

    Crouzon craniofacial dysostosis (CFD, MIM 123500) is an abnormality of craniofacial development characterized by premature craniosynostosis, maxillary hypoplasia, and shallow orbits. We have mapped the CFD gene locus using a candidate gene approach to a 7 centiMorgan region on chromosome 10q in three CFD families. A maximal multipoint LOD score of 12.33 was achieved for a locus 2 cM distal to the microsatellite marker D10S209. A comparison of several physical, cytogenetic, and linkage maps revealed that the cytogenetic bands, 10q25-q26, most likely contain this CFD locus. The PAX2 gene, which has been mapped near another marker which in turn has been mapped to 10q25, was analyzed as a candidate gene. PAX2 was chosen for analysis because mutations in other members of the PAX gene family have been identified with human craniofacial abnormalities (e.g. Waardenburg syndrome). A YAC contig, consisting of 5 overlapping groups and composed of 11 YACs that spans the entire 7 cM region, was assembled for PAX2 analyses. None of these YACs supported PAX2-specific amplification using primer sets for both the second and third PAX2 exons. Control amplifications for YAC vector sequences produced robust amplifications in all cases. In addition, SSCP analyses of amplification products generated from the second and third PAX2 exons and the 3{prime} untranslated region of the PAX2 gene from both affected and unaffected family members in two of the kindreds failed to reveal any polymorphisms. Although it remains theoretically possible, due to artifacts in the YAC contigs, it is unlikely that PAX2 is the CFD gene.

  5. Fine mapping and candidate gene analysis of purple pericarp gene Pb in rice (Oryza sativa L.)

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Purple rice is a type of rice with anthocyanins deposited in its grain pericarp. The rice Pb gene controlling purple pericarp character is known to be on chromosome 4, and the purple color is dominant over white color. In this study, we fine mapped the Pb gene using two F2 segregating populations, i.e. Pei'ai 64S (white) × Yunanheixiannuo (purple) and Pei'ai 64S × Chuanheinuo (purple). In the first-pass mapping, the Pb gene was located in the region downstream the SSR marker RM3820. In the fine mapping, the candidate region was saturated with InDel and CAPS markers developed specifically for this study. Eventually, the Pb gene was mapped within the 25-kb region delimited by the upstream marker RID3 and the downstream marker RID4. The delimited region contained two annotated genes, Ra and bhlh16 (TIGR Rice Genome, R.5). The former is a homologue of the Myc transcription factor Lc controlling anthocyanin biosynthesis in maize, and the latter is a homologue of the TT8 gene, which is also an Myc transcription factor gene controlling the pericarp pigmentation in Arabidopsis thaliana. Sequence analysis showed that the exon 7 of the Ra gene of Yunanheixiannuo and Chuanheinuo had a 2-bp (GT) deletion compared with those of the white rice varieties Pei'ai 64S, 9311 and Nipponbare. A CAPS marker, CAPSRa, was developed according to the GT deletion for analysis of the two F2 segregating populations and 106 rice lines. The results showed that all F2 plants with white pericarp, and all non-purple rice lines (63 white and 22 red) contained no GT deletion, but all 20 purple rice lines contained the GT deletion. These results suggested that the Ra gene may be the Pb gene and the purple pericarp characteristic of rice is caused by the GT deletion within exon 7 of the Ra gene.

  6. Identification of estrogen-regulated genes by microarray analysis of the uterus of immature rats exposed to endocrine disrupting chemicals

    Directory of Open Access Journals (Sweden)

    Leung Peter CK

    2006-09-01

    Full Text Available Abstract Environmental estrogenic compounds which bind to the estrogen receptor (ER can block or alter endogenous functions of estrogen in reproductive and developmental stages. A microarray technology is a very valuable method for the prediction of hormone-responsive activities in various gene expressions. Thus, we investigated the altered gene expression by estrogen and endocrine disruptors (EDs using microarray technology in the uterus of immature rats. In this study, the expression levels of only 555 genes (7.42% among the 7636 genes spotted on microarray chips were enhanced by more than two-fold following treatment with estradiol (E2, suggesting that direct or rapid response to E2 is widespread at the mRNA levels in these genes. In addition, elevated expression levels of the genes (over 2-fold were observed by diethylstilbestrol (DES; 9.01%, octyl-phenol (OP; 8.81%, nonyl-phenol (NP; 9.51%, bisphenol-A (BPA; 8.26% or genistein (9.97% in the uterus of immature rats. The expression levels of representative genes, i.e., calbindin-D9k (CaBP-9k; vitamin D-dependent calcium-binding protein, oxytocin, adipocyte complement related protein (MW 30 kDa, lactate dehydrogenase A and calcium binding protein A6 (S100a6; calcyclin, were confirmed in these tissues by real-time PCR. In addition, the mRNA levels of these genes by real-time PCR were increased at follicular phase when E2 level was elevated during estrous cycle of adult female rats. In conclusion, these results indicate distinct altered expression of responsive genes following exposure to E2 and estrogenic compounds, and implicate distinct effects of endogenous E2 and environmental endocrine disrupting chemicals in the uterus of immature rats.

  7. Hyperspectral microarray scanning: impact on the accuracy and reliability of gene expression data

    Directory of Open Access Journals (Sweden)

    Martinez M Juanita

    2005-05-01

    Full Text Available Abstract Background Commercial microarray scanners and software cannot distinguish between spectrally overlapping emission sources, and hence cannot accurately identify or correct for emissions not originating from the labeled cDNA. We employed our hyperspectral microarray scanner coupled with multivariate data analysis algorithms that independently identify and quantitate emissions from all sources to investigate three artifacts that reduce the accuracy and reliability of microarray data: skew toward the green channel, dye separation, and variable background emissions. Results Here we demonstrate that several common microarray artifacts resulted from the presence of emission sources other than the labeled cDNA that can dramatically alter the accuracy and reliability of the array data. The microarrays utilized in this study were representative of a wide cross-section of the microarrays currently employed in genomic research. These findings reinforce the need for careful attention to detail to recognize and subsequently eliminate or quantify the presence of extraneous emissions in microarray images. Conclusion Hyperspectral scanning together with multivariate analysis offers a unique and detailed understanding of the sources of microarray emissions after hybridization. This opportunity to simultaneously identify and quantitate contaminant and background emissions in microarrays markedly improves the reliability and accuracy of the data and permits a level of quality control of microarray emissions previously unachievable. Using these tools, we can not only quantify the extent and contribution of extraneous emission sources to the signal, but also determine the consequences of failing to account for them and gain the insight necessary to adjust preparation protocols to prevent such problems from occurring.

  8. Accuracy of cDNA microarray methods to detect small gene expression changes induced by neuregulin on breast epithelial cells

    Directory of Open Access Journals (Sweden)

    Ahmed Sharlin

    2004-07-01

    Full Text Available Abstract Background cDNA microarrays are a powerful means to screen for biologically relevant gene expression changes, but are often limited by their ability to detect small changes accurately due to "noise" from random and systematic errors. While experimental designs and statistical analysis methods have been proposed to reduce these errors, few studies have tested their accuracy and ability to identify small, but biologically important, changes. Here, we have compared two cDNA microarray experimental design methods with northern blot confirmation to reveal changes in gene expression that could contribute to the early antiproliferative effects of neuregulin on MCF10AT human breast epithelial cells. Results We performed parallel experiments on identical samples using a dye-swap design with ANOVA and an experimental design that excludes systematic biases by "correcting" experimental/control hybridization ratios with control/control hybridizations on a spot-by-spot basis. We refer to this approach as the "control correction method" (CCM. Using replicate arrays, we identified a decrease in proliferation genes and an increase in differentiation genes. Using an arbitrary cut-off of 1.7-fold and p values Conclusions We validated two experimental design paradigms for cDNA microarray experiments capable of detecting small (

  9. Single-cell multiple gene expression analysis based on single-molecule-detection microarray assay for multi-DNA determination

    Energy Technology Data Exchange (ETDEWEB)

    Li, Lu [School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100 (China); Wang, Xianwei [School of Life Sciences, Shandong University, Jinan 250100 (China); Zhang, Xiaoli [School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100 (China); Wang, Jinxing [School of Life Sciences, Shandong University, Jinan 250100 (China); Jin, Wenrui, E-mail: jwr@sdu.edu.cn [School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100 (China)

    2015-01-07

    Highlights: • A single-molecule-detection (SMD) microarray for 10 samples is fabricated. • The based-SMD microarray assay (SMA) can determine 8 DNAs for each sample. • The limit of detection of SMA is as low as 1.3 × 10{sup −16} mol L{sup −1}. • The SMA can be applied in single-cell multiple gene expression analysis. - Abstract: We report a novel ultra-sensitive and high-selective single-molecule-detection microarray assay (SMA) for multiple DNA determination. In the SMA, a capture DNA (DNAc) microarray consisting of 10 subarrays with 9 spots for each subarray is fabricated on a silanized glass coverslip as the substrate. On the subarrays, the spot-to-spot spacing is 500 μm and each spot has a diameter of ∼300 μm. The sequence of the DNAcs on the 9 spots of a subarray is different, to determine 8 types of target DNAs (DNAts). Thus, 8 types of DNAts are captured to their complementary DNAcs at 8 spots of a subarray, respectively, and then labeled with quantum dots (QDs) attached to 8 types of detection DNAs (DNAds) with different sequences. The ninth spot is used to detect the blank value. In order to determine the same 8 types of DNAts in 10 samples, the 10 DNAc-modified subarrays on the microarray are identical. Fluorescence single-molecule images of the QD-labeled DNAts on each spot of the subarray are acquired using a home-made single-molecule microarray reader. The amounts of the DNAts are quantified by counting the bright dots from the QDs. For a microarray, 8 types of DNAts in 10 samples can be quantified in parallel. The limit of detection of the SMA for DNA determination is as low as 1.3 × 10{sup −16} mol L{sup −1}. The SMA for multi-DNA determination can also be applied in single-cell multiple gene expression analysis through quantification of complementary DNAs (cDNAs) corresponding to multiple messenger RNAs (mRNAs) in single cells. To do so, total RNA in single cells is extracted and reversely transcribed into their cDNAs. Three

  10. Single-cell multiple gene expression analysis based on single-molecule-detection microarray assay for multi-DNA determination

    International Nuclear Information System (INIS)

    Highlights: • A single-molecule-detection (SMD) microarray for 10 samples is fabricated. • The based-SMD microarray assay (SMA) can determine 8 DNAs for each sample. • The limit of detection of SMA is as low as 1.3 × 10−16 mol L−1. • The SMA can be applied in single-cell multiple gene expression analysis. - Abstract: We report a novel ultra-sensitive and high-selective single-molecule-detection microarray assay (SMA) for multiple DNA determination. In the SMA, a capture DNA (DNAc) microarray consisting of 10 subarrays with 9 spots for each subarray is fabricated on a silanized glass coverslip as the substrate. On the subarrays, the spot-to-spot spacing is 500 μm and each spot has a diameter of ∼300 μm. The sequence of the DNAcs on the 9 spots of a subarray is different, to determine 8 types of target DNAs (DNAts). Thus, 8 types of DNAts are captured to their complementary DNAcs at 8 spots of a subarray, respectively, and then labeled with quantum dots (QDs) attached to 8 types of detection DNAs (DNAds) with different sequences. The ninth spot is used to detect the blank value. In order to determine the same 8 types of DNAts in 10 samples, the 10 DNAc-modified subarrays on the microarray are identical. Fluorescence single-molecule images of the QD-labeled DNAts on each spot of the subarray are acquired using a home-made single-molecule microarray reader. The amounts of the DNAts are quantified by counting the bright dots from the QDs. For a microarray, 8 types of DNAts in 10 samples can be quantified in parallel. The limit of detection of the SMA for DNA determination is as low as 1.3 × 10−16 mol L−1. The SMA for multi-DNA determination can also be applied in single-cell multiple gene expression analysis through quantification of complementary DNAs (cDNAs) corresponding to multiple messenger RNAs (mRNAs) in single cells. To do so, total RNA in single cells is extracted and reversely transcribed into their cDNAs. Three types of c

  11. Identification of Candidate Genes related to Bovine Marbling using Protein-Protein Interaction Networks

    OpenAIRE

    Lim, Dajeong; Kim, Nam-Kuk; Park, Hye-Sun; Lee, Seung-Hwan; Cho, Yong-Min; Oh, Sung Jong; Kim, Tae-Hun; Kim, Heebal

    2011-01-01

    Complex traits are determined by the combined effects of many loci and are affected by gene networks or biological pathways. Systems biology approaches have an important role in the identification of candidate genes related to complex diseases or traits at the system level. The present study systemically analyzed genes associated with bovine marbling score and identified their relationships. The candidate nodes were obtained using MedScan text-mining tools and linked by protein-protein intera...

  12. Identification of candidate methylation-responsive genes in ovarian cancer

    Directory of Open Access Journals (Sweden)

    Dickerson Erin B

    2007-01-01

    Full Text Available Abstract Background Aberrant methylation of gene promoter regions has been linked to changes in gene expression in cancer development and progression. Genes associated with CpG islands (CGIs are especially prone to methylation, but not all CGI-associated genes display changes in methylation patterns in cancers. Results In order to identify genes subject to regulation by methylation, we conducted gene expression profile analyses of an ovarian cancer cell line (OVCAR-3 before and after treatment with the demethylating agent 5-aza-deoxycytidine (5-aza-dC. An overlapping subset of these genes was found to display significant differences in gene expression between normal ovarian surface epithelial cells and malignant cells isolated from ovarian carcinomas. While 40% of all human genes are associated with CGIs, > 94% of the overlapping subset of genes is associated with CGIs. The predicted change in methylation status of genes randomly selected from the overlapping subset was experimentally verified. Conclusion We conclude that correlating genes that are upregulated in response to 5-aza-dC treatment of cancer cell lines with genes that are down-regulated in cancer cells may be a useful method to identify genes experiencing epigenetic-mediated changes in expression over cancer development.

  13. In Silico Analysis of Microarray-Based Gene Expression Profiles Predicts Tumor Cell Response to Withanolides

    Directory of Open Access Journals (Sweden)

    Thomas Efferth

    2012-05-01

    Full Text Available Withania somnifera (L. Dunal (Indian ginseng, winter cherry, Solanaceae is widely used in traditional medicine. Roots are either chewed or used to prepare beverages (aqueous decocts. The major secondary metabolites of Withania somnifera are the withanolides, which are C-28-steroidal lactone triterpenoids. Withania somnifera extracts exert chemopreventive and anticancer activities in vitro and in vivo. The aims of the present in silico study were, firstly, to investigate whether tumor cells develop cross-resistance between standard anticancer drugs and withanolides and, secondly, to elucidate the molecular determinants of sensitivity and resistance of tumor cells towards withanolides. Using IC50 concentrations of eight different withanolides (withaferin A, withaferin A diacetate, 3-azerininylwithaferin A, withafastuosin D diacetate, 4-B-hydroxy-withanolide E, isowithanololide E, withafastuosin E, and withaperuvin and 19 established anticancer drugs, we analyzed the cross-resistance profile of 60 tumor cell lines. The cell lines revealed cross-resistance between the eight withanolides. Consistent cross-resistance between withanolides and nitrosoureas (carmustin, lomustin, and semimustin was also observed. Then, we performed transcriptomic microarray-based COMPARE and hierarchical cluster analyses of mRNA expression to identify mRNA expression profiles predicting sensitivity or resistance towards withanolides. Genes from diverse functional groups were significantly associated with response of tumor cells to withaferin A diacetate, e.g. genes functioning in DNA damage and repair, stress response, cell growth regulation, extracellular matrix components, cell adhesion and cell migration, constituents of the ribosome, cytoskeletal organization and regulation, signal transduction, transcription factors, and others.

  14. Identification of candidate B-lymphoma genes by cross-species gene expression profiling.

    Directory of Open Access Journals (Sweden)

    Van S Tompkins

    Full Text Available Comparative genome-wide expression profiling of malignant tumor counterparts across the human-mouse species barrier has a successful track record as a gene discovery tool in liver, breast, lung, prostate and other cancers, but has been largely neglected in studies on neoplasms of mature B-lymphocytes such as diffuse large B cell lymphoma (DLBCL and Burkitt lymphoma (BL. We used global gene expression profiles of DLBCL-like tumors that arose spontaneously in Myc-transgenic C57BL/6 mice as a phylogenetically conserved filter for analyzing the human DLBCL transcriptome. The human and mouse lymphomas were found to have 60 concordantly deregulated genes in common, including 8 genes that Cox hazard regression analysis associated with overall survival in a published landmark dataset of DLBCL. Genetic network analysis of the 60 genes followed by biological validation studies indicate FOXM1 as a candidate DLBCL and BL gene, supporting a number of studies contending that FOXM1 is a therapeutic target in mature B cell tumors. Our findings demonstrate the value of the "mouse filter" for genomic studies of human B-lineage neoplasms for which a vast knowledge base already exists.

  15. Meta-analysis of multiple microarray datasets reveals a common gene signature of metastasis in solid tumors

    OpenAIRE

    Hilsenbeck Susan G; Daves Marla H; Lau Ching C; Man Tsz-Kwong

    2011-01-01

    Abstract Background Metastasis is the number one cause of cancer deaths. Expression microarrays have been widely used to study metastasis in various types of cancer. We hypothesize that a meta-analysis of publicly available gene expression datasets in various tumor types can identify a signature of metastasis that is common to multiple tumor types. This common signature of metastasis may help us to understand the shared steps in the metastatic process and identify useful biomarkers that could...

  16. Novel candidate targets of beta-catenin/T-cell factor signaling identified by gene expression profiling of ovarian endometrioid adenocarcinomas.

    Science.gov (United States)

    Schwartz, Donald R; Wu, Rong; Kardia, Sharon L R; Levin, Albert M; Huang, Chiang-Ching; Shedden, Kerby A; Kuick, Rork; Misek, David E; Hanash, Samir M; Taylor, Jeremy M G; Reed, Heather; Hendrix, Neali; Zhai, Yali; Fearon, Eric R; Cho, Kathleen R

    2003-06-01

    The activity of beta-catenin (beta-cat), a key component of the Wnt signaling pathway, is deregulated in about 40% of ovarian endometrioid adenocarcinomas (OEAs), usually as a result of CTNNB1 gene mutations. The function of beta-cat in neoplastic transformation is dependent on T-cell factor (TCF) transcription factors, but specific genes activated by the interaction of beta-cat with TCFs in OEAs and other cancers with Wnt pathway defects are largely unclear. As a strategy to identify beta-cat/TCF transcriptional targets likely to contribute to OEA pathogenesis, we used oligonucleotide microarrays to compare gene expression in primary OEAs with mutational defects in beta-cat regulation (n = 11) to OEAs with intact regulation of beta-cat activity (n = 17). Both hierarchical clustering and principal component analysis based on global gene expression distinguished beta-cat-defective tumors from those with intact beta-cat regulation. We identified 81 potential beta-cat/TCF targets by selecting genes with at least 2-fold increased expression in beta-cat-defective versus beta-cat regulation-intact tumors and significance in a t test (P CST1 and EDN3, reporter and chromatin immunoprecipitation assays directly implicated beta-cat and TCF in their regulation. Analysis of presumptive regulatory elements in 67 of the 81 candidate genes for which complete genomic sequence data were available revealed an apparent difference in the location and abundance of consensus TCF-binding sites compared with the patterns seen in control genes. Our findings imply that analysis of gene expression profiling data from primary tumor samples annotated with detailed molecular information may be a powerful approach to identify key downstream targets of signaling pathways defective in cancer cells. PMID:12782598

  17. EXONSAMPLER: a computer program for genome-wide and candidate gene exon sampling for targeted next-generation sequencing.

    Science.gov (United States)

    Cosart, Ted; Beja-Pereira, Albano; Luikart, Gordon

    2014-11-01

    The computer program EXONSAMPLER automates the sampling of thousands of exon sequences from publicly available reference genome sequences and gene annotation databases. It was designed to provide exon sequences for the efficient, next-generation gene sequencing method called exon capture. The exon sequences can be sampled by a list of gene name abbreviations (e.g. IFNG, TLR1), or by sampling exons from genes spaced evenly across chromosomes. It provides a list of genomic coordinates (a bed file), as well as a set of sequences in fasta format. User-adjustable parameters for collecting exon sequences include a minimum and maximum acceptable exon length, maximum number of exonic base pairs (bp) to sample per gene, and maximum total bp for the entire collection. It allows for partial sampling of very large exons. It can preferentially sample upstream (5 prime) exons, downstream (3 prime) exons, both external exons, or all internal exons. It is written in the Python programming language using its free libraries. We describe the use of EXONSAMPLER to collect exon sequences from the domestic cow (Bos taurus) genome for the design of an exon-capture microarray to sequence exons from related species, including the zebu cow and wild bison. We collected ~10% of the exome (~3 million bp), including 155 candidate genes, and ~16,000 exons evenly spaced genomewide. We prioritized the collection of 5 prime exons to facilitate discovery and genotyping of SNPs near upstream gene regulatory DNA sequences, which control gene expression and are often under natural selection. PMID:24751285

  18. Identification of two genes potentially associated in iron-heme homeostasis in human carotid plaque using microarray analysis

    Indian Academy of Sciences (India)

    Hanène Ayari; Giampiero Bricca

    2013-06-01

    Classic characteristics are poor predictors of the risk of thromboembolism. Thus, better markers for the carotid atheroma plaque formation and symptom causing are needed. Our objective was to study by microarray analysis gene expression of genes involved in homeostasis of iron and heme in carotid atheroma plaque from the same patient. mRNA gene expression was measured by an Affymetrix GeneChip Human Gene 1.0 ST arrays (Affymetrix, Santa Clara, CA, USA) using RNA prepared from 68 specimens of endarteriectomy from 34 patients. Two genes involved in iron-heme homeostasis, CD163 and heme oxygenase (HO-1), were analysed in 34 plaques. CD163 (2.18, =1.45E−08) and HO-1 (fold-change 2.67, =2.07E−09) mRNAs were induced. We suggest that atheroma plaques show a more pronounced induction of CD163 and HO-1. Although further evidence is needed, our results support previous data. To our knowledge, this is the first report comparing gene expression between intact arterial tissue and carotid plaque using microarray analysis.

