MUT-14 and SMUT-1 DEAD Box RNA Helicases Have Overlapping Roles in Germline RNAi and Endogenous siRNA Formation.

MUT-14 and SMUT-1 DEAD Box RNA Helicases Have Overlapping Roles in Germline RNAi and Endogenous siRNA Formation.
Curr Biol. 2014 Mar 26;
Authors: Phillips CM, Montgomery BE, Breen PC, Roovers EF, Rim YS, Ohsumi TK, Newman MA, van Wolfswinkel JC, Ketting RF, Ruvkun G, Montgomery TA
Abstract
More than 2,000 C. elegans genes are targeted for RNA silencing by the mutator complex, a specialized small interfering RNA (siRNA) amplification module which is nucleated by the Q/N-rich protein MUT-16. The mutator complex localizes to Mutator foci adjacent to P granules at the nuclear periphery in germ cells [1]. Here, we show that the DEAD box RNA helicase smut-1 functions redundantly in the mutator pathway with its paralog mut-14 during RNAi. Mutations in both smut-1 and mut-14 also cause widespread loss of endogenous siRNAs. The targets of mut-14 and smut-1 largely overlap with the targets of other mutator class genes; however, the mut-14 smut-1 double mutant and the mut-16 mutant display the most dramatic depletion of siRNAs, suggesting that they act at a similarly early step in siRNA formation. mut-14 and smut-1 are predominantly expressed in the germline and, unlike other mutator class genes, are specifically required for RNAi targeting germline genes. A catalytically inactive, dominant-negative missense mutant of MUT-14 is RNAi defective in vivo; however, mutator complexes containing the mutant protein retain the ability to synthesize si...

Source: Current Biology - March 26, 2014 Category: Biology Authors: Phillips CM, Montgomery BE, Breen PC, Roovers EF, Rim YS, Ohsumi TK, Newman MA, van Wolfswinkel JC, Ketting RF, Ruvkun G, Montgomery TA Tags: Curr Biol Source Type: research