Pervasive epigenetic effects of Drosophila euchromatic transposable elements impact their evolution
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ABSTRACT:
OTHER RELATED OMICS DATASETS IN: PRJNA373933PRJNA373904PRJNA373899
ORGANISM(S): Drosophila simulans Drosophila melanogaster
PROVIDER: GSE94742 | GEO | 2017/07/01
SECONDARY ACCESSION(S): PRJNA373904
REPOSITORIES: GEO
Similar Datasets
Project description:Transposable elements (TEs) are widespread genomic parasites, and their evolution has remained a critical question in evolutionary genomics. Here, we study the relatively unexplored epigenetic impacts of TEs and provide the first genome-wide quantification of such effects in D. melanogaster and D. simulans. Surprisingly, the spread of repressive epigenetic marks (histone H3K9me2) to nearby DNA occurs at >50% of euchromatic TEs, and can extend up to 20 kb. This results in differential epigenetic states of genic alleles and, in turn, selection against TEs. Interestingly, the lower TE content in D. simulans compared to D. melanogaster correlates with stronger epigenetic effects of TEs and higher levels of host genetic factors known to promote epigenetic silencing. Our study demonstrates that the epigenetic effects of euchromatic TEs, and host genetic factors modulating such effects, play a critical role in the evolution of TEs both within and between species.
| S-EPMC5505702 | biostudies-literature
Project description:We study the relatively unexplored evolutionary consequences of the epigenetic effects of transpoable elements (TEs) by providing the first genome-wide quantification of such effects in wild-derived D. melanogaster and D. simulans strains. Surprisingly, over half of euchromatic TEs show spread of repressive epigenetic marks to nearby DNA, resulting in differential epigenetic states of homologous genic alleles and, in return, selection against TEs. Interestingly, compared to D. melanogaster, the lower TE content in D. simulans is correlated with stronger epigenetic effects of TEs and higher levels of host genetic factors known to promote epigenetic silencing. We conclude that the epigenetic effects of euchromatic TEs, and host genetic factors modulating such effects, play a critical role in the population dynamics of TEs within and between species.
2017-07-01 | GSE94741 | GEO
Project description:We study the relatively unexplored evolutionary consequences of the epigenetic effects of transpoable elements (TEs) by providing the first genome-wide quantification of such effects in wild-derived D. melanogaster and D. simulans strains. Surprisingly, over half of euchromatic TEs show spread of repressive epigenetic marks to nearby DNA, resulting in differential epigenetic states of homologous genic alleles and, in return, selection against TEs. Interestingly, compared to D. melanogaster, the lower TE content in D. simulans is correlated with stronger epigenetic effects of TEs and higher levels of host genetic factors known to promote epigenetic silencing. We conclude that the epigenetic effects of euchromatic TEs, and host genetic factors modulating such effects, play a critical role in the population dynamics of TEs within and between species.
2017-07-01 | GSE94735 | GEO
Project description:Pervasive epigenetic effects of Drosophila euchromatic transposable elements impact their evolution
| PRJNA373904 | ENA
Project description:Pervasive epigenetic effects of Drosophila euchromatic transposable elements impact their evolution [ChIP-seq]
| PRJNA373899 | ENA
Project description:Pervasive epigenetic effects of Drosophila euchromatic transposable elements impact their evolution [RNA-seq]
| PRJNA373933 | ENA
Project description:The Long interspersed nuclear element 1 (LINE-1) is a primary source of genetic variation in humans and other mammals. Despite its importance, LINE-1 activity remains difficult to study because of its highly repetitive nature. Here, we developed and validated a method called TeXP to gauge LINE-1 activity accurately. TeXP builds mappability signatures from LINE-1 subfamilies to deconvolve the effect of pervasive transcription from autonomous LINE-1 activity. In particular, it apportions the multiple reads aligned to the many LINE-1 instances in the genome into these two categories. Using our method, we evaluated well-established cell lines, cell-line compartments and healthy tissues and found that the vast majority (91.7%) of transcriptome reads overlapping LINE-1 derive from pervasive transcription. We validated TeXP by independently estimating the levels of LINE-1 autonomous transcription using ddPCR, finding high concordance. Next, we applied our method to comprehensively measure LINE-1 activity across healthy somatic cells, while backing out the effect of pervasive transcription. Unexpectedly, we found that LINE-1 activity is present in many normal somatic cells. This finding contrasts with earlier studies showing that LINE-1 has limited activity in healthy somatic tissues, except for neuroprogenitor cells. Interestingly, we found that the amount of LINE-1 activity was associated with the with the amount of cell turnover, with tissues with low cell turnover rates (e.g. the adult central nervous system) showing lower LINE-1 activity. Altogether, our results show how accounting for pervasive transcription is critical to accurately quantify the activity of highly repetitive regions of the human genome.
