Mutations in GCR3, a gene involved in the expression of glycolytic genes in Saccharomyces cerevisiae, suppress the temperature-sensitive growth of hpr1 mutants.
To study the functions of DNA topoisomerase I and Hpr1 protein, a suppressor mutant of the temperature-sensitive growth of an hpr1 top1-5ts double mutant was isolated. The isolated triple mutant showed cold-sensitive growth. By complementation of this phenotype, the suppressor gene was cloned. DNA sequencing showed it to be GCR3, a gene involved in the expression of glycolytic genes. Further analysis showed that gcr3 mutations also suppressed the temperature-sensitive growth of hpr1 single mutants. Experiments with gcr3 truncation mutants also suggested a genetic interaction between GCR3 and HPR1. The fact that top1 suppressed the growth defect of gcr3 suggested an interaction between those two genes also. Plasmid DNA isolated from gcr3 mutants was significantly more negatively supercoiled than normal, suggesting that Gcr3 protein, like topoisomerase I and Hpr1p, affects chromatin structure, perhaps during transcription.
Uemura
H
H
Department of Molecular Biology, National Institute of Bioscience and Human-Technology, Ibaraki, Japan.
Pandit
S
S
Jigami
Y
Y
Sternglanz
R
R
D000483:Alleles; D000595:Amino Acid Sequence; D004264:DNA Topoisomerases, Type I / Q000235:genetics; D005656:Fungal Proteins / Q000235:genetics*; D015966:Gene Expression Regulation, Fungal; D006019:Glycolysis; D007438:Introns; D008969:Molecular Sequence Data; D009687:Nuclear Proteins / Q000235:genetics*; D010957:Plasmids; D039381:RNA Cap-Binding Proteins; D012441:Saccharomyces cerevisiae / Q000235:genetics*; D029701:Saccharomyces cerevisiae Proteins; D013489:Suppression, Genetic; D013696:Temperature
D005656:Fungal Proteins; C063494:HPR1 protein, S cerevisiae; D009687:Nuclear Proteins; D039381:RNA Cap-Binding Proteins; C101398:STO1 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D004264:DNA Topoisomerases, Type I