Highly efficient transactivation by the yeast Kluyveromyces lactis transcription factor LAC9 and its inhibition by the negative regulator GAL80 in mammalian cells.
Expression of the LAC9 gene from the yeast Kluyveromyces lactis in HepG2 human hepatoblastoma cells efficiently induced luciferase expression from reporter plasmids containing the four LAC9 binding sites from the K. lactis GAL1-GAL10 gene linked to a basal promoter. Induction was approximately 100fold and was dependent on the presence of the UAS sequence and an intact reading frame in the LAC9 gene. Additional cotransfection of constructs expressing the K. lactis GAL80 gene reduced luciferase activity by up to 98%. This inhibition was not affected by addition of 14mM galactose to the medium. No further yeast-specific factors appear necessary for efficient inhibition of LAC9 by GAL80, but additional gene products may be required for activation by galactose.
Schulz
W A
WA
Institut für Physiologische Chemie I, Heinrich-Heine-Universität, Düsseldorf.
Ebling
B
B
Hasse
A
A
Zenke
F
F
Breunig
K
K
D000818:Animals; D001483:Base Sequence; D002478:Cells, Cultured; D005656:Fungal Proteins / Q000494:pharmacology*; D015966:Gene Expression Regulation, Fungal; D006801:Humans; D007716:Kluyveromyces / Q000201:enzymology / Q000235:genetics*; D007786:Lactose Factors / Q000378:metabolism*; D008114:Liver Neoplasms, Experimental / Q000378:metabolism; D008156:Luciferases / Q000235:genetics / Q000378:metabolism; D008969:Molecular Sequence Data; D010957:Plasmids; D012097:Repressor Proteins; D029701:Saccharomyces cerevisiae Proteins; D014157:Transcription Factors / Q000378:metabolism*; D015533:Transcriptional Activation; D014407:Tumor Cells, Cultured
D005656:Fungal Proteins; C055002:GAL80 protein, S cerevisiae; D012097:Repressor Proteins; D029701:Saccharomyces cerevisiae Proteins; D014157:Transcription Factors; D008156:Luciferases