Adaptive evolution of KoRV-A retroviral silencing in wild koalas [RNA-seq]
Ontology highlight
ABSTRACT:
PROVIDER: PRJNA1158232 | ENA |
REPOSITORIES: ENA
Similar Datasets
Project description:Koala Retrovirus-A is spreading through wild koalas in a north to south wave while transducing the germline, generating heritable genetic modifications as it transitions to an endogenous retrovirus. In animals south of Brisbane, we previously found that KoRV-A is expressed in the germline, but the resulting unspliced genomic transcripts are processed into sense strand piRNAs, post-transcriptionally suppressing replication. Here we show that this initial “innate” response is prevalent in animals south of the Brisbane River, but KoRV-A promoters are methylated and the virus is transcriptionally silenced in a subpopulation of animals north of the river. Transcriptional silencing correlates with capture of an anti-sense KoRV-A provirus by the 3’UTR of the MAP4K4 gene. The resulting hybrid transcripts are processed into anti-sense piRNAs, which transcriptionally silence established endogenous retroviruses in the germline. This provirus is sweeping through northern koalas, supporting a direct role in adaptive evolution of KoRV-A transcriptional silencing.
2025-01-15 | GSE276616 | GEO
Project description:Koala Retrovirus-A is spreading through wild koalas in a north to south wave while transducing the germline, generating heritable genetic modifications as it transitions to an endogenous retrovirus. In animals south of Brisbane, we previously found that KoRV-A is expressed in the germline, but the resulting unspliced genomic transcripts are processed into sense strand piRNAs, post-transcriptionally suppressing replication. Here we show that this initial “innate” response is prevalent in animals south of the Brisbane River, but KoRV-A promoters are methylated and the virus is transcriptionally silenced in a subpopulation of animals north of the river. Transcriptional silencing correlates with capture of an anti-sense KoRV-A provirus by the 3’UTR of the MAP4K4 gene. The resulting hybrid transcripts are processed into anti-sense piRNAs, which transcriptionally silence established endogenous retroviruses in the germline. This provirus is sweeping through northern koalas, supporting a direct role in adaptive evolution of KoRV-A transcriptional silencing.
2025-01-15 | GSE276618 | GEO
Project description:Adaptive evolution of KoRV-A retroviral silencing in wild koalas [DNA-seq]
| PRJNA1158239 | ENA
Project description:Antisense piRNAs guide silencing of established transposons during germline development, and sense piRNAs drive ping-pong amplification of the antisense pool, but how the germline responds to genome invasion is not understood. The KoRV-A gammaretrovirus infects the soma and germline and is sweeping through wild koalas by a combination of horizontal and vertical transfer, allowing direct analysis of retroviral invasion of the germline genome. Gammaretroviruses produce spliced Env mRNAs and unspliced transcripts encoding Gag, Pol and the viral genome, but KoRV-A piRNAs are almost exclusively derived from unspliced genomic transcripts and are strongly sense strand biased. Significantly, selective piRNA processing of unspliced proviral transcripts is conserved from insects to placental mammals. We speculate that bypassed splicing generates a conserved molecular pattern that directs proviral genomic transcripts to the piRNA biogenesis machinery, and that this “innate” piRNA response suppresses transposition until antisense piRNAs are produced, establishing sequence-specific adaptive immunity.
2019-10-12 | GSE128122 | GEO
Project description:Koala Retrovirus-A is a gamma-retrovirus sweeping wild koalas via a combination of horizontal and vertical transfer, contributing substantial genomic diversity across and even within koala populations. While studies have estimated KoRV-A's integration into the koala genome occurred 120–50,000 years ago, the origin and spread patterns of its endogenization remain unclear. Here, we analyze KoRV-A germline insertions using whole-genome sequencing data from 405 wild koalas, encompassing nearly the full koala habitat range. We map a trajectory of KoRV-A evolution and propose that KoRV-A first entered the koala germline genome near Coffs Harbour. As KoRV-A spread, replication-competitive subtypes emerged, two of which recombined with an ancient endogenous retrovirus, PhER, resulting in distinct recombination variants across northern and southern koala populations. Additionally, we identified a geographic barrier north of Sydney, which has slowed the southward spread of KoRV-A into Sydney and beyond.
