Isolation of the TYE2 gene reveals its identity to SWI3 encoding a general transcription factor in Saccharomyces cerevisiae.

The TYE2 gene was identified by recessive mutations which result in a significant reduction of Ty-mediated ADH2 expression. We cloned the TYE2 gene and analyzed its sequence. A large open reading frame of 825 codons was found encoding a rather hydrophilic, 93-kilodalton protein which contains a highly acidic region at its N-terminus. By sequence comparison we found that TYE2 is identical to gene SWI3 which has recently been shown to encode a nuclear protein which may function as a global transcription activation factor. The TYE2/SWI3 protein is necessary for the initiation of Ty1 transcription at its major initiation site in the delta element. Furthermore TYE2 function seems to be important for the expression of a variety of Ty-unrelated functions such as ADH1 expression, sporulation, growth on maltose, galactose, raffinose, and on non-fermentable carbon sources.