A NOVEL CROSS-PHYLUM FAMILY OF PROTEINS COMPRISES A KRR1 (YCL059C) GENE WHICH IS ESSENTIAL FOR VIABILITY OF SACCHAROMYCES-CEREVISIAE CELLS

We demonstrate here that the open reading frame (ORF) YCL059c, discove red during the systematic sequencing of chromosome III [Oliver et al., Nature 357 (1992) 38-46], codes for a protein essential for yeast: ne ither spore germination nor cell division occur in strains deleted for this gene. We have cloned the wild-type (wt) gene and shown that it c omplements the deletion. A relatively abundant RNA transcript correspo nds to the gene. The protein has no similarity to proteins of known fu nction. Interestingly, however, it is homologous to several expressed sequence tags (EST) of unknown function from Caenorhabditis elegans, O ryza sativa and Homo sapiens. Thus, a novel family of proteins of pres umably nuclear localization, with a characteristic highly basic motif, KRR-R, transcends various phyla, and plays an important role in cellu lar processes. We propose to call this essential gene KRR1.