[Regulation of tandem repeats on the function of flocculation protein in Saccharomyces cerevisiae].

Objective: There are a large numbers of tandem repeats in FLO1, which are highly dynamic components in genome leading to the unstable flocculation profiles in Saccharomyces cerevisiae. The effects of repeated unite B or D deletion on the function of flocculation protein was studied to provide theory basis for constructing genetically stable flocculation gene with minimal size.

Methods: We cloned the intact flocculation gene FLO1 from S. cerevisiae YS59 by PCR, and constructed the derived genes FLO1b and FLO1d with repeated unite B or D deletion respectively by fusion PCR. We analyzed the physiological characteristics of flocculation in yeast strains YSF1, YSF1b and YSF1d containing FLO1, FLO1b and FLO1d respectively.

Results: YSF1b and YSF1d displayed almost the same level of Flo1-type flocculation as YSF1. However, flocculation of YSF1b and YSF1d, especially YSF1d was more tolerant to pH change and mannose concentration than strain YSF1.

Conclusion: Tandem repeats regulate the function of flocculation protein. Deletion of repeated unite B or D, especially D increases the stability of flocculation protein.