Genome-wide analysis of transcript isoform variation in humans
Ontology highlight
ABSTRACT:
ORGANISM(S): Homo sapiens
PROVIDER: GSE9372 | GEO | 2008/01/13
SECONDARY ACCESSION(S): PRJNA103079
REPOSITORIES: GEO
Similar Datasets
Project description:In addition to the differences between populations in transcriptional and translational regulation of genes, alternative pre-mRNA splicing (AS) is also likely to play an important role in regulating gene expression and generating variation in mRNA and protein isoforms. Recently, the genetic contribution to transcript isoform variation has been reported in individuals of recent European descent. We report here results of an investigation of the differences in AS patterns between human populations. AS patterns in 176 HapMap lymphoblastoid cell lines derived from individuals of European and African ancestry were evaluated using the Affymetrix GeneChip Human Exon 1.0 ST Array. A variety of biological processes such as immune response and mRNA metabolic process were found to be enriched among the differentially spliced genes. The differentially spliced genes also include some involved in human diseases that have different prevalence or susceptibility between populations. The genetic contribution to the population differences in transcript isoform variation was then evaluated by a genome-wide association using the HapMap genotypic data on single nucleotide polymorphisms (SNPs). The results suggest that local and distant genetic variants account for a substantial fraction of the observed transcript isoform variation between human populations. Exon level expression on 176 HapMap cell lines.
2010-08-19 | E-GEOD-9703 | biostudies-arrayexpress
Project description:Variation in gene expression is a fundamental aspect of human phenotypic variation. Several studies have analyzed gene expression levels in populations of different continental ancestry, and concluded that there is variation across populations at a fraction of expressed genes. Here we analyze gene expression levels in African American cell lines, which differ from previously analyzed cell lines in that samples from this population have variable proportions of continental ancestry. We show that for most genes examined, gene expression varies with genetic ancestry. Experiment Overall Design: Lymphoblastoid cell lines (LCL) for 60 HapMap CEU, 60 HapMap YRI, and 82 AFA from the Human Variation Panel were obtained from Coriell Cell Repositories. LCLs were grown in culture, total RNA was extracted and hybridized to Affymetrix HG-FOCUS arrays.
2009-01-14 | E-GEOD-10824 | biostudies-arrayexpress
Project description:Elucidating cytosine modification difference between human populations can enhance our understanding of ethnic specificity in complex traits such as disease predisposition and drug response. In this study, cytosine modification levels in 133 HapMap lymphoblastoid cell lines (LCLs) derived from individuals of European or African ancestry were profiled using the Illumina HumanMethylation450 BeadChip. Approximately 13% of the analyzed CpG sites showed differential modification between the two populations at false discovery rate (FDR) of 1%. CpG sites with greater modification levels in European descents were enriched in the proximal regulatory regions, while those greater in African descents were biased toward gene bodies. More than half of the detected population-specific cytosine modifications could be explained by genetic variation. A substantial proportion of local modification quantitative trait loci (mQTL) exhibited population-specific effects, suggesting that genetic epistasis and/or genotype × environment interaction could be common. Distinct inter-individual correlations were observed between gene expression and cytosine modifications in both proximal promoters and gene bodies, demonstrating a regulatory role of inter-individual variation in cytosine modification. Furthermore, a number of SNPs (single nucleotide polymorphisms) previously identified for complex traits with known racial disparities could be annotated as mQTLs for population-specific CpGs. Our findings revealed abundant population-specific cytosine modifications and the underlying genetic basis, as well as the relatively independent contribution of genetic and epigenetic variations to population differences in gene expression. 60 HapMap CEU and 73 HapMap YRI samples from Coriell Insitute were profiled for cytosine modification levels.
