Gene expression profile of alg-3(tm1155);alg-4(ok1041) animals compared to wild type

Gametogenesis is thermosensitive in numerous metazoa ranging from worms to man. In C. elegans a variety of germ-line nuage- (P-granule) -associated RNA-binding proteins including the Piwi-clade Argonaute, PRG-1, have been implicated in temperature-dependent fertility. Here, we describe the role of two AGO-class paralogs, alg-3 (T22B3.2) and alg-4 (ZK757.3) in promoting male fertility at elevated temperatures. A rescuing GFP::alg-3 transgene is localized in P-granules beginning at the late pachytene stage of male gametogenesis. alg-3/4 double mutants lack a subgroup of small RNAs, named 26G-RNAs, which target and appear to down-regulate numerous spermatogenesis-expressed mRNAs. These findings add to a growing number of AGO pathways required for temperature-dependent fertility in C. elegans and support a model in which AGOs and their small RNA co-factors function to promote robustness in gene-expression networks. Total RNA was extracted from C. elegans alg-3(tm1155);alg-4(ok1041) double-mutant and N2 wild type animals.