Project description:Comparative studies of gene regulation suggest an important role for natural selection in shaping gene expression patterns within and between species. Most of these studies, however, estimated gene expression levels using microarray probes designed to hybridize to only a small proportion of each gene. Here we used recently-developed RNA sequencing protocols, which side-step this limitation, to assess intra- and inter-species variation in gene regulatory processes in considerably more detail than was previously possible. Specifically, we used RNAseq to study transcript levels in humans, chimpanzees, and rhesus macaques, using liver RNA samples from three males and three females from each species. Our approach allowed us to identify a large number of genes whose expression levels likely evolve under natural selection in primates. These include a subset of genes with conserved sexually dimorphic expression patterns across the three species, which we found to be enriched for genes involved in lipid metabolism. Our data also suggest that while alternative splicing is tightly regulated within and between species, sex-specific and lineage-specific changes in the expression of different splice forms are also frequent. Intriguingly, among genes in which a change in exon usage occurred exclusively in the human lineage, we found an enrichment of genes involved in anatomical structure and morphogenesis, raising the possibility that differences in the regulation of alternative splicing have been an important force in human evolution. Keywords: Gene Regulation Study Examination of gene expression levels in livers from three primate species (human, chimpanzee, and rhesus macaque), using 3 male and 3 female samples from each species.
Project description:Comparative studies of gene regulation suggest an important role for natural selection in shaping gene expression patterns within and between species. Most of these studies, however, estimated gene expression levels using microarray probes designed to hybridize to only a small proportion of each gene. Here we used recently-developed RNA sequencing protocols, which side-step this limitation, to assess intra- and inter-species variation in gene regulatory processes in considerably more detail than was previously possible. Specifically, we used RNAseq to study transcript levels in humans, chimpanzees, and rhesus macaques, using liver RNA samples from three males and three females from each species. Our approach allowed us to identify a large number of genes whose expression levels likely evolve under natural selection in primates. These include a subset of genes with conserved sexually dimorphic expression patterns across the three species, which we found to be enriched for genes involved in lipid metabolism. Our data also suggest that while alternative splicing is tightly regulated within and between species, sex-specific and lineage-specific changes in the expression of different splice forms are also frequent. Intriguingly, among genes in which a change in exon usage occurred exclusively in the human lineage, we found an enrichment of genes involved in anatomical structure and morphogenesis, raising the possibility that differences in the regulation of alternative splicing have been an important force in human evolution. Keywords: Gene Regulation Study
Project description:We used long-oligonucleotide microarrays to investigate whether alternative splicing in Drosophila is regulated in a sex-, stage-, or tissue-specific manner. To examine sex-specific splicing, we compared gene expression profiles of male and female pupae 12 hours after pupariation. To examine stage-specific splicing, we compared expression profiles of mixed-sex, 0-24 hour old embryos and mixed-sex, 12 hour old pupae. To examine tissue-specific splicing, we compared expression profiles of adult male heads and abdomens 24-48 hours after eclosion. To examine tissue-specific splicing, we compared expression profiles of adult male heads and abdomens at 24-48 hours after eclosion. Keywords: tissue-specific expression profiles
Project description:Many multi-exon genes are subject to alternative splicing, which is thought to increase phenotypic complexity by allowing a single locus to produce multiple functionally distinct proteins. However, genetic and developmental variation in alternative splicing has never been examined systematically. We therefore undertook a genome-wide analysis of sex- and genotypic-specific splicing in Drosophila in conjunction with sex- and line-specific transcription. Keywords: microarray, sexual dimorphism, alternative splicing, genetical genomics, genetic variation
Project description:We used long-oligonucleotide microarrays to investigate whether alternative splicing in Drosophila is regulated in a sex-, stage-, or tissue-specific manner. To examine sex-specific splicing, we compared gene expression profiles of male and female pupae 12 hours after pupariation. To examine stage-specific splicing, we compared expression profiles of mixed-sex, 0-24 hour old embryos and mixed-sex, 12 hour old pupae. To examine tissue-specific splicing, we compared expression profiles of adult male heads and abdomens 24-48 hours after eclosion. To examine tissue-specific splicing, we compared expression profiles of adult male heads and abdomens at 24-48 hours after eclosion. Keywords: tissue-specific expression profiles Drosophila isogenic line WI89 was used. Mixed-sex, mixed-stage embryos were harvested from plates on which females had been allowed to oviposit for 24 hours. To obtain synchronized cohorts of pupae, male and female white prepupae were collected at 0-1 hour after pupariation and aged for 12 hours at 25C. Mixed-sex pupal samples were generated by mixing equal amount of male and female pupal RNA. Adult heads and abdomens were dissected from 24-48 hour old males. mRNA was isolated and labeled without amplification.
Project description:Upstream of N-ras (UNR) is a conserved RNA-binding protein that regulates mRNA translation and stability by binding to sites generally located in untranslated regions (UTRs). In Drosophila, sex-specific binding of UNR to various RNAs plays key roles in the control of X chromosome dosage compensation in both sexes. In order to investigate broader sex-specific functions of UNR, we have identified its RNA targets in adult male and female flies by high-throughput RNA binding and transcriptome analysis. Here we show that UNR binds to a large set of protein-coding transcripts and to a smaller set of non-coding RNAs in a sex-specific fashion. The analyses also reveal a strong correlation between sex-specific binding of UNR and sex-specific differential expression of UTRs in target genes. Validation experiments indicate that UNR indeed recognizes sex-specifically processed transcripts. These results suggest that UNR exploits the transcript diversity generated by alternative processing and alternative promoter usage to bind and regulate target genes in a sex-specific manner.
Project description:Upstream of N-ras (UNR) is a conserved RNA-binding protein that regulates mRNA translation and stability by binding to sites generally located in untranslated regions (UTRs). In Drosophila, sex-specific binding of UNR to various RNAs plays key roles in the control of X chromosome dosage compensation in both sexes. In order to investigate broader sex-specific functions of UNR, we have identified its RNA targets in adult male and female flies by high-throughput RNA binding and transcriptome analysis. Here we show that UNR binds to a large set of protein-coding transcripts and to a smaller set of non-coding RNAs in a sex-specific fashion. The analyses also reveal a strong correlation between sex-specific binding of UNR and sex-specific differential expression of UTRs in target genes. Validation experiments indicate that UNR indeed recognizes sex-specifically processed transcripts. These results suggest that UNR exploits the transcript diversity generated by alternative processing and alternative promoter usage to bind and regulate target genes in a sex-specific manner. Of the total 6 chips, three are independent immunoprecipitations, while the other three microarrays are their dye-swaps (same IPs).