Cloning and characterization of WMSU1, a Williopsis saturnus var. mrakii gene encoding a new yeast SUN protein involved in the cell wall structure

• Published in: Yeast (Chichester, England) Vol. 19; no. 13; pp. 1127 - 1138
• Main Authors: Guyard, Cyril, Cailliez, Jean‐Charles, Tissier, Jean‐Pierre, Dei‐Cas, Eduardo, Mercenier, Annick, Menozzi, Franco D.
• Format: Journal Article
• Language: English
• Published: Chichester, UK John Wiley & Sons, Ltd 30.09.2002
• Subjects: Amino Acid Sequence; Base Sequence; Cell Wall - chemistry; Cloning, Molecular; Escherichia coli - genetics; Fungal Proteins - chemistry; Fungal Proteins - genetics; Genes, Fungal; Molecular Sequence Data; Phenotype; Pichia - genetics; Saccharomyces cerevisiae - genetics; SUN gene family; Williopsis saturnus var. mrakii MUCL 41968; yeast cell wall
• ISSN: 0749-503X; 1097-0061
• DOI: 10.1002/yea.898

SUN proteins of Saccharomyces cerevisiae have been defined on the basis of high homologies in their C‐terminal domain. Recently, two of these four proteins were shown to be involved in cell wall morphogenesis (Mouassite et al., 2000a). In the present study, we have isolated WMSU1 (Accession No. AF418983), a new SUN‐related gene, from W. saturnus var. mrakii MUCL 41968. Sequencing of the gene revealed an open reading frame coding for 402 amino acids. The predicted amino acid sequence of WMSU1 is closely related to the S. cerevisiae SUN proteins and to other yeast proteins involved in cell wall metabolism. WMSU1 is proposed to encode a cell wall protein since its predicted product contains a signal sequence, a Kex2p cleavage site and a serine/threonine‐rich N‐terminal domain. Southern blot analysis of the W. saturnus var. mrakii MUCL 41968 genome using the highly conserved domain of WMSU1 as a probe suggested that the isolated gene belongs to a multigenic family. Expression of WMSU1 in E. coli led to a 45 kDa protein, which appeared to be toxic to this host. Scanning electron microscopy analysis of a recombinant S. cerevisiae producing Wmsu1p showed that this strain exhibited an altered cell wall, thus pointing to a probable role of this protein in the cell wall structure. Copyright © 2002 John Wiley & Sons, Ltd.