YBR1012 AN ESSENTIAL GENE FROM SACCHAROMY CES-CEREVISIAE - CONSTRUCTION OF AN RNA ANTISENSE CONDITIONAL ALLELE AND ISOLATION OF A MULTICOPYSUPPRESSOR

The gene YBR1012 was identified during the systematic sequencing of ch romosome II of the yeast Saccharomyces cerevisiae. We have inactivated the gene and shown that it is essential for cellular viability Using antisense RNA technology, we have constructed a conditional allele, ex pression of the antisense RNA strongly inhibits growth. To our knowled ge this is the first successful use of antisense RNA technology in S. cerevisiae. Comparison of the deduced ybr 1012p sequence with the data banks revealed the presence of a putative phosphatidylinasitol kinase domain and a strong homology to the Schizosaccharomyces pombe rad3p. These results suggest that ybr 1012p may be involved in signal transdu ction, possibly related to the control of replication and/or DNA damag e repair. The link with DNA damage repair was reinforced by the isolat ion of the DUN1 gene as a multicopy suppressor of the YBR1012 deletion .