  19. Transcriptome network analysis reveals candidate genes for renal cell carcinoma

    OpenAIRE

    Wei Zhai; Yun-Fei Xu; Min Liu; Jun-Hua Zheng

    2012-01-01

    Context: Renal cell carcinoma (RCC) is a kidney cancer that originates in renal parenchyma and it is the most common type of kidney cancer with approximately 80% lethal cases. Aims: To interpret the mechanism, explore the regulation of TF-target genes and TF-pathway, and identify the potential key genes of renal cell carcinoma. Settings and Design: After constructing a regulation network from differently expressed genes and transcription factors, pathway regulation network and gene onto...

  20. Gene expression profiling of whole blood: Comparison of target preparation methods for accurate and reproducible microarray analysis

    Directory of Open Access Journals (Sweden)

    Choi Dongseok

    2009-01-01

    Full Text Available Abstract Background Peripheral blood is an accessible and informative source of transcriptomal information for many human disease and pharmacogenomic studies. While there can be significant advantages to analyzing RNA isolated from whole blood, particularly in clinical studies, the preparation of samples for microarray analysis is complicated by the need to minimize artifacts associated with highly abundant globin RNA transcripts. The impact of globin RNA transcripts on expression profiling data can potentially be reduced by using RNA preparation and labeling methods that remove or block globin RNA during the microarray assay. We compared four different methods for preparing microarray hybridization targets from human whole blood collected in PAXGene tubes. Three of the methods utilized the Affymetrix one-cycle cDNA synthesis/in vitro transcription protocol but varied treatment of input RNA as follows: i. no treatment; ii. treatment with GLOBINclear; or iii. treatment with globin PNA oligos. In the fourth method cDNA targets were prepared with the Ovation amplification and labeling system. Results We find that microarray targets generated with labeling methods that reduce globin mRNA levels or minimize the impact of globin transcripts during hybridization detect more transcripts in the microarray assay compared with the standard Affymetrix method. Comparison of microarray results with quantitative PCR analysis of a panel of genes from the NF-kappa B pathway shows good correlation of transcript measurements produced with all four target preparation methods, although method-specific differences in overall correlation were observed. The impact of freezing blood collected in PAXGene tubes on data reproducibility was also examined. Expression profiles show little or no difference when RNA is extracted from either fresh or frozen blood samples. Conclusion RNA preparation and labeling methods designed to reduce the impact of globin mRNA transcripts can

  1. Gene expression microarray analysis of the spinal trigeminal nucleus in a rat model of migraine with aura

    Institute of Scientific and Technical Information of China (English)

    Ruozhuo Liu; Shengyuan Yu; Fengpeng Li; Enchao Qiu

    2012-01-01

    Cortical spreading depression can trigger migraine with aura and activate the trigeminal vascular system. To examine gene expression profiles in the spinal trigeminal nucleus in rats following cortical spreading depression-induced migraine with aura, a rat model was established by injection of 1 M potassium chloride, which induced cortical spreading depression. DNA microarray analysis revealed that, compared with the control group, the cortical spreading depression group showed seven upregulated genes-myosin heavy chain 1/2, myosin light chain 1, myosin light chain (phosphorylatable, fast skeletal muscle), actin alpha 1, homeobox B8, carbonic anhydrase 3 and an unknown gene. Two genes were downregulated-RGD1563441 and an unknown gene. Real-time quantitative reverse transcription-PCR and bioinformatics analysis indicated that these genes are involved in motility, cell migration, CO2 /nitric oxide homeostasis and signal transduction.

  2. Identification of late O{sub 3}-responsive genes in Arabidopsis thaliana by cDNA microarray analysis

    Energy Technology Data Exchange (ETDEWEB)

    D' Haese, D. [Univ. of Antwerp, Dept. of Biology, Antwerp (BE) and Univ. of Newcastle, School of Biology and Psychology, Div. of Biology, Newcastle-Upon-Tyne (United Kingdom); Horemans, N.; Coen, W. De; Guisez, Y. [Univ. of Antwerp, Dept. of Biology, Antwerp (Belgium)

    2006-09-15

    To better understand the response of a plant to 0{sub 3} stress, an integrated microarray analysis was performed on Arabidopsis plants exposed during 2 days to purified air or 150 nl l{sup -1} O{sub 3}, 8 h day-l. Agilent Arabidopsis 2 Oligo Microarrays were used of which the reliability was confirmed by quantitative real-time PCR of nine randomly selected genes. We confirmed the O{sub 3} responsiveness of heat shock proteins (HSPs), glutathione-S-tranferases and genes involved in cell wall stiffening and microbial defence. Whereas, a previous study revealed that during an early stage of the O{sub 3} stress response, gene expression was strongly dependent on jasmonic acid and ethylene, we report that at a later stage (48 h) synthesis of jasrnonic acid and ethylene was downregulated. In addition, we observed the simultaneous induction of salicylic acid synthesis and genes involved in programmed cell death and senescence. Also typically, the later stage of the response to O{sub 3} appeared to be the induction of the complete pathway leading to the biosynthesis of anthocyanin diglucosides and the induction of thioredoxin-based redox control. Surprisingly absent in the list of induced genes were genes involved in ASC-dependent antioxidation, few of which were found to be induced after 12 h of 0{sub 3} exposure in another study. We discuss these and other particular results of the microarray analysis and provide a map depicting significantly affected genes and their pathways highlighting their interrelationships and subcellular localization. (au)

  3. Difference in gene expression of macrophage between normal spleen and portal hypertensive spleen idendified by cDNA microarray

    Institute of Scientific and Technical Information of China (English)

    Feng Yan; Xiao-Min Wang

    2007-01-01

    AIM: To identify the difference in gene expression of microphage (Mφ) between normal spleen and portal hypertensive spleen using cDNA microarrays and find new gene functions associated with hypersplenism in portal hypertension.METHODS: The Biostar-H140s chip containing 14112 spots of cDNAs were used to investigate the difference of the expression. The total RNA extracted from macrophages isolated from both normal spleen and portal hypertensive spleen was reversely transcribed to cDNA with the incorporation of fluorescent (cy3 and cy5) labeled dCTP to prepare the hybridization probes.After hybridization, the gene chip was scanned for the fluorescent intensity. The differentially expressed genes were screened. That was repeated three times,and only the genes which had differential expression in all three chips were considered to be associated with hypersplenism in portal hypertension.RESULTS: Eight hundred and ninety-six, 1330 and 898 genes were identified to be differentially expressed in three chips, respectively. One hundred and twenty-one genes (0.86%) were identified to be differentially expressed in all three chips, including 21 up-regulated genes and 73 down-regulated genes. The differentially expressed genes were related to ionic channel and transport protein, cyclin, cytoskeleton, cell receptor, cell signal conduct, metabolism, immune, and so on. These genes might be related to the hypersplenism in portal hypertension.CONCLUSION: The investigations based on cDNA microarray can screen differentially expressed genes of macrophages between normal spleen and portal hypertensive spleen, thus may provide a new idea in studying the pathogenesis of hypersplenism in portal hypertension.

  4. Genetics of human longevity with emphasis on the relevance of HSP70 as candidate genes

    DEFF Research Database (Denmark)

    Singh, Ripudaman; Kølvrå, Steen; Rattan, Suresh I S

    2007-01-01

    mechanisms. One such pathway includes the battery of stress response genes, especially the heat shock protein HSP70 genes. Three such genes, HSPA1A, HSPA1B and HSPA1L, are present within the MHC-III region on the short arm of chromosome 6. We and others have found alleles, genotypes and haplotypes which have...... heat shock. Stress response genes, particularly HSP70, are now the major candidates in the gene-longevity association studies....

  5. Molecular Evolution of Candidate Genes for Crop-Related Traits in Sunflower (Helianthus annuus L.)

    OpenAIRE

    Mandel, Jennifer R.; McAssey, Edward V.; Nambeesan, Savithri; García-Navarro, Elena; Burke, John M.

    2014-01-01

    Evolutionary analyses aimed at detecting the molecular signature of selection during crop domestication and/or improvement can be used to identify genes or genomic regions of likely agronomic importance. Here, we describe the DNA sequence-based characterization of a pool of candidate genes for crop-related traits in sunflower. These genes, which were identified based on homology to genes of known effect in other study systems, were initially sequenced from a panel of improved lines. All genes...

  6. Expression of the dyslexia candidate gene kiaa0319-like in insect cells

    NARCIS (Netherlands)

    Holster, S.; Oers, van M.M.; Roode, E.C.; Tsang, O.W.H.; Yeung, V.S.Y.; Vlak, J.M.; Waye, M.M.Y.

    2013-01-01

    The human kiaa0319-like gene is one of the candidate genes for developmental dyslexia, but the exact function of the encoded KIAA0319L (KL) protein is not known. To allow functional analysis a purified, biologically active KL protein is required. The kiaa0319-like gene was expressed in insect cells

  7. A Latent Variable Approach for Meta-Analysis of Gene Expression Data from Multiple Microarray Experiments

    OpenAIRE

    Chinnaiyan Arul M.; Shen Ronglai; Choi Hyungwon; Ghosh Debashis

    2007-01-01

    Abstract Background With the explosion in data generated using microarray technology by different investigators working on similar experiments, it is of interest to combine results across multiple studies. Results In this article, we describe a general probabilistic framework for combining high-throughput genomic data from several related microarray experiments using mixture models. A key feature of the model is the use of latent variables that represent quantities that can be combined across...

  8. Epidermal growth factor gene is a newly identified candidate gene for gout.

    Science.gov (United States)

    Han, Lin; Cao, Chunwei; Jia, Zhaotong; Liu, Shiguo; Liu, Zhen; Xin, Ruosai; Wang, Can; Li, Xinde; Ren, Wei; Wang, Xuefeng; Li, Changgui

    2016-01-01

    Chromosome 4q25 has been identified as a genomic region associated with gout. However, the associations of gout with the genes in this region have not yet been confirmed. Here, we performed two-stage analysis to determine whether variations in candidate genes in the 4q25 region are associated with gout in a male Chinese Han population. We first evaluated 96 tag single nucleotide polymorphisms (SNPs) in eight inflammatory/immune pathway- or glucose/lipid metabolism-related genes in the 4q25 region in 480 male gout patients and 480 controls. The SNP rs12504538, located in the elongation of very-long-chain-fatty-acid-like family member 6 gene (Elovl6), was found to be associated with gout susceptibility (Padjusted = 0.00595). In the second stage of analysis, we performed fine mapping analysis of 93 tag SNPs in Elovl6 and in the epidermal growth factor gene (EGF) and its flanking regions in 1017 male patients gout and 1897 healthy male controls. We observed a significant association between the T allele of EGF rs2298999 and gout (odds ratio = 0.77, 95% confidence interval = 0.67-0.88, Padjusted = 6.42 × 10(-3)). These results provide the first evidence for an association between the EGF rs2298999 C/T polymorphism and gout. Our findings should be validated in additional populations. PMID:27506295

  9. Identification of self-consistent modulons from bacterial microarray expression data with the help of structured regulon gene sets

    KAUST Repository

    Permina, Elizaveta A.

    2013-01-01

    Identification of bacterial modulons from series of gene expression measurements on microarrays is a principal problem, especially relevant for inadequately studied but practically important species. Usage of a priori information on regulatory interactions helps to evaluate parameters for regulatory subnetwork inference. We suggest a procedure for modulon construction where a seed regulon is iteratively updated with genes having expression patterns similar to those for regulon member genes. A set of genes essential for a regulon is used to control modulon updating. Essential genes for a regulon were selected as a subset of regulon genes highly related by different measures to each other. Using Escherichia coli as a model, we studied how modulon identification depends on the data, including the microarray experiments set, the adopted relevance measure and the regulon itself. We have found that results of modulon identification are highly dependent on all parameters studied and thus the resulting modulon varies substantially depending on the identification procedure. Yet, modulons that were identified correctly displayed higher stability during iterations, which allows developing a procedure for reliable modulon identification in the case of less studied species where the known regulatory interactions are sparse. Copyright © 2013 Taylor & Francis.

  10. Discovering biological progression underlying microarray samples.

    Directory of Open Access Journals (Sweden)

    Peng Qiu

    2011-04-01

    Full Text Available In biological systems that undergo processes such as differentiation, a clear concept of progression exists. We present a novel computational approach, called Sample Progression Discovery (SPD, to discover patterns of biological progression underlying microarray gene expression data. SPD assumes that individual samples of a microarray dataset are related by an unknown biological process (i.e., differentiation, development, cell cycle, disease progression, and that each sample represents one unknown point along the progression of that process. SPD aims to organize the samples in a manner that reveals the underlying progression and to simultaneously identify subsets of genes that are responsible for that progression. We demonstrate the performance of SPD on a variety of microarray datasets that were generated by sampling a biological process at different points along its progression, without providing SPD any information of the underlying process. When applied to a cell cycle time series microarray dataset, SPD was not provided any prior knowledge of samples' time order or of which genes are cell-cycle regulated, yet SPD recovered the correct time order and identified many genes that have been associated with the cell cycle. When applied to B-cell differentiation data, SPD recovered the correct order of stages of normal B-cell differentiation and the linkage between preB-ALL tumor cells with their cell origin preB. When applied to mouse embryonic stem cell differentiation data, SPD uncovered a landscape of ESC differentiation into various lineages and genes that represent both generic and lineage specific processes. When applied to a prostate cancer microarray dataset, SPD identified gene modules that reflect a progression consistent with disease stages. SPD may be best viewed as a novel tool for synthesizing biological hypotheses because it provides a likely biological progression underlying a microarray dataset and, perhaps more importantly, the

  11. Identification of genes regulated by Wnt/β-catenin pathway and involved in apoptosis via microarray analysis

    Directory of Open Access Journals (Sweden)

    Chen Quan

    2006-09-01

    Full Text Available Abstract Background Wnt/β-catenin pathway has critical roles in development and oncogenesis. Although significant progress has been made in understanding the downstream signaling cascade of this pathway, little is known regarding Wnt/β-catenin pathway modification of the cellular apoptosis. Methods To identify potential genes regulated by Wnt/β-catenin pathway and involved in apoptosis, we used a stably integrated, inducible RNA interference (RNAi vector to specific inhibit the expression and the transcriptional activity of β-catenin in HeLa cells. Meanwhile, we designed an oligonucleotide microarray covering 1384 apoptosis-related genes. Using oligonucleotide microarrays, a series of differential expression of genes was identified and further confirmed by RT-PCR. Results Stably integrated inducible RNAi vector could effectively suppress β-catenin expression and the transcriptional activity of β-catenin/TCF. Meanwhile, depletion of β-catenin in this manner made the cells more sensitive to apoptosis. 130 genes involved in some important cell-apoptotic pathways, such as PTEN-PI3K-AKT pathway, NF-κB pathway and p53 pathway, showed significant alteration in their expression level after the knockdown of β-catenin. Conclusion Coupling RNAi knockdown with microarray and RT-PCR analyses proves to be a versatile strategy for identifying genes regulated by Wnt/β-catenin pathway and for a better understanding the role of this pathway in apoptosis. Some of the identified β-catenin/TCF directed or indirected target genes may represent excellent targets to limit tumor growth.

  12. Candidate gene analysis of organ pigmentation loci in the Solanaceae

    OpenAIRE

    Thorup, T. A.; Tanyolac, B.; Livingstone, K D; Popovsky, S.; Paran, I.; Jahn, Molly

    2000-01-01

    Ten structural genes from the Capsicum (pepper) carotenoid biosynthetic pathway have been localized on a (Capsicum annuum × Capsicum chinense)F2 genetic map anchored in Lycopersicon (tomato). The positions of these genes were compared with positions of the same genes in tomato when known, and with loci from pepper, potato, and tomato that affect carotenoid levels in different tissues. C2, one of three phenotypically defined loci determining pepper fruit color, ...

  13. Profound influence of microarray scanner characteristics on gene expression ratios: analysis and procedure for correction

    Directory of Open Access Journals (Sweden)

    Myklebost Ola

    2004-02-01

    Full Text Available Abstract Background High throughput gene expression data from spotted cDNA microarrays are collected by scanning the signal intensities of the corresponding spots by dedicated fluorescence scanners. The major scanner settings for increasing the spot intensities are the laser power and the voltage of the photomultiplier tube (PMT. It is required that the expression ratios are independent of these settings. We have investigated the relationships between PMT voltage, spot intensities, and expression ratios for different scanners, in order to define an optimal scanning procedure. Results All scanners showed a limited intensity range from 200 to 50 000 (mean spot intensity, for which the expression ratios were independent of PMT voltage. This usable intensity range was considerably less than the maximum detection range of the PMTs. The use of spot and background intensities outside this range led to errors in the ratios. The errors at high intensities were caused by saturation of pixel intensities within the spots. An algorithm was developed to correct the intensities of these spots, and, hence, extend the upper limit of the usable intensity range. Conclusions It is suggested that the PMT voltage should be increased to avoid intensities of the weakest spots below the usable range, allowing the brightest spots to reach the level of saturation. Subsequently, a second set of images should be acquired with a lower PMT setting such that no pixels are in saturation. Reliable data for spots with saturation in the first set of images can easily be extracted from the second set of images by the use of our algorithm. This procedure would lead to an increase in the accuracy of the data and in the number of data points achieved in each experiment compared to traditional procedures.

  14. The Gene Expression Profile of D-galactose Induced Aging Model Rat Using cDNA Microarray

    Institute of Scientific and Technical Information of China (English)

    Li Min(李珉); Wang Gang; Zhang Wei; Wang Miqu; Zhang Yizheng

    2004-01-01

    In order to study the molecular mechanism of D-galactose induced aging model, cDNA microarray is used to analyze gene expression profiles of both normal and D-galactose induced aging model rats. D-galactose induced aging model rats are injected with D-galactose, while normal rats are injected with physiological saline as control. After 7 weeks, the two groups of rats are killed simultaneously. Their livers are harvested for genome-wide expression analysis. D-galactose treated rats showed changes in gene expression associated with increase or decrease in xenobiotic metabolism, protein metabolism and energy metabolism.

