0000000000530269
AUTHOR
Lahcen Jaafar
Characterization of a disulphide-bound Pir-cell wall protein (Pir-CWP) ofYarrowia lipolytica
In this work we have studied the disulphide-bound group of cell wall mannoproteins of Yarrowia lipolytica and Candida albicans. In the case of Y. lipolytica, SDS-PAGE analysis of the beta-mercaptoethanol-extracted material from the purified cell walls of the yeast form, showed the presence of a main polypeptide of 45 kDa and some minor bands in the 100-200 kDa range. This pattern of bands is similar to that obtained in identical extracts in Saccharomyces cerevisiae (Moukadiri et al., 1999), and besides, all these bands cross-react with an antibody raised against beta-mercaptoethanol-extracted material from the purified cell walls of S. cerevisiae, suggesting that the 45 kDa band could be th…
RHO1(YlRHO1) is a non-essential gene inYarrowia lipolyticaand complementsrho1Δlethality inSaccharomyces cerevisiae
The synthesis of beta-1,3-glucan, the structural component of the yeast cell wall that gives shape to the cell, occurs at the plasma membrane and is the result of the activity of at least a two-component complex. Fks1p is the catalytic subunit directly responsible for the synthesis of beta-1,3-glucan, whilst the second subunit, Rho1p, has a GTP-dependent regulatory role (Yamochi et al., 1994). RHO1 has been characterized in Saccharomyces cerevisiae (Yamochi et al., 1994), and in several other fungal species. In this work, we have used degenerate oligonucleotides derived from the conserved regions of Rho1ps to isolate the RHO1 gene of Yarrowia lipolytica. The gene isolated in this way, which…
Isolation of theMNN9gene ofYarrowia lipolytica(YlMNN9) and phenotype analysis of a mutantylmnn9Δ strain
In this work we describe the isolation of the Yarrowia lipolytica homologue of Saccharomyces cerevisiae MNN9 gene, which we have named YlMNN9, and the phenotype analysis of a Y. lipolytica strain containing the disrupted YlMNN9 allele. YlMNN9 was cloned using degenerate consensus oligonucleotides to generate specific probes that were in turn used to screen mini-gene libraries. The gene is defined by a 1014 bp ORF predicted to encode a protein 337 amino acids long that shares significant homology with the Mnn9ps of S. cerevisiae, Candida albicans and Hansenula polymorpha, including a putative N-terminal transmembrane domain. Disruption of YlMNN9 leads to phenotypes such as resistance to sodi…
Characterization of a glycosylphosphatidylinositol-bound cell-wall protein (GPI-CWP) in Yarrowia lipolytica.
The structure and composition of the cell wall of yeast has so far been studied mainly in Saccharomyces cerevisiae. It is basically made up of three components: beta-glucans, chitin and mannose-containing glycoproteins, also called mannoproteins. Most covalently bound cell-wall mannoproteins belong to the so-called glycosylphosphatidylinositol cell-wall protein (GPI-CWP) family, cell-wall proteins that are bound through the remnant of a GPI residue to 1,6-beta-glucan. The non-conventional yeast Yarrowia lipolytica shares Generally Regarded As Safe (GRAS) status with S. cerevisiae, has some industrial applications and is increasingly being proposed as a host for the production of recombinant…
Identification of Two Mannoproteins Released from Cell Walls of a Saccharomyces cerevisiae mnn1 mnn9 Double Mutant by Reducing Agents
The cell wall of Saccharomyces cerevisiae represents some 30% of the total weight of the cell and is made up of β-glucans, mannose-containing glycoproteins (mannoproteins), and small amounts of chitin (9, 15). The mannoproteins can be divided into three groups according to the linkages that bind them to the structure of the cell wall: (i) noncovalently bound, (ii) covalently bound to the structural glucan, and (iii) disulfide bound to other proteins that are themselves covalently bound to the structural glucan of the cell wall (8). Our work has focused on the disulfide-bound mannoproteins, probably the least well known of the three groups mentioned above. Previous work (25) showed that trea…