A model for Tup1-mediated regulation of cell fate at the WOR1 promoter.

Tup1 associates at the WOR1 promoter and represses WOR1 expression. In opaque cells, Wor1 binds along the WOR1 promoter and inhibits Tup1-mediated repression of WOR1 expression. The effect of temperature and carbon source on Wor1 and Tup1 occupancy at the WOR1 promoter is shown. Dark blue or yellow indicates high levels of Wor1 and Tup1, while light colors depict decreased Wor1 or Tup1 at the promoter. Grey circles depict several other well-characterized phase regulators. Grey lines indicate reduced or lost activity.