Regulatory effect of FLO1 tandem repeats on the flocculation characteristics and genetic stability in Saccharomyces cerevisiae

Abstract:

Abstract:［Objective］There are a large number of tandem repeats in FLO1，which are highly dynamic components in genome leading to the unstable flocculation profiles in Saccharomyces cerevisiae． The effects of complete or partial deletion of repeated DNA sequence A in FLO1 on the flocculation characteristics and genetic stability in yeast were studied to provide theoretical guide for construction genetically stable flocculation gene with minimal size． ［Methods］ We constructed the derived gene FLO1a with complete deletion of repeated DNA sequence A in the central domain by fusion PCR，and isolated the derived genes FLO1a1 － FLO1a5 with partial deletion of repeated DNA sequence A at different sites using E．coli DH5α carrying the FLO1 gene as selective model． We analyzed the physiological characteristics and genetic stability of flocculation in yeast strains YSF1，YSF1a，and YSF1a1 － YSF1a5 containing FLO1，FLO1a and FLO1a1－FLO1a5 respectively． ［Results］ No obvious flocculation was observed for yeast strain YSF1a，but various levels of flocculation were observed for strains YSF1a1 － YSF1a5． Flocculation of YSF1a3，YSF1a4 and YSF1a5 were more tolerant to environmental changes than that of strain YSF1，and displayed more genetic stability． ［Conclusion］Repeated DNA sequence A is important for the function of flocculation protein．