  15. Analysis of microarray-identified genes and microRNAs associated with drug resistance in ovarian cancer.

    Science.gov (United States)

    Zou, Jing; Yin, Fuqiang; Wang, Qi; Zhang, Wei; Li, Li

    2015-01-01

    The aim of this study was to identify potential microRNAs and genes associated with drug resistance in ovarian cancer through web-available microarrays. The drug resistant-related microRNA microarray dataset GS54665 and mRNA dataset GSE33482, GSE28646, and GSE15372 were downloaded from the Gene Expression Omnibus database. Dysregulated microRNAs/genes were screened with GEO2R and were further identified in SKOV3 (SKOV3/DDP) and A2780 (A2780/DDP) cells by real-time quantitative PCR (qRT-PCR), and then their associations with drug resistance was analyzed by comprehensive bioinformatic analyses. Nine microRNAs (microRNA-199a-5p, microRNA-199a-3p, microRNA-199b-3p, microRNA-215, microRNA-335, microRNA-18b, microRNA-363, microRNA-645 and microRNA-141) and 38 genes were identified to be differentially expressed in drug-resistant ovarian cancer cells, with seven genes (NHSL1, EPHA3, USP51, ZSCAN4, EPHA7, SNCA and PI15) exhibited exactly the same expression trends in all three microarrays. Biological process annotation and pathway enrichment analysis of the 9 microRNAs and 38 genes identified several drug resistant-related signaling pathways, and the microRNA-mRNA interaction revealed the existence of a targeted regulatory relationship between the 9 microRNAs and most of the 38 genes. The expression of 9 microRNAs and the 7 genes by qRT-PCR in SKOV3/DDP and A2780/DDP cells indicating a consistent expression profile with the microarrays. Among those, the expression of EPHA7 and PI15 were negatively correlated with that of microRNA-141, and they were also identified as potential targets of this microRNA via microRNA-mRNA interaction. We thus concluded that microRNA-141, EPHA7, and PI15 might jointly participate in the regulation of drug resistance in ovarian cancer and serve as potential targets in targeted therapies. PMID:26261572

  16. Using the candidate gene approach for detecting genes underlying seed oil concentration and yield in soybean.

    Science.gov (United States)

    Eskandari, Mehrzad; Cober, Elroy R; Rajcan, Istvan

    2013-07-01

    Increasing the oil concentration in soybean seeds has been given more attention in recent years because of demand for both edible oil and biodiesel production. Oil concentration in soybean is a complex quantitative trait regulated by many genes as well as environmental conditions. To identify genes governing seed oil concentration in soybean, 16 putative candidate genes of three important gene families (GPAT: acyl-CoA:sn-glycerol-3-phosphate acyltransferase, DGAT: acyl-CoA:diacylglycerol acyltransferase, and PDAT: phospholipid:diacylglycerol acyltransferase) involved in triacylglycerol (TAG) biosynthesis pathways were selected and their sequences retrieved from the soybean database ( http://www.phytozome.net/soybean ). Three sequence mutations were discovered in either coding or noncoding regions of three DGAT soybean isoforms when comparing the parents of a 203 recombinant inbreed line (RIL) population; OAC Wallace and OAC Glencoe. The RIL population was used to study the effects of these mutations on seed oil concentration and other important agronomic and seed composition traits, including seed yield and protein concentration across three field locations in Ontario, Canada, in 2009 and 2010. An insertion/deletion (indel) mutation in the GmDGAT2B gene in OAC Wallace was significantly associated with reduced seed oil concentration across three environments and reduced seed yield at Woodstock in 2010. A mutation in the 3' untranslated (3'UTR) region of GmDGAT2C was associated with seed yield at Woodstock in 2009. A mutation in the intronic region of GmDGAR1B was associated with seed yield and protein concentration at Ottawa in 2010. The genes identified in this study had minor effects on either seed yield or oil concentration, which was in agreement with the quantitative nature of the traits. However, the novel gene-specific markers designed in the present study can be used in soybean breeding for marker-assisted selection aimed at increasing seed yield and oil

  17. Identification of microdeletions in candidate genes for cleft lip and/or palate

    DEFF Research Database (Denmark)

    Shi, Min; Mostowska, Adrianna; Jugessur, Astanand;

    2009-01-01

    contribute to a particular disease. METHODS: We performed a candidate gene analysis involving 1,221 SNPs in 333 candidate genes for orofacial clefting, using 2,823 samples from 725 two- and three-generation families with a proband having cleft lip with or without cleft palate. We used SNP genotyping, DNA......, TBX1, and TFAP2A are likely to be etiologic. CONCLUSIONS: These deletions suggest the potential roles of genes or regulatory elements contained within deleted regions in the etiology of clefting. Our analysis took advantage of genotypes from a candidate-gene-based SNP survey and proved to be an...... efficient analytical approach to interrogate genes potentially involved in clefting. This can serve as a model to find genes playing a role in complex traits in general....

  18. Multicenter Evaluation of a New DNA Microarray for Rapid Detection of Clinically Relevant bla Genes from ? -Lactam-Resistant Gram-Negative Bacteria

    OpenAIRE

    Bogaerts, P.; Hujer, A.M.; Naas, T.; de Castro, R. R.; A. Endimiani; Nordmann, P.; Glupczynski, Y.; Bonomo, R.A.

    2011-01-01

    A new commercial low-density microarray which identifies common extended-spectrum β-lactamase plasmid-mediated cephalosporinase genes, as well as carbapenemase (blaKPC and blaNDM) genes, was evaluated. We tested 207 clinical and reference/collection isolates of the Enterobacteriaceae possessing different bla genes. Overall, the sensitivity and specificity of the microarray were 100% for the detection of the plasmid-mediated blaAmpC, blaKPC, and blaNDM genes using bla gene sequencing as the re...

  19. Predicting sensation seeking from dopamine genes: A candidate system approach

    OpenAIRE

    Derringer, Jaime; Robert F Krueger; Dick, Danielle M; Saccone, Scott; Grucza, Richard A.; Agrawal, Arpana; Lin, Peng; Almasy, Laura; Edenberg, Howard J.; Foroud, Tatiana; Nurnberger, John I.; Hesselbrock, Victor M.; Kramer, John R.; Kuperman, Samuel; Porjesz, Bernice

    2010-01-01

    Sensation seeking is a heritable personality trait that has been reliably linked to behavior disorders. The dopamine system has been hypothesized to contribute to individual differences in sensation seeking, and both experimental and observational studies in humans and non-human animals provide evidence for this relationship. We present here a candidate-system approach to genetic association analysis of sensation seeking, in which single nucleotide polymorphisms (SNPs) from a number of dopami...

  20. Genes associated with heavy metal tolerance and accumulation in Zn/Cd hyperaccumulator Arabidopsis halleri: a genomic survey with cDNA microarray.

    Science.gov (United States)

    Chiang, Huai-Chih; Lo, Jing-Chi; Yeh, Kuo-Chen

    2006-11-01

    To survive in variable soil conditions, plants possess homeostatic mechanisms to maintain a suitable concentration of essential heavy metal ions. Certain plants, inhabiting heavy metal-enriched or -contaminated soil, thus are named hyperaccumulators. Studying hyperaccumulators has great potential to provide information for phytoremediation. To better understand the hyperaccumulating mechanism, we used an Arabidopsis cDNA microarray to compare the gene expression of the Zn/Cd hyperaccumulator Arabidopsis halleri and a nonhyperaccumulator, Arabidopsis thaliana. By analyzing the expression of metal-chelators, antioxidation-related genes, and transporters, we revealed a few novel molecular features. We found that metallothionein 2b and 3, APX and MDAR4 in the ascorbate-glutathione pathway, and certain metal transporters in P(1B)-type ATPase, ZIP, Nramp, and CDF families, are expressed at higher levels in A. halleri than in A. thaliana. We further validated that the enzymatic activity of ascorbate peroxidase and class III peroxidases are highly elevated in A. halleri. This observation positively correlates with the higher ability of A. halleri to detoxify H2O2 produced by cadmium and paraquat treatments. We thus suggest that higher peroxidase activities contribute to the heavy metal tolerance in A. halleri by alleviating the ROS damage. We have revealed genes that could be candidates for the future engineering of plants with large biomass for use in phytoremediation. PMID:17144312

  1. Quantitative DNA methylation analysis of candidate genes in cervical cancer.

    Directory of Open Access Journals (Sweden)

    Erin M Siegel

    Full Text Available Aberrant DNA methylation has been observed in cervical cancer; however, most studies have used non-quantitative approaches to measure DNA methylation. The objective of this study was to quantify methylation within a select panel of genes previously identified as targets for epigenetic silencing in cervical cancer and to identify genes with elevated methylation that can distinguish cancer from normal cervical tissues. We identified 49 women with invasive squamous cell cancer of the cervix and 22 women with normal cytology specimens. Bisulfite-modified genomic DNA was amplified and quantitative pyrosequencing completed for 10 genes (APC, CCNA, CDH1, CDH13, WIF1, TIMP3, DAPK1, RARB, FHIT, and SLIT2. A Methylation Index was calculated as the mean percent methylation across all CpG sites analyzed per gene (~4-9 CpG site per sequence. A binary cut-point was defined at >15% methylation. Sensitivity, specificity and area under ROC curve (AUC of methylation in individual genes or a panel was examined. The median methylation index was significantly higher in cases compared to controls in 8 genes, whereas there was no difference in median methylation for 2 genes. Compared to HPV and age, the combination of DNA methylation level of DAPK1, SLIT2, WIF1 and RARB with HPV and age significantly improved the AUC from 0.79 to 0.99 (95% CI: 0.97-1.00, p-value = 0.003. Pyrosequencing analysis confirmed that several genes are common targets for aberrant methylation in cervical cancer and DNA methylation level of four genes appears to increase specificity to identify cancer compared to HPV detection alone. Alterations in DNA methylation of specific genes in cervical cancers, such as DAPK1, RARB, WIF1, and SLIT2, may also occur early in cervical carcinogenesis and should be evaluated.

  2. Quantitative DNA methylation analysis of candidate genes in cervical cancer.

    Science.gov (United States)

    Siegel, Erin M; Riggs, Bridget M; Delmas, Amber L; Koch, Abby; Hakam, Ardeshir; Brown, Kevin D

    2015-01-01

    Aberrant DNA methylation has been observed in cervical cancer; however, most studies have used non-quantitative approaches to measure DNA methylation. The objective of this study was to quantify methylation within a select panel of genes previously identified as targets for epigenetic silencing in cervical cancer and to identify genes with elevated methylation that can distinguish cancer from normal cervical tissues. We identified 49 women with invasive squamous cell cancer of the cervix and 22 women with normal cytology specimens. Bisulfite-modified genomic DNA was amplified and quantitative pyrosequencing completed for 10 genes (APC, CCNA, CDH1, CDH13, WIF1, TIMP3, DAPK1, RARB, FHIT, and SLIT2). A Methylation Index was calculated as the mean percent methylation across all CpG sites analyzed per gene (~4-9 CpG site) per sequence. A binary cut-point was defined at >15% methylation. Sensitivity, specificity and area under ROC curve (AUC) of methylation in individual genes or a panel was examined. The median methylation index was significantly higher in cases compared to controls in 8 genes, whereas there was no difference in median methylation for 2 genes. Compared to HPV and age, the combination of DNA methylation level of DAPK1, SLIT2, WIF1 and RARB with HPV and age significantly improved the AUC from 0.79 to 0.99 (95% CI: 0.97-1.00, p-value = 0.003). Pyrosequencing analysis confirmed that several genes are common targets for aberrant methylation in cervical cancer and DNA methylation level of four genes appears to increase specificity to identify cancer compared to HPV detection alone. Alterations in DNA methylation of specific genes in cervical cancers, such as DAPK1, RARB, WIF1, and SLIT2, may also occur early in cervical carcinogenesis and should be evaluated. PMID:25826459

  3. Functional epigenomics approach to identify methylated candidate tumour suppressor genes in renal cell carcinoma

    OpenAIRE

    Morris, M.

    2008-01-01

    Promoter region hypermethylation and transcriptional silencing is a frequent cause of tumour suppressor gene (TSG) inactivation in many human cancers. Previously, to identify candidate epigenetically inactivated TSGs in renal cell carcinoma (RCC), we monitored changes in gene expression in four RCC cell lines after treatment with the demethylating agent 5-azacytidine. This enabled us to identify HAI-2/SPINT2 as a novel epigenetically inactivated candidate RCC TSG. To identify further candidat...

  4. Incorporating feature ranking and evolutionary methods for the classification of high-dimensional DNA microarray gene expression data

    Directory of Open Access Journals (Sweden)

    Mani Abedini

    2013-05-01

    Full Text Available AbstractBackgroundDNA microarray gene expression classification poses a challenging task to the machine learning domain. Typically, the dimensionality of gene expression data sets could go from several thousands to over 10,000 genes. A potential solution to this issue is using feature selection to reduce the dimensionality.AimThe aim of this paper is to investigate how we can use feature quality information to improve the precision of microarray gene expression classification tasks. Method We propose two evolutionary machine learning models based on the eXtended Classifier System (XCS and a typical feature selection methodology. The first one, which we call FS-XCS, uses feature selection for feature reduction purposes. The second model is GRD-XCS, which uses feature ranking to bias the rule discovery process of XCS.ResultsThe results indicate that the use of feature selection / ranking methods is essential for tackling high-dimensional classification tasks, such as microarray gene expression classification. However, the results also suggest that using feature ranking to bias the rule discovery process performs significantly better than using the feature reduction method. In other words, using feature quality information to develop a smarter learning procedure is more efficient than reducing the feature set. ConclusionOur findings have shown that extracting feature quality information can assist the learning process and improve classification accuracy. On the other hand, relying exclusively on the feature quality information might potentially decrease the classification performance (e.g., using feature reduction. Therefore, we recommend a hybrid approach that uses feature quality information to direct the learning process by highlighting the more informative features, but at the same time not restricting the learning process to explore other features.

  5. Monitoring expression profiles of rice (Oryza sativa L.) genes under abiotic stresses using cDNA Microarray Analysis (abstract)

    International Nuclear Information System (INIS)

    Transcript regulation in response to cold, drought, high salinity and ABA application was investigated in rice (Oryza sativa L., Nipponbare) with microarray analysis including approx. 1700 independent DNA elements derived from three cDNA libraries constructed from 15-day old rice seedlings stressed with drought, cold and high salinity. A total of 141 non-redundant genes were identified, whose expression ratios were more than three-fold compared with the control genes for at least one of stress treatments in microarray analysis. However, after RNA gel blot analysis, a total of 73 genes were identified, among them the transcripts of 36, 62, 57 and 43 genes were found increased after cold, drought, high salinity and ABA application, respectively. Sixteen of these identified genes have been reported previously to be stress inducible in rice, while 57 of which are novel that have not been reported earlier as stress responsive in rice. We observed a strong association in the expression patterns of stress responsive genes and found 15 stress inducible genes that responded to all four treatments. Based on Venn diagram analysis, 56 genes were induced by both drought and high salinity, whereas 22 genes were upregulated by both cold and high salinity stress. Similarly 43 genes were induced by both drought stress and ABA application, while only 17 genes were identified as cold and ABA inducible genes. These results indicated the existence of greater cross talk between drought, ABA and high salinity stress signaling processes than those between cold and ABA, and cold and high salinity stress signaling pathways. The cold, drought, high salinity and ABA inducible genes were classified into four gene groups from their expression profiles. Analysis of data enabled us to identify a number of promoters and possible cis-acting DNA elements of several genes induced by a variety of abiotic stresses by combining expression data with genomic sequence data of rice. Comparative analysis of

  6. Microarray analysis of inflammatory response-related gene expression in the uteri of dogs with pyometra.

    Science.gov (United States)

    Bukowska, D; Kempisty, B; Zawierucha, P; Jopek, K; Piotrowska, H; Antosik, P; Ciesiółka, S; Woźna, M; Brüssow, K P; Jaśkowski, J M

    2014-01-01

    Pyometra, which is accompanied by bacterial contamination of the uterus, is defined as a complex disease associated with the activation of several systems, including the immune system. The objective of the study was to evaluate the gene expression profile in dogs with pyometra compared with those that were clinically normal. The study included uteri from 43 mongrel bitches (23 with pyometra, 20 clinically healthy). RNA used for the microarray study was pooled to four separated vials for control and pyometra. A total of 17,138 different transcripts were analyzed on the uteri of female dogs with pyometra and of healthy controls. From 264 inflammatory response-related transcripts, we found 23 transcripts that revealed a 10- to 77-fold increased expression. Thereby, the expression of interleukin 8 (IL8), interleukin-1-beta (IL1B), interleukin 18 receptor (IL18RAP), interleukin 1-alpha (IL1A), interleukin receptor antagonist (IL1RN) and interleukin 6 (IL6) increased 77-, 20-, 17-, 13-, 13- and 11-fold, respectively. Furthermore, the expression of the calcium binding proteins S100A8 was 44-fold higher, and that of S100A12 and S100A9 37-fold, respectively, in the uteri of canines with pyometra compared with that of the controls. Moreover, the expression of the transcripts of toll-like receptors (TLR8 and TLR2), integrin beta 2 (ITGB2), chemokine ligand 3 (CCL3), semaphorin 7A (SEMA7A), CD14 and prostaglandin-endoperoxide synthase 2 (PTGS2) was increased between 10- and 18-fold. Furthermore, after using RT-qPCR we found an increased expression of AOAH, IL1A, IL8, CCL3, IL1RN and SERPINE 1 mRNAs which can be served also as markers of the occurrence of pyometra in domestic bitches. In summary, it is concluded that up-regulation of interleukins may be used as a marker of the inflammatory response in dogs with pyometra. Moreover, all of the 23 up-regulated transcripts may be novel molecular markers of the pathogenesis of canine pyometra. Several proteins--–products of these

  7. Congenital diaphragmatic hernia candidate genes derived from embryonic transcriptomes

    DEFF Research Database (Denmark)

    Russell, Meaghan K; Longoni, Mauro; Wells, Julie;

    2012-01-01

    expression profiling of developing embryonic diaphragms would help identify genes likely to be associated with diaphragm defects. We generated a time series of whole-transcriptome expression profiles from laser captured embryonic mouse diaphragms at embryonic day (E)11.5 and E12.5 when experimental...... undetected diaphragmatic defects. Our study demonstrates the utility of genetic characterization of normal development as an integral part of a disease gene identification and prioritization strategy for CDH, an approach that can be extended to other diseases and developmental anomalies....... perturbations lead to CDH phenotypes, and E16.5 when the diaphragm is fully formed. Gene sets defining biologically relevant pathways and temporal expression trends were identified by using a series of bioinformatic algorithms. These developmental sets were then compared with a manually curated list of genes...

  8. Quantitative DNA Methylation Analysis of Candidate Genes in Cervical Cancer

    OpenAIRE

    Erin M Siegel; Riggs, Bridget M; Delmas, Amber L.; Koch, Abby; Hakam, Ardeshir; Brown, Kevin D.

    2015-01-01

    Aberrant DNA methylation has been observed in cervical cancer; however, most studies have used non-quantitative approaches to measure DNA methylation. The objective of this study was to quantify methylation within a select panel of genes previously identified as targets for epigenetic silencing in cervical cancer and to identify genes with elevated methylation that can distinguish cancer from normal cervical tissues. We identified 49 women with invasive squamous cell cancer of the cervix and ...

  9. Microarray analysis of expression of cell death-associated genes in rat spinal cord cells exposed to cyclic tensile stresses in vitro

    Directory of Open Access Journals (Sweden)

    Roberts Sally

    2010-07-01

    Full Text Available Abstract Background The application of mechanical insults to the spinal cord results in profound cellular and molecular changes, including the induction of neuronal cell death and altered gene expression profiles. Previous studies have described alterations in gene expression following spinal cord injury, but the specificity of this response to mechanical stimuli is difficult to investigate in vivo. Therefore, we have investigated the effect of cyclic tensile stresses on cultured spinal cord cells from E15 Sprague-Dawley rats, using the FX3000® Flexercell Strain Unit. We examined cell morphology and viability over a 72 hour time course. Microarray analysis of gene expression was performed using the Affymetrix GeneChip System®, where categorization of identified genes was performed using the Gene Ontology (GO and Kyoto Encyclopedia of Genes and Genomes (KEGG systems. Changes in expression of 12 genes were validated with quantitative real-time reverse transcription polymerase chain reaction (RT-PCR. Results The application of cyclic tensile stress reduced the viability of cultured spinal cord cells significantly in a dose- and time-dependent manner. Increasing either the strain or the strain rate independently was associated with significant decreases in spinal cord cell survival. There was no clear evidence of additive effects of strain level with strain rate. GO analysis identified 44 candidate genes which were significantly related to "apoptosis" and 17 genes related to "response to stimulus". KEGG analysis identified changes in the expression levels of 12 genes of the mitogen-activated protein kinase (MAPK signaling pathway, which were confirmed to be upregulated by RT-PCR analysis. Conclusions We have demonstrated that spinal cord cells undergo cell death in response to cyclic tensile stresses, which were dose- and time-dependent. In addition, we have identified the up regulation of various genes, in particular of the MAPK pathway, which

  10. Candidate gene linkage analysis indicates genetic heterogeneity in Marfan syndrome

    Directory of Open Access Journals (Sweden)

    L.V.S. Teixeira

    2011-08-01

    Full Text Available Marfan syndrome (MFS is an autosomal dominant disease of the connective tissue that affects the ocular, skeletal and cardiovascular systems, with a wide clinical variability. Although mutations in the FBN1 gene have been recognized as the cause of the disease, more recently other loci have been associated with MFS, indicating the genetic heterogeneity of this disease. We addressed the issue of genetic heterogeneity in MFS by performing linkage analysis of the FBN1 and TGFBR2 genes in 34 families (345 subjects who met the clinical diagnostic criteria for the disease according to Ghent. Using a total of six microsatellite markers, we found that linkage with the FBN1 gene was observed or not excluded in 70.6% (24/34 of the families, and in 1 family the MFS phenotype segregated with the TGFBR2 gene. Moreover, in 4 families linkage with the FBN1 and TGFBR2 genes was excluded, and no mutations were identified in the coding region of TGFBR1, indicating the existence of other genes involved in MFS. Our results suggest that the genetic heterogeneity of MFS may be greater that previously reported.

