Project description:This data series contains the sequences and read counts of Piwi-interacting RNAs and other small RNAs from mouse and rat testes extracts. In a search for different classes of small RNAs that might be involved in transcriptional gene silencing, we encountered a novel class of small RNAs within mammalian testes. This study reports the identification of small RNAs and their relative abundance levels to each other based on the deep coverage of the cDNA library. Keywords: High-throughput pyrosequencing by the 454 Life Sciences Genome Sequencer 20™ System
Project description:This data series contains the sequences and read counts of Piwi-interacting RNAs and other small RNAs from mouse and rat testes extracts. In a search for different classes of small RNAs that might be involved in transcriptional gene silencing, we encountered a novel class of small RNAs within mammalian testes. This study reports the identification of small RNAs and their relative abundance levels to each other based on the deep coverage of the cDNA library. Keywords: High-throughput pyrosequencing by the 454 Life Sciences Genome Sequencer 20™ System We constructed a cDNA library from small RNAs purified from Q column fractions of testes extracts. Briefly, gel-purified small RNAs from the column fractions were ligated with adaptor oligos on both 3' and 5' ends of the small RNAs. Reverse-transcription and PCR amplification was then performed on the ligated small RNAs to yield a cDNA library. This cDNA library was finally converted by PCR into a single-stranded DNA library compatible for coupling to beads on the 454 Life Sciences Genome Sequencer 20™ System. Reads and sequences of the small RNAs were processed from linker sequences, examined for matches to the mouse or rat genomes, and tallied.
Project description:The piRNA machinery is known for its role in mediating epigenetic silencing of transposons. Recent studies suggest that this function also involves piRNA-guided cleavage of transposon-derived transcripts. As many piRNAs also appear to have the capacity to target diverse mRNAs, this raises the intriguing possibility that piRNAs may act extensively as siRNAs to degrade specific mRNAs. To directly test this hypothesis, we compared mouse PIWI (MIWI)-associated piRNAs with experimentally identified cleaved mRNA fragments from mouse testes, and observed cleavage sites that predominantly occur at position 10 from the 5' end of putative targeting piRNAs. We also noted strong biases for U and A residues at nucleotide positions 1 and 10, respectively, in both piRNAs and mRNA fragments, features that resemble the pattern of piRNA amplification by the 'ping-pong' cycle. Through mapping of MIWI-RNA interactions by CLIP-seq and gene expression profiling, we found that many potential piRNA-targeted mRNAs directly interact with MIWI and show elevated expression levels in the testes of Miwi catalytic mutant mice. Reporter-based assays further revealed the importance of base pairing between piRNAs and mRNA targets and the requirement for both the slicer activity and piRNA-loading ability of MIWI in piRNA-mediated target repression. Importantly, we demonstrated that proper turnover of certain key piRNA targets is essential for sperm formation. Together, these findings reveal the siRNA-like function of the piRNA machinery in mouse testes and its central requirement for male germ cell development and maturation.
Project description:The piRNA machinery is known for its role in mediating epigenetic silencing of transposons. Recent studies suggest that this function also involves piRNA-guided cleavage of transposon-derived transcripts. As many piRNAs also appear to have the capacity to target diverse mRNAs, this raises the intriguing possibility that piRNAs may act extensively as siRNAs to degrade specific mRNAs. To directly test this hypothesis, we compared mouse PIWI (MIWI)-associated piRNAs with experimentally identified cleaved mRNA fragments from mouse testes, and observed cleavage sites that predominantly occur at position 10 from the 5' end of putative targeting piRNAs. We also noted strong biases for U and A residues at nucleotide positions 1 and 10, respectively, in both piRNAs and mRNA fragments, features that resemble the pattern of piRNA amplification by the 'ping-pong' cycle. Through mapping of MIWI-RNA interactions by CLIP-seq and gene expression profiling, we found that many potential piRNA-targeted mRNAs directly interact with MIWI and show elevated expression levels in the testes of Miwi catalytic mutant mice. Reporter-based assays further revealed the importance of base pairing between piRNAs and mRNA targets and the requirement for both the slicer activity and piRNA-loading ability of MIWI in piRNA-mediated target repression. Importantly, we demonstrated that proper turnover of certain key piRNA targets is essential for sperm formation. Together, these findings reveal the siRNA-like function of the piRNA machinery in mouse testes and its central requirement for male germ cell development and maturation. CLIP-Seq (Crosslinking Immunoprecipitation coupled with high-throughput sequencing) experiments targeting Miwi in isolated round spermatids from mouse testis.
Project description:Piwi-interacting RNAs are 25-32 nt small RNAs bound to Piwi proteins. To know the steps where factors involved in the piRNA biogenesis (MILI, MIWI2, ZUC (MitoPLD), MVH) work, we sequenced small RNAs from mutant mouse testes and analyzed piRNAs. Examination of small RNAs in testes of mutant mouse
Project description:Piwi-interacting RNAs are 25-32 nt small RNAs bound to Piwi proteins. To know the steps where factors involved in the piRNA biogenesis (MILI, MIWI2, ZUC (MitoPLD), MVH) work, we sequenced small RNAs from mutant mouse testes and analyzed piRNAs.
