G3 (Bethesda). 2011 Oct;1(5):369-76. doi: 10.1534/g3.111.000570. Epub 2011 Oct 1.
In Neurospora crassa, genes lacking a pairing partner during meiosis are suppressed by a process known as meiotic silencing by unpaired DNA (MSUD). To identify novel MSUD components, we have developed a high-throughput reverse-genetic screen for use with the N. crassa knockout library. Here we describe the screening method and the characterization of a gene (sad-3) subsequently discovered. SAD-3 is a putative helicase required for MSUD and sexual spore production. It exists in a complex with other known MSUD proteins in the perinuclear region, a center for meiotic silencing activity. Orthologs of SAD-3 include Schizosaccharomyces pombe Hrr1, a helicase required for RNAi-induced heterochromatin formation. Both SAD-3 and Hrr1 interact with an RNA-directed RNA polymerase and an Argonaute, suggesting that certain aspects of silencing complex formation may be conserved between the two fungal species.
在粗糙脉孢菌中，减数分裂过程中缺乏配对伙伴的基因会被一种称为未配对 DNA 的减数沉默（meiotic silencing by unpaired DNA，MSUD）的过程所抑制。为了鉴定新的 MSUD 组成部分，我们开发了一种高通量的反向遗传筛选方法，用于粗糙脉孢菌的敲除文库。在这里，我们描述了筛选方法以及随后发现的一个基因（sad-3）的特征。SAD-3 是一种在 MSUD 和有性孢子产生过程中所需的假定解旋酶。它与核周区域（减数沉默活性的中心）中的其他已知 MSUD 蛋白存在复合物。SAD-3 的同源物包括酿酒酵母 Hrr1，这是一种 RNAi 诱导异染色质形成所必需的解旋酶。Sad-3 和 Hrr1 都与 RNA 指导的 RNA 聚合酶和 Argonaute 相互作用，这表明沉默复合物形成的某些方面在这两个真菌物种之间可能是保守的。
