Cloning of the yeast SFL2 gene: its disruption results in pleiotropic phenotypes characteristic for tup1 mutants.

We have identified a yeast gene, SFL2 (suppressor gene for flocculation), which complemented a newly isolated sfl2 mutant. This mutation causes asexual cell aggregation. The strain bearing the SFL2 gene disruption exhibited pleiotropic phenotypes characteristic for tup1 mutants. Physical mapping and complementation analysis suggested that the cloned SFL2 gene is identical to the TUP1 gene. The SFL2 gene encodes a 669-amino acid protein which has domains rich in glutamine, as does the SSN6 protein.