- Expression of GUT1, which encodes glycerol kinase in Saccharomyces cerevisiae, is controlled by the positive regulators Adr1p, Ino2p and Ino4p and the negative regulator Opi1p in a carbon source-dependent fashion. Grauslund, M., Lopes, J.M., Rønnow, B. Nucleic Acids Res. (1999)