CHARACTERIZATION OF CWL1(-POMBE WHOSE OVEREXPRESSION CAUSES CELL-LYSIS(), A GENE FROM SCHIZOSACCHAROMYCES)

From a Schizosaccharomyces pombe genomic library we have isolated the gene cwll(+) that causes cell lysis when it is overexpressed in the ab sence of an osmotic stabilizer. Southern hybridization showed that cwl l(+) exists as a single copy in the S. pombe genome. The cwll(+) gene nucleotide sequence revealed a putative open reading frame of 924 bp e ncoding a polypeptide of 308 amino acids with a calculated M(r) of 27 000. The cwll(+) DNA hybridizes to a major RNA transcript of 1.5 kb wh ose 5' end maps at a position 452 bp upstream from the predicted trans lation start. Comparison of the amino acid sequence with those include d in the current databases, showed no significant similarity to any kn own sequences. Cells overexpressing the cwll(+) gene under the control of the S. pombe nmt inducible promoter displayed a reduced cell wall content, were unable to separate after division and lysed drastically in the absence of osmotic stabilizer. Disruption of the cwll(+) gene c aused no noticeable phenotype. The sequence has been deposited in the EMBL data library under Accession Number X9445.