2025-01-15 | GSE282118 | GEO
Project description:Koala Retrovirus-A is a gamma-retrovirus sweeping wild koalas via a combination of horizontal and vertical transfer, contributing substantial genomic diversity across and even within koala populations. While studies have estimated KoRV-A's integration into the koala genome occurred 120–50,000 years ago, the origin and spread patterns of its endogenization remain unclear. Here, we analyze KoRV-A germline insertions using whole-genome sequencing data from 405 wild koalas, encompassing nearly the full koala habitat range. We map a trajectory of KoRV-A evolution and propose that KoRV-A first entered the koala germline genome near Coffs Harbour. As KoRV-A spread, replication-competitive subtypes emerged, two of which recombined with an ancient endogenous retrovirus, PhER, resulting in distinct recombination variants across northern and southern koala populations. Additionally, we identified a geographic barrier north of Sydney, which has slowed the southward spread of KoRV-A into Sydney and beyond.
2025-01-15 | GSE282117 | GEO
Project description:A Saccharomyces cerevisiae population was cultured for many generations under conditions to which it is not optimally adapted. These experiments were designed to investigate adaptive evolution under natural selection. This study is described in more detail in Ferea TL, et al. 1999. Proc Natl Acad Sci USA 96:9721-6
2002-02-11 | E-GEOD-29 | biostudies-arrayexpress
Project description:A Saccharomyces cerevisiae population was cultured for many generations under conditions to which it is not optimally adapted. These experiments were designed to investigate adaptive evolution under natural selection. This study is described in more detail in Ferea TL, et al. 1999. Proc Natl Acad Sci USA 96:9721-6 Keywords: other
2002-02-12 | GSE29 | GEO
Project description:Viruses that carry a positive-sense, single-stranded (+ssRNA) RNA translate their genomes soon after entering the host cell to produce viral proteins, with the exception of retroviruses. A distinguishing feature of retroviruses is reverse transcription, where the +ssRNA genome serves as a template to synthesize a double-stranded DNA copy that subsequently integrates into the host genome. As retroviral RNAs are produced by the host cell transcriptional machinery and are largely indistinguishable from cellular mRNAs, we investigated the potential of incoming retroviral genomes to directly express proteins. Here we show through multiple, complementary methods that retroviral genomes are translated after entry. Our findings challenge the notion that retroviruses require reverse transcription to produce viral proteins. Synthesis of retroviral proteins in the absence of productive infection has significant implications for basic retrovirology, immune responses and gene therapy applications.
2024-01-26 | PXD046777 | Pride
Project description:Although the relationship between phenotypic plasticity and evolutionary dynamics has attracted large interest, very little is known about the contribution of phenotypic plasticity to adaptive evolution. In this study, we analyzed phenotypic and genotypic changes in E. coli cells during adaptive evolution to ethanol stress. To quantify the phenotypic changes, transcriptome analyses were performed. We previously obtained 6 independently evolved ethanol tolerant E. coli strains, strains A through F, by culturing cells under 5% ethanol stress for about 1000 generations and found a significantly larger growth rate than the parent strains (Horinouchi et al, 2010, PMID: 20955615). To elucidate the phenotypic changes that occurred during adaptive evolution, we quantified the time-series of the expression changes by microarray analysis. Starting from frozen stocks obtained at 6 time points (0, 384, 744, 1224, 1824 and 2496 hours) in laboratory evolution, cells were cultured under 5% ethanol stress, and mRNA samples were obtained in the exponential growth phase for microarray analysis.
2014-07-21 | E-GEOD-59050 | biostudies-arrayexpress