Vreteno, a gonad-specific protein, is essential for germline development and primary piRNA biogenesis in Drosophila.

Here, we analyzed small RNA libraries derived from ovarian tissues heterozygous or mutant for the Tudor gene, Vreteno. In the absence of vret, Piwi-bound piRNAs are lost without changes in piRNA precursor transcript production, supporting a role for Vret in primary piRNA biogenesis. In the germline, piRNAs can engage in an Aub/Argonaute 3 (AGO3)-dependent amplification in the absence of Vret, suggesting that Vret function can distinguish between primary piRNAs loaded into Piwi/Aub complexes and piRNAs engaged in the amplification cycle. We propose that Vret acts at an early step in primary piRNA processing where it plays an essential role in transposon regulation. Keyword : Epigenetics Overall design: 2 libraries were analyzed, with 1 being a control (heterozygote).

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Zamparini AL, Davis MY, Malone CD, Vieira E, Zavadil J, Sachidanandam R, Hannon GJ, Lehmann R