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Updated: Jun 10, 2026
Microarray Analysis for Saccharomyces cerevisiae
Published on: April 7, 2011
Identification of the MNN3 gene of Saccharomyces cerevisiae
Isaac Corbacho1, Isabel Olivero, Luis M Hernández
1Department of Biomedical Sciences, Microbiology, University of Extremadura, 06006 Badajoz, Spain.
Abstract:
The MNN3 gene of Saccharomyces cerevisiae has been identified as a synonym of VPS74. We have compared phenotype characteristics of the original mnn3 mutant, including low dye binding phenotype, size of external invertase, clump formation, and sodium orthovanadate resistance and found these to be identical to those shown by vps74Δ. Mating of both haploid strains resulted in non-complementation of mutant phenotypes. Finally, a vector containing wild-type VPS74 complemented the defects of both vps74Δ and mnn3. This work completes the identification of the entire collection of genes that are defective in mnn mutants. In addition, we have identified the mnn3 mutation by sequencing the VPS74 gene from the original mnn3 strain. We found a single amino acid change of Arg97 to Cys. This unique alteration seems to be sufficient to account for the phenotype of mnn3.
Insights
The Saccharomyces cerevisiae MNN3 gene is identical to VPS74. This study confirms Vps74
Area of Science:
- Molecular and Cellular Biology
- Yeast Genetics
- Protein Function
Background:
- The MNN3 gene in Saccharomyces cerevisiae was previously uncharacterized.
- Mutations in MNN genes cause defects in cell wall mannoprotein synthesis.
- Understanding MNN gene function is crucial for yeast cell biology.
Purpose of the Study:
- To identify the MNN3 gene.
- To characterize the function of the MNN3 gene and its protein product.
- To complete the identification of all MNN genes in yeast.
Main Methods:
- Phenotypic analysis of mnn3 and vps74 deletion mutants.
- Complementation studies using a VPS74-expressing vector.
- Gene sequencing to identify mutations in the mnn3 strain.
Main Results:
- The MNN3 gene was identified as a synonym for VPS74.
- Phenotypic characteristics of mnn3 and vps74Δ mutants were identical.
- A single amino acid change (Arg97 to Cys) in VPS74 explains the mnn3 phenotype.
- Wild-type VPS74 complemented both mnn3 and vps74Δ defects.
Conclusions:
- MNN3 is VPS74, completing the identification of MNN genes.
- The Arg97Cys substitution in Vps74 causes the observed mnn3 mutant phenotype.
- This study provides a comprehensive understanding of MNN gene functions in yeast.
