SCR: novel human suppressors of cdc2/cdc13 mutants of Schizosaccharomyces pombe harbour motifs for RNA binding proteins.

By phenotypic complementation of the cdc2 and the cdc13 mutants of the fission yeast Schizosaccharomyces pombe, we have cloned two novel multicopy suppressors from a cDNA library of the human fibroblast. They encode homologous proteins containing two regions that are highly conserved among RNA binding proteins. We named them scr2 and scr3, the acronyms of the suppressor of cdc2 (cdc13) with RNA binding motif. They encode proteins of 403 (Scr2) and 407 (Scr3) amino acids. Western blot analysis showed that the amount of Cdc2 increased when either rat kidney fibroblasscr2 or scr3 was introduced into the cdc2-L7 and cdc13-117 mutant cells of S.pombe. No conspicuous alteration in the transcript level was detected as judged by Northern analysis. Considering that the cdc2+ suppresses the cdc13 mutant and vice versa, one of the possible interpretations of these result is that these genes suppress the mutants through the induction of the translation of Cdc2.