2013-07-01 | E-GEOD-39672 | biostudies-arrayexpress
Project description:In addition to the differences between populations in transcriptional and translational regulation of genes, alternative pre-mRNA splicing (AS) is also likely to play an important role in regulating gene expression and generating variation in mRNA and protein isoforms. Recently, the genetic contribution to transcript isoform variation has been reported in individuals of recent European descent. We report here results of an investigation of the differences in AS patterns between human populations. AS patterns in 176 HapMap lymphoblastoid cell lines derived from individuals of European and African ancestry were evaluated using the Affymetrix GeneChip Human Exon 1.0 ST Array. A variety of biological processes such as immune response and mRNA metabolic process were found to be enriched among the differentially spliced genes. The differentially spliced genes also include some involved in human diseases that have different prevalence or susceptibility between populations. The genetic contribution to the population differences in transcript isoform variation was then evaluated by a genome-wide association using the HapMap genotypic data on single nucleotide polymorphisms (SNPs). The results suggest that local and distant genetic variants account for a substantial fraction of the observed transcript isoform variation between human populations.
2009-03-23 | GSE9703 | GEO
Project description:Alternative pre-mRNA splicing increases proteomic diversity and provides a potential mechanism underlying both phenotypic diversity and susceptibility to genetic disorders in human populations. To investigate the variation in splicing among humans on a genomewide scale, we use a comprehensive exon-targeted microarray to examine alternative splicing in lymphoblasts derived from the CEPH HapMap population. We show the identification of transcripts containing annotated and novel sequence verified exon skipping, intron retention, and cryptic splice site usage that are specific between individuals. Using family-based linkage analysis, we demonstrate Mendelian inheritance and segregation of specific splice isoforms with regulatory haplotypes for three genes. Allelic association was further used to identify individual SNPs or regulatory haplotype blocks linked to the alternative splicing event, taking advantage of the high-resolution genotype information from the CEPH HapMap population. Keywords: Comparative genomic hybridiation within a 3 generation pedigree
2007-08-08 | GSE7952 | GEO
Project description:Cisplatin, a platinating agent commonly used in treating several cancers is associated with nephrotoxicity, neurotoxicity and ototoxicity that have hindered its utility. To gain a better understanding of the genetic variants associated with cisplatin induced toxicity, we present a step-wise approach integrating genotypes, gene expression and sensitivity of HapMap cell lines to cisplatin. Cell lines derived from 30 trios of European descent (CEU) and 30 trios of African descent (YRI) were utilized to develop a preclinical model to identify genetic variants and gene expression that contribute to cisplatin induced cytotoxicity in two different populations. Cytotoxicity was determined as cell growth inhibition at increasing concentrations of cisplatin for 48 h. Gene expression on 176 HapMap cell lines (87 CEU and 89 YRI) was determined using the Affymetrix GeneChip® Human Exon 1.0 ST Array. We identified 6, 2 and 9 representative SNPs that contribute to cisplatin-induced cytotoxicity through their effects on 8, 2 and 16 gene expressions in the combined, CEPH and Yoruban populations, respectively. These genetic variants contribute to 27, 29 and 45% of the overall variation in cell sensitivity to cisplatin in the combined, CEPH and Yoruban populations, respectively. Our whole genome approach can be used to elucidate expression quantitative trait loci contributing to a wide range of cellular phenotypes. Keywords: exon array
2007-06-06 | GSE7761 | GEO
Project description:Gene expression is a complex quantitative trait partially regulated by genetic variation in DNA sequence. Population differences in gene expression could contribute to some of the observed differences in susceptibility to common diseases and responses to drug treatments. We characterize gene expression in the full set of HapMap lymphoblastoid cell lines derived from individuals of European and African ancestry for 9,156 transcript clusters (gene-level) evaluated using the Affymetrix GeneChip® Human Exon 1.0 ST Array. Gene expression was found to differ significantly between these samples for 383 transcript clusters. Biological processes including ribosome biogenesis and antimicrobial humoral response were found to be enriched in these differential genes, suggesting their possible roles in contributing to the population differences at a higher level than mRNA expression and the population differences in response to environmental information. Genome-wide association studies for local or distant genetic variants that correlate with the differentially expressed genes enabled identification of significant associations with one or more single nucleotide polymorphisms (SNPs), consistent with the hypothesis that genetic factors and not simply population identity or other characteristics (age of cell lines, length of culture etc.) contribute to differences in gene expression in these samples. Our results provided a comprehensive view of the genes differentially expressed between populations and the enriched biological processes involved in these genes. We also provided an evaluation of the contribution of genetic variation and non-genetic factors to the population differences in gene expression. Keywords: exon array
2008-05-08 | GSE7851 | GEO
Project description:B lymphoblastoid cell lines were obtained from Coriell Cell Repositories. Cell lines were grown according to Coriell guidelines and total RNA was extracted, labeled, and hybridized to an Affymetrix Human Genome Focus Array as previously described. We found extensive variation in gene-expression levels and estimate that ~83% of genes are differentially expressed among individuals and that ~17% of genes are differentially expressed among populations. By decomposing total gene-expression variation into within- versus among-population components, we find that most expression variation is due to variation among individuals rather than among populations, which parallels observations of extant patterns of human genetic variation. Experiment Overall Design: We used microarrays to survey patterns of natural gene expression variation in 16 HapMap individuals derived from the CEU and YRI samples.
