Genetic and Molecular Characterization of Suppressors of Sir4 Mutations in Saccharomyces Cerevisiae
AUTOR(ES)
Schnell, R.
RESUMO
In order to learn more about other proteins that may be involved in repression of HML and HMR in Saccharomyces cerevisiae, extragenic suppressor mutations were identified that could restore repression in cells defective in SIR4, a gene required for function of the silencer elements flanking HML and HMR. These suppressor mutations, which define at least three new genes, SAN1, SAN2 and SAN3, arose at the frequency expected for loss-of-function mutations following mutagenesis. All san mutations were recessive. Suppression by san1 was allele-nonspecific, since san1 could suppress two very different alleles of SIR4, and was locus-specific since san1 was unable to suppress a SIR3 mutation or a variety of mutations conferring auxotrophies. The SAN1 gene was cloned, sequenced, and used to construct a null allele. The null allele had the same phenotype as the EMS-induced mutations and exhibited no pleiotropies of its own. Thus, the SAN1 gene was not essential. SAN1-mediated suppression was neither due to compensatory mutations in interacting proteins, nor to translational missense suppression. SAN1 may act posttranslationally to control the stability or activity of the SIR4 protein.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=1203690Documentos Relacionados
- Extragenic Suppressors of Mar2(sir3) Mutations in Saccharomyces Cerevisiae
- Enhancement of Telomere-Plasmid Segregation by the X-Telomere Associated Sequence in Saccharomyces Cerevisiae Involves Sir2, Sir3, Sir4 and Abf1
- Silent information regulator protein complexes in Saccharomyces cerevisiae: A SIR2/SIR4 complex and evidence for a regulatory domain in SIR4 that inhibits its interaction with SIR3
- Map Positions of Yeast Genes SIR1, SIR3 and SIR4
- Isolation and Characterization of Extragenic Suppressors of Mutations in the Ssa Hsp70 Genes of Saccharomyces Cerevisiae