SEQUENCE AND FUNCTION-ANALYSIS OF A 9.74-KB FRAGMENT OF SACCHAROMYCES-CEREVISIAE CHROMOSOME-X INCLUDING THE BCK1 GENE

In the framework of the European BIOTECH project for sequencing the Sa ccharomyces cerevisiae genome, we have determined the nucleotide seque nce of the cosmid clone 233 provided by F. Galibert (Rennes Cedex, Fra nce). We present here 9743 base pairs of sequence derived from the lef t arm of chromosome X. This sequence reveals three new open reading fr ames and includes the published sequence (5' end and open reading fram e) of the gene BCK1/SLK1/SSP31 also identified as ORFAA. Deletion muta nts of two earlier unknown open reading frames J0840 and J0904 are via ble and the open reading frame J0902 is essential for yeast growth. Th e sequence has been entered in the EMBL data library under accession n umber X77923.