This Article Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Copyright Information Books from ASM Press MicrobeWorld Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Chauvin, C. Articles by Jean-Jean, O. Search for Related Content PubMed PubMed Citation Articles by Chauvin, C. Articles by Jean-Jean, O.

Involvement of Human Release Factors eRF3a and eRF3b in Translation Termination and Regulation of the Termination Complex Formation

Unité de Biochimie Cellulaire, UMR 7098 CNRS-Université Paris 6, 9 quai Saint-Bernard, 75005 Paris, France,¹ Université de Rennes 1, CNRS UMR 6061, IFR 140 GFAS, 2 Avenue Pr. Léon Bernard, 35043 Rennes Cedex, France,² Faculté de Médecine et de Pharmacie, Université Cheick Anta Diop, Dakar, Sénégal³

Received 2 March 2005/ Returned for modification 25 March 2005/ Accepted 14 April 2005

eRF3 is a GTPase associated with eRF1 in a complex that mediates translation termination in eukaryotes. In mammals, two genes encode two distinct forms of eRF3, eRF3a and eRF3b, which differ in their N-terminal domains. Both bind eRF1 and stimulate its release activity in vitro. However, whether both proteins can function as termination factors in vivo has not been determined. In this study, we used short interfering RNAs to examine the effect of eRF3a and eRF3b depletion on translation termination efficiency in human cells. By measuring the readthrough at a premature nonsense codon in a reporter mRNA, we found that eRF3a silencing induced an important increase in readthrough whereas eRF3b silencing had no significant effect. We also found that eRF3a depletion reduced the intracellular level of eRF1 protein by affecting its stability. In addition, we showed that eRF3b overexpression alleviated the effect of eRF3a silencing on readthrough and on eRF1 cellular levels. These results suggest that eRF3a is the major factor acting in translation termination in mammals and clearly demonstrate that eRF3b can substitute for eRF3a in this function. Finally, our data indicate that the expression level of eRF3a controls the formation of the termination complex by modulating eRF1 protein stability.

This article has been cited by other articles:

• Chauvin, C., Jean-Jean, O. (2008). Proteasomal degradation of human release factor eRF3a regulates translation termination complex formation. RNA 14: 240-245 [Abstract] [Full Text]  
• Chauvin, C., Salhi, S., Jean-Jean, O. (2007). Human Eukaryotic Release Factor 3a Depletion Causes Cell Cycle Arrest at G1 Phase through Inhibition of the mTOR Pathway. Mol. Cell. Biol. 27: 5619-5629 [Abstract] [Full Text]