Maternal and zygotic gene regulatory effects of endogenous RNAi pathways in C. elegans. Caenorhabditis elegans

Small interfering RNAs (siRNAs) and their partner Argonaute proteins regulate the expression of target RNAs. When sperm and egg meet upon fertilization, a diverse set of proteins and RNA, including siRNA-Argonaute complexes, is passed on to the developing progeny. Thus, these two players are important to initiate specific gene expression programs in the next generation. The nematode Caenorhabditis elegans expresses several classes of siRNAs. 26G-RNAs are a particular class of siRNAs that are divided into two subpopulations: one expressed in the spermatogenic gonad and another expressed in oocytes and embryos. In this work, we describe the dynamics whereby oogenic 26G-RNAs setup gene silencing in the next generation. We also show several ways that spermatogenic 26G-RNAs and their partner Argonautes, ALG-3 and ALG-4, use to regulate their targets. Finally, we show that ALG-3 and ALG-4 are fine-tuning their own expression, a rare role of Argonaute proteins. Altogether, we provide new insights into how siRNAs and Argonautes are regulating gene expression.