Mode of action for Mss11p: a central factor in the FLO11 transcription machinery.
Dewald van Dyk (1), Isak S. Pretorius (2), Florian F. Bauer (1)
(1) Inst. for Wine Biotechnology, Stellenbosch University, Victoria Street, Stellenbosch, 7600, South Africa; (2) The Australian Wine Research Institute, Waite Road, Urrbrae, Adelaide SA 5064, South Australia, Australia
The ability of S. cerevisiae to grow invasively into substrates and to form cell filaments (pseudohyphae) is largely dependent on the expression of the FLO11 gene. This gene encodes a cell wall glycoprotein which facilitates cell-substrate and cell-cell adhesion, usually as a part of an adaptive response to nutritional signals. Several groups have shown that a wide array of factors act on the large promoter of FLO11. Our previous work suggests that Mss11p, a transcriptional activator, plays a central role in FLO11 regulation, since most of the factors tested in our initial study required its presence to either induce or repress transcription. It has been shown that Mss11p interacts with Rpb3p, a component of RNA pol II complex, which might account for the pivotal role it plays in FLO11 transcription. To further our knowledge regarding the role played by Mss11p in regulating transcription, we are in the process of assessing functional relationships between a series of FLO11 regulators and Mss11p. Our genetic analysis indicates functional relationships exist between Mss11p and several other regulators, including Flo8p, Sfl1p, Ssn6p and Tup1p. Physical interactions between Mss11p, these regulators and components of RNA pol II associated complexes are also currently under investigation. Genetic and biochemical data illustrating the identified functional relationships will be presented.