2008-06-15 | E-GEOD-7236 | biostudies-arrayexpress
Project description:Transcript abundance results from the balance between transcription and mRNA decay, and varies pervasively in humans. We have examined the effect of DNA variation on mRNA half-life differences by conducting a genome-wide survey of mRNA stability in seven human HapMap lymphoblastoid cell lines (LCLs). We determined the mRNA half-life for each gene from the ratio of 4-thio-uridine (4sU)-labeled nascent RNAs to total RNAs. 5,145 (46%) of 11,132 analyzed genes showed inter-individual mRNA half-life differences at a false discovery rate, FDR<0.05. As previously reported, we found transcription to be the main factor influencing transcript abundance. Although mRNA half-life explained only ~6% of transcript abundance on average, it explained ~16% for the subset of genes (~10%) showing inter-individual mRNA half-life differences (P<0.001). We confirmed previously reported correlations of mRNA half-life with transcript length, 3M-bM-^@M-^Y-UTR length, and number of exon-junctions per kb of transcript. The number of miRNA targets in 3M-bM-^@M-^Y-UTRs was negatively correlated with half-life (P=2.2M-CM-^W10-16), a new observation that is consistent with the role of miRNA in inducing mRNA degradation. Notably, coding GC and GC3 content showed positive correlations with mRNA half-life in genes with inter-individual mRNA half-life differences, implying a role of mRNA stability in shaping synonymous codon usage bias. Consistently, G or C alleles of coding SNPs were found associated with longer mRNA half-life (P=0.021). As expected, we also found that nonsense SNPs were associated with shorter mRNA half-life (P=0.009). Our results strongly suggest that inter-individual mRNA stability differences are widespread and affected by DNA sequence and composition variation. A total of 7 HapMap LCLs were used to measure mRNA half-life. Total RNAs and the 4sU-labeled-newly synthesized RNAs (nascent RNAs) were isolated from the same cell culture and were assayed simultaneously with human Exon array. For 3 LCLs, we included 3 biological replicates (i.e., independent cell cultures) and for 1 LCL we also included technical duplicates. mRNA half-life was calculated from the ratio of nascent RNAs/total RNAs. We used ANOVA to test inter-individual difference of mRNA half-life between 3 subjects who have biological replicates and technical duplicates. We examined the Spearman rank correlation of mRNA half-life with a number of gene features, including transcript length, intron length, 5'-UTR length and folding energy, 3'-UTR length and folding energy, microRNA target sites, GC and GC3 contents, etc. We also performed linear regression to test the effects of specific type of sequence variants (nonsense SNPs, SNPs within miRNA target sites, and coding synonymous and nonsynonymous SNPs) on mRNA half-life across 3 subjects that have whole genome sequencing data available (1000 genome project June 2011 release).
2013-01-01 | E-GEOD-34204 | biostudies-arrayexpress