  11. Aberrant methylation of candidate tumor suppressor genes in neuroblastoma.

    Science.gov (United States)

    Hoebeeck, Jasmien; Michels, Evi; Pattyn, Filip; Combaret, Valérie; Vermeulen, Joëlle; Yigit, Nurten; Hoyoux, Claire; Laureys, Geneviève; De Paepe, Anne; Speleman, Frank; Vandesompele, Jo

    2009-01-18

    CpG island hypermethylation has been recognized as an alternative mechanism for tumor suppressor gene inactivation. In this study, we performed methylation-specific PCR (MSP) to investigate the methylation status of 10 selected tumor suppressor genes in neuroblastoma. Seven of the investigated genes (CD44, RASSF1A, CASP8, PTEN, ZMYND10, CDH1, PRDM2) showed high frequencies (> or =30%) of methylation in 33 neuroblastoma cell lines. In 42 primary neuroblastoma tumors, the frequencies of methylation were 69%, CD44; 71%, RASSF1A; 56%, CASP8; 25%, PTEN; 15%, ZMYND10; 8%, CDH1; and 0%, PRDM2. Furthermore, CASP8 and CDH1 hypermethylation was significantly associated with poor event-free survival. Meta-analysis of 115 neuroblastoma tumors demonstrated a significant correlation between CASP8 methylation and MYCN amplification. In addition, there was a correlation between ZMYND10 methylation and MYCN amplification. The MSP data, together with optimized mRNA re-expression experiments (in terms of concentration and time of treatment and use of proper reference genes) further strengthen the notion that epigenetic alterations could play a significant role in NB oncogenesis. This study thus warrants the need for a global profiling of gene promoter hypermethylation to identify genome-wide aberrantly methylated genes in order to further understand neuroblastoma pathogenesis and to identify prognostic methylation markers. PMID:18819746

  12. Type I interferon related genes are common genes on the early stage after vaccination by meta-analysis of microarray data.

    Science.gov (United States)

    Zhang, Junnan; Shao, Jie; Wu, Xing; Mao, Qunying; Wang, Yiping; Gao, Fan; Kong, Wei; Liang, Zhenglun

    2015-01-01

    The objective of this study was to find common immune mechanism across different kinds of vaccines. A meta-analysis of microarray datasets was performed using publicly available microarray Gene Expression Omnibus (GEO) and Array Express data sets of vaccination records. Seven studies (out of 35) were selected for this meta-analysis. A total of 447 chips (145 pre-vaccination and 302 post-vaccination) were included. Significance analysis of microarrays (SAM) program was used for screening differentially expressed genes (DEGs). Functional pathway enrichment for the DEGs was conducted in DAVID Gene Ontology (GO) database. Twenty DEGs were identified, of which 10 up-regulated genes involved immune response. Six of which were type I interferon (IFN) related genes, including LY6E, MX1, OAS3, IFI44L, IFI6 and IFITM3. Ten down-regulated genes mainly mediated negative regulation of cell proliferation and cell motion. Results of a subgroup analysis showed that although the kinds of genes varied widely between days 3 and 7 post vaccination, the pathways between them are basically the same, such as immune response and response to viruses, etc. For an independent verification of these 6 type I IFN related genes, peripheral blood mononuclear cells (PBMCs) were collected at baseline and day 3 after the vaccination from 8 Enterovirus 71(EV71) vaccinees and were assayed by RT-PCR. Results showed that the 6 DEGs were also upregulated in EV71 vaccinees. In summary, meta-analysis methods were used to explore the immune mechanism of vaccines and results indicated that the type I IFN related genes and corresponding pathways were common in early immune responses for different kinds of vaccines. PMID:25839220

  13. Type I interferon related genes are common genes on the early stage after vaccination by meta-analysis of microarray data

    Science.gov (United States)

    Zhang, Junnan; Shao, Jie; Wu, Xing; Mao, Qunying; Wang, Yiping; Gao, Fan; Kong, Wei; Liang, Zhenglun

    2015-01-01

    The objective of this study was to find common immune mechanism across different kinds of vaccines. A meta-analysis of microarray datasets was performed using publicly available microarray Gene Expression Omnibus (GEO) and Array Express data sets of vaccination records. Seven studies (out of 35) were selected for this meta-analysis. A total of 447 chips (145 pre-vaccination and 302 post-vaccination) were included. Significance analysis of microarrays (SAM) program was used for screening differentially expressed genes (DEGs). Functional pathway enrichment for the DEGs was conducted in DAVID Gene Ontology (GO) database. Twenty DEGs were identified, of which 10 up-regulated genes involved immune response. Six of which were type I interferon (IFN) related genes, including LY6E, MX1, OAS3, IFI44L, IFI6 and IFITM3. Ten down-regulated genes mainly mediated negative regulation of cell proliferation and cell motion. Results of a subgroup analysis showed that although the kinds of genes varied widely between days 3 and 7 post vaccination, the pathways between them are basically the same, such as immune response and response to viruses, etc. For an independent verification of these 6 type I IFN related genes, peripheral blood mononuclear cells (PBMCs) were collected at baseline and day 3 after the vaccination from 8 Enterovirus 71(EV71) vaccinees and were assayed by RT-PCR. Results showed that the 6 DEGs were also upregulated in EV71 vaccinees. In summary, meta-analysis methods were used to explore the immune mechanism of vaccines and results indicated that the type I IFN related genes and corresponding pathways were common in early immune responses for different kinds of vaccines. PMID:25839220

  14. PathoPlant: a platform for microarray expression data to analyze co-regulated genes involved in plant defense responses.

    Science.gov (United States)

    Bülow, Lorenz; Schindler, Martin; Hehl, Reinhard

    2007-01-01

    Plants react to pathogen attack by expressing specific proteins directed toward the infecting pathogens. This involves the transcriptional activation of specific gene sets. PathoPlant, a database on plant-pathogen interactions and signal transduction reactions, has now been complemented by microarray gene expression data from Arabidopsis thaliana subjected to pathogen infection and elicitor treatment. New web tools enable identification of plant genes regulated by specific stimuli. Sets of genes co-regulated by multiple stimuli can be displayed as well. A user-friendly web interface was created for the submission of gene sets to be analyzed. This results in a table, listing the stimuli that act either inducing or repressing on the respective genes. The search can be restricted to certain induction factors to identify, e.g. strongly up- or down-regulated genes. Up to three stimuli can be combined with the option of induction factor restriction to determine similarly regulated genes. To identify common cis-regulatory elements in co-regulated genes, a resulting gene list can directly be exported to the AthaMap database for analysis. PathoPlant is freely accessible at http://www.pathoplant.de. PMID:17099232

  15. Microarray analysis of extracellular matrix genes expression in myocardium of mouse with Coxsackie virus B3 myocarditis

    Institute of Scientific and Technical Information of China (English)

    张召才; 李双杰; 杨英珍; 陈瑞珍; 葛均波; 陈灏珠

    2004-01-01

    Background Extracellular matrix (ECM) orchestrates cell behaviour including growth, death, apoptosis, adhesion, migration, and invasion by activating several signalling pathways. Certain components of ECM, such as integrins, may act as receptors or co-receptors of enterovirus. ECM-activated gene expressions in myocardium of viral heart disease including myocarditis and partial cardiomyopathy remain elusive. This study was to investigate the expression of ECM-activated genes in myocardium of mouse with viral myocarditis. Methods BALB/c mice were infected with Coxsackie virus B3 (CVB3) to establish an animal model of myocarditis. Uninfected mice were also prepared and served as controls. Specific mRNA expression pattern in myocarditic mouse heart was analysed by an in-house cDNA microarray containing 8192 genes. Overexpressed ECM genes were selected and subsequently confirmed by Northern blot analysis. Results Nine ECM genes were isolated, from the array of 8192 genes, as overexpressed genes in hearts of myocarditic mice in comparison with controls. Subsequent Northern blot analysis confirmed that four of the nine genes were highly expressed. Expression of these four genes, Fin15, Ilk, Lamr1 and ADAMTS-1, has not been reported previously to be induced by Coxsackie virus. Conclusion CVB3-induced myocarditis is associated with gene expression profiles of certain ECM components.

  16. cDNA microarray in isolation of novel differentially expressed genes related to human glioma and clone of a novel full-length gene

    Institute of Scientific and Technical Information of China (English)

    QI Zhen-yu; HUI Guo-zhen; LI Yao; ZHOU Zong-xiang; GU Shao-hua; YING Kang; XIE Yi

    2005-01-01

    Background This investigation was undertaken to obtain differentially expressed genes related to human glioma using cDNA microarray and the characterization of one novel full-length gene. Methods Total RNA was extracted from human glioma tissues and normal brain tissues, and mRNA was used to make probes. After hybridization and washing, the results were scanned using a computer system. The gene named 681F05 clone was an expressed gene to human glioma through four-time hybridization and scanning. Subsequently northern blot analysis was performed by northern blot, 5'RACE and bioinformatics. Results Fifteen differentially expressed genes to human glioma were obtained through four-time hybridization and scanning. Northern blot analysis confirmed that 681F05 clone was low-expressed in human brain tissues and over-expressed in human glioma tissues. The analysis of BLASTn and BLASTx showed that 681F05 clone is two cDNA clones encoding two novel proteins that are highly identified to the cyclophilin isoform 10 of C. Elgans, respectively. Sequence analysis revealed the two cDNA clones are two different splicing variants of a novel cycophilin-like gene (PPIL3a and PPIL3b).Conclusions cDNA microarray technology can be successfully used to identify differentially expressed genes. The novel full-length gene of human PPIL3 may be correlated with the formation of human glioma.

  17. DNA Microarray Technique

    Directory of Open Access Journals (Sweden)

    Thakare SP

    2012-11-01

    Full Text Available DNA Microarray is the emerging technique in Biotechnology. The many varieties of DNA microarray or DNA chip devices and systems are described along with their methods for fabrication and their use. It also includes screening and diagnostic applications. The DNA microarray hybridization applications include the important areas of gene expression analysis and genotyping for point mutations, single nucleotide polymorphisms (SNPs, and short tandem repeats (STRs. In addition to the many molecular biological and genomic research uses, this review covers applications of microarray devices and systems for pharmacogenomic research and drug discovery, infectious and genetic disease and cancer diagnostics, and forensic and genetic identification purposes.

  18. Candidates in Astroviruses, Seadornaviruses, Cytorhabdoviruses and Coronaviruses for +1 frame overlapping genes accessed by leaky scanning

    Directory of Open Access Journals (Sweden)

    Atkins John F

    2010-01-01

    Full Text Available Abstract Background Overlapping genes are common in RNA viruses where they serve as a mechanism to optimize the coding potential of compact genomes. However, annotation of overlapping genes can be difficult using conventional gene-finding software. Recently we have been using a number of complementary approaches to systematically identify previously undetected overlapping genes in RNA virus genomes. In this article we gather together a number of promising candidate new overlapping genes that may be of interest to the community. Results Overlapping gene predictions are presented for the astroviruses, seadornaviruses, cytorhabdoviruses and coronaviruses (families Astroviridae, Reoviridae, Rhabdoviridae and Coronaviridae, respectively.

  19. Gene expression profiling in Barrett's esophagus and cardia intestinal metaplasia:A comparative analysis using cDNA microarray

    Institute of Scientific and Technical Information of China (English)

    Ying Chang; Jun Gong; Bin Liu; Jun Zhang; Fei Dai

    2004-01-01

    AIM: To study the difference of gene expression profile changes in Barrett's esophagus (BE) and cardia intestinal metaplasia (CIM) and to screen the novel genes in the early stage by cDNA microarray.METHODS: cDNA retrotranscribed from an equal amount of mRNA from BE and CIM epithelial tissues was labeled with Cy3 and Cy5 fluorescence as probes. The mixed probe was hybridized with three pieces of BiostarH-40 s double dot human whole gene chip. The chips were scanned with a ScanArray 4000. The acquired images were analyzed using GenePix Pro 3.0 software.RESULTS: A total of 141 genes were screened out that exhibited different expression in all three chips. There were 74 upregulated and 67 downregulated genes in gene expression profiles of BE which were two times of that in CIM.CONCLUSION: There is a difference in gene expression level between BE and CIM epithelia. These 141 genes probably relate to the occurrence and development of BE and the progression to adenocarcinoma.

  20. LOD score exclusion analyses for candidate disease susceptibility genes using case-parents design

    Institute of Scientific and Technical Information of China (English)

    DENG Hongwen; GAO Guimin

    2006-01-01

    The focus of almost all the association studies of candidate genes is to test for their importance. We recently developed a LOD score approach that can be used to test against the importance of candidate genes for complex diseases and quantitative traits in random samples. As a complementary method to regular association analyses, our LOD score approach is powerful but still affected by the population admixture, though it is more conservative. To control the confounding effect of population heterogeneity, we develop here a LOD score exclusion analysis using case-parents design, the basic design of the transmission disequilibrium test (TDT) approach that is immune to population admixture. In the analysis, specific genetic effects and inheritance models at candidate genes can be analyzed and if a LOD score is ≤ - 2.0, the locus can be excluded from having an effect larger than that specified. Simulations show that this approach has reasonable power to exclude a candidate gene having small genetic effects if it is not a disease susceptibility locus (DSL) with sample size often employed in TDT studies. Similar to association analyses with the TDT in nuclear families, our exclusion analyses are generally not affected by population admixture. The exclusion analyses may be implemented to rule out candidate genes with no or minor genetic effects as supplemental analyses for the TDT. The utility of the approach is illustrated with an application to test the importance of vitamin D receptor (VDR) gene underlying the differential risk to osteoporosis.

  1. Mapping of Candidate Genes Involved in Bud Dormancy and Flowering Time in Sweet Cherry (Prunus avium.

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    Sophie Castède

    Full Text Available The timing of flowering in perennial plants is crucial for their survival in temperate climates and is regulated by the duration of bud dormancy. Bud dormancy release and bud break depend on the perception of cumulative chilling during endodormancy and heat during the bud development. The objectives of this work were to identify candidate genes involved in dormancy and flowering processes in sweet cherry, their mapping in two mapping progenies 'Regina' × 'Garnet' and 'Regina' × 'Lapins', and to select those candidate genes which co-localized with quantitative trait loci (QTLs associated with temperature requirements for bud dormancy release and flowering. Based on available data on flowering processes in various species, a list of 79 candidate genes was established. The peach and sweet cherry orthologs were identified and primers were designed to amplify sweet cherry candidate gene fragments. Based on the amplified sequences of the three parents of the mapping progenies, SNPs segregations in the progenies were identified. Thirty five candidate genes were genetically mapped in at least one of the two progenies and all were in silico mapped. Co-localization between candidate genes and QTLs associated with temperature requirements and flowering date were identified for the first time in sweet cherry. The allelic composition of the candidate genes located in the major QTL for heat requirements and flowering date located on linkage group 4 have a significant effect on these two traits indicating their potential use for breeding programs in sweet cherry to select new varieties adapted to putative future climatic conditions.

  2. Mapping of Candidate Genes Involved in Bud Dormancy and Flowering Time in Sweet Cherry (Prunus avium).

    Science.gov (United States)

    Castède, Sophie; Campoy, José Antonio; Le Dantec, Loïck; Quero-García, José; Barreneche, Teresa; Wenden, Bénédicte; Dirlewanger, Elisabeth

    2015-01-01

    The timing of flowering in perennial plants is crucial for their survival in temperate climates and is regulated by the duration of bud dormancy. Bud dormancy release and bud break depend on the perception of cumulative chilling during endodormancy and heat during the bud development. The objectives of this work were to identify candidate genes involved in dormancy and flowering processes in sweet cherry, their mapping in two mapping progenies 'Regina' × 'Garnet' and 'Regina' × 'Lapins', and to select those candidate genes which co-localized with quantitative trait loci (QTLs) associated with temperature requirements for bud dormancy release and flowering. Based on available data on flowering processes in various species, a list of 79 candidate genes was established. The peach and sweet cherry orthologs were identified and primers were designed to amplify sweet cherry candidate gene fragments. Based on the amplified sequences of the three parents of the mapping progenies, SNPs segregations in the progenies were identified. Thirty five candidate genes were genetically mapped in at least one of the two progenies and all were in silico mapped. Co-localization between candidate genes and QTLs associated with temperature requirements and flowering date were identified for the first time in sweet cherry. The allelic composition of the candidate genes located in the major QTL for heat requirements and flowering date located on linkage group 4 have a significant effect on these two traits indicating their potential use for breeding programs in sweet cherry to select new varieties adapted to putative future climatic conditions. PMID:26587668

  3. Gene expression profiling of Spodoptera frugiperda hemocytes and fat body using cDNA microarray reveals polydnavirus-associated variations in lepidopteran host genes transcript levels

    OpenAIRE

    Barat-Houari, M; Hilliou, F.; Jousset, F-X; Sofer, L; Deleury, E.; Rocher, J.; Ravallec, M.; Galibert, L; Delobel, P; Feyereisen, R.; Fournier, P.; Volkoff, A-N.

    2006-01-01

    Background Genomic approaches provide unique opportunities to study interactions of insects with their pathogens. We developed a cDNA microarray to analyze the gene transcription profile of the lepidopteran pest Spodoptera frugiperda in response to injection of the polydnavirus HdIV associated with the ichneumonid wasp Hyposoter didymator. Polydnaviruses are associated with parasitic ichneumonoid wasps and are required for their development within the lepidopteran host, in which they act as p...

  4. Resolution of large and small differences in gene expression using models for the Bayesian analysis of gene expression levels and spotted DNA microarrays

    Directory of Open Access Journals (Sweden)

    Townsend Jeffrey P

    2004-05-01

    Full Text Available Abstract Background The detection of small yet statistically significant differences in gene expression in spotted DNA microarray studies is an ongoing challenge. Meeting this challenge requires careful examination of the performance of a range of statistical models, as well as empirical examination of the effect of replication on the power to resolve these differences. Results New models are derived and software is developed for the analysis of microarray ratio data. These models incorporate multiplicative small error terms, and error standard deviations that are proportional to expression level. The fastest and most powerful method incorporates additive small error terms and error standard deviations proportional to expression level. Data from four studies are profiled for the degree to which they reveal statistically significant differences in gene expression. The gene expression level at which there is an empirical 50% probability of a significant call is presented as a summary statistic for the power to detect small differences in gene expression. Conclusions Understanding the resolution of difference in gene expression that is detectable as significant is a vital component of experimental design and evaluation. These small differences in gene expression level are readily detected with a Bayesian analysis of gene expression level that has additive error terms and constrains samples to have a common error coefficient of variation. The power to detect small differences in a study may then be determined by logistic regression.

  5. Whole genome amplification of DNA for genotyping pharmacogenetics candidate genes.

    Directory of Open Access Journals (Sweden)

    Santosh ePhilips

    2012-03-01

    Full Text Available Whole genome amplification (WGA technologies can be used to amplify genomic DNA when only small amounts of DNA are available. The Multiple Displacement Amplification Phi polymerase based amplification has been shown to accurately amplify DNA for a variety of genotyping assays; however, it has not been tested for genotyping many of the clinically relevant genes important for pharmacogenetic studies, such as the cytochrome P450 genes, that are typically difficult to genotype due to multiple pseudogenes, copy number variations, and high similarity to other related genes. We evaluated whole genome amplified samples for Taqman™ genotyping of SNPs in a variety of pharmacogenetic genes. In 24 DNA samples from the Coriell human diversity panel, the call rates and concordance between amplified (~200-fold amplification and unamplified samples was 100% for two SNPs in CYP2D6 and one in ESR1. In samples from a breast cancer clinical trial (Trial 1, we compared the genotyping results in samples before and after WGA for four SNPs in CYP2D6, one SNP in CYP2C19, one SNP in CYP19A1, two SNPs in ESR1, and two SNPs in ESR2. The concordance rates were all >97%. Finally, we compared the allele frequencies of 143 SNPs determined in Trial 1 (whole genome amplified DNA to the allele frequencies determined in unamplified DNA samples from a separate trial (Trial 2 that enrolled a similar population. The call rates and allele frequencies between the two trials were 98% and 99.7%, respectively. We conclude that the whole genome amplified DNA is suitable for Taqman™ genotyping for a wide variety of pharmacogenetically relevant SNPs.

  6. Parallel bacterial evolution within multiple patients identifies candidate pathogenicity genes

    OpenAIRE

    Lieberman, Tami D; Michel, Jean-Baptiste; Aingaran, Mythili; Potter-Bynoe, Gail; Roux, Damien; Davis, Michael R.; Skurnik, David; Leiby, Nicholas; LiPuma, John J.; Goldberg, Joanna B.; McAdam, Alexander J.; Priebe, Gregory P.; Kishony, Roy

    2011-01-01

    Bacterial pathogens evolve during the infection of their human hosts 1-8 , but separating adaptive and neutral mutations remains challenging 9-11 . Here, we identify bacterial genes under adaptive evolution by tracking recurrent patterns of mutations in the same pathogenic strain during the infection of multiple patients. We conducted a retrospective study of a Burkholderia dolosa outbreak among people with cystic fibrosis, sequencing the genomes of 112 isolates collected from 14 individuals ...

