Related Experiment Videos
Mutations in the pho2 (bas2) transcription factor that differentially affect activation with its partner proteins
Leena T Bhoite1, Jason M Allen, Emily Garcia
1Department of Pathology, University of Utah Health Sciences Center, Salt Lake City, Utah 84132, USA.
Abstract:
The yeast PHO2 gene encodes a homeodomain protein that exemplifies combinatorial control in transcriptional activation. Pho2 alone binds DNA in vitro with low affinity, but in vivo it activates transcription with at least three disparate DNA-binding proteins: the zinc finger protein Swi5, the helix-loop-helix factor Pho4, and Bas1, an myb-like activator. Pho2 + Swi5 activates HO, Pho2 + Pho4 activates PHO5, and Pho2 + Bas1 activates genes in the purine and histidine biosynthesis pathways. We have conducted a genetic screen and identified 23 single amino acid substitutions in Pho2 that differentially affect its ability to activate its specific target genes. Analysis of the mutations suggests that the central portion of Pho2 serves as protein-protein interactive surface, with a requirement for distinct amino acids for each partner protein.
Insights
The yeast PHO2 gene
Area of Science:
- Molecular Biology
- Yeast Genetics
- Transcriptional Regulation
Background:
- The yeast PHO2 gene encodes a homeodomain protein crucial for transcriptional activation.
- Pho2 interacts with multiple DNA-binding proteins in vivo, demonstrating combinatorial control.
- These interactions are essential for activating diverse gene sets, including HO, PHO5, and biosynthesis pathways.
Purpose of the Study:
- To investigate the functional significance of specific amino acid residues in the Pho2 protein.
- To identify mutations in Pho2 that differentially affect its interaction with partner proteins and target gene activation.
- To elucidate the role of the central region of Pho2 in mediating protein-protein interactions.
Main Methods:
- Genetic screening to identify single amino acid substitutions in the PHO2 gene.
- Analysis of mutant Pho2 proteins for altered DNA binding and transcriptional activation capabilities.
- Mapping of mutations to understand their impact on protein-protein interaction interfaces.
Main Results:
- 23 single amino acid substitutions in Pho2 were identified with differential effects on target gene activation.
- Mutations revealed that the central region of Pho2 is critical for protein-protein interactions.
- Distinct amino acids within this region are required for interaction with specific partner proteins like Swi5, Pho4, and Bas1.
Conclusions:
- The central region of Pho2 acts as a versatile protein-protein interaction surface.
- Combinatorial control of transcription by Pho2 relies on specific amino acid residues for each interacting partner.
- Understanding these interactions provides insights into the mechanisms of eukaryotic transcriptional regulation.