Institute of Molecular Biology, D-55128 Mainz, Germany;
Genes Dev. 2014 Apr 1;28(7):683-8. doi: 10.1101/gad.238220.114.
The Piwi-piRNA pathway represents a small RNA-based mechanism responsible for the recognition and silencing of invading DNA. Biogenesis of piRNAs (21U-RNAs) is poorly understood. In Caenorhabditis elegans, the piRNA-binding Argonaute protein PRG-1 is the only known player acting downstream from precursor transcription. From a screen aimed at the isolation of piRNA-induced silencing-defective (Pid) mutations, we identified, among known Piwi pathway components, PID-1 as a novel player. PID-1 is a mostly cytoplasmic, germline-specific factor essential for 21U-RNA biogenesis, affecting an early step in the processing or transport of 21U precursor transcripts. We also show that maternal 21U-RNAs are essential to initiate silencing.
Piwi-piRNA 通路代表了一种基于小 RNA 的机制，负责识别和沉默入侵的 DNA。piRNA（21U-RNAs）的生物发生过程还不太清楚。在秀丽隐杆线虫中，piRNA 结合 Argonaute 蛋白 PRG-1 是已知的唯一在转录前体下游起作用的因子。从一个旨在分离 piRNA 诱导沉默缺陷（Pid）突变的筛选中，我们在已知的 Piwi 通路成分中发现，PID-1 是一个新的因子。PID-1 是一种主要存在于细胞质中的、生殖系特异性的因子，对 21U-RNA 的生物发生是必需的，影响 21U 前体转录本的加工或运输的早期步骤。我们还表明，母源 21U-RNAs 对于起始沉默是必需的。
