Gene overexpression as a tool for identifying new trans-acting factors involved in translation termination in Saccharomyces cerevisiae.
In eukaryotes, translation termination is dependent on the availability of both release factors, eRF1 and eRF3; however, the precise mechanisms involved remain poorly understood. In particular, the fact that the phenotype of release factor mutants is pleiotropic could imply that other factors and interactions are involved in translation termination. To identify unknown elements involved in this process, we performed a genetic screen using a reporter strain in which a leaky stop codon is inserted in the lacZ reporter gene, attempting to isolate factors modifying termination efficiency when overexpressed. Twelve suppressors and 11 antisuppressors, increasing or decreasing termination readthrough, respectively, were identified and analyzed for three secondary phenotypes often associated with translation mutations: thermosensitivity, G418 sensitivity, and sensitivity to osmotic pressure. Interestingly, among these candidates, we identified two genes, SSO1 and STU2, involved in protein transport and spindle pole body formation, respectively, suggesting puzzling connections with the translation termination process.
Namy
Olivier
O
Laboratoire de Génétique Moléculaire de la Traduction, Institut de Génétique et Microbiologie, CNRS UMR8621, Université Paris-Sud, 91405 Orsay Cedex, France.
Hatin
Isabelle
I
Stahl
Guillaume
G
Liu
Hongmei
H
Barnay
Stephanie
S
Bidou
Laure
L
Rousset
Jean-Pierre
JP
D003599:Cytoskeleton / Q000502:physiology; D005656:Fungal Proteins / Q000235:genetics / Q000502:physiology; D015870:Gene Expression; D005822:Genetic Vectors; D008565:Membrane Proteins / Q000235:genetics / Q000502:physiology; D008869:Microtubule-Associated Proteins / Q000235:genetics / Q000502:physiology; D014176:Protein Biosynthesis / Q000235:genetics* / Q000502:physiology; D021381:Protein Transport; D050765:Qa-SNARE Proteins; D012351:RNA, Transfer, Gln / Q000235:genetics / Q000502:physiology; D012441:Saccharomyces cerevisiae / Q000235:genetics* / Q000502:physiology; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000502:physiology*
D005656:Fungal Proteins; D008565:Membrane Proteins; D008869:Microtubule-Associated Proteins; D050765:Qa-SNARE Proteins; D012351:RNA, Transfer, Gln; C084006:SSO1 protein, S cerevisiae; C109414:STU2 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins