Reference: Russell SJ and Johnston SA (2001) Evidence that proteolysis of Gal4 cannot explain the transcriptional effects of proteasome ATPase mutations. J Biol Chem 276(13):9825-31

Reference Help

Abstract


The Gal system of Saccharomyces cerevisiae is a paradigm for eukaryotic gene regulation. Expression of genes required for growth on galactose is regulated by the transcriptional activator Gal4. The activation function of Gal4 has been localized to 34 amino acids near the C terminus of the protein. The gal4D allele of GAL4 encodes a truncated protein in which only 14 amino acids of the activation domain remain. Expression of GAL genes is dramatically reduced in gal4D strains and these strains are unable to grow on galactose as the sole carbon source. Overexpression of gal4D partially relieves the defect in GAL gene expression and allows growth on galactose. A search for extragenic suppressors of gal4D identified recessive mutations in the SUG1 and SUG2 genes, which encode ATPases of the 19S regulatory complex of the proteasome. The proteasome is responsible for the ATP-dependent degradation of proteins marked for destruction by the ubiquitin system. It has been commonly assumed that effects of SUG1 and SUG2 mutations on transcription are explained by alterations in the proteolysis of gal4D protein. We have investigated this assumption. Surprisingly, we find that SUG1 and SUG2 alleles that are unable to suppress gal4D cause a larger increase in gal4D protein levels than do suppressing alleles. In addition, mutations in genes encoding subunits of the proteolytic 20S sub-complex of the proteasome increase the levels of gal4D protein but do not rescue its transcriptional activity. Therefore, an alteration in the proteolysis of gal4D by the proteasome cannot explain the effects of mutations in SUG1 and SUG2 on expression of GAL genes. These findings suggest that the 19S regulatory complex may play a more direct role in transcription.

Reference Type
Journal Article
Authors
Russell SJ, Johnston SA
Primary Lit For
Additional Lit For
Review For

Interaction Annotations


Increase the total number of rows showing on this page by using the pull-down located below the table, or use the page scroll at the table's top right to browse through the table's pages; use the arrows to the right of a column header to sort by that column; filter the table using the "Filter" box at the top of the table; click on the small "i" buttons located within a cell for an annotation to view further details about experiment type and any other genes involved in the interaction.

Interactor Interactor Type Assay Annotation Action Modification Phenotype Source Reference

Gene Ontology Annotations


Increase the total number of rows showing on this page using the pull-down located below the table, or use the page scroll at the table's top right to browse through the table's pages; use the arrows to the right of a column header to sort by that column; filter the table using the "Filter" box at the top of the table.

Gene Gene Ontology Term Qualifier Aspect Method Evidence Source Assigned On Annotation Extension Reference

Phenotype Annotations


Increase the total number of rows showing on this page using the pull-down located below the table, or use the page scroll at the table's top right to browse through the table's pages; use the arrows to the right of a column header to sort by that column; filter the table using the "Filter" box at the top of the table; click on the small "i" buttons located within a cell for an annotation to view further details.

Gene Phenotype Experiment Type Mutant Information Strain Background Chemical Details Reference

Regulation Annotations


Increase the total number of rows displayed on this page using the pull-down located below the table, or use the page scroll at the table's top right to browse through the table's pages; use the arrows to the right of a column header to sort by that column; to filter the table by a specific experiment type, type a keyword into the Filter box (for example, “microarray”); download this table as a .txt file using the Download button or click Analyze to further view and analyze the list of target genes using GO Term Finder, GO Slim Mapper, SPELL, or YeastMine.

Regulator Target Experiment Assay Construct Conditions Strain Background Reference