YEAST zyxwvutsrqponm VOL. 12: 983-990 (1996) Yeast Sequencing Reports Characterization of zyxw cwZl+, a Gene from Schizosaccharomyces pombe Whose Overexpression causes Cell Lysis CARLOS GODOY, MANUEL ARELLANO, MARGARITA DIAZ, ANGEL DURAN AND PILAR PEREZ* Znstituto de Microbiologia Bioquimira, Consejo Superior de Investigaciones Cientijicas and Universidad de Salamanca, 37007 Salamanca, Spain3 Received 6 February 1996; accepted 26 April 1996 From a Schizosaccharornyces pombe genomic library we have isolated the gene cwllf that causes cell lysis when it is overexpressed in the absence of an osmotic stabilizer. Southern hybridization showed that cwlI+ exists as a single copy in the S. pombe genome. The cwll+ gene nucleotide sequence revealed a putative open reading frame of 924 bp encoding a polypeptide of 308 amino acids with a calculated M, of 27 000. The cwll+ DNA hybridizes to a major RNA transcript of 1.5 kb whose 5' end maps at a position 452 bp upstream from the predicted translation start. Comparison of the amino acid sequence with those included in the current databases, showed no significant similarity to any known 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 zyxwvu cw11+ gene caused no noticeable phenotype, The sequence has been deposited in the EMBL data library under Accession Number X9445. KEY WORDS zyxwvutsrqpon ~ fission yeast; dominant genetics; cell wall regulation INTRODUCTION The major structural polymer of budding and fission yeast cell wall is a linear 1,3-P-glucan branched with some 1,6-P-glucan (Fleet, 1991). In Saccharomyces cerevisiae, several genes involved in 1,3-P-glucan biosynthesis have been isolated by different approaches. Based on the sequence of internal peptides derived from a protein band enriched in the process of 1,3-p-glucan synthase purification, two 1,3-P-glucan synthase-related genes, GSCl and GSC2, have been isolated (Inoue et al., 1995). Genes defined by complementing mutations of resistance to 1,3-P-glucan synthesis inhibitors in S. cerevisiae such as echinocandin *Corresponding author. analogs (Douglas et al., 1994; El-Sherbeini and Clemas, 1995), papulacandin B (Castro et al., 1995) or Hansenula mrakii killer toxin (Yamamoto et al., 1986; Hong et al., 1994; Kusuhara et al., 1994) have also been described. A third genetic strategy has been to isolate mutants hypersensitive to different agents known to affect the cell wall assembly, such as calcofluor white (Ram et al., 1994). With such techniques, several genes have been described. FKS1IETG1ICWH53ICND1I GSCIIPBRI (Douglas et al., 1994; Eng et al., 1994; Ram et al., 1995; Inoue et al., 1995; Castro et al., 1995) is a gene encoding a large polypeptide with 16 potential transmembrane domains that might be a structural component of 1,3-P-glucan syn- thase (Inoue et al., 1995). A second gene, FKS2I GSC2, highly homologous to FKSIIGSCI, has CCC 0749-503)3/96/100983-08 zyxwvutsr 0 1996 by John Wiley & Sons Ltd