  7. A putative greigite-type magnetosome gene cluster from the candidate phylum Latescibacteria.

    Science.gov (United States)

    Lin, Wei; Pan, Yongxin

    2015-04-01

    The intracellular biomineralization of magnetite and/or greigite magnetosomes in magnetotactic bacteria (MTB) is strictly controlled by a group of conserved genes, termed magnetosome genes, which are organized as clusters (or islands) in MTB genomes. So far, all reported MTB are affiliated within the Proteobacteria phylum, the Nitrospirae phylum and the candidate division OP3. Here, we report the discovery of a putative magnetosome gene cluster structure from the draft genome of an uncultivated bacterium belonging to the candidate phylum Latescibacteria (formerly candidate division WS3) recently recovered by Rinke and colleagues, which contains 10 genes with homology to magnetosome mam genes of magnetotactic Proteobacteria and Nitrospirae. Moreover, these genes are phylogenetically closely related to greigite-type magnetosome genes that were only found from the Deltaproteobacteria MTB before, suggesting that the greigite genes may originate earlier than previously imagined. These findings indicate that some members of Latescibacteria may be capable of forming greigite magnetosomes, and thus may play previously unrecognized roles in environmental iron and sulfur cycles. The conserved genomic structure of magnetosome gene cluster in Latescibacteria phylum supports the hypothesis of horizontal transfer of these genes among distantly related bacterial groups in nature. PMID:25382584

  8. Identification of hypoxia-responsive genes in a dopaminergic cell line by subtractive cDNA libraries and microarray analysis.

    Science.gov (United States)

    Beitner-Johnson, D; Seta, K; Yuan, Y; Kim, H -W.; Rust, R T.; Conrad, P W.; Kobayashi, S; Millhorn, D E.

    2001-07-01

    Transplantation of dopamine-secreting cells harvested from fetal mesencephalon directly into the striatum has had limited success as a therapy for Parkinson's disease. A major problem is that the majority of the cells die during the first 3 weeks following transplantation. Hypoxia in the tissue surrounding the graft is a potential cause of the cell death. We have used subtractive cDNA libraries and microarray analysis to identify the gene expression profile that regulates tolerance to hypoxia. An improved understanding of the molecular basis of hypoxia-tolerance may allow investigators to engineer cells that can survive in the hypoxic environment of the brain parenchyma following transplantation. PMID:11331199

  9. The effect of oxythioquinox exposure on normal human mammary epithelial cell gene expression: A microarray analysis study

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    Weston Ainsley

    2004-09-01

    Full Text Available Abstract Background Inter-individual variation in normal human mammary epithelial cells in response to oxythioquinox (OTQ is reported. Gene expression signatures resulting from chemical exposures are generally created from analysis of exposures in rat, mouse or other genetically similar animal models, limiting information about inter-individual variations. This study focused on the effect of inter-individual variation in gene expression signatures. Methods Gene expression was studied in primary normal human mammary epithelial cells (NHMECs derived from four women undergoing reduction mammoplasty [Cooperative Human Tissue Network (National Cancer Institute and National Disease Research Interchange]. Gene transcription in each cell strain was analyzed using high-density oligonucleotide DNA microarrays (HuGeneFL, Affymetrix™ and changes in the expression of selected genes were verified by real-time polymerase chain reaction at extended time points (ABI. DNA microarrays were hybridized to materials prepared from total RNA that was collected after OTQ treatment for 15, 60 and 120 min. RNA was harvested from the vehicle control (DMSO at 120 min. The gene expression profile included all genes altered by at least a signal log ratio (SLR of ± 0.6 and p value ≤ 0.05 in three of four cell strains analyzed. Results RNA species were clustered in various patterns of expression highlighting genes with altered expression in one or more of the cell strains, including metabolic enzymes and transcription factors. Of the clustered RNA species, only 36 were found to be altered at one time point in three or more of the cell strains analyzed (13 up-regulated, 23 down-regulated. Cluster analysis examined the effects of OTQ on the cells with specific p53 polymorphisms. The two strains expressing the major variant of p53 had 83 common genes altered (35 increased, 48 decreased at one or more time point by at least a 0.6 signal log ratio (SLR. The intermediate variant

  10. A quantitative comparison of cell-type-specific microarray gene expression profiling methods in the mouse brain.

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    Benjamin W Okaty

    Full Text Available Expression profiling of restricted neural populations using microarrays can facilitate neuronal classification and provide insight into the molecular bases of cellular phenotypes. Due to the formidable heterogeneity of intermixed cell types that make up the brain, isolating cell types prior to microarray processing poses steep technical challenges that have been met in various ways. These methodological differences have the potential to distort cell-type-specific gene expression profiles insofar as they may insufficiently filter out contaminating mRNAs or induce aberrant cellular responses not normally present in vivo. Thus we have compared the repeatability, susceptibility to contamination from off-target cell-types, and evidence for stress-responsive gene expression of five different purification methods--Laser Capture Microdissection (LCM, Translating Ribosome Affinity Purification (TRAP, Immunopanning (PAN, Fluorescence Activated Cell Sorting (FACS, and manual sorting of fluorescently labeled cells (Manual. We found that all methods obtained comparably high levels of repeatability, however, data from LCM and TRAP showed significantly higher levels of contamination than the other methods. While PAN samples showed higher activation of apoptosis-related, stress-related and immediate early genes, samples from FACS and Manual studies, which also require dissociated cells, did not. Given that TRAP targets actively translated mRNAs, whereas other methods target all transcribed mRNAs, observed differences may also reflect translational regulation.

  11. Integrating Colon Cancer Microarray Data: Associating Locus-Specific Methylation Groups to Gene Expression-Based Classifications

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    Ana Barat

    2015-11-01

    Full Text Available Recently, considerable attention has been paid to gene expression-based classifications of colorectal cancers (CRC and their association with patient prognosis. In addition to changes in gene expression, abnormal DNA-methylation is known to play an important role in cancer onset and development, and colon cancer is no exception to this rule. Large-scale technologies, such as methylation microarray assays and specific sequencing of methylated DNA, have been used to determine whole genome profiles of CpG island methylation in tissue samples. In this article, publicly available microarray-based gene expression and methylation data sets are used to characterize expression subtypes with respect to locus-specific methylation. A major objective was to determine whether integration of these data types improves previously characterized subtypes, or provides evidence for additional subtypes. We used unsupervised clustering techniques to determine methylation-based subgroups, which are subsequently annotated with three published expression-based classifications, comprising from three to six subtypes. Our results showed that, while methylation profiles provide a further basis for segregation of certain (Inflammatory and Goblet-like finer-grained expression-based subtypes, they also suggest that other finer-grained subtypes are not distinctive and can be considered as a single subtype.

  12. DNA microarray-based experimental strategy for trustworthy expression profiling of the hippocampal genes by astaxanthin supplementation in adult mouse.

    Science.gov (United States)

    Yook, Jang Soo; Shibato, Junko; Rakwal, Randeep; Soya, Hideaki

    2016-03-01

    Naturally occurring astaxantin (ASX) is one of the noticeable carotenoid and dietary supplement, which has strong antioxidant and anti-inflammatory properties, and neuroprotective effects in the brain through crossing the blood-brain barrier. Specially, we are interested in the role of ASX as a brain food. Although ASX has been suggested to have potential benefit to the brain function, the underlying molecular mechanisms and events mediating such effect remain unknown. Here we examined molecular factors in the hippocampus of adult mouse fed ASX diets (0.1% and 0.5% doses) using DNA microarray (Agilent 4 × 44 K whole mouse genome chip) analysis. In this study, we described in detail our experimental workflow and protocol, and validated quality controls with the housekeeping gene expression (Gapdh and Beta-actin) on the dye-swap based approach to advocate our microarray data, which have been uploaded to Gene Expression Omnibus (accession number GSE62197) as a gene resource for the scientific community. This data will also form an important basis for further detailed experiments and bioinformatics analysis with an aim to unravel the potential molecular pathways or mechanisms underlying the positive effects of ASX supplementation on the brain, in particular the hippocampus. PMID:26981356

  13. DNA microarray-based experimental strategy for trustworthy expression profiling of the hippocampal genes by astaxanthin supplementation in adult mouse

    Directory of Open Access Journals (Sweden)

    Jang Soo Yook

    2016-03-01

    Full Text Available Naturally occurring astaxantin (ASX is one of the noticeable carotenoid and dietary supplement, which has strong antioxidant and anti-inflammatory properties, and neuroprotective effects in the brain through crossing the blood–brain barrier. Specially, we are interested in the role of ASX as a brain food. Although ASX has been suggested to have potential benefit to the brain function, the underlying molecular mechanisms and events mediating such effect remain unknown. Here we examined molecular factors in the hippocampus of adult mouse fed ASX diets (0.1% and 0.5% doses using DNA microarray (Agilent 4 × 44 K whole mouse genome chip analysis. In this study, we described in detail our experimental workflow and protocol, and validated quality controls with the housekeeping gene expression (Gapdh and Beta-actin on the dye-swap based approach to advocate our microarray data, which have been uploaded to Gene Expression Omnibus (accession number GSE62197 as a gene resource for the scientific community. This data will also form an important basis for further detailed experiments and bioinformatics analysis with an aim to unravel the potential molecular pathways or mechanisms underlying the positive effects of ASX supplementation on the brain, in particular the hippocampus.

  14. Identifying Novel Candidate Genes Related to Apoptosis from a Protein-Protein Interaction Network

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    Baoman Wang

    2015-01-01

    Full Text Available Apoptosis is the process of programmed cell death (PCD that occurs in multicellular organisms. This process of normal cell death is required to maintain the balance of homeostasis. In addition, some diseases, such as obesity, cancer, and neurodegenerative diseases, can be cured through apoptosis, which produces few side effects. An effective comprehension of the mechanisms underlying apoptosis will be helpful to prevent and treat some diseases. The identification of genes related to apoptosis is essential to uncover its underlying mechanisms. In this study, a computational method was proposed to identify novel candidate genes related to apoptosis. First, protein-protein interaction information was used to construct a weighted graph. Second, a shortest path algorithm was applied to the graph to search for new candidate genes. Finally, the obtained genes were filtered by a permutation test. As a result, 26 genes were obtained, and we discuss their likelihood of being novel apoptosis-related genes by collecting evidence from published literature.

  15. The complete spectrum of yeast chromosome instability genes identifies candidate CIN cancer genes and functional roles for ASTRA complex components.

    Directory of Open Access Journals (Sweden)

    Peter C Stirling

    2011-04-01

    Full Text Available Chromosome instability (CIN is observed in most solid tumors and is linked to somatic mutations in genome integrity maintenance genes. The spectrum of mutations that cause CIN is only partly known and it is not possible to predict a priori all pathways whose disruption might lead to CIN. To address this issue, we generated a catalogue of CIN genes and pathways by screening ∼ 2,000 reduction-of-function alleles for 90% of essential genes in Saccharomyces cerevisiae. Integrating this with published CIN phenotypes for other yeast genes generated a systematic CIN gene dataset comprised of 692 genes. Enriched gene ontology terms defined cellular CIN pathways that, together with sequence orthologs, created a list of human CIN candidate genes, which we cross-referenced to published somatic mutation databases revealing hundreds of mutated CIN candidate genes. Characterization of some poorly characterized CIN genes revealed short telomeres in mutants of the ASTRA/TTT components TTI1 and ASA1. High-throughput phenotypic profiling links ASA1 to TTT (Tel2-Tti1-Tti2 complex function and to TORC1 signaling via Tor1p stability, consistent with the role of TTT in PI3-kinase related kinase biogenesis. The comprehensive CIN gene list presented here in principle comprises all conserved eukaryotic genome integrity pathways. Deriving human CIN candidate genes from the list allows direct cross-referencing with tumor mutational data and thus candidate mutations potentially driving CIN in tumors. Overall, the CIN gene spectrum reveals new chromosome biology and will help us to understand CIN phenotypes in human disease.

  16. A microarray study of gene and protein regulation in human and rat brain following middle cerebral artery occlusion

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    Kumar Pat

    2007-11-01

    Full Text Available Abstract Background Altered gene expression is an important feature of ischemic cerebral injury and affects proteins of many functional classes. We have used microarrays to investigate the changes in gene expression at various times after middle cerebral artery occlusion in human and rat brain. Results Our results demonstrated a significant difference in the number of genes affected and the time-course of expression between the two cases. The total number of deregulated genes in the rat was 335 versus 126 in the human, while, of 393 overlapping genes between the two array sets, 184 were changed only in the rat and 36 in the human with a total of 41 genes deregulated in both cases. Interestingly, the mean fold changes were much higher in the human. The expression of novel genes, including p21-activated kinase 1 (PAK1, matrix metalloproteinase 11 (MMP11 and integrase interactor 1, was further analyzed by RT-PCR, Western blotting and immunohistochemistry. Strong neuronal staining was seen for PAK1 and MMP11. Conclusion Our findings confirmed previous studies reporting that gene expression screening can detect known and unknown transcriptional features of stroke and highlight the importance of research using human brain tissue in the search for novel therapeutic agents.

  17. An up-down bit pattern approach to coregulated and negative-coregulated gene clustering of microarray data.

    Science.gov (United States)

    Chen, Jiun-Rung; Chang, Ye-In

    2011-12-01

    Biclustering, which performs simultaneous clustering of rows (e.g., genes) and columns (e.g., conditions), has been shown to be important for analyzing microarray data. To find biclusters, there have been many methods proposed. Most of these methods can find only clusters with coregulated patterns, which means that the expression levels of genes in a found cluster rise and fall simultaneously. However, for real microarray data, there exist negative-correlated patterns, which means that the tendencies of expression levels of some genes may be completely inverse to those of the other genes under some conditions. Although one method called Co-gclustering was proposed to simultaneously find clusters with correlated and negative-correlated patterns, its time complexity is exponential to the number of conditions, which may not be efficient. Therefore, in this article, we propose a new method, Up-Down Bit pattern (UDB), to efficiently find clusters with correlated and negative-correlated patterns. First, we utilize up-down bit patterns to record those condition pairs where one gene is upregulated or downregulated. One gene is upregulated (or downregulated) under condition pair a and b if its expression level shows an upward (or downward) tendency from condition a to condition b. Then, we apply a heuristic idea on these up-down bit patterns to efficiently find clusters, which will reduce the time complexity from exponential time to polynomial time. From the experimental results, we show that the UDB method is more efficient than the Co-gclustering method. PMID:21210736

  18. Integrating genes and phenotype: a wheat-Arabidopsis-rice glycosyltransferase database for candidate gene analyses.

    Science.gov (United States)

    Sado, Pierre-Etienne; Tessier, Dominique; Vasseur, Marc; Elmorjani, Khalil; Guillon, Fabienne; Saulnier, Luc

    2009-02-01

    Glycosyltransferases (GTs) constitute a very large multi-gene superfamily, containing several thousand members identified in sequenced organisms especially in plants. GTs are key enzymes involved in various biological processes such as cell wall formation, storage polysaccharides biosynthesis, and glycosylation of various metabolites. GTs have been identified in rice (Oryza sativa) and Arabidopsis thaliana, but their precise function has been demonstrated biochemically for only a few. In this work we have established a repertoire of virtually all the wheat (Triticum aestivum) GT sequences, using the large publicly available banks of expressed sequences. Based on sequence similarity with Arabidopsis and rice GTs compiled in the carbohydrate active enzyme database (CAZY), we have identified and classified these wheat sequences. The results were used to feed a searchable database available on the web ( http://wwwappli.nantes.inra.fr:8180/GTIDB ) that can be used for initiating an exhaustive candidate gene survey in wheat applied to a particular biological process. This is illustrated through the identification of GT families which are expressed during cell wall formation in wheat grain maturation. PMID:19005709

  19. Comprehensive microarray-based analysis for stage-specific larval camouflage pattern-associated genes in the swallowtail butterfly, Papilio xuthus

    Directory of Open Access Journals (Sweden)

    Futahashi Ryo

    2012-05-01

    Full Text Available Abstract Background Body coloration is an ecologically important trait that is often involved in prey-predator interactions through mimicry and crypsis. Although this subject has attracted the interest of biologists and the general public, our scientific knowledge on the subject remains fragmentary. In the caterpillar of the swallowtail butterfly Papilio xuthus, spectacular changes in the color pattern are observed; the insect mimics bird droppings (mimetic pattern as a young larva, and switches to a green camouflage coloration (cryptic pattern in the final instar. Despite the wide variety and significance of larval color patterns, few studies have been conducted at a molecular level compared with the number of studies on adult butterfly wing patterns. Results To obtain a catalog of genes involved in larval mimetic and cryptic pattern formation, we constructed expressed sequence tag (EST libraries of larval epidermis for P. xuthus, and P. polytes that contained 20,736 and 5,376 clones, respectively, representing one of the largest collections available in butterflies. A comparison with silkworm epidermal EST information revealed the high expression of putative blue and yellow pigment-binding proteins in Papilio species. We also designed a microarray from the EST dataset information, analyzed more than five stages each for six markings, and confirmed spatial expression patterns by whole-mount in situ hybridization. Hence, we succeeded in elucidating many novel marking-specific genes for mimetic and cryptic pattern formation, including pigment-binding protein genes, the melanin-associated gene yellow-h3, the ecdysteroid synthesis enzyme gene 3-dehydroecdysone 3b-reductase, and Papilio-specific genes. We also found many cuticular protein genes with marking specificity that may be associated with the unique surface nanostructure of the markings. Furthermore, we identified two transcription factors, spalt and ecdysteroid signal-related E75, as genes

  20. Cholesterol tethered bioresponsive polycation as a candidate for gene delivery

    International Nuclear Information System (INIS)

    The efficient unpacking of viral protein shell gave the inspiration for the synthesized vectors. In this research, novel cholesterol tethered bioresponsive polyethylenimine (PEI) was specially designed via disulfide-containing cross-linker. The cholesterol lipid had proved to increase the permeability of gene vector through cell membrane. The acid-base titration indicated that the synthesized polycation possessed efficient proton sponge effect, which was suggested to increase endosomal release of pDNA complexes into the cytoplasm. The cholesterol tethered polycation could effectively induce DNA condensation and form spherical particles with diameter about 200 nm at N/P ratio of 10. At glutathione concentration of 3 mM, the polyplexes were unpacked due to the bioresponsive cleavage of the disulfide bonds. The in-vitro experiment indicated that the polyplexes showed efficient transfection efficiency to HEK293T cells. All the results indicated that the bioresponsive polycation could be served as an effective trigger to control the release of DNA at the intracellular environment. The novel bioresponsive polycation might have great potential in non-viral gene delivery research and application.

  1. Cholesterol tethered bioresponsive polycation as a candidate for gene delivery

    Energy Technology Data Exchange (ETDEWEB)

    Zhu Ying [Second Affiliated Hospital, Medical College, Zhejiang University, Hangzhou 310009 (China); Wang Youxiang, E-mail: yx_wang@zju.edu.cn [Department of Polymer Science and Engineering, Zhejiang University, Hangzhou 310027 (China); Key Laboratory of Macromolecular Synthesis and Functionalization, Ministry of Education, Zhejiang University, Hangzhou 310027 (China); Hu Qiaoling; Shen Jiacong [Department of Polymer Science and Engineering, Zhejiang University, Hangzhou 310027 (China); Key Laboratory of Macromolecular Synthesis and Functionalization, Ministry of Education, Zhejiang University, Hangzhou 310027 (China)

    2009-04-30

    The efficient unpacking of viral protein shell gave the inspiration for the synthesized vectors. In this research, novel cholesterol tethered bioresponsive polyethylenimine (PEI) was specially designed via disulfide-containing cross-linker. The cholesterol lipid had proved to increase the permeability of gene vector through cell membrane. The acid-base titration indicated that the synthesized polycation possessed efficient proton sponge effect, which was suggested to increase endosomal release of pDNA complexes into the cytoplasm. The cholesterol tethered polycation could effectively induce DNA condensation and form spherical particles with diameter about 200 nm at N/P ratio of 10. At glutathione concentration of 3 mM, the polyplexes were unpacked due to the bioresponsive cleavage of the disulfide bonds. The in-vitro experiment indicated that the polyplexes showed efficient transfection efficiency to HEK293T cells. All the results indicated that the bioresponsive polycation could be served as an effective trigger to control the release of DNA at the intracellular environment. The novel bioresponsive polycation might have great potential in non-viral gene delivery research and application.

