THE NOVEL NUCLEAR GENE DSS-1 OF SACCHAROMYCES-CEREVISIAE IS NECESSARYFOR MITOCHONDRIAL BIOGENESIS

A previously unknown nuclear gene DSS-1 from Saccharomyces cerevisiae was cloned and sequenced. The gene was isolated as a multicopy suppres sor of a disruption of the SUV-3 gene coding for a DEAD/H box protein involved in processing and turnover of mitochondrial transcripts. The DSS-1 gene codes for a 970 amino-acid protein of molecular weight 111 kDa and is necessary for mitochondrial biogenesis. Amino-acid sequence analysis indicates the presence of motifs characteristic for Escheric hia coli RNase II, the dis3 protein from Schizosaccharomyces pombe, th e cyt4 protein participating in RNA processing and turnover in Neurosp ora crassa mitochondria, and the vacB protein from Shigella flexneri. We suggest that the DSS-1 protein may be a component of the mitochondr ial 3'-5' exoribonuclease complex.