ANALYSIS OF A 33.1 KB FRAGMENT FROM THE LEFT ARM OF SACCHAROMYCES-CEREVISIAE CHROMOSOME-X, INCLUDING PUTATIVE PROTEINS WITH LEUCINE ZIPPERS, A FUNGAL ZN(II)(2)-CYS(6) BINUCLEAR CLUSTER DOMAIN AND A PUTATIVE ALPHA-2-SCB-ALPHA-2 BINDING-SITE

In the framework of the European BIOTECH project for sequencing the Sa ccharomyces cerevisiae genome, we have determined the nucleotide seque nce of the left part of the cosmid clone 232 and the cosmid clone 233 provided by F. Galibert (Rennes Cedex, France). We present here 33,099 base pairs of sequence derived from the left arm of chromosome X of s train S288C. This sequence reveals 17 open reading frames (ORFs) with more than 299 base pairs, including the published sequences for ARG3, LIGTR/LIG1, ORF2, ACT3 and SCP160. Two other ORFs showed similarity wi th S. cerevisiae genes: one with the CAN1 gene coding for an arginine permease, and one with genes encoding the family of transcriptional ac tivators containing a fungal Zn(II)(2)-Cys(6) binuclear cluster domain like that found in Ppr1p or Ga14p. Both putative proteins contain a l eucine zipper motif, the Can1p homologue has 12 putative membrane-span ning domains and a putative alpha 2-SCB-alpha 2 binding site. In a dip loid disruption mutant of ORF JO922 coding for the transcriptional act ivator homologue, no colonies appeared before 10 days after transforma tion and then grew slowly. In contrast, haploid disruption mutants sho wed a growth phenotype like wild-type cells. One ORF showed weak simil arity to the rad4 gene product of Schizosaccharomyces pombe and is ess ential for yeast growth. Five ORFs showed similarity to putative genes on the right arm of chromosome XI of S. cerevisiae. Two of them have similarity to each other and belong to a family of extracellular prote ins that groups mammalian SCP/Tpx-1, insects Ag3/Ag5, plants PR-1 and fungi Sc7/Sc14. Three small ORFs are completely contained in the large r ORFs on the corresponding complementary strand and thus probably do not represent real genes. The DNA sequence has been deposited in the E MBL data library under Accession Number X83502.