  2. A software framework for microarray and gene expression object model (MAGE-OM) array design annotation

    Science.gov (United States)

    Qureshi, Matloob; Ivens, Alasdair

    2008-01-01

    Background The MIAME and MAGE-OM standards defined by the MGED society provide a specification and implementation of a software infrastructure to facilitate the submission and sharing of data from microarray studies via public repositories. However, although the MAGE object model is flexible enough to support different annotation strategies, the annotation of array descriptions can be complex. Results We have developed a graphical Java-based application (Adamant) to assist with submission of Microarray designs to public repositories. Output of the application is fully compliant with the standards prescribed by the various public data repositories. Conclusion Adamant will allow researchers to annotate and submit their own array designs to public repositories without requiring programming expertise, knowledge of the MAGE-OM or XML. The application has been used to submit a number of ArrayDesigns to the Array Express database. PMID:18366695

  3. Association of adipocyte genes with ASP expression: a microarray analysis of subcutaneous and omental adipose tissue in morbidly obese subjects

    Directory of Open Access Journals (Sweden)

    Lu HuiLing

    2010-01-01

    Full Text Available Abstract Background Prevalence of obesity is increasing to pandemic proportions. However, obese subjects differ in insulin resistance, adipokine production and co-morbidities. Based on fasting plasma analysis, obese subjects were grouped as Low Acylation Stimulating protein (ASP and Triglyceride (TG (LAT vs High ASP and TG (HAT. Subcutaneous (SC and omental (OM adipose tissues (n = 21 were analysed by microarray, and biologic pathways in lipid metabolism and inflammation were specifically examined. Methods LAT and HAT groups were matched in age, obesity, insulin, and glucose, and had similar expression of insulin-related genes (InsR, IRS-1. ASP related genes tended to be increased in the HAT group and were correlated (factor B, adipsin, complement C3, p Results HAT adipose tissue demonstrated increased lipid related genes for storage (CD36, DGAT1, DGAT2, SCD1, FASN, and LPL, lipolysis (HSL, CES1, perilipin, fatty acid binding proteins (FABP1, FABP3 and adipocyte differentiation markers (CEBPα, CEBPβ, PPARγ. By contrast, oxidation related genes were decreased (AMPK, UCP1, CPT1, FABP7. HAT subjects had increased anti-inflammatory genes TGFB1, TIMP1, TIMP3, and TIMP4 while proinflammatory PIG7 and MMP2 were also significantly increased; all genes, p Conclusion Taken together, the profile of C5L2 receptor, ASP gene expression and metabolic factors in adipose tissue from morbidly obese HAT subjects suggests a compensatory response associated with the increased plasma ASP and TG.

  4. A software framework for microarray and gene expression object model (MAGE-OM) array design annotation

    OpenAIRE

    Ivens Alasdair; Qureshi Matloob

    2008-01-01

    Abstract Background The MIAME and MAGE-OM standards defined by the MGED society provide a specification and implementation of a software infrastructure to facilitate the submission and sharing of data from microarray studies via public repositories. However, although the MAGE object model is flexible enough to support different annotation strategies, the annotation of array descriptions can be complex. Results We have developed a graphical Java-based application (Adamant) to assist with submi...

  5. Kernelized partial least squares for feature reduction and classification of gene microarray data

    OpenAIRE

    Land Walker H; Qiao Xingye; Margolis Daniel E; Ford William S; Paquette Christopher T; Perez-Rogers Joseph F; Borgia Jeffrey A; Yang Jack Y; Deng Youping

    2011-01-01

    Abstract Background The primary objectives of this paper are: 1.) to apply Statistical Learning Theory (SLT), specifically Partial Least Squares (PLS) and Kernelized PLS (K-PLS), to the universal "feature-rich/case-poor" (also known as "large p small n", or "high-dimension, low-sample size") microarray problem by eliminating those features (or probes) that do not contribute to the "best" chromosome bio-markers for lung cancer, and 2.) quantitatively measure and verify (by an independent means...

  6. Differential gene expression in recombinant Pichia pastoris analysed by heterologous DNA microarray hybridisation

    OpenAIRE

    Porro Danilo; Maurer Michael; Valli Minoska; Gasser Brigitte; Branduardi Paola; Sauer Michael; Mattanovich Diethard

    2004-01-01

    Abstract Background Pichia pastoris is a well established yeast host for heterologous protein expression, however, the physiological and genetic information about this yeast remains scanty. The lack of a published genome sequence renders DNA arrays unavailable, thereby hampering more global investigations of P. pastoris from the beginning. Here, we examine the suitability of Saccharomyces cerevisiae DNA microarrays for heterologous hybridisation with P. pastoris cDNA. Results We could show th...

  7. Development of a miniaturised microarray-based assay for the rapid identification of antimicrobial resistance genes in Gram-negative bacteria

    NARCIS (Netherlands)

    Batchelor, M.; Hopkins, K.L.; Liebana, E.; Slickers, P.; Ehricht, R.; Mafura, M.; Aerestrup, F.; Mevius, D.J.; Clifton-Hadley, F.A.; Woodward, M.; Davies, R.; Threlfall, J.; Anjum, F.M.

    2008-01-01

    We describe the development of a miniaturised microarray for the detection of antimicrobial resistance genes in Gram-negative bacteria. Included on the array are genes encoding resistance to aminoglycosides, trimethoprim, sulphonamides, tetracyclines and ß-lactams, including extended-spectrum ß-lact

  8. Removing Batch Effects from Longitudinal Gene Expression - Quantile Normalization Plus ComBat as Best Approach for Microarray Transcriptome Data

    Science.gov (United States)

    Müller, Christian; Schillert, Arne; Röthemeier, Caroline; Trégouët, David-Alexandre; Proust, Carole; Binder, Harald; Pfeiffer, Norbert; Beutel, Manfred; Lackner, Karl J.; Schnabel, Renate B.; Tiret, Laurence; Wild, Philipp S.; Blankenberg, Stefan

    2016-01-01

    Technical variation plays an important role in microarray-based gene expression studies, and batch effects explain a large proportion of this noise. It is therefore mandatory to eliminate technical variation while maintaining biological variability. Several strategies have been proposed for the removal of batch effects, although they have not been evaluated in large-scale longitudinal gene expression data. In this study, we aimed at identifying a suitable method for batch effect removal in a large study of microarray-based longitudinal gene expression. Monocytic gene expression was measured in 1092 participants of the Gutenberg Health Study at baseline and 5-year follow up. Replicates of selected samples were measured at both time points to identify technical variability. Deming regression, Passing-Bablok regression, linear mixed models, non-linear models as well as ReplicateRUV and ComBat were applied to eliminate batch effects between replicates. In a second step, quantile normalization prior to batch effect correction was performed for each method. Technical variation between batches was evaluated by principal component analysis. Associations between body mass index and transcriptomes were calculated before and after batch removal. Results from association analyses were compared to evaluate maintenance of biological variability. Quantile normalization, separately performed in each batch, combined with ComBat successfully reduced batch effects and maintained biological variability. ReplicateRUV performed perfectly in the replicate data subset of the study, but failed when applied to all samples. All other methods did not substantially reduce batch effects in the replicate data subset. Quantile normalization plus ComBat appears to be a valuable approach for batch correction in longitudinal gene expression data. PMID:27272489

  9. Identification of Candidate Genes related to Bovine Marbling using Protein-Protein Interaction Networks

    Directory of Open Access Journals (Sweden)

    Dajeong Lim, Nam-Kuk Kim, Hye-Sun Park, Seung-Hwan Lee, Yong-Min Cho, Sung Jong Oh, Tae-Hun Kim, Heebal Kim

    2011-01-01

    Full Text Available Complex traits are determined by the combined effects of many loci and are affected by gene networks or biological pathways. Systems biology approaches have an important role in the identification of candidate genes related to complex diseases or traits at the system level. The present study systemically analyzed genes associated with bovine marbling score and identified their relationships. The candidate nodes were obtained using MedScan text-mining tools and linked by protein-protein interaction (PPI from the Human Protein Reference Database (HPRD. To determine key node of marbling, the degree and betweenness centrality (BC were used. The hub nodes and biological pathways of our network are consistent with the previous reports about marbling traits, and also suggest unknown candidate genes associated with intramuscular fat. Five nodes were identified as hub genes, which was consistent with the network analysis using quantitative reverse-transcription PCR (qRT-PCR. Key nodes of the PPI network have positive roles (PPARγ, C/EBPα, and RUNX1T1 and negative roles (RXRA, CAMK2A in the development of intramuscular fat by several adipogenesis-related pathways. This study provides genetic information for identifying candidate genes for the marbling trait in bovine.

  10. Identification of MSRA gene on chromosome 8p as a candidate metastasis suppressor for human hepatitis B virus-positive hepatocellular carcinoma

    International Nuclear Information System (INIS)

    The prognosis of patients with hepatocellular carcinoma (HCC) still remains very dismal, which is mainly due to metastasis. In our previous studies, we found that chromosome 8p deletions might contribute to metastasis of HCC. In this study, we aimed to identify the candidate metastatic suppressor gene on chromosome 8p. Oligo-nucleotide microarrays which included 322 genes on human chromosome 8p were constructed to analyze the difference in gene expression profiles between HCC tissues with and without metastasis. The leading differentially expressed genes were identified and selected for further analysis by real-time PCR and Western blotting. Recombinant expression plasmid vectors for each target gene were constructed and transfected into HCC cells and its in vitro effects on proliferation and invasion of HCC cells were also investigated. Sixteen leading differentially expressed genes were identified from the HCC tissues with metastasis compared with those without metastasis (p < 0.01, q < 16 %). Among of the 10 significantly down-regulated genes in HCC with metastasis, methionine sulfoxide reductase A (MSRA) had the lowest p value and false discovery rate (FDR), and was considered as a potential candidate for metastasis suppressor gene. Real-time PCR and Western blotting confirmed that the mRNA and protein expression levels of MSRA were significantly decreased in HCC with metastasis compared with those without metastasis (p < 0.001), and MSRA mRNA level in HCCLM6 cells (with high metastatic potential) was also much lower than that of other HCC cell lines. Transfection of a recombinant expression plasmid vector and overexpression of MSRA gene could obviously inhibit cell colony formation (4.33 ± 2.92 vs. 9.17 ± 3.38, p = 0.008) and invasion (7.40 ± 1.67 vs. 17.20 ± 2.59, p= 0.0001) of HCCLM6 cell line. MSRA gene on chromosome 8p might possess metastasis suppressor activity in HCC

  11. A transcription map of the 6p22.3 reading disability locus identifying candidate genes

    Directory of Open Access Journals (Sweden)

    Gruen Jeffrey R

    2003-06-01

    Full Text Available Abstract Background Reading disability (RD is a common syndrome with a large genetic component. Chromosome 6 has been identified in several linkage studies as playing a significant role. A more recent study identified a peak of transmission disequilibrium to marker JA04 (G72384 on chromosome 6p22.3, suggesting that a gene is located near this marker. Results In silico cloning was used to identify possible candidate genes located near the JA04 marker. The 2 million base pairs of sequence surrounding JA04 was downloaded and searched against the dbEST database to identify ESTs. In total, 623 ESTs from 80 different tissues were identified and assembled into 153 putative coding regions from 19 genes and 2 pseudogenes encoded near JA04. The identified genes were tested for their tissue specific expression by RT-PCR. Conclusions In total, five possible candidate genes for RD and other diseases mapping to this region were identified.

  12. Mapping a candidate gene (MdMYB10 for red flesh and foliage colour in apple

    Directory of Open Access Journals (Sweden)

    Allan Andrew C

    2007-07-01

    Full Text Available Abstract Background Integrating plant genomics and classical breeding is a challenge for both plant breeders and molecular biologists. Marker-assisted selection (MAS is a tool that can be used to accelerate the development of novel apple varieties such as cultivars that have fruit with anthocyanin through to the core. In addition, determining the inheritance of novel alleles, such as the one responsible for red flesh, adds to our understanding of allelic variation. Our goal was to map candidate anthocyanin biosynthetic and regulatory genes in a population segregating for the red flesh phenotypes. Results We have identified the Rni locus, a major genetic determinant of the red foliage and red colour in the core of apple fruit. In a population segregating for the red flesh and foliage phenotype we have determined the inheritance of the Rni locus and DNA polymorphisms of candidate anthocyanin biosynthetic and regulatory genes. Simple Sequence Repeats (SSRs and Single Nucleotide Polymorphisms (SNPs in the candidate genes were also located on an apple genetic map. We have shown that the MdMYB10 gene co-segregates with the Rni locus and is on Linkage Group (LG 09 of the apple genome. Conclusion We have performed candidate gene mapping in a fruit tree crop and have provided genetic evidence that red colouration in the fruit core as well as red foliage are both controlled by a single locus named Rni. We have shown that the transcription factor MdMYB10 may be the gene underlying Rni as there were no recombinants between the marker for this gene and the red phenotype in a population of 516 individuals. Associating markers derived from candidate genes with a desirable phenotypic trait has demonstrated the application of genomic tools in a breeding programme of a horticultural crop species.

  13. Gene expression analysis in sections and tissue microarrays of archival tissues by mRNA in situ hybridization

    OpenAIRE

    Henke, R.T.; A. Maitra; Palk, S.; Wellstein, A.

    2005-01-01

    Altered expression of genes in diseased tissues can prognosticate a distinct natural progression of the disease as well as predict sensitivity or resistance to particular therapies. Archival tissues from patients with a known medical history and treatments are an invaluable resource to validate the utility of candidate genes for prognosis and prediction of therapy outcomes. However, stored tissues with associated long-term follow-up information typically are fo...

  14. Understanding Autoimmune Mechanisms in Multiple Sclerosis Using Gene Expression Microarrays: Treatment Effect and Cytokine-related Pathways

    Directory of Open Access Journals (Sweden)

    A. Achiron

    2004-01-01

    Full Text Available Multiple sclerosis (MS is a central nervous system disease in which activated autoreactive T-cells invade the blood brain barrier and initiate an inflammatory response that leads to myelin destruction and axonal loss. The etiology of MS, as well as the mechanisms associated with its unexpected onset, the unpredictable clinical course spanning decades, and the different rates of progression leading to disability over time, remains an enigma. We have applied gene expression microarrays technology in peripheral blood mononuclear cells (PBMC to better understand MS pathogenesis and better target treatment approaches. A signature of 535 genes were found to distinguish immunomodulatory treatment effects between 13 treated and 13 untreated MS patients. In addition, the expression pattern of 1109 gene transcripts that were previously reported to significantly differentiate between MS patients and healthy subjects were further analyzed to study the effect of cytokine-related pathways on disease pathogenesis. When relative gene expression for 26 MS patients was compared to 18 healthy controls, 30 genes related to various cytokine-associated pathways were identified. These genes belong to a variety of families such as interleukins, small inducible cytokine subfamily and tumor necrosis factor ligand and receptor. Further analysis disclosed seven cytokine-associated genes within the immunomodulatory treatment signature, and two cytokine-associated genes SCYA4 (small inducible cytokine A4 and FCAR (Fc fragment of IgA, CD89 that were common to both the MS gene expression signature and the immunomodulatory treatment gene expression signature. Our results indicate that cytokine-associated genes are involved in various pathogenic pathways in MS and also related to immunomodulatory treatment effects.

  15. Use of a Microarray to Detect Expression of Genes for Lignin-Degrading Enzymes in Soil Fungi

    Science.gov (United States)

    Bailey, V. L.; Smith, J. L.; Bolton, H.

    2003-12-01

    Lignin is a complex biopolymer that is degraded by fungi. Several extracellular enzymes have been implicated in degradation and include lignin peroxidases, laccases, manganese peroxidases, and glyoxal oxidases. Versions of these enzymes are produced by multiple species of fungi, and in some cases, multiple versions of a single enzyme may be produced by the same species of fungus. Previous research has indicated changes in fungal activity and diversity along a tallgrass prairie restoration chronosequence (Fermi National Lab, IL). A cDNA microarray was designed to interrogate the expression and microbial source of these lignin degrading enzymes in the chronosequence soils. We hypothesized that less diversity in gene expression would be detected in a farmed soil than in a restored prairie soil. The array had 46 oligonucleotides (15-25mer) that represent each of the enzymes listed above. Messenger RNA was extracted from 32 one-gram subsamples of the target soils then all of the extracts were pooled prior to RNA precipitation and mRNA purification. Aminoallyl modified dUTPs were incorporated during reverse transcription, after which the cDNA was labeled with Alexa-555 dye. The labeled cDNA was hybridized with the microarray for 24 hours and then imaged. Preliminary results support the hypothesis that fewer genes were expressed in the farmed soil than in the restored soil.

  16. Neuroprotective changes of striatal degeneration-related gene expression by acupuncture in an MPTP mouse model of Parkinsonism: microarray analysis.

    Science.gov (United States)

    Choi, Yeong-Gon; Yeo, Sujung; Hong, Yeon-Mi; Lim, Sabina

    2011-04-01

    Acupuncture at acupoints GB34 and LR3 has been reported to inhibit nigrostriatal degeneration in Parkinsonism models, yet the genes related to this preventive effect of acupuncture on the nigrostriatal dopaminergic system remain elusive. This study investigated gene expression profile changes in the striatal region of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced Parkinsonism models after acupuncture at the acupoints GB34 and LR3 using a whole transcript genechip microarray (Affymetrix genechip mouse gene 1.0 ST array). It was confirmed that acupuncture at these acupoints could inhibit the decrease of tyrosine hydroxylase and dopamine transporter in the nigrostriatal region of the MPTP model while acupuncture at the non-acupoints could not counteract this decrease. Genechip gene array analysis (fold change cutoff 1.3 and P < 0.05) showed that 12 of the 69 probes up-regulated in MPTP when compared to the control were down-regulated by acupuncture at the acupoints. Of these 12 probes, 11 probes (nine annotated genes) were exclusively down-regulated by acupuncture only at the acupoints; the Gfral gene was excluded because it was commonly down-regulated by acupuncture at both the acupoints and the non-acupoints. In addition, 28 of the 189 probes down-regulated in MPTP when compared to the control were up-regulated by acupuncture at the acupoints. Of these 28 probes, 19 probes (seven annotated genes) were exclusively up-regulated by acupuncture only at the acupoints while nine probes were commonly up-regulated by acupuncture at both the acupoints and the non-acupoints. The regulation patterns of representative genes in real-time RT-PCR correlated with those of the genes in the microarray. These results suggest that the 30 probes (16 annotated genes), which are affected by MPTP and acupuncture only at the acupoints, are responsible for exerting in the striatal regions the inhibitory effect of acupuncture at the acupoints on MPTP-induced striatal

  17. A Microarray Based Genomic Hybridization Method for Identification of New Genes in Plants: Case Analyses of Arabidopsis and Oryza

    Institute of Scientific and Technical Information of China (English)

    Chuanzhu Fan; Maria D. Vibranovski; Ying Chen; Manyuan Long

    2007-01-01

    To systematically estimate the gene duplication events in closely related species, we have to use comparative genomic approaches, either through genomic sequence comparison or comparative genomic hybridization (CGH). Given the scarcity of complete genomic sequences of plant species, in the present study we adopted an array based CGH to investigate gene duplications in the genus Arabidopsis. Fragment genomic DNA from four species, namely Arabidopsis thaliana, A. lyrata subsp. lyrata, A. lyrata subsp. petraea, and A. halleri, was hybridized to Affymetrix (Santa Clara, CA, USA) tiling arrays that are designed from the genomic sequences of A. thaliana. Pairwise comparisons of signal intensity were made to infer the potential duplicated candidates along each phylo-genetic branch. Ninety-four potential candidates of gene duplication along the genus were identified. Among them, the majority (69 of 94) were A. thaliana lineage specific. This result indicates that the array based CGH approach may be used to identify candidates of duplication in other plant genera containing closely related species, such as Oryza, particularly for the AA genome species. We compared the degree of gene duplication through retrotransposon between O. sativa and A. thaliana and found a strikingly higher number of chimera retroposed genes in rice. The higher rate of gene duplication through retroposition and other mechanisms may indicate that the grass species is able to adapt to more diverse environments.

  18. Social cognitive role of schizophrenia candidate gene GABRB2.

    Directory of Open Access Journals (Sweden)

    Shui Ying Tsang

    Full Text Available The occurrence of positive selection in schizophrenia-associated GABRB2 suggests a broader impact of the gene product on population fitness. The present study considered the possibility of cognition-related GABRB2 involvement by examining the association of GABRB2 with psychosis and altruism, respectively representing psychiatric and psychological facets of social cognition. Four single nucleotide polymorphisms (SNPs were genotyped for quantitative trait analyses and population-based association studies. Psychosis was measured by either the Positive and Negative Syndrome Scale (PANSS or antipsychotics dosage, and altruism was based on a self-report altruism scale. The minor alleles of SNPs rs6556547, rs1816071 and rs187269 in GABRB2 were correlated with high PANSS score for positive symptoms in a Han Chinese schizophrenic cohort, whereas those of rs1816071 and rs1816072 were associated with high antipsychotics dosage in a US Caucasian schizophrenic cohort. Moreover, strongly significant GABRB2-disease associations were found among schizophrenics with severe psychosis based on high PANSS positive score, but no significant association was observed for schizophrenics with only mild psychosis. Interestingly, in addition to association with psychosis in schizophrenics, rs187269 was also associated with altruism in healthy Han Chinese. Furthermore, parallel to correlation with severe psychosis, its minor allele was correlated with high altruism scores. These findings revealed that GABRB2 is associated with psychosis, the core symptom and an endophenotype of schizophrenia. Importantly, the association was found across the breadth of the psychiatric (psychosis to psychological (altruism spectrum of social cognition suggesting GABRB2 involvement in human cognition.

  19. Gametogenesis in the Pacific oyster Crassostrea gigas: a microarrays-based analysis identifies sex and stage specific genes.

