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:We examined genome-wide patterns of DNA methylation from whole genome DNA methylation maps of five tissues (brain, kidney, lung, skeletal muscle, and pancreas) from one male koala and one female koala (Phascolarctos cinereus), and present the first whole genome, multi-tissue “methylome atlas” with information on tissue- and sex-specific variation of DNA methylation for a marsupial.
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Project description:The koala retrovirus (KoRV) is implicated in several diseases affecting the koala (Phascolarctos cinereus). KoRV provirus can be present in the genome of koalas as an endogenous retrovirus (present in all cells via germline integration) or as exogenous retrovirus responsible for somatic integrations of proviral KoRV (present in a limited number of cells). This ongoing invasion of the koala germline by KoRV provides a powerful opportunity to assess the viral strategies used by KoRV in an individual. Analysis of a high-quality genome sequence of a single koala revealed 133 KoRV integration sites. Most integrations contain full-length, endogenous provirus; KoRV-A subtype. The second most frequent integrations contain an endogenous recombinant element (recKoRV) in which most of the KoRV protein-coding region has been replaced with an ancient, endogenous retroelement. A third set of integrations, with very low sequence coverage, may represent somatic cell integrations of KoRV-A, KoRV-B and two recently designated additional subgroups, KoRV-D and KoRV-E. KoRV-D and KoRV-E are missing several genes required for viral processing, suggesting they have been transmitted as defective viruses. Our results represent the first comprehensive analyses of KoRV integration and variation in a single animal and provide further insights into the process of retroviral-host species interactions.
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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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