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Small RNA species in the mammalian meiotic nucleus

ABSTRACT: MiRNAs and possibly the recently discovered piRNAs can function in reversible gene silencing. In meiosis, transcriptional silencing of the XY bivalent and the late pairing regions of autosomes is a necessary event and defects in these processes lead to infertility. The exact mechanisms of meiotic gene silencing are not well understood but it is thought that some RNA component might be involved at least in the XY transcriptional silencing, similar to Xist silencing of the X chromosome in females. We wanted to investigate if small RNA species are present in the meiotic nucleus and, if so, to determine their localization pattern. We found both miRNAs and piRNAs in the nucleus of spermatogenic cells. In Sertoli cells, miRNAs and piRNAs are localized to the fibrillogranular compartment of the nucleolus, while in meiotic cells they are found mainly in the XY-associated dense body but also are associated with chromosome cores, telomerers and the sex chromatin. Interestingly, in MIWI null male mice, the nucleolar localization of miRNAs is decreased while the localization of piRNAs is diminished. However, the meiotic localization of these two components is not affected. These data suggest that small RNA species might have different roles during different stages of male gametogenesis and undergo differential regulation. Based on the localization of miRNAs and piRNAs in the male-specific, XY-associated dense body, it is probable that at least some are involved in the silencing of the XY bivalent. Others might be involved in translational repression of transcripts used in later stages of spermiogenesis when transcription is halted. Keywords: total RNA direct hybridization

ORGANISM(S): Mus musculus

PROVIDER: GSE8118 | GEO | 2008/02/22

SECONDARY ACCESSION(S): PRJNA100991

REPOSITORIES: GEO

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