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Translation of aberrant mRNAs lacking a termination codon or with a shortened 3′‐UTR is repressed after initiation in yeast
Author(s) -
Inada Toshifumi,
Aiba Hiroji
Publication year - 2005
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1038/sj.emboj.7600636
Subject(s) - biology , translation (biology) , genetics , five prime untranslated region , yeast , start codon , stop codon , three prime untranslated region , untranslated region , eukaryotic translation , messenger rna , gene
A novel mRNA surveillance for mRNA lacking a termination codon (nonstop mRNA) has been proposed in which Ski7p is thought to recognize stalled ribosomes at the 3′ end of mRNA. Here we report our analysis of translation and decay of nonstop mRNAs in Saccharomyces cerevisiae . Although the reduction of nonstop mRNAs was only 4.5‐fold, a level that is sufficient for residual protein synthesis, translation products of nonstop mRNAs were hardly detectable. We show that nonstop mRNAs were associated with polysomes, but not with Pab1p. We also show that ribosomes translating nonstop mRNA formed stable and heavy polysome complexes with mRNA. These data suggest that ribosome stalling at the 3′ end of nonstop mRNA may block further rounds of translation, hence repressing protein synthesis. Furthermore, it was found that the 5′ → 3′ decay pathway was accelerated for nonstop mRNA decay in the absence of Ski7p. We also found that translation of aberrant mRNAs with a shortened 3′‐UTR was repressed, suggesting that an improper spatial distance between the termination codon and the 3′ end of mRNA results in translation repression.