Extragenic suppressors of Saccharomyces cerevisiae prp4 mutations identify a negative regulator of PRP genes.
The PRP4 gene encodes a protein that is a component of the U4/U6 small nuclear ribonucleoprotein particle and is necessary for both spliceosome assembly and pre-mRNA splicing. To identify genes whose products interact with the PRP4 gene or gene product, we isolated second-site suppressors of temperature-sensitive prp4 mutations. We limited ourselves to suppressors with a distinct phenotype, cold sensitivity, to facilitate analysis of mutants. Ten independent recessive suppressors were obtained that identified four complementation groups, spp41, spp42, spp43 and spp44 (suppressor of prp4, numbers 1-4). spp41-spp44 suppress the pre-mRNA splicing defect as well as the temperature-sensitive phenotype of prp4 strains. Each of these spp mutations also suppresses prp3; spp41 and spp42 suppress prp11 as well. Neither spp41 nor spp42 suppressors null alleles of prp3 or prp4, indicating that the suppression does not occur via a bypass mechanism. The spp41 and spp42 mutations are neither allele- nor gene-specific in their pattern of suppression and do not result in a defect in pre-mRNA splicing. Thus the SPP41 and SPP42 gene products are unlikely to participate directly in mRNA splicing or interact directly with Prp3p or Prp4p. Expression of PRP3-lacZ and PRP4-lacZ gene fusions is increased in spp41 strains, suggesting that wild-type Spp41p represses expression of PRP3 and PRP4. SPP41 was cloned and sequenced and found to be essential. spp43 is allelic to the previously identified suppressor srn1, which encodes a negative regulator of gene expression.
Maddock
J R
JR
Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213.
Weidenhammer
E M
EM
Adams
C C
CC
Lunz
R L
RL
Woolford
J L
JL
D000483:Alleles; D000595:Amino Acid Sequence; D001483:Base Sequence; D003080:Cold Temperature; D017931:DNA Primers / Q000235:genetics; D004271:DNA, Fungal / Q000235:genetics; D005656:Fungal Proteins / Q000235:genetics; D005800:Genes, Fungal; D005804:Genes, Lethal; D005809:Genes, Regulator; D016153:Genes, Suppressor; D005816:Genetic Complementation Test; D008040:Genetic Linkage; D008957:Models, Genetic; D008969:Molecular Sequence Data; D009154:Mutation; D010641:Phenotype; D017346:Protein Serine-Threonine Kinases / Q000235:genetics; D012326:RNA Splicing / Q000235:genetics; D000072260:RNA Splicing Factors; D012097:Repressor Proteins; D017414:Ribonucleoprotein, U4-U6 Small Nuclear / Q000235:genetics*; D012441:Saccharomyces cerevisiae / Q000235:genetics* / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins; D013489:Suppression, Genetic
D017931:DNA Primers; D004271:DNA, Fungal; D005656:Fungal Proteins; D000072260:RNA Splicing Factors; D012097:Repressor Proteins; D017414:Ribonucleoprotein, U4-U6 Small Nuclear; C087740:SPP41 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; C083212:PRP4 protein, S cerevisiae; D017346:Protein Serine-Threonine Kinases