    Directory of Open Access Journals (Sweden)

    Nolwenn M Dheilly

    Full Text Available BACKGROUND: The Pacific oyster Crassostrea gigas (Mollusca, Lophotrochozoa is an alternative and irregular protandrous hermaphrodite: most individuals mature first as males and then change sex several times. Little is known about genetic and phenotypic basis of sex differentiation in oysters, and little more about the molecular pathways regulating reproduction. We have recently developed and validated a microarray containing 31,918 oligomers (Dheilly et al., 2011 representing the oyster transcriptome. The application of this microarray to the study of mollusk gametogenesis should provide a better understanding of the key factors involved in sex differentiation and the regulation of oyster reproduction. METHODOLOGY/PRINCIPAL FINDINGS: Gene expression was studied in gonads of oysters cultured over a yearly reproductive cycle. Principal component analysis and hierarchical clustering showed a significant divergence in gene expression patterns of males and females coinciding with the start of gonial mitosis. ANOVA analysis of the data revealed 2,482 genes differentially expressed during the course of males and/or females gametogenesis. The expression of 434 genes could be localized in either germ cells or somatic cells of the gonad by comparing the transcriptome of female gonads to the transcriptome of stripped oocytes and somatic tissues. Analysis of the annotated genes revealed conserved molecular mechanisms between mollusks and mammals: genes involved in chromatin condensation, DNA replication and repair, mitosis and meiosis regulation, transcription, translation and apoptosis were expressed in both male and female gonads. Most interestingly, early expressed male-specific genes included bindin and a dpy-30 homolog and female-specific genes included foxL2, nanos homolog 3, a pancreatic lipase related protein, cd63 and vitellogenin. Further functional analyses are now required in order to investigate their role in sex differentiation in oysters

  20. Third chromosome candidate genes for conspecific sperm precedence between D. simulans and D. mauritiana

    Directory of Open Access Journals (Sweden)

    Brouwers Barb

    2010-04-01

    Full Text Available Abstract Background Male - female incompatibilities can be critical in keeping species as separate and discrete units. Premating incompatibilities and postzygotic hybrid sterility/inviability have been widely studied as isolating barriers between species. In recent years, a number of studies have brought attention to postmating prezygotic barriers arising from male - male competition and male - female interactions. Yet little is known about the genetic basis of postmating prezygotic isolation barriers between species. Results Using D. simulans lines with mapped introgressions of D. mauritiana into their third chromosome, we find at least two D. mauritiana introgressions causing male breakdown in competitive paternity success. Eighty one genes within the mapped introgressed regions were identified as broad-sense candidates on the basis of male reproductive tract expression and male-related function. The list of candidates was narrowed down to five genes based on differences in male reproductive tract expression between D. simulans and D. mauritiana. Another ten genes were confirmed as candidates using evidence of adaptive gene coding sequence diversification in the D. simulans and/or D. mauritiana lineage. Our results show a complex genetic basis for conspecific sperm precedence, with evidence of gene interactions between at least two third chromosome loci. Pleiotropy is also evident from correlation between conspecific sperm precedence and female induced fecundity and the identification of candidate genes that might exert an effect through genetic conflict and immunity. Conclusions We identified at least two loci responsible for conspecific sperm precedence. A third of candidate genes within these two loci are located in the 89B cytogenetic position, highlighting a possible major role for this chromosome position during the evolution of species specific adaptations to postmating prezygotic reproductive challenges.

  1. Gene Microarray Analyses of Daboia russelli russelli Daboiatoxin Treatment of THP-1 Human Macrophages Infected with Burkholderia pseudomallei.

    Science.gov (United States)

    Perumal Samy, R; Manikandan, J; Pachiappan, A; Ooi, E E; Aw, L T; Stiles, B G; Franco, O L; Kandasamy, M; Mathi, K M; Rane, G; Siveen, K S; Arunachalam, C; Zayed, M E; Alharbi, S A; Kumar, A P; Sethi, G; Lim, L H K; Chow, V T

    2015-01-01

    Burkholderia pseudomallei is the causative agent of melioidosis and represents a potential bioterrorism threat. In this study, the transcriptomic responses of B. pseudomallei infection of a human macrophage cell model were investigated using whole-genome microarrays. Gene expression profiles were compared between infected THP-1 human monocytic leukemia cells with or without treatment with Daboia russelli russelli daboiatoxin (DRRDbTx) or ceftazidime (antibiotic control). Microarray analyses of infected and treated cells revealed differential upregulation of various inflammatory genes such as interleukin-1 (IL-1), IL-6, tumor necrosis factor-alpha (TNF-α), cyclooxygenase (COX-2), vascular endothelial growth factor (VEGF), chemokine C-X-C motif ligand 4 (CXCL4), transcription factor p65 (NF-kB); and several genes involved in immune and stress responses, cell cycle, and lipid metabolism. Moreover, following DRR-DbTx treatment of infected cells, there was enhanced expression of the tolllike receptor 2 (TLR-2) mediated signaling pathway involved in recognition and initiation of acute inflammatory responses. Importantly, we observed that highly inflammatory cytokine gene responses were similar in infected cells exposed to DRR-DbTx or ceftazidime after 24 h. Additionally, there were increased transcripts associated with cell death by caspase activation that can promote host tissue injury. In summary, the transcriptional responses during B. pseudomallei infection of macrophages highlight a broad range of innate immune mechanisms that are activated within 24 h post-infection. These data provide insights into the transcriptomic kinetics following DRR-DbTx treatment of human macrophages infected with B. pseudomallei. PMID:26592245

  2. Identification of candidate cancer-causing genes in mouse brain tumors by retroviral tagging.

    Science.gov (United States)

    Johansson, Fredrik K; Brodd, Josefin; Eklöf, Charlotta; Ferletta, Maria; Hesselager, Göran; Tiger, Carl-Fredrik; Uhrbom, Lene; Westermark, Bengt

    2004-08-01

    Murine retroviruses may cause malignant tumors in mice by insertional mutagenesis of host genes. The use of retroviral tagging as a means of identifying cancer-causing genes has, however, almost entirely been restricted to hematopoietic tumors. The aim of this study was to develop a system allowing for the retroviral tagging of candidate genes in malignant brain tumors. Mouse gliomas were induced by a recombinant Moloney murine leukemia virus encoding platelet-derived growth factor (PDGF) B-chain. The underlying idea was that tumors evolve through a combination of PDGF-mediated autocrine growth stimulation and insertional mutagenesis of genes that cooperate with PDGF in gliomagenesis. Common insertion sites (loci that were tagged in more than one tumor) were identified by cloning and sequencing retroviral flanking segments, followed by blast searches of mouse genome databases. A number of candidate brain tumor loci (Btls) were identified. Several of these Btls correspond to known tumor-causing genes; these findings strongly support the underlying idea of our experimental approach. Other Btls harbor genes with a hitherto unproven role in transformation or oncogenesis. Our findings indicate that retroviral tagging with a growth factor-encoding virus may be a powerful means of identifying candidate tumor-causing genes in nonhematopoietic tumors. PMID:15273287

  3. Analysis of breast cancer metastasis candidate genes from next generation-sequencing via systematic functional genomics

    DEFF Research Database (Denmark)

    Blomstrøm, Monica Marie

    2016-01-01

    ) and non-CSCs. The main goal of this project was to functionally characterize a set of candidate genes recovered from next-generation sequencing analysis for their role in breast cancer metastasis formation. The starting gene set comprised 104 gene variants; i.e. 57 wildtype and 47 mutated variants....... During the project, the aim was to generate a panel of genetically identical (“isogenic”) MCF7 breast cancer cell lines with inducible overexpression of the gene variants, and to analyze these for effects on breast cancer growth and invasion in vitro under standardized conditions. Moreover, it was aimed...

  4. The candidate tumor suppressor CST6 alters the gene expression profile of human breast carcinoma cells: Down-regulation of the potent mitogenic, motogenic, and angiogenic factor autotaxin

    International Nuclear Information System (INIS)

    We recently coined CST6 as a novel candidate tumor suppressor gene for breast cancer. CST6 indeed is expressed in the normal human breast epithelium, but little or not at all in breast carcinomas and breast cancer cell lines. Moreover, ectopic expression of CST6 in human breast cancer cells suppressed cell proliferation, migration, invasion, and orthotopic tumor growth. To obtain insights into the molecular mechanism by which CST6 exhibits its pleiotropic effects on tumor cells, we compared global gene expression profiles in mock- and CST6-transfected human MDA-MB-435S cells. Out of 12,625 transcript species, 61 showed altered expression. These included genes for extracellular matrix components, cytokines, kinases, and phosphatases, as well as several key transcription factors. TaqMan PCR assays were used to confirm the microarray data for 7 out of 11 genes. One down-regulated gene product, secreted autotaxin/lyso-phospholipase D, was of particular interest because its down-regulation by CST6 could explain most of CST6's effect on the breast cancer cells. This study thus provides First evidence that CST6 plays a role in the modulation of genes, particularly, genes that are highly relevant to breast cancer progression

  5. Fast DNA serotyping and antimicrobial resistance gene determination of salmonella enterica with an oligonucleotide microarray-based assay.

    Science.gov (United States)

    Braun, Sascha D; Ziegler, Albrecht; Methner, Ulrich; Slickers, Peter; Keiling, Silke; Monecke, Stefan; Ehricht, Ralf

    2012-01-01

    Salmonellosis caused by Salmonella (S.) belongs to the most prevalent food-borne zoonotic diseases throughout the world. Therefore, serotype identification for all culture-confirmed cases of Salmonella infection is important for epidemiological purposes. As a standard, the traditional culture method (ISO 6579:2002) is used to identify Salmonella. Classical serotyping takes 4-5 days to be completed, it is labor-intensive, expensive and more than 250 non-standardized sera are necessary to characterize more than 2,500 Salmonella serovars currently known. These technical difficulties could be overcome with modern molecular methods. We developed a microarray based serogenotyping assay for the most prevalent Salmonella serovars in Europe and North America. The current assay version could theoretically discriminate 28 O-antigens and 86 H-antigens. Additionally, we included 77 targets analyzing antimicrobial resistance genes. The Salmonella assay was evaluated with a set of 168 reference strains representing 132 serovars previously serotyped by conventional agglutination through various reference centers. 117 of 132 (81%) tested serovars showed an unique microarray pattern. 15 of 132 serovars generated a pattern which was shared by multiple serovars (e.g., S. ser. Enteritidis and S. ser. Nitra). These shared patterns mainly resulted from the high similarity of the genotypes of serogroup A and D1. Using patterns of the known reference strains, a database was build which represents the basis of a new PatternMatch software that can serotype unknown Salmonella isolates automatically. After assay verification, the Salmonella serogenotyping assay was used to identify a field panel of 105 Salmonella isolates. All were identified as Salmonella and 93 of 105 isolates (88.6%) were typed in full concordance with conventional serotyping. This microarray based assay is a powerful tool for serogenotyping. PMID:23056321

  6. Discovery of molecular mechanisms of traditional Chinese medicinal formula Si-Wu-Tang using gene expression microarray and connectivity map.

    Directory of Open Access Journals (Sweden)

    Zhining Wen

    Full Text Available To pursue a systematic approach to discovery of mechanisms of action of traditional Chinese medicine (TCM, we used microarrays, bioinformatics and the "Connectivity Map" (CMAP to examine TCM-induced changes in gene expression. We demonstrated that this approach can be used to elucidate new molecular targets using a model TCM herbal formula Si-Wu-Tang (SWT which is widely used for women's health. The human breast cancer MCF-7 cells treated with 0.1 µM estradiol or 2.56 mg/ml of SWT showed dramatic gene expression changes, while no significant change was detected for ferulic acid, a known bioactive compound of SWT. Pathway analysis using differentially expressed genes related to the treatment effect identified that expression of genes in the nuclear factor erythroid 2-related factor 2 (Nrf2 cytoprotective pathway was most significantly affected by SWT, but not by estradiol or ferulic acid. The Nrf2-regulated genes HMOX1, GCLC, GCLM, SLC7A11 and NQO1 were upregulated by SWT in a dose-dependent manner, which was validated by real-time RT-PCR. Consistently, treatment with SWT and its four herbal ingredients resulted in an increased antioxidant response element (ARE-luciferase reporter activity in MCF-7 and HEK293 cells. Furthermore, the gene expression profile of differentially expressed genes related to SWT treatment was used to compare with those of 1,309 compounds in the CMAP database. The CMAP profiles of estradiol-treated MCF-7 cells showed an excellent match with SWT treatment, consistent with SWT's widely claimed use for women's diseases and indicating a phytoestrogenic effect. The CMAP profiles of chemopreventive agents withaferin A and resveratrol also showed high similarity to the profiles of SWT. This study identified SWT as an Nrf2 activator and phytoestrogen, suggesting its use as a nontoxic chemopreventive agent, and demonstrated the feasibility of combining microarray gene expression profiling with CMAP mining to discover mechanisms

  7. Pharmacogenetic effects of 'candidate gene complexes' on stroke in the GenHAT study

    DEFF Research Database (Denmark)

    Sørensen, Izel F; Vazquez, Ana I; Irvin, Marguerite R;

    2014-01-01

    Americans and 539 whites who had experienced stroke in the GenHAT study were genotyped for 768 single nucleotide polymorphisms (SNPs) in 280 candidate genes. To detect a genotype-by-treatment interaction, we used the Pearson's χ-test to assess whether the genotype frequencies differed at the single SNP...... level for the three drug treatment groups. From these single SNP analyses, we derived a summary statistic for the degree of association at the gene and gene complex levels. This was done by grouping SNPs using information on gene locations and defining gene complexes on the basis of protein...... groups. In African Americans, SNP rs12143842 showed a significant association (P<0.001) with drug treatment. At the gene level, HNRNPA1P4 and NOS1AP in African Americans and PRICKLE1 and NINJ2 in non-Hispanic whites were significantly associated (P<0.01) with drug treatment, whereas none of the gene...

  8. Functional characterization of satrawberry (Fragaria x ananassa) ripening-related genes identified thoroughout a custom-made oligo-based microarray platform

    OpenAIRE

    Medina Puche, Laura

    2015-01-01

    “Caracterización funcional de genes de fresa (Fragaria × ananassa) relacionados con la maduración identificados a través de una plataforma de microarrays de oligos hecha a medida” A lo largo del desarrollo de esta Tesis se han estudiado los cambios transcriptómicos que ocurren en el receptáculo del fruto de fresa (Fragaria × ananassa) durante su desarrollo y maduración usando una plataforma de microarrays de oligos. Este análisis permitió seleccionar varios genes de interés ...

  9. A Measure of the Signal-to-Noise Ratio of Microarray Samples and Studies Using Gene Correlations

    Science.gov (United States)

    Venet, David; Detours, Vincent; Bersini, Hugues

    2012-01-01

    Background The quality of gene expression data can vary dramatically from platform to platform, study to study, and sample to sample. As reliable statistical analysis rests on reliable data, determining such quality is of the utmost importance. Quality measures to spot problematic samples exist, but they are platform-specific, and cannot be used to compare studies. Results As a proxy for quality, we propose a signal-to-noise ratio for microarray data, the “Signal-to-Noise Applied to Gene Expression Experiments”, or SNAGEE. SNAGEE is based on the consistency of gene-gene correlations. We applied SNAGEE to a compendium of 80 large datasets on 37 platforms, for a total of 24,380 samples, and assessed the signal-to-noise ratio of studies and samples. This allowed us to discover serious issues with three studies. We show that signal-to-noise ratios of both studies and samples are linked to the statistical significance of the biological results. Conclusions We showed that SNAGEE is an effective way to measure data quality for most types of gene expression studies, and that it often outperforms existing techniques. Furthermore, SNAGEE is platform-independent and does not require raw data files. The SNAGEE R package is available in BioConductor. PMID:23251415

  10. Physiological and molecular characterization of drought responses and identification of candidate tolerance genes in cassava

    OpenAIRE

    Turyagyenda, Laban F.; Kizito, Elizabeth B.; Ferguson, Morag; Baguma, Yona; Agaba, Morris; Jagger J W Harvey; Osiru, David S. O.

    2013-01-01

    Cassava is an important root crop to resource-poor farmers in marginal areas, where its production faces drought stress constraints. Given the difficulties associated with cassava breeding, a molecular understanding of drought tolerance in cassava will help in the identification of markers for use in marker-assisted selection and genes for transgenic improvement of drought tolerance. This study was carried out to identify candidate drought-tolerance genes and expression-based markers of droug...

  11. Candidate gene study to investigate the genetic determinants of normal variation in central corneal thickness

    OpenAIRE

    Dimasi, David P.; Kathryn P Burdon; Hewitt, Alex W; Savarirayan, Ravi; Healey, Paul R.; Mitchell, Paul; Mackey, David A.; Craig, Jamie E

    2010-01-01

    Purpose The genetic component underlying variation in central corneal thickness (CCT) in the normal population remains largely unknown. As CCT is an identified risk factor for open-angle glaucoma, understanding the genes involved in CCT determination could improve our understanding of the mechanisms involved in this association. Methods To identify novel CCT genes, we selected eight different candidates based on a range of criteria. These included; aquaporin 1 (AQ1), aquaporin 5 (AQ5), decori...

  12. Identification of key genes in hepatocellular carcinoma and validation of the candidate gene, cdc25a, using gene set enrichment analysis, meta-analysis and cross-species comparison

    OpenAIRE

    Lu, Xiaoxu; Sun, Wen; Tang, Yanping; Zhu, Lingqun; Li, Yuan; Ou, Chao; Yang, Chun; Su, Jianjia; LUO, CHENGPIAO; Hu, Yanling; Cao, Ji

    2015-01-01

    The aim of the present study was to determine key pathways and genes involved in the pathogenesis of hepatocellular carcinoma (HCC) through bioinformatic analyses of HCC microarray data based on cross-species comparison. Microarray data of gene expression in HCC in different species were analyzed using gene set enrichment analysis (GSEA) and meta-analysis. Reverse transcription-quantitative polymerase chain reaction and western blotting were performed to determine the mRNA and protein express...

  13. SSHscreen and SSHdb, generic software for microarray based gene discovery: application to the stress response in cowpea

    Directory of Open Access Journals (Sweden)

    Oelofse Dean

    2010-04-01

    Full Text Available Abstract Background Suppression subtractive hybridization is a popular technique for gene discovery from non-model organisms without an annotated genome sequence, such as cowpea (Vigna unguiculata (L. Walp. We aimed to use this method to enrich for genes expressed during drought stress in a drought tolerant cowpea line. However, current methods were inefficient in screening libraries and management of the sequence data, and thus there was a need to develop software tools to facilitate the process. Results Forward and reverse cDNA libraries enriched for cowpea drought response genes were screened on microarrays, and the R software package SSHscreen 2.0.1 was developed (i to normalize the data effectively using spike-in control spot normalization, and (ii to select clones for sequencing based on the calculation of enrichment ratios with associated statistics. Enrichment ratio 3 values for each clone showed that 62% of the forward library and 34% of the reverse library clones were significantly differentially expressed by drought stress (adjusted p value 88% of the clones in both libraries were derived from rare transcripts in the original tester samples, thus supporting the notion that suppression subtractive hybridization enriches for rare transcripts. A set of 118 clones were chosen for sequencing, and drought-induced cowpea genes were identified, the most interesting encoding a late embryogenesis abundant Lea5 protein, a glutathione S-transferase, a thaumatin, a universal stress protein, and a wound induced protein. A lipid transfer protein and several components of photosynthesis were down-regulated by the drought stress. Reverse transcriptase quantitative PCR confirmed the enrichment ratio values for the selected cowpea genes. SSHdb, a web-accessible database, was developed to manage the clone sequences and combine the SSHscreen data with sequence annotations derived from BLAST and Blast2GO. The self-BLAST function within SSHdb grouped

  14. Biclustering using Parallel Fuzzy Approach for Analysis of Microarray Gene Expression Data

    OpenAIRE

    Dwitiya Tyagi-Tiwari; Sujoy Das; Manoj Jha; Namita Srivastava

    2015-01-01

    Biclusters are required to analyzing gene expression patterns of genes comparing rows in expression profiles and analyzing expression profiles of samples by comparing columns in gene expression matrix. In the process of biclustering we need to cluster genes and samples. The algorithm presented in this paper is based upon the two-way clustering approach in which the genes and samples are clustered using parallel fuzzy C-means clustering using message passing interface, we call it MFCM. MFCM ap...

  15. Screening and functional pathway analysis of genes associated with pediatric allergic asthma using a DNA microarray

    OpenAIRE

    Lu, Li-Qun; Liao, Wei

    2015-01-01

    The present study aimed to identify differentially expressed genes (DEGs) associated with pediatric allergic asthma, and to analyze the functional pathways of the selected target genes, in order to explore the pathogenesis of the disease. The GSE18965 gene expression profile was downloaded from the Gene Expression Omnibus database and was preprocessed. This gene expression profile consisted of seven normal samples and nine samples from patients with pediatric allergic asthma. The DEGs between...

