Tpa1p is part of an mRNP complex that influences translation termination, mRNA deadenylation, and mRNA turnover in Saccharomyces cerevisiae.
In this report, we show that the Saccharomyces cerevisiae protein Tpa1p (for termination and polyadenylation) influences translation termination efficiency, mRNA poly(A) tail length, and mRNA stability. Tpa1p is encoded by the previously uncharacterized open reading frame YER049W. Yeast strains carrying a deletion of the TPA1 gene (tpa1Delta) exhibited increased readthrough of stop codons, and coimmunoprecipitation assays revealed that Tpa1p interacts with the translation termination factors eRF1 and eRF3. In addition, the tpa1Delta mutation led to a 1.5- to 2-fold increase in the half-lives of mRNAs degraded by the general 5'-->3' pathway or the 3'-->5' nonstop decay pathway. In contrast, this mutation did not have any affect on the nonsense-mediated mRNA decay pathway. Examination of mRNA poly(A) tail length revealed that poly(A) tails are longer than normal in a tpa1Delta strain. Consistent with a potential role in regulating poly(A) tail length, Tpa1p was also found to coimmunoprecipitate with the yeast poly(A) binding protein Pab1p. These results suggest that Tpa1p is a component of a messenger ribonucleoprotein complex bound to the 3' untranslated region of mRNAs that affects translation termination, deadenylation, and mRNA decay.
Keeling
Kim M
KM
Department of Microbiology, BBRB 432/Box 8, 1530 3rd Avenue South, University of Alabama at Birmingham, Birmingham, AL 35294-2170, USA. dbedwell@uab.edu
Salas-Marco
Joe
J
Osherovich
Lev Z
LZ
Bedwell
David M
DM
D020413:3' Untranslated Regions; D021581:Active Transport, Cell Nucleus; D001483:Base Sequence; D004271:DNA, Fungal / Q000235:genetics; D005800:Genes, Fungal; D008954:Models, Biological; D009154:Mutation; D010443:Peptide Chain Termination, Translational; D010454:Peptide Termination Factors / Q000235:genetics / Q000378:metabolism*; D010641:Phenotype; D039102:Poly(A)-Binding Proteins / Q000378:metabolism; D020871:RNA Stability; D012331:RNA, Fungal / Q000235:genetics / Q000378:metabolism*; D012261:Ribonucleoproteins / Q000235:genetics / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000235:genetics* / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism*
D020413:3' Untranslated Regions; D004271:DNA, Fungal; D010454:Peptide Termination Factors; D039102:Poly(A)-Binding Proteins; D012331:RNA, Fungal; D012261:Ribonucleoproteins; D029701:Saccharomyces cerevisiae Proteins; C026452:messenger ribonucleoprotein; C450100:pab1 protein, S cerevisiae