YBR1012 an essential gene from S. cerevisiae : construction of an RNA antisense conditional allele and isolation of a multicopy suppressor

The gene YBR1012 was identified during the systematic sequencing of chromosome 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, expression of the antisense RNA strongly inhibits growth. To our knowledge this is the first successful use of antisense RNA technology in S. cerevisiae. Comparison of the deduced ybr1012p sequence with the data banks revealed the presence of a putative phosphatidylinositol kinase domain and a strong homology to the Schizosaccharomyces pombe rad3p. These results suggest that ybr1012p may be involved in signal transduction, possibly related to the control of replication and/or DNA damage repair. The link with DNA damage repair was reinforced by the isolation of the DUN1 gene as a multicopy suppressor of the YBR1012 deletion.