The piRNA Response to Retroviral Invasion of the Koala Genome
Ontology highlight
ABSTRACT:
PROVIDER: PRJNA526502 | ENA |
REPOSITORIES: ENA
Dataset's files
| Action | DRS | |||
|---|---|---|---|---|
| SRR8708130_1.fastq.gz | Fastqsanger.gz | |||
| SRR8708130_2.fastq.gz | Fastqsanger.gz | |||
| SRR8708140_1.fastq.gz | Fastqsanger.gz | |||
| SRR8708140_2.fastq.gz | Fastqsanger.gz | |||
| SRR8708150.fastq.gz | Fastqsanger.gz |
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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.
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Project description:Antisense Piwi-interacting RNAs (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.
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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.
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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.
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Project description:The aims of this study were to investigate the proteome of koala (Phascolarctos cinereus) spermatozoa and that of the prostatic bodies with which they form intimate contact at the moment of ejaculation. For this purpose, spermatozoa and prostatic bodies were obtained from four adult male koala by electroejaculation and analysed by high performance liquid chromatography coupled to a mass spectrometer. This strategy successfully identified and 744 koala sperm and 1,297 prostatic body proteins, which were subsequently attributed to 482 and 776 unique gene products, respectively. Gene ontology curation of the koala sperm proteome revealed an abundance of proteins mapping to the canonical sirtuin and 14-3-3 signalling pathways. By contrast, protein ubiquitination and unfolding protein response pathways dominated the equivalent analysis of proteins uniquely identified in koala prostatic bodies. In terms of functional annotation, koala sperm proteins commonly mapped to the categories of cellular compromise/inflammatory response, whilst those of the prostatic body revealed an over-representation of molecular chaperone and stress-related proteins associated with cell survival. Cross-species comparisons demonstrated that the koala sperm proteome displays greater conservation with that of eutherians (human; 93%) as opposed to reptile (crocodile; 39%) and avian (rooster; 27%) spermatozoa. Similarly, koala prostatic body proteins also presented a relatively high degree of overlap (70%) with those identified in sub-populations of large human seminal plasma extracellular vesicles. Together, this work contributes our overall understanding of the core sperm proteome and has identified candidate markers that may contribute to the exceptional longevity of koala spermatozoa during ex vivo storage.
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