Residues in the Swi5 zinc finger protein that mediate cooperative DNA binding with the Pho2 homeodomain protein
| Autor: | David J. Stillman, Leena Bhoite |
|---|---|
| Rok vydání: | 1998 |
| Předmět: |
Transcriptional Activation
Saccharomyces cerevisiae Proteins Molecular Sequence Data Cell Cycle Proteins Saccharomyces cerevisiae Biology DNA-binding protein Fungal Proteins chemistry.chemical_compound Genes Reporter Gene Expression Regulation Fungal Point Mutation Protein–DNA interaction Amino Acid Sequence Phosphorylation Deoxyribonucleases Type II Site-Specific Promoter Regions Genetic Molecular Biology Transcription factor Zinc finger Homeodomain Proteins Transcriptional Regulation Point mutation Single-Strand Specific DNA and RNA Endonucleases Promoter Zinc Fingers Cell Biology Molecular biology Cyclin-Dependent Kinases Cell biology DNA-Binding Proteins chemistry Trans-Activators DNA construct DNA Plasmids Transcription Factors |
| Zdroj: | Molecular and cellular biology. 18(11) |
| ISSN: | 0270-7306 |
| Popis: | The Swi5 zinc finger and the Pho2 homeodomain DNA-binding proteins bind cooperatively to the HO promoter. Pho2 (also known as Bas2 or Grf10) activates transcription of diverse genes, acting with multiple distinct DNA-binding proteins. We have performed a genetic screen to identify amino acid residues in Swi5 that are required for synergistic transcriptional activation of a reporter construct in vivo. Nine unique amino acid substitutions within a 24-amino-acid region of Swi5, upstream of the DNA-binding domain, reduce expression of promoters that require both Swi5 and Pho2 for activation. In vitro DNA binding experiments show that the mutant Swi5 proteins bind DNA normally, but some mutant Swi5 proteins (resulting from SWI5* mutations) show reduced cooperative DNA binding with Pho2. In vivo experiments show that these SWI5* mutations sharply reduce expression of promoters that require both SWI5 and PHO2, while expression of promoters that require SWI5 but are PHO2 independent is largely unaffected. This suggests that these SWI5* mutations do not affect the ability of Swi5 to bind DNA or activate transcription but specifically affect the region of Swi5 required for interaction with Pho2. Two-hybrid experiments show that amino acids 471 to 513 of Swi5 are necessary and sufficient for interaction with Pho2 and that the SWI5* point mutations cause a severe reduction in this two-hybrid interaction. Analysis of promoter activation by these mutants suggests that this small region of Swi5 has at least two distinct functions, conferring specificity for activation of the HO promoter and for interaction with Pho2. |
| Databáze: | OpenAIRE |
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