| S-EPMC6715295 | biostudies-literature
Project description:Transposable elements (TEs) are mobile genomic sequences that are normally repressed to avoid proliferation and genome instability. Gene silencing mechanisms repress TEs by RNA degradation or heterochromatin formation. Heterochromatin maintenance is therefore important to keep TEs silent. Loss of heterochromatic domains has been linked to lamin mutations, which have also been associated with derepression of TEs. In fact, lamins are structural components of the nuclear lamina (NL), which is considered a pivotal structure in the maintenance of heterochromatin domains at the nuclear periphery in a silent state. Here, we show that a lethal phenotype associated with Lamin loss-of-function mutations is influenced by Drosophilagypsy retrotransposons located in euchromatic regions, suggesting that NL dysfunction has also effects on active TEs located in euchromatic loci. In fact, expression analysis of different long terminal repeat (LTR) retrotransposons and of one non-LTR retrotransposon located near active genes shows that Lamin inactivation determines the silencing of euchromatic TEs. Furthermore, we show that the silencing effect on euchromatic TEs spreads to the neighboring genomic regions, with a repressive effect on nearby genes. We propose that NL dysfunction may have opposed regulatory effects on TEs that depend on their localization in active or repressed regions of the genome.
| S-EPMC7140440 | biostudies-literature
Project description:Early nutrition affects adult metabolism in humans and other mammals, potentially via persistent alterations in DNA methylation. With viable yellow agouti (A(vy)) mice, which harbor a transposable element in the agouti gene, we tested the hypothesis that the metastable methylation status of specific transposable element insertion sites renders them epigenetically labile to early methyl donor nutrition. Our results show that dietary methyl supplementation of a/a dams with extra folic acid, vitamin B(12), choline, and betaine alter the phenotype of their A(vy)/a offspring via increased CpG methylation at the A(vy) locus and that the epigenetic metastability which confers this lability is due to the A(vy) transposable element. These findings suggest that dietary supplementation, long presumed to be purely beneficial, may have unintended deleterious influences on the establishment of epigenetic gene regulation in humans.
| S-EPMC165709 | biostudies-literature
Project description:Transposable elements are potent agents of genomic change during evolution, but require access to chromatin for insertion-and not all genes provide equivalent access. To test whether the regulatory features of heat-shock genes render their proximal promoters especially susceptible to the insertion of transposable elements in nature, we conducted an unbiased screen of the proximal promoters of 18 heat-shock genes in 48 natural populations of Drosophila. More than 200 distinctive transposable elements had inserted into these promoters; greater than 96% are P elements. By contrast, few or no P element insertions segregate in natural populations in a "negative control" set of proximal promoters lacking the distinctive regulatory features of heat-shock genes. P element transpositions into these same genes during laboratory mutagenesis recapitulate these findings. The natural P element insertions cluster in specific sites in the promoters, with up to eight populations exhibiting P element insertions at the same position; laboratory insertions are into similar sites. By contrast, a "positive control" set of promoters resembling heat-shock promoters in regulatory features harbors few P element insertions in nature, but many insertions after experimental transposition in the laboratory. We conclude that the distinctive regulatory features that typify heat-shock genes (in Drosophila) are especially prone to mutagenesis via P elements in nature. Thus in nature, P elements create significant and distinctive variation in heat-shock genes, upon which evolutionary processes may act.
| S-EPMC1592238 | biostudies-literature