Roles of piwi-interacting RNAs and small interfering RNAs in regulating gene expression in Caenorhabditis elegans

Abstract

There are three distinct classes of small RNAs found in animals: microRNAs (miRNAs), piwi interacting RNAs (piRNAs), and small interfering RNAs (siRNAs). miRNAs are required throughout development, whereas piRNAs and siRNAs are best known for their roles in germline development and genome defense (see Chapter 1 for an overview of piRNA and siRNA pathways). To identify the roles of piRNAs and siRNAs in regulating gene expression in the germ cells of Caenorhabditis elegans, we subjected small RNAs and messenger RNAs (mRNAs) from the distal gonads of piRNA and siRNA mutants to high-throughput sequencing. We identified extensive roles for piRNAs and siRNAs in regulating gene expression during germline development, including an unexpected role for piRNAs in preventing histone silencing by the siRNA pathway (see Chapter 2).