Identification of a putative DEAD-box RNA helicase and a zinc-finger protein in Candida albicans by functional complementation of the S. cerevisiae rok1 mutation.

摘要

Two genes, CHR1 and CSR1, of C. albicans were identified by functional complementation of the S. cerevisiae rok1 mutation. The Rok1 protein is a member of the DEAD protein family of ATP-dependent RNA helicases. ROK1 is required for cell cycle progression and also for rRNA processing. The CHR1 gene product of 578 amino acids is highly homologous to the Rok1 protein (54% identity) and is considered to be a putative DEAD-box RNA helicase. It is predicted that the CSR1 gene encodes a 73 kDa protein of612 amino acids with 5 zinc-finger motifs at the C-terminal region. CHR1 or CSR1 on a high-copy number plasmid showed a slow-growth phenotype in a condition where the ROK1 expression is turned on from the GAL1 promoter. This result is consistent with thelethality caused by the ROK1 overexpression. It is concluded that CHR1 encodes a functional homologue of Rok1 protein and CSR1 is a heterologous suppressor of the rok1 mutation. The GenBank Accession Nos for the CHR1 and CSR1 sequences are AF140505 andAF140504, respectively.