High impact information on ROX3

• Expression of GPD2 is also unaffected by ROX1 and ROX3, encoding putative regulators of hypoxic and stress-controlled gene expression [1].
• SSN genes that affect transcriptional repression in Saccharomyces cerevisiae encode SIN4, ROX3, and SRB proteins associated with RNA polymerase II [2].
• Serine 699 phosphorylation requires Gal4p's DNA binding function and is influenced by the function of the RNA polymerase II holoenzyme component Gal11p [3].
• The ROX3 gene encodes an essential nuclear protein involved in CYC7 gene expression in Saccharomyces cerevisiae [4].
• A second lower molecular size complex was also identified, termed Mediator core (Medc), which lacked pol II, Srb8-11, Rox3, Nut1, and the Rgrl module [5].

Biological context of ROX3

• ROX3 was cloned by complementation of a glucose-inducible flocculating phenotype of an amber mutant and has been mapped as a new leftmost marker on chromosome 2 [6].
• We show that a defined, single interaction between a DNA-bound derivative of the activator Gal4 and Gal11P, a mutant form of the RNA polymerase II holoenzyme component Gal11, suffices for stimulating DNA replication as it does for transcription [7].

Associations of ROX3 with chemical compounds

• The ROX3 mutant has only a modest defect in glucose repression of GAL1 but is substantially compromised in galactose induction of GAL1 expression [6].

Regulatory relationships of ROX3

• The ROX3 gene was identified during a hunt for mutants with increased expression of the heme-regulated CYC7 gene, which encodes the minor species of cytochrome c in the yeast Saccharomyces cerevisiae [4].

Other interactions of ROX3

• A selection for high-copy suppressors of a ROX3 temperature-sensitive allele resulted in the isolation of RTS1, encoding a protein with homology to the B' regulatory subunit of protein phosphatase 2A0 [8].
• Mutations in the ROX3 gene prevented CYC7 RNA accumulation during heat shock and osmotic stress [8].
• We have identified two of these as the previously described GRR1/CAT80 and ROX3 genes [6].

Analytical, diagnostic and therapeutic context of ROX3

• Yeast Rox3 protein, implicated by genetic evidence in both negative and positive transcriptional regulation, is identified as a mediator subunit by peptide sequence determination and is shown to copurify and co-immunoprecipitate with RNA polymerase II holoenzyme [9].

References