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GAL3-GAL80 transcription regulation complex Overview

GO Annotations consist of four mandatory components: a gene product, a term from one of the three Gene Ontology (GO) controlled vocabularies (Molecular Function, Biological Process, and Cellular Component), a reference, and an evidence code.


Summary
Acts to relieve the repression of the GAL4 positive regulator of gene expression. The GAL network is a small set of genes that regulates galactose import and metabolism. The transcriptional activator GAL4 activates a set of enzymatic and regulatory genes by binding to their promoter regions. When galactose is the sole carbon source, the galactose-metabolizing enzymes are expressed at 1000 times their level in glucose. In the absence of galactose, GAL4 activity is repressed by forming a complex with the transcriptional repressor GAL80 (CPX-1044). In the presence of galactose and ATP, the GAL3-GAL80 complex forms, removing GAL80 from the GAL4-activation domain, which is then able to recruit the transcriptional machinery. It is also possible a tripartite complex forms (GAL4-GAL80-GAL3), which counterbalances the effect of GAL80 on GAL4 and allows GAL4 to interact with promoters. GAL3 primarily binds with ATP and galactose in the cytoplasm, then moves into the nucleus to interact with GAL80. A paralogous complex, GAL1-GAL80 (CPX-1043) can also form but appears to have lower activity as a transcriptional inducer of GAL genes. It is possible that GAL3-GAL80 may be involved solely in the short-term response to galactose and GAL1-GAL80 is required for continued expression of the GAL genes.
GO Slim Terms

The yeast GO Slim terms are higher level terms that best represent the major S. cerevisiae biological processes, functions, and cellular components. The GO Slim terms listed here are the broader parent terms for the specific terms to which this gene product is annotated, and thus represent the more general processes, functions, and components in which it is involved.

carbohydrate metabolic process, response to chemical, small molecule metabolic process, nucleus, organelle