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.
Mesh Terms:
Alleles, Amino Acid Sequence, Base Sequence, Cold Temperature, DNA Primers, DNA, Fungal, Fungal Proteins, Genes, Fungal, Genes, Lethal, Genes, Regulator, Genes, Suppressor, Genetic Complementation Test, Linkage (Genetics), Models, Genetic, Molecular Sequence Data, Mutation, Phenotype, Protein-Serine-Threonine Kinases, RNA Splicing, Repressor Proteins, Ribonucleoprotein, U4-U6 Small Nuclear, Saccharomyces cerevisiae, Saccharomyces cerevisiae Proteins, Suppression, Genetic
Alleles, Amino Acid Sequence, Base Sequence, Cold Temperature, DNA Primers, DNA, Fungal, Fungal Proteins, Genes, Fungal, Genes, Lethal, Genes, Regulator, Genes, Suppressor, Genetic Complementation Test, Linkage (Genetics), Models, Genetic, Molecular Sequence Data, Mutation, Phenotype, Protein-Serine-Threonine Kinases, RNA Splicing, Repressor Proteins, Ribonucleoprotein, U4-U6 Small Nuclear, Saccharomyces cerevisiae, Saccharomyces cerevisiae Proteins, Suppression, Genetic
Genetics
Date: Mar. 01, 1994
PubMed ID: 8005438
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