piRNA production requires heterochromatin formation in Drosophila. Drosophila melanogaster

Here, we analyzed two small RNA libraries derived from ovarian tissue mutant for either the Drosophila SETDB1 gene, or the Bam gene. Here we show that deposition of histone 3 lysine 9 by the methyltransferase dSETDB1 (egg) is required for piRNA cluster transcription. In the absence of dSETDB1, cluster precursor transcription collapses in germline and somatic gonadal cells and TEs are activated, resulting in germline loss and a block in germline stem cell differentiation. We propose that heterochromatin protects the germline by activating the piRNA pathway. Keyword : Epigenetics Overall design: 2 libraries were analyzed, with 1 being a developmental control (Bam Mutant).

本研究分析了两个分别来自果蝇（Drosophila）SETDB1基因或Bam基因突变卵巢组织的小RNA文库。研究证实，甲基转移酶dSETDB1（又名egg）介导的组蛋白3赖氨酸9（histone 3 lysine 9）修饰，是piRNA簇转录所必需的。当缺失dSETDB1时，生殖系与体细胞性腺细胞内的簇前体转录本发生崩溃，转座因子（TEs, Transposable Elements）被激活，进而引发生殖系丢失以及生殖系干细胞分化阻滞。本研究提出，异染色质可通过激活piRNA通路实现对生殖系的保护。关键词：表观遗传学（Epigenetics）。整体实验设计：共分析2个文库，其中1个作为发育对照（Bam突变体）。