Investigation of the stability of yeast rad52 mutant proteins uncovers post-translational and transcriptional regulation of Rad52p.
We investigated the stability of the Saccharomyces cerevisiae Rad52 protein to learn how a cell controls its quantity and longevity. We measured the cellular levels of wild-type and mutant forms of Rad52p when expressed from the RAD52 promoter and the half-lives of the various forms of Rad52p when expressed from the GAL1 promoter. The wild-type protein has a half-life of 15 min. rad52 mutations variably affect the cellular levels of the protein products, and these levels correlate with the measured half-lives. While missense mutations in the N terminus of the protein drastically reduce the cellular levels of the mutant proteins, two mutations--one a deletion of amino acids 210-327 and the other a missense mutation of residue 235--increase the cellular level and half-life more than twofold. These results suggest that Rad52p is subject to post-translational regulation. Proteasomal mutations have no effect on Rad52p half-life but increase the amount of RAD52 message. In contrast to Rad52p, the half-life of Rad51p is >2 hr, and RAD51 expression is unaffected by proteasomal mutations. These differences between Rad52p and Rad51p suggest differential regulation of two proteins that interact in recombinational repair.
Asleson
Erin N
EN
Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, Minnesota 55455, USA.
Livingston
Dennis M
DM
D003546:Cysteine Endopeptidases / Q000235:genetics; D004268:DNA-Binding Proteins / Q000235:genetics* / Q000378:metabolism; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism; D015966:Gene Expression Regulation, Fungal; D009097:Multienzyme Complexes / Q000235:genetics; D009154:Mutation; D046988:Proteasome Endopeptidase Complex; D011499:Protein Processing, Post-Translational; D012333:RNA, Messenger; D051135:Rad51 Recombinase; D051721:Rad52 DNA Repair and Recombination Protein; D012441:Saccharomyces cerevisiae / Q000235:genetics* / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins; D014158:Transcription, Genetic
D004268:DNA-Binding Proteins; D005656:Fungal Proteins; D009097:Multienzyme Complexes; C497197:RAD52 protein, S cerevisiae; D012333:RNA, Messenger; D051721:Rad52 DNA Repair and Recombination Protein; D029701:Saccharomyces cerevisiae Proteins; C495151:RAD51 protein, S cerevisiae; D051135:Rad51 Recombinase; D003546:Cysteine Endopeptidases; D046988:Proteasome Endopeptidase Complex