A genetic screen for proteins involved in Non‐Stop mRNA decay in C. elegans

Abstract

Non‐stop mRNAs, which lack a stop codon due to mutation or errors in mRNA transcription or processing, serve as templates for production of aberrant and potentially toxic protein products. Ultimately, translation of non‐stop mRNAs leads to a failure in normal translation termination and ribosome collisions, which in eukaryotes initiates ubiquitin‐dependent degradation of the protein product and Non‐Stop Decay (NSD) of the problematic mRNA. Ribosome collisions in yeast are linked to activation of cellular stress responses and failure to resolve stalled ribosomes leads to neurodegeneration in mice, highlighting the biological importance of mRNA quality control.In the nematode Caenorhabditis elegans, loss of the core NSD components pelo‐1 and skih‐2 leads to temperature‐sensitive sterility, as does the loss of endogenous siRNAs that are triggered by NSD at some loci. To further probe the link between NSD and the biology of germ cells, we have used an RNAi approach to screen for temperature‐sensitive reduction in brood size for the C. elegans orthologs of several proteins known to be part of the NSD machinery in other organisms. Preliminary results have identified 2 NSD‐associated genes with conditionally reduced brood sizes. We will present progress on examining the requirement of these genes for Non‐Stop decay in C. elegans, as well as investigation of their specific contributions to the biology of the germ line.