Yeast frameshift suppressor mutations in the genes coding for transcription factor Mbf1p and ribosomal protein S3: evidence for autoregulation of S3 synthesis.
The SUF13 and SUF14 genes were identified among extragenic suppressors of +1 frameshift mutations. SUF13 is synonymous with MBF1, a single-copy nonessential gene coding for a POLII transcription factor. The suf13-1 mutation is a two-nucleotide deletion in the SUF13/MBF1 coding region. A suf13::TRP1 null mutant suppresses +1 frameshift mutations, indicating that suppression is caused by loss of SUF13 function. The suf13-1 suppressor alters sensitivity to aminoglycoside antibiotics and reduces the accumulation of his4-713 mRNA, suggesting that suppression is mediated at the translational level. The SUF14 gene is synonymous with RPS3, a single-copy essential gene that codes for the ribosomal protein S3. The suf14-1 mutation is a missense substitution in the coding region. Increased expression of S3 limits the accumulation of SUF14 mRNA, suggesting that expression is autoregulated. A frameshift mutation in SUF14 that prevents full-length translation eliminated regulation, indicating that S3 is required for regulation. Using CUP1-SUF14 and SUF14-lacZ fusions, run-on transcription assays, and estimates of mRNA half-life, our results show that transcription plays a minor role if any in regulation and that the 5'-UTR is necessary but not sufficient for regulation. A change in mRNA decay rate may be the primary mechanism for regulation.
Laboratories of Genetics and Molecular Biology, University of Wisconsin, Madison, Wisconsin 53706, USA.
J L
JL
Hendrick
P G
PG
Wilson
I I
II
Edelman
M G
MG
Sandbaken
D
D
Ursic
M R
MR
Culbertson
D020121:5' Untranslated Regions; D000483:Alleles; D003300:Copper / Q000494:pharmacology; D016208:Databases, Factual; D004305:Dose-Response Relationship, Drug; D016368:Frameshift Mutation; D018628:Gene Dosage; D005800:Genes, Fungal; D008957:Models, Genetic; D009154:Mutation; D010641:Phenotype; D010957:Plasmids / Q000235:genetics / Q000378:metabolism; D011401:Promoter Regions, Genetic; D012333:RNA, Messenger / Q000378:metabolism; D012269:Ribosomal Proteins / Q000096:biosynthesis* / Q000235:genetics*; D029701:Saccharomyces cerevisiae Proteins; D013489:Suppression, Genetic; D013997:Time Factors; D015534:Trans-Activators / Q000235:genetics*; D014157:Transcription Factors; D014158:Transcription, Genetic; D014170:Transformation, Genetic
D020121:5' Untranslated Regions; C106951:MBF1 protein, S cerevisiae; D012333:RNA, Messenger; D012269:Ribosomal Proteins; D029701:Saccharomyces cerevisiae Proteins; D015534:Trans-Activators; D014157:Transcription Factors; C044152:ribosomal protein S3; D003300:Copper