Mutations in STS1 suppress the defect in 3' mRNA processing caused by the rna15-2 mutation in Saccharomyces cerevisiae.
In a search for proteins associated with Rna15p in processing the 3' ends of messenger RNAs, we have looked for suppressors that correct, even partially, the thermosensitive growth defect of the rna15-2 mutant. Mutations in a single locus that we named SSM5, were able to suppress both the thermosensitivity of cell growth and the mRNA 3' processing defect associated with the rna15-2 mutation, but only slightly alleviated the thermosensitive growth defect of an rna14-1 mutant. The ssm5-1 mutant is sensitive to hydroxyurea at 37 degrees C, a drug that inhibits DNA synthesis. By screening for complementation of the hydroxyurea-sensitive phenotype we cloned the corresponding wild-type gene and found that it corresponds to the essential gene STS1 (also named DBF8). Sts1p has an apparent molecular weight of 30 kDa and was confirmed to be a cytosolic protein by immunofluorescence analysis. Western blot analysis indicates that the thermosensitive mutant strains rna15-2, rna14-1 and pap1-1 present a very low level of the Rna15p at 37 degrees C. The ssm5-1 mutation restores the level of Rna15p in the rna15-2 ssm5-1 double mutant. Use of the two-hybrid system suggests that Sts1p does not interact directly with Rna15p, but may be active as a homodimer. The present data suggest that Sts1p may play a role in the transport of Rna15p from the cytoplasm to the nucleus.
Centre de Génétique Moléculaire du C.N.R.S., Laboratoire propre associé à I'Université Pierre et Marie Curie, Gif sur Yvette, France.
N
N
Amrani
M E
ME
Dufour
N
N
Bonneaud
F
F
Lacroute
D018528:ATP-Binding Cassette Transporters / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D000483:Alleles; D026905:Amino Acid Transport Systems; D001483:Base Sequence; D005656:Fungal Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D015966:Gene Expression Regulation, Fungal; D016153:Genes, Suppressor; D005816:Genetic Complementation Test; D008565:Membrane Proteins / Q000235:genetics; D008969:Molecular Sequence Data; D009154:Mutation; D009687:Nuclear Proteins / Q000235:genetics* / Q000378:metabolism; D000073718:Pancreatitis-Associated Proteins; D011061:Poly A / Q000235:genetics / Q000378:metabolism; D011062:Polynucleotide Adenylyltransferase; D012323:RNA Processing, Post-Transcriptional; D012333:RNA, Messenger; D012441:Saccharomyces cerevisiae / Q000235:genetics* / Q000502:physiology; D029701:Saccharomyces cerevisiae Proteins; D012641:Selection, Genetic; D013347:Subcellular Fractions; D013696:Temperature; D039221:mRNA Cleavage and Polyadenylation Factors
D018528:ATP-Binding Cassette Transporters; D026905:Amino Acid Transport Systems; C429560:BAP3 protein, S cerevisiae; D005656:Fungal Proteins; D008565:Membrane Proteins; D009687:Nuclear Proteins; D000073718:Pancreatitis-Associated Proteins; C000612141:REG3A protein, human; D012333:RNA, Messenger; C085810:STS1 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D039221:mRNA Cleavage and Polyadenylation Factors; C512638:RNA14 protein, S cerevisiae; C512635:RNA15 protein, S cerevisiae; D011061:Poly A; C429559:PAP1 protein, S cerevisiae; D011062:Polynucleotide Adenylyltransferase