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Translational readthrough of the PDE2 stop codon modulates cAMP levels in Saccharomyces cerevisiae
Author(s) -
Namy Olivier,
DuchateauNguyen Guillemette,
Rousset JeanPierre
Publication year - 2002
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1046/j.1365-2958.2002.02770.x
Subject(s) - orfs , biology , open reading frame , stop codon , saccharomyces cerevisiae , genetics , start codon , translation (biology) , yeast , messenger rna , gene , peptide sequence
Summary The efficiency of translation termination in yeast can vary several 100‐fold, depending on the context around the stop codon. We performed a computer analysis designed to identify yeast open reading frames (ORFs) containing a readthrough motif surrounding the termination codon. Eight ORFs were found to display inefficient stop codon recognition, one of which, PDE2 , encodes the high‐affinity cAMP phosphodiesterase. We demonstrate that Pde2p stability is very impaired by the readthrough‐dependent extension of the protein. A 20‐fold increase in readthrough of PDE2 was observed in a [ PSI + ] as compared with a [ psi – ] strain. Consistent with this observation, an important increase in cAMP concentration was observed in suppressor backgrounds. These results provide a molecular explanation for at least some of the secondary phenotypes associated with suppressor backgrounds.