Allele-specific suppressors of lin-1(R175Opal) identify functions of MOC-3 and DPH-3 in tRNA modification complexes in Caenorhabditis elegans
2010 (English)In: Genetics, ISSN 0016-6731, E-ISSN 1943-2631, Vol. 185, no 4, 1235-1247 p.Article in journal (Refereed) Published
The elongator (ELP) complex consisting of Elp1-6p has been indicated to play roles in multiple cellular processes. In yeast, the ELP complex has been shown to genetically interact with Uba4p/Urm1p and Kti11-13p for a function in tRNA modification. Through a Caenorhabditis elegans genetic suppressor screen and positional cloning, we discovered that loss-of-function mutations of moc-3 and dph-3, orthologs of the yeast UBA4 and KTI11, respectively, effectively suppress the Multivulva (Muv) phenotype of the lin-1(e1275, R175Opal) mutation. These mutations do not suppress the Muv phenotype caused by other lin-1 alleles or by gain-of-function alleles of ras or raf that act upstream of lin-1. The suppression can also be reverted by RNA interference of lin-1. Furthermore, we showed that dph-3(lf) also suppressed the defect of lin-1(e1275) in promoting the expression of a downstream target (egl-17). These results indicate that suppression by the moc-3 and dph-3 mutations is due to the elevated activity of lin-1(e1275) itself rather than the altered activity of a factor downstream of lin-1. We further showed that loss-of-function mutations of urm-1 and elpc-1-4, the worm counterparts of URM1 and ELP complex components in yeast, also suppressed lin-1(e1275). We also confirmed that moc-3(lf) and dph-3(lf) have defects in tRNA modifications as do the mutants of their yeast orthologs. These results, together with the observation of a likely readthrough product from a lin-1(e1275)∷gfp fusion transgene indicate that the aberrant tRNA modification led to failed recognition of a premature stop codon in lin-1(e1275). Our genetic data suggest that the functional interaction of moc-3/urm-1 and dph-3 with the ELP complex is an evolutionarily conserved mechanism involved in tRNA functions that are important for accurate translation.
Place, publisher, year, edition, pages
Genetics Society of America , 2010. Vol. 185, no 4, 1235-1247 p.
adp-ribosylating toxins, saccharomyces-cerevisiae, c-elegans, elongator complex, cell fates, vulval induction, transcriptional elongation, modifier urm1, ets-domain, protein
IdentifiersURN: urn:nbn:se:umu:diva-43347DOI: 10.1534/genetics.110.118406ISI: 000281907700009OAI: oai:DiVA.org:umu-43347DiVA: diva2:413118