Project description:In animal germline cells, Piwi-interacting RNAs (piRNAs) silence retrotransposons through post-transcriptional and transcriptional mechanisms. However, little is known, especially in mammals, about the functions of piRNAs beyond retrotransposon suppression1-5. In mammalian spermatocytes, piRNAs are known to be abundantly expressed6-10. Here, we show that a subset of coding and noncoding RNAs in mouse spermatocytes is degraded by the piRNA pathway. By analyzing the germline trasnscriptome of mice deficient in piRNA biogenesis, we identify hundreds of mRNAs as direct targets of piRNAs. Remarkably, the 3' untranslated region (UTR) of the mRNAs up-regulated in the piRNA pathway mutants are highly enriched with retrotransposon sequenes, implying that these sequences serve as regulatory elements for piRNA-mediated regulation. Furthermore, deficiencies of piRNAs derived from pseudogenes result in increased mRNA levels of their cognate genes, indicating that pseudogenes regulate their functional cognates via piRNAs. Moreover, we identify a large population of testis-enriched long intergenic noncoding RNAs (lincRNAs), some of which are also degraded by the piRNA pathway. Collectively, our results reveal that the piRNA pathway regulates the expression of both mRNAs and lincRNAs in addition to retrotransposon RNAs during meiosis and the key role of retrotransposons and pseudogenes, two major types of genomic sequences, in this regulation by acting as piRNA sources and/or regulatory elements in target RNAs. Small RNAs in Stambp-ps1 mutant testes were sequenced using Illumina HiSeq.
Project description:Animal germ cells produce PIWI-interacting RNAs (piRNAs), small silencing RNAs that suppress transposons and enable gamete maturation. Mammalian transposon-silencing piRNAs accumulate early in spermatogenesis, whereas pachytene piRNAs are produced later during post-natal spermatogenesis and account for >95% of all piRNAs in the adult mouse testis. Mutants defective for pachytene piRNA pathway proteins fail to produce mature sperm, but neither the piRNA precursor transcripts nor the trigger for pachytene piRNA production is known. Here, we show that the transcription factor A-MYB initiates pachytene piRNA production. A-MYB drives transcription of both pachytene piRNA precursor RNAs and the mRNAs for core piRNA biogenesis factors, including MIWI, the protein through which pachytene piRNAs function. A-MYB regulation of piRNA pathway proteins and piRNA genes creates a coherent feed-forward loop that ensures the robust accumulation of pachytene piRNAs. This regulatory circuit, which can be detected in rooster testes, likely predates the divergence of birds and mammals. Transcriptome and ChIP sequencing in mouse and rooster testes
Project description:Animal germ cells produce PIWI-interacting RNAs (piRNAs), small silencing RNAs that suppress transposons and enable gamete maturation. Mammalian transposon-silencing piRNAs accumulate early in spermatogenesis, whereas pachytene piRNAs are produced later during post-natal spermatogenesis and account for >95% of all piRNAs in the adult mouse testis. Mutants defective for pachytene piRNA pathway proteins fail to produce mature sperm, but neither the piRNA precursor transcripts nor the trigger for pachytene piRNA production is known. Here, we show that the transcription factor A-MYB initiates pachytene piRNA production. A-MYB drives transcription of both pachytene piRNA precursor RNAs and the mRNAs for core piRNA biogenesis factors, including MIWI, the protein through which pachytene piRNAs function. A-MYB regulation of piRNA pathway proteins and piRNA genes creates a coherent feed-forward loop that ensures the robust accumulation of pachytene piRNAs. This regulatory circuit, which can be detected in rooster testes, likely predates the divergence of birds and mammals. ChIP sequencing in mouse and rooster testes.
Project description:Animal germ cells produce PIWI-interacting RNAs (piRNAs), small silencing RNAs that suppress transposons and enable gamete maturation. Mammalian transposon-silencing piRNAs accumulate early in spermatogenesis, whereas pachytene piRNAs are produced later during post-natal spermatogenesis and account for >95% of all piRNAs in the adult mouse testis. Mutants defective for pachytene piRNA pathway proteins fail to produce mature sperm, but neither the piRNA precursor transcripts nor the trigger for pachytene piRNA production is known. Here, we show that the transcription factor A-MYB initiates pachytene piRNA production. A-MYB drives transcription of both pachytene piRNA precursor RNAs and the mRNAs for core piRNA biogenesis factors, including MIWI, the protein through which pachytene piRNAs function. A-MYB regulation of piRNA pathway proteins and piRNA genes creates a coherent feed-forward loop that ensures the robust accumulation of pachytene piRNAs. This regulatory circuit, which can be detected in rooster testes, likely predates the divergence of birds and mammals. smallRNA-Seq in mouse and rooster testes