Project description:Whole-chromatin profile (FAIRE-seq) in three Drosophila species (D. melanogaster, D. pseudoobscura and D. virilis) in eye-antennal imaginal discs at the stage of third instar wandering larvae. By the use of Ornstein-Uhlenbeck methods, we assess the evolutionary forces acting on regulatory elements (cis-level) on chromatin activity across Drosophila eye-antennal imaginal discs at the stage of third instar larvae.
Project description:Piwi interacting (pi)RNAs repress diverse transposable elements in the germ cells of metazoans and are essential for fertility in both invertebrates and vertebrates. The precursors of piRNAs are transcribed from distinct genomic regions, the so-called piRNA clusters; however, how piRNA clusters are differentiated from the rest of the genome is not known. To address this question, we studied piRNA biogenesis in two Drosophila virilis strains that show differential ability to generate piRNAs from several genomic regions. We found that active piRNA biogenesis correlates with high levels of histone 3 lysine 9 trimethylation (H3K9me3) over genomic regions that give rise to piRNAs. Furthermore, piRNA biogenesis in the progeny requires the trans-generational inheritance of an epigenetic signal, presumably in form of homologous piRNAs that are generated in the maternal germline and deposited into the oocyte. The inherited piRNAs enhance piRNA biogenesis by installment of H3K9me3 mark on piRNA clusters and by promoting ping-pong processing of homologous transcripts into mature piRNAs. We submitted the resequencing data together with the functional genomic datasets because it was generated with the sole purpose of supporting those. The SRA accession numbers are SRR1536176 and SRR1536175. ChIP-seq against H3K9me3 and Pol2, Total RNA-seq, in Drosophila virilis Strain9 and Strain160 as well as crosses between them
Project description:Piwi-interacting RNAs (piRNAs) play a crucial role in silencing transposable elements (TEs) in the germ cells of Metazoa by acting as sequence-specific guides. Originating from distinct genomic loci, called piRNA clusters, piRNA can trigger an epigenetic conversion of TE insertions into piRNA clusters by means of paramutation-like process. However, the variability in piRNA clusters' capacity to induce such conversion remains poorly understood. Here, we investigated two Drosophila virilis strains with differing capacities to produce piRNAs from the RhoGEF3 and Adar gene loci. We found that active piRNA generation correlates with high levels of the heterochromatic mark H3K9me3 over genomic regions that give rise to piRNAs. Importantly, maternal transmission of piRNAs drives their production in the progeny, even from homologous loci previously inactive in piRNA biogenesis. The subtelomeric RhoGEF3 locus, once epigenetically converted, maintained enhanced piRNA production in subsequent generations lacking the original allele carrying the active piRNA cluster. In contrast, piRNA expression from the converted Adar locus was lost in offspring lacking the inducer allele. Our findings highlight that the paramutation-like behavior of piRNA clusters is influenced not only by piRNAs but also by structural features of chromosomal regions, providing new insights into epigenetic regulation in Drosophila.
2025-03-20 | GSE292339 | GEO
Project description:Transposable elements in Drosophila rDNA cluster.
Project description:ChIP followed by next generation sequencing over 5 developmental time points of Drosophila virilis embryos (w[-], white eye mutation line) against 5 key mesodermal factors (Twist, Tinman, Mef2, Bagpipe and Biniou) were performed. The aim was to compare binding profiles of these 5 mesodermal factors between two Drosophila species, D. melanogaster (Zinzen et al., 2009) and D. virilis (this study). D. virilis specific antibodies were used for this purpose for 4 of the 5 factors (D. melanogaster Anti-body for Mef2 showed high specificity in D. virilis). Two biological replicates for each condition were sequenced using Illumina HiSeq.
Project description:The abundance of transposable elements and DNA repeat sequences in mammalian genomes raises the question whether such insertions represent passive evolutionary baggage or may influence the expression of complex traits. We addressed this question in Drosophila melanogaster where the effects of single transposable elements on complex traits can be assessed in genetically identical individuals reared in controlled environments. Here we demonstrate that single P-element insertions in the intergenic region between the Gustatory receptor 5a (Gr5a) and Trapped in endoderm 1 (Tre1), which encodes an orphan receptor, exert complex pleiotropic effects on fitness traits, including selective nutrient intake, resistance to starvation and heat stress, and life span. Mutations in this region interact epistatically with downstream components of the insulin signaling pathway. Transposon-induced sex-specific and sex-antagonistic effects further accentuate the complex influences intergenic transposable elements can contribute to complex phenotypes. Keywords: Transcriptional profiles of P-element insertion lines in the Tre1/GR5a region of Drosophila
Project description:DNA methylation is an essential epigenetic modification, present in both unique DNA sequences and repetitive elements, but its exact function in repetitive elements remains obscure. Here, we describe the genome-wide comparative analysis of the 5mC, 5hmC, 5fC and 5caC profiles of repetitive elements in mouse embryonic fibroblasts and mouse embryonic stem cells. We provide evidence for distinct and highly specific DNA methylation/oxidation patterns of the repetitive elements in both cell types, which mainly affect CA repeats and evolutionary conserved mouse-specific transposable elements including IAP-LTRs, SINEs B1m/B2m and L1Md-LINEs. DNA methylation controls the expression of these retro-elements, which are clustered at specific locations in the mouse genome. We show that TDG is implicated in the regulation of their unique DNA methylation/oxidation signatures and their dynamics. Our data suggest the existence of novel epigenetic code for the most recently acquired evolutionary conserved repeats that could play a major role in cell differentiation. This SuperSeries is composed of the SubSeries listed below.
Project description:DNA methylation is an essential epigenetic modification, present in both unique DNA sequences and repetitive elements, but its exact function in repetitive elements remains obscure. Here, we describe the genome-wide comparative analysis of the 5mC, 5hmC, 5fC and 5caC profiles of repetitive elements in mouse embryonic fibroblasts and mouse embryonic stem cells. We provide evidence for distinct and highly specific DNA methylation/oxidation patterns of the repetitive elements in both cell types, which mainly affect CA repeats and evolutionary conserved mouse-specific transposable elements including IAP-LTRs, SINEs B1m/B2m and L1Md-LINEs. DNA methylation controls the expression of these retro-elements, which are clustered at specific locations in the mouse genome. We show that TDG is implicated in the regulation of their unique DNA methylation/oxidation signatures and their dynamics. Our data suggest the existence of novel epigenetic code for the most recently acquired evolutionary conserved repeats that could play a major role in cell differentiation.