Genetic basis of flocculation phenotype conversion in Saccharomyces cerevisiae

• Published in: FEMS yeast research Vol. 7; no. 8; pp. 1362 - 1370
• Main Authors: Liu, Nan, Wang, Dongli, Wang, Zhao Yue, He, Xiu Ping, Zhang, Borun
• Format: Journal Article
• Language: English
• Published: Oxford, UK Oxford, UK : Blackwell Publishing Ltd 01-12-2007; Blackwell Publishing Ltd; Oxford University Press
• Subjects: Amino Acid Sequence; Cell Adhesion - genetics; Cell Adhesion - physiology; DNA, Fungal - chemistry; DNA, Fungal - genetics; FLO1 gene; Flocculation; Genetic variability; Genetic Variation; Mannose-Binding Lectins; Molecular Sequence Data; Open Reading Frames; Phenotype; Phenotypes; physiological characteristics; Recombination, Genetic; repeated sequence; Repetitive Sequences, Nucleic Acid - genetics; Saccharomyces cerevisiae; Saccharomyces cerevisiae - genetics; Saccharomyces cerevisiae - physiology; Saccharomyces cerevisiae Proteins - genetics; Saccharomyces cerevisiae Proteins - physiology; Sequence Alignment; Sequence Analysis, DNA; Sequence Deletion; Transformation, Genetic; Yeast; physiological characteristics; repeated sequence; gene; genetic variability
• ISSN: 1567-1356; 1567-1364
• DOI: 10.1111/j.1567-1364.2007.00294.x

Two NewFlo-type flocculent transformants Saccharomyces cerevisiae YTS-S and YTS-L were obtained from a partial yeast genomic library. Even though both of the transformants displayed the same flocculation phenotype, they represented different physiological characteristics during detailed investigation. Analysis of the two transformants YTS-L and YTS-S confirmed the presence of FLONL and FLONS genes, respectively. The 3396-bp ORF of FLONS encoded a protein of 1132 amino acids. Meanwhile, the presence of a 1686-bp ORF encoding a 562-amino acid protein was revealed in FLONL. Both FLONL and FLONS showed high identity to FLO1 gene. Aligned with the intact FLO1 gene, FLONS lost two internal repeated regions, whereas one repeated sequence was inserted into the middle of the FLONL gene. All of the altered regions could be found in the middle repetitive sequence of the FLO1 gene. The results indicate that FLONL and FLONS are both derived forms of the FLO1 gene. Genetic variability triggered by tandem repeats in FLO1 gene is believed to be responsible for the differential phenotypic properties of the yeast strains YTS-S and YTS-L.