SCE3, A SUPPRESSOR OF THE SCHIZOSACCHAROMYCES-POMBE SEPTATION MUTANT CDC11, ENCODES A PUTATIVE RNA-BINDING PROTEIN

In the fission yeast Schizosaccharomyces pombe, the cdc11 gene is requ ired for the initiation of septum formation at the end of mitosis. The sce3 gene was cloned as a multi-copy suppressor of the heat-sensitive mutant cdc11-136. When over-expressed, it rescues all mutants of cdc1 1 and also a heat-sensitive allele of cdc14, but not the cdc14 null mu tant. Deletion shows that sce3 is not essential for cell proliferation . It encodes a putative RNA-binding protein which shows homology to hu man elF4B. Immunolocalisation indicates that Sce3p is located predomin antly in the cytoplasm. Elevated expression of sce3 increases the stea dy-state level of cdcl4 mRNA. Possible mechanisms of its action are di scussed.