  16. A Latent Variable Approach for Meta-Analysis of Gene Expression Data from Multiple Microarray Experiments

    Directory of Open Access Journals (Sweden)

    Chinnaiyan Arul M

    2007-09-01

    Full Text Available Abstract Background With the explosion in data generated using microarray technology by different investigators working on similar experiments, it is of interest to combine results across multiple studies. Results In this article, we describe a general probabilistic framework for combining high-throughput genomic data from several related microarray experiments using mixture models. A key feature of the model is the use of latent variables that represent quantities that can be combined across diverse platforms. We consider two methods for estimation of an index termed the probability of expression (POE. The first, reported in previous work by the authors, involves Markov Chain Monte Carlo (MCMC techniques. The second method is a faster algorithm based on the expectation-maximization (EM algorithm. The methods are illustrated with application to a meta-analysis of datasets for metastatic cancer. Conclusion The statistical methods described in the paper are available as an R package, metaArray 1.8.1, which is at Bioconductor, whose URL is http://www.bioconductor.org/.

  17. Expressed sequence tags from larval gut of the European corn borer (Ostrinia nubilalis: Exploring candidate genes potentially involved in Bacillus thuringiensis toxicity and resistance

    Directory of Open Access Journals (Sweden)

    Crespo Andre LB

    2009-06-01

    chymotrypsin-like protease genes, and 1 aminopeptidase genes in the resistant strain as compared with the susceptible strain. In contrast, the expression of 3 trypsin- like and 3 chymotrypsin-like protease genes, 2 aminopeptidase genes, and 2 alkaline phosphatase genes were increased in the resistant strain. Such differential expressions of the candidate genes may suggest their involvement in Cry1Ab resistance. Indeed, certain trypsin-like and chymotrypsin-like proteases have previously been found to activate or degrade Bt protoxins and toxins, whereas several aminopeptidases, cadherin-like proteins and alkaline phosphatases have been demonstrated to serve as Bt receptor proteins in other insect species. Conclusion We developed a relatively large EST database consisting of 12,519 high-quality sequences from a total of 15,000 cDNAs from the larval gut of ECB. To our knowledge, this database represents the largest gut-specific EST database from a lepidopteran pest. Our work provides a foundation for future research to develop an ECB gut-specific DNA microarray which can be used to analyze the global changes of gene expression in response to Bt protoxins/toxins and the genetic difference(s between Bt- resistant and susceptible strains. Furthermore, we identified 52 candidate genes that may potentially be involved in Bt toxicity and resistance. Differential expressions of 15 out of the 41 selected candidate genes examined by RT-PCR, including 5 genes with apparently decreased expression and 10 with increased expression in Cry1Ab-resistant strain, may help us conclusively identify the candidate genes involved in Bt resistance and provide us with new insights into the mechanism of Cry1Ab resistance in ECB.

  18. A Candidate Gene Analysis of Methylphenidate Response in Attention-Deficit/Hyperactivity Disorder

    Science.gov (United States)

    McGough, James J.; McCracken, James T.; Loo, Sandra K.; Manganiello, Marc; Leung, Michael C.; Tietjens, Jeremy R.; Trinh, Thao; Baweja, Shilpa; Suddath, Robert; Smalley, Susan L.; Hellemann, Gerhard; Sugar, Catherine A.

    2009-01-01

    Objective: This study examines the potential role of candidate genes in moderating treatment effects of methylphenidate (MPH) in attention-deficit/hyperactivity disorder (ADHD). Method: Eighty-two subjects with ADHD aged 6 to 17 years participated in a prospective, double-blind, placebo-controlled, multiple-dose, crossover titration trial of…

  19. Bioinformatics-Driven Identification and Examination of Candidate Genes for Non-Alcoholic Fatty Liver Disease

    DEFF Research Database (Denmark)

    Banasik, Karina; Justesen, Johanne M.; Hornbak, Malene;

    2011-01-01

    Objective: Candidate genes for non-alcoholic fatty liver disease (NAFLD) identified by a bioinformatics approach were examined for variant associations to quantitative traits of NAFLD-related phenotypes. Research Design and Methods: By integrating public database text mining, trans-organism protein...

  20. Candidate genes for cross-resistance against DNA-damaging drugs

    DEFF Research Database (Denmark)

    Wittig, Rainer; Nessling, Michelle; Will, Rainer D;

    2002-01-01

    Drug resistance of tumor cells leads to major drawbacks in the treatment of cancer. To identify candidate genes for drug resistance, we compared the expression patterns of the drug-sensitive human malignant melanoma cell line MeWo and three derived sublines with acquired resistance to the DNA-dam...

  1. No association of candidate genes with cannabis use in a large sample of Australian twin families

    NARCIS (Netherlands)

    Verweij, C.J.H.; Zietsch, B.P.; Liu, J.Z.; Medland, S.E.; Lynskey, M.T.; Madden, P.A.F.; Agrawal, A.; Montgomery, G.W.; Heath, A.C.; Martin, N.G.

    2012-01-01

    While there is solid evidence that cannabis use is heritable, attempts to identify genetic influences at the molecular level have yielded mixed results. Here, a large twin family sample (n = 7452) was used to test for association between 10 previously reported candidate genes and lifetime frequency

  2. Candidate fire blight resistance genes in Malus identified with the use of genomic tools and approaches

    Science.gov (United States)

    The goal of this research is to utilize current advances in Rosaceae genomics to identify DNA markers for use in marker-assisted selection of durable resistance to fire blight. Candidate fire blight resistance genes were selected and ranked based upon differential expression after inoculation with ...

  3. Mapping and expression of candidate genes for development rate in rainbow trout (Oncorhynchus mykiss)

    Science.gov (United States)

    Development rate has important implications for many aspects of an individual's biology. In rainbow trout (Oncorhynchus mykiss), a major QTL for embryonic development rate has been detected on chromosome 5, but at present, few candidate genes have been mapped to this region. This paucity of known ge...

  4. Batch correction of microarray data substantially improves the identification of genes differentially expressed in Rheumatoid Arthritis and Osteoarthritis

    Directory of Open Access Journals (Sweden)

    Kupfer Peter

    2012-06-01

    Full Text Available Abstract Background Batch effects due to sample preparation or array variation (type, charge, and/or platform may influence the results of microarray experiments and thus mask and/or confound true biological differences. Of the published approaches for batch correction, the algorithm “Combating Batch Effects When Combining Batches of Gene Expression Microarray Data” (ComBat appears to be most suitable for small sample sizes and multiple batches. Methods Synovial fibroblasts (SFB; purity > 98% were obtained from rheumatoid arthritis (RA and osteoarthritis (OA patients (n = 6 each and stimulated with TNF-α or TGF-β1 for 0, 1, 2, 4, or 12 hours. Gene expression was analyzed using Affymetrix Human Genome U133 Plus 2.0 chips, an alternative chip definition file, and normalization by Robust Multi-Array Analysis (RMA. Data were batch-corrected for different acquiry dates using ComBat and the efficacy of the correction was validated using hierarchical clustering. Results In contrast to the hierarchical clustering dendrogram before batch correction, in which RA and OA patients clustered randomly, batch correction led to a clear separation of RA and OA. Strikingly, this applied not only to the 0 hour time point (i.e., before stimulation with TNF-α/TGF-β1, but also to all time points following stimulation except for the late 12 hour time point. Batch-corrected data then allowed the identification of differentially expressed genes discriminating between RA and OA. Batch correction only marginally modified the original data, as demonstrated by preservation of the main Gene Ontology (GO categories of interest, and by minimally changed mean expression levels (maximal change 4.087% or variances for all genes of interest. Eight genes from the GO category “extracellular matrix structural constituent” (5 different collagens, biglycan, and tubulointerstitial nephritis antigen-like 1 were differentially expressed between RA and OA (RA

  5. 基因表达谱芯片数据挖掘系统%Gene expression microarray data mining system

    Institute of Scientific and Technical Information of China (English)

    李荣

    2009-01-01

    Microarray is a kind of important tool used in genomics research, which is closely related with data mining techno-logy.Bridging the research on data mining and bioinformatics, this paper designed and implemented several gene expression microarray data mining analysis models and a data mining system. It was highly scalable and its system entities were indepen-dent. In addition, the complicated algorithms were transparent to users.%基因芯片是基因组研究的重要工具,其数据分析极大依赖于数据挖掘技术.结合数据挖掘技术和生物信息学研究,设计并实现了若干基因表达谱芯片数据挖掘分析模型及相应的数据挖掘系统,具有良好的收缩性和实体独立性,底层复杂的数据挖掘算法对用户透明.

  6. Meta-analysis of microarray data using a pathway-based approach identifies a 37-gene expression signature for systemic lupus erythematosus in human peripheral blood mononuclear cells

    Directory of Open Access Journals (Sweden)

    Fang Hong

    2011-05-01

    Full Text Available Abstract Background A number of publications have reported the use of microarray technology to identify gene expression signatures to infer mechanisms and pathways associated with systemic lupus erythematosus (SLE in human peripheral blood mononuclear cells. However, meta-analysis approaches with microarray data have not been well-explored in SLE. Methods In this study, a pathway-based meta-analysis was applied to four independent gene expression oligonucleotide microarray data sets to identify gene expression signatures for SLE, and these data sets were confirmed by a fifth independent data set. Results Differentially expressed genes (DEGs were identified in each data set by comparing expression microarray data from control samples and SLE samples. Using Ingenuity Pathway Analysis software, pathways associated with the DEGs were identified in each of the four data sets. Using the leave one data set out pathway-based meta-analysis approach, a 37-gene metasignature was identified. This SLE metasignature clearly distinguished SLE patients from controls as observed by unsupervised learning methods. The final confirmation of the metasignature was achieved by applying the metasignature to a fifth independent data set. Conclusions The novel pathway-based meta-analysis approach proved to be a useful technique for grouping disparate microarray data sets. This technique allowed for validated conclusions to be drawn across four different data sets and confirmed by an independent fifth data set. The metasignature and pathways identified by using this approach may serve as a source for identifying therapeutic targets for SLE and may possibly be used for diagnostic and monitoring purposes. Moreover, the meta-analysis approach provides a simple, intuitive solution for combining disparate microarray data sets to identify a strong metasignature. Please see Research Highlight: http://genomemedicine.com/content/3/5/30

  7. Microarray gene expression profiles from mature gonad tissues of Atlantic bluefin tuna, Thunnus thynnus in the Gulf of Mexico

    Directory of Open Access Journals (Sweden)

    Gardner Luke D

    2012-10-01

    Full Text Available Abstract Background Bluefin tunas are highly prized pelagic fish species representing a significant economic resource to fisheries throughout the world. Atlantic bluefin tuna (Thunnus thynnus populations have significantly declined due to overexploitation. As a consequence of their value and population decline, T. thynnus has been the focus of considerable research effort concerning many aspects of their life history. However, in-depth understanding of T. thynnus reproductive biology is still lacking. Knowledge of reproductive physiology is a very important tool for determining effective fisheries and aquaculture management. Transcriptome techniques are proving powerful and provide novel insights into physiological processes. Construction of a microarray from T. thynnus ESTs sourced from reproductive tissues has provided an ideal platform to study the reproductive physiology of bluefin tunas. The aim of this investigation was to compare transcription profiles from the ovaries and testes of mature T. thynnus to establish sex specific variations underlying their reproductive physiology. Results Male and females T. thynnus gonad tissues were collected from the wild and histologically staged. Sub-samples of sexually mature tissues were also measured for their mRNA differential expression among the sexes using the custom microarray design BFT 4X44K. A total of 7068 ESTs were assessed for differential expression of which 1273 ESTs were significantly different (p2 fold change in expression according to sex. Differential expression for 13 of these ESTs was validated with quantitative PCR. These include genes involved in egg envelope formation, hydration, and lipid transport/accumulation more highly expressed in ovaries compared with testis, while genes involved in meiosis, sperm motility and lipid metabolism were more highly expressed in testis compared with ovaries. Conclusions This investigation has furthered our knowledge of bluefin tunas

  8. Differential and correlation analyses of microarray gene expression data in the CEPH Utah families

    DEFF Research Database (Denmark)

    Tan, Qihua; Zhao, Jinghua; Li, Shuxia;

    2008-01-01

    focusing on the demographic characteristics such as age and sex on differential gene expression patterns. Our results show that the differential gene expression pattern between age groups is dominated by down-regulated transcriptional activities in the old subjects. Functional analysis on age......-regulated genes identifies cell-cell signaling as an important functional category implicated in human aging. Sex-dependent gene expression is characterized by genes that may escape X-inactivation and, most interestingly, such a pattern is not affected by the aging process. Analysis on sibship correlation on gene...... expression revealed a large number of significant genes suggesting the importance of a genetic mechanism in regulating transcriptional activities. In addition, we observe an interesting pattern of sibship correlation on gene expression that increases exponentially with the mean of gene expression reflecting...

  9. Microarray-based gene expression profiles in rabbit retina due to negative pressure suction.

    Science.gov (United States)

    Zhao, H X; Niu, C M; Guan, W Y

    2012-01-01

    We investigated a possible molecular pathogenesis involving retinal ganglion cell apoptosis following transient high intraocular pressure. Changes in the gene expression profiles of the retina were detected via gene chip methodology. Twelve New Zealand white rabbits were randomly assigned to control and 3-min negative pressure suction groups. The control group was treated only with a laser, and the experimental group was also treated with suction for 3 min, using a negative pressure generator. Total RNA was then extracted from the retinal tissue at different recovery stages to analyze gene expression profiles using the Agilent rabbit one-way gene chip. The groups were then compared. Immediately after negative pressure suction induction, 704 genes were differentially expressed. Among these, 485 genes were upregulated, and 219 were downregulated. Expression of the genes encoding CRYAA, CRYAB, and TLR3 genes, which are involved in apoptosis, was elevated. The KRT18 gene, which is involved in apoptosis, had reduced expression. Seven days after negative pressure suction, 482 genes were differentially expressed. Among these, 178 genes were upregulated, and 304 were downregulated. Expression of the genes encoding CRYAB, IL1-BETA and IL1R1, which are involved in apoptosis, was upregulated. Ten days after negative pressure suction, 402 genes were differentially expressed. Of these, 213 genes were upregulated, and 189 were downregulated. Apoptosis genes CRYAB, CRYBA3, CRYBB2, IL1- BETA, and IL1R1 showed higher expression levels. We concluded that negative pressure suction for long periods of time (for example, 3 min) results in changes in gene expression. Genes with higher fold changes help protect retinal ganglion cells from apoptosis. We suggest that promoting the expression of these genes should be considered as a new means for treating ischemic-hypoxic retinopathy. PMID:22653643

  10. A cross-species genetic analysis identifies candidate genes for mouse anxiety and human bipolar disorder

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    David G Ashbrook

    2015-07-01

    Full Text Available Bipolar disorder (BD is a significant neuropsychiatric disorder with a lifetime prevalence of ~1%. To identify genetic variants underlying BD genome-wide association studies (GWAS have been carried out. While many variants of small effect associated with BD have been identified few have yet been confirmed, partly because of the low power of GWAS due to multiple comparisons being made. Complementary mapping studies using murine models have identified genetic variants for behavioral traits linked to BD, often with high power, but these identified regions often contain too many genes for clear identification of candidate genes. In the current study we have aligned human BD GWAS results and mouse linkage studies to help define and evaluate candidate genes linked to BD, seeking to use the power of the mouse mapping with the precision of GWAS. We use quantitative trait mapping for open field test and elevated zero maze data in the largest mammalian model system, the BXD recombinant inbred mouse population, to identify genomic regions associated with these BD-like phenotypes. We then investigate these regions in whole genome data from the Psychiatric Genomics Consortium’s bipolar disorder GWAS to identify candidate genes associated with BD. Finally we establish the biological relevance and pathways of these genes in a comprehensive systems genetics analysis.We identify four genes associated with both mouse anxiety and human BD. While TNR is a novel candidate for BD, we can confirm previously suggested associations with CMYA5, MCTP1 and RXRG. A cross-species, systems genetics analysis shows that MCTP1, RXRG and TNR coexpress with genes linked to psychiatric disorders and identify the striatum as a potential site of action. CMYA5, MCTP1, RXRG and TNR are associated with mouse anxiety and human BD. We hypothesize that MCTP1, RXRG and TNR influence intercellular signaling in the striatum.

  11. A cross-species genetic analysis identifies candidate genes for mouse anxiety and human bipolar disorder.

    Science.gov (United States)

    Ashbrook, David G; Williams, Robert W; Lu, Lu; Hager, Reinmar

    2015-01-01

    Bipolar disorder (BD) is a significant neuropsychiatric disorder with a lifetime prevalence of ~1%. To identify genetic variants underlying BD genome-wide association studies (GWAS) have been carried out. While many variants of small effect associated with BD have been identified few have yet been confirmed, partly because of the low power of GWAS due to multiple comparisons being made. Complementary mapping studies using murine models have identified genetic variants for behavioral traits linked to BD, often with high power, but these identified regions often contain too many genes for clear identification of candidate genes. In the current study we have aligned human BD GWAS results and mouse linkage studies to help define and evaluate candidate genes linked to BD, seeking to use the power of the mouse mapping with the precision of GWAS. We use quantitative trait mapping for open field test and elevated zero maze data in the largest mammalian model system, the BXD recombinant inbred mouse population, to identify genomic regions associated with these BD-like phenotypes. We then investigate these regions in whole genome data from the Psychiatric Genomics Consortium's bipolar disorder GWAS to identify candidate genes associated with BD. Finally we establish the biological relevance and pathways of these genes in a comprehensive systems genetics analysis. We identify four genes associated with both mouse anxiety and human BD. While TNR is a novel candidate for BD, we can confirm previously suggested associations with CMYA5, MCTP1, and RXRG. A cross-species, systems genetics analysis shows that MCTP1, RXRG, and TNR coexpress with genes linked to psychiatric disorders and identify the striatum as a potential site of action. CMYA5, MCTP1, RXRG, and TNR are associated with mouse anxiety and human BD. We hypothesize that MCTP1, RXRG, and TNR influence intercellular signaling in the striatum. PMID:26190982

  12. Gene Expression Analysis in Tubule Interstitial Compartments Reveals Candidate Agents for IgA Nephropathy

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    Jinling Wang

    2014-09-01

    Full Text Available Background/Aims: Our aim was to explore the molecular mechanism underlying development of IgA nephropathy and discover candidate agents for IgA nephropathy. Methods: The differentially expressed genes (DEGs between patients with IgA nephropathy and normal controls were identified by the data of GSE35488 downloaded from GEO (Gene Expression Omnibus database. The co-expressed gene pairs among DEGs were screened to construct the gene-gene interaction network. Gene Ontology (GO enrichment analysis was performed to analyze the functions of DEGs. The biologically active small molecules capable of targeting IgA nephropathy were identified using the Connectivity Map (cMap database. Results: A total of 55 genes involved in response to organic substance, transcription factor activity and response to steroid hormone stimulus were identified to be differentially expressed in IgA nephropathy patients compared to healthy individuals. A network with 45 co-expressed gene pairs was constructed. DEGs in the network were significantly enriched in response to organic substance. Additionally, a group of small molecules were identified, such as doxorubicin and thapsigargin. Conclusion: Our work provided a systematic insight in understanding the mechanism of IgA nephropathy. Small molecules such as thapsigargin might be potential candidate agents for the treatment of IgA nephropathy.

  13. Evaluation of candidate reference genes for gene expression normalization in Brassica juncea using real time quantitative RT-PCR.

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    Ruby Chandna

    Full Text Available The real time quantitative reverse transcription PCR (qRT-PCR is becoming increasingly important to gain insight into function of genes. Given the increased sensitivity, ease and reproducibility of qRT-PCR, the requirement of suitable reference genes for normalization has become important and stringent. It is now known that the expression of internal control genes in living organism vary considerably during developmental stages and under different experimental conditions. For economically important Brassica crops, only a couple of reference genes are reported till date. In this study, expression stability of 12 candidate reference genes including ACT2, ELFA, GAPDH, TUA, UBQ9 (traditional housekeeping genes, ACP, CAC, SNF, TIPS-41, TMD, TSB and ZNF (new candidate reference genes, in a diverse set of 49 tissue samples representing different developmental stages, stress and hormone treated conditions and cultivars of Brassica juncea has been validated. For the normalization of vegetative stages the ELFA, ACT2, CAC and TIPS-41 combination would be appropriate whereas TIPS-41 along with CAC would be suitable for normalization of reproductive stages. A combination of GAPDH, TUA, TIPS-41 and CAC were identified as the most suitable reference genes for total developmental stages. In various stress and hormone treated samples, UBQ9 and TIPS-41 had the most stable expression. Across five cultivars of B. juncea, the expression of CAC and TIPS-41 did not vary significantly and were identified as the most stably expressed reference genes. This study provides comprehensive information that the new reference genes selected herein performed better than the traditional housekeeping genes. The selection of most suitable reference genes depends on the experimental conditions, and is tissue and cultivar-specific. Further, to attain accuracy in the results more than one reference genes are necessary for normalization.

  14. Phylogenetic analyses of peanut resistance gene candidates and screening of different genotypes for polymorphic markers.

    Science.gov (United States)

    Radwan, Osman E; Ahmed, Talaat A; Knapp, Steven J

    2010-01-01

    The nucleotide-binding-site-leucine-rich-repeat (NBS-LRR)-encoding