Sequencing and Analysis of a 35·4 kb Region on the Left Arm of Chromosome IV from Saccharomyces cerevisiae Reveal 23 Open Reading Frames

The complete DNA sequence of cosmid clone 31A5 containing a 35 452 bp segment from the left arm of chromosome IV from Saccharomyces cerevisiae, was determined from an ordered set of subclones in combination with primer walking on the cosmid. The sequence contains 23 open reading frames (ORFs) of more than 100 amino acid residues and the tRNA-Val2a gene. Five ORFs corresponded to the known yeast genes SNQ2, SES1, GCV1, RPL2B and RPS18A. The DNA sequence for RPS18A is interrupted by an intron. One ORF corresponded to a part of the yeast gene HEX2 at the end of the cosmid insert. Four ORFs encoded putative proteins which showed strong homologies to other previously known proteins, three of yeast origin and one of non-yeast origin. Two ORFs were classified as having borderline homologies: one had similarity to two protein families and another to two protein products of unknown function from other species. The remaining 11 ORFs bore no significant similarity to any published protein. The complete DNA sequence has been submitted to the EMBL data library, Accession Number X95966.