Nucleotide sequence of the COR region: a cluster of six genes in the yeast Saccharomyces cerevisiae.
We have determined the nucleotide (nt) sequence of the 7.5-kb COR segment that encompasses a cluster of six genes (CYC1, UTR1, UTR3, OSM1, tRNA(Gly) and RAD7) located on chromosome X of the yeast Saccharomyces cerevisiae. This sequence revealed five open reading frames and a tRNA gene which correspond in position, size and orientation to the transcripts previously identified by Barry et al. [Mol. Cell. Biol. 7 (1987) 632-638]. The extensively studied CYC1 gene encodes iso-1-cytochrome c; the UTR1 and UTR3 genes encode dispensible proteins whose functions are unknown; the OSM1 gene encodes a protein required for growth on hypertonic media; the tRNA(Gly) gene encodes a glycine tRNA; and the RAD7 gene encodes a protein required for repair of UV-induced damage. The OSM1 protein contains a signal sequence for secretion and a region similar to GTP-binding domains. The RAD7 protein displays 5'-untranslated elements similar to those of the stress-inducible gene UB14. The nt sequence upstream from the tRNA(Gly) gene contains a diverged copy of the sigma repeated element. This cluster of COR genes appears to have an ancestral relationship with the cluster of ARC genes on chromosome V.