Genetic Characterization of smg-8 Mutants Reveals No Role in C. elegans Nonsense Mediated Decay

Jacqueline Rosains,Susan E Mango,Georg Stoecklin

doi:10.1371/journal.pone.0049490

Jacqueline Rosains, Susan E Mango + Show 1 more

Open Access

https://doi.org/10.1371/journal.pone.0049490

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Journal: PloS one	Publication Date: Nov 16, 2012
Citations: 35	License type: CC BY 4.0

Affiliation: Harvard University

Abstract

The nonsense mediated decay (NMD) pathway degrades mRNAs bearing premature translation termination codons. In mammals, SMG-8 has been implicated in the NMD pathway, in part by its association with SMG-1 kinase. Here we use four independent assays to show that C. elegans smg-8 is not required to degrade nonsense-containing mRNAs. We examine the genetic requirement for smg-8 to destabilize the endogenous, natural NMD targets produced by alternative splicing of rpl-7a and rpl-12. We test smg-8 for degradation of the endogenous, NMD target generated by unc-54(r293), which lacks a normal polyadenylation site. We probe the effect of smg-8 on the exogenous NMD target produced by myo-3::GFP, which carries a long 3′ untranslated region that destabilizes mRNAs. None of these known NMD targets is influenced by smg-8 mutations. In addition, smg-8 animals lack classical Smg mutant phenotypes such as a reduced brood size or abnormal vulva. We conclude that smg-8 is unlikely to encode a component critical for NMD.

Highlights

The nonsense mediated decay (NMD) pathway is an evolutionarily conserved mRNA surveillance mechanism that recognizes and degrades transcripts bearing premature translation termination codons [1,2]
Our findings suggest that smg-8 is unlikely to be a key component for NMD in C. elegans
Results and Discussion smg-8 Mutants do not Exhibit Phenotypes Associated with NMD Mutants

Summary

Introduction

The nonsense mediated decay (NMD) pathway is an evolutionarily conserved mRNA surveillance mechanism that recognizes and degrades transcripts bearing premature translation termination codons [1,2]. When a known component of the NMD pathway, such as smg-1, smg-2 or smg-3, is mutated, the mRNA isoform containing the PTC is stabilized, generating a robust upper band (Figure 2B). For smg-8(tm2937), a very faint upper band was observed, comparable to that of the wild-type strain (Figure 2B).

Results

Conclusion