Functional analysis of ScSwi1 and CaSwi1 in invasive and pseudohyphal growth of Saccharomyces cerevisiae.

Here we reported that, in Saccharomyces cerevisiae, deleting Swi1 (ScSwi1), a core component in Swi/Snf complex, caused defects of invasive growth, pseudohyphal growth, FLO11 expression, and proper cell separation. Re-introduction of SWI1 into the swi1 mutants could suppress all defects observed. We also showed that overproducing Swi1 could suppress the defect of flo8 cells in pseudohyphal growth in diploids, but not invasive growth in haploids. Overexpression of SWI1 could not bypass the requirement of Ste12 or Tec1 in invasive growth or pseudohyphal growth. We concluded that the Swi/Snf complex was required for FLO11 expression and proper cell separation, and both the FLO8 and STE12 genes should be present for the complex to function for the invasive growth but only the STE12 gene was required for the pseudohyphal growth. Ectopic expression of Candida albicans SWI1 (CaSWI1) could partially complement the defects examined of haploid Scswi1 mutants, but failed to complement the defects examined of diploid Scswi1/ Scswi1 mutants. Overexpressing CaSwi1 mitigated invasive and pseudohyphal growth defects resulting from deletions in the MAP kinase and cAMP pathways. The integrity of S. cerevisiae Swi/Snf complex is required for invasive and filamentous growth promoted by overexpressing CaSwi1.