The GAL1 gene is prevented from transcription through Mig1 protein. These proteins are highly specific in their binding that it binds exactly between the UAS element and the promoter region of the GAL1 gene. Tup1 is a protein complex that would be recruited by the Mig1 protein which has deacetylase activity. It deacetalyse the histone proteins thus represses it from being transcribed.