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Updated: May 7, 2026
08:48
Targeted in Situ Mutagenesis of Histone Genes in Budding Yeast
Published on: January 26, 2017
Yeast HAP1 activator binds to two upstream activation sites of different sequence
Cell
|April 10, 1987
Summary
The HAP1 protein binds to two different DNA sequences in yeast, CYC7 and CYC1 genes, despite their lack of similarity. This binding interaction provides insights into gene regulation mechanisms.
Area of Science:
- Molecular Biology
- Yeast Genetics
- Protein-DNA Interactions
Background:
- The HAP1 protein is a transcription factor in yeast.
- HAP1 is known to bind to the upstream activation site (UAS) of the CYC1 gene.
Purpose of the Study:
- To investigate the binding of HAP1 to the CYC7 gene's UAS.
- To compare the binding characteristics of HAP1 to CYC7 and CYC1 UAS sequences.
- To explore the mechanisms by which HAP1 recognizes distinct DNA sequences.
Main Methods:
- In vitro binding assays to determine HAP1-DNA interactions.
- DNA sequence analysis to compare CYC1 and CYC7 UAS.
- Competition assays to assess binding affinities.
- Site-directed mutagenesis to create HAP1 variants.
Main Results:
- HAP1 binds in vitro to the UAS of the yeast CYC7 gene.
- The CYC7 UAS sequence shows no obvious similarity to the HAP1-binding site on the CYC1 gene.
- HAP1 binding sites on CYC1 and CYC7 genes compete with each other and exhibit comparable affinities.
- While overall interaction features are similar, precise contact points differ between the two sites.
- A HAP1 mutant (HAP1-18) loses binding to CYC1 UAS but retains binding to CYC7 UAS.
Conclusions:
- HAP1 can recognize and bind to distinct DNA sequences with differing sequences but similar structural features.
- The study highlights the complexity of transcription factor-DNA recognition.
- Mechanisms for differential sequence recognition by a single protein are proposed.
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