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RPH1 and GIS1 are damage-responsive repressors of PHR1
1Department of Biochemistry, School of Medicine, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-7260, USA.
Molecular and Cellular Biology
|October 19, 1999
Summary
Researchers identified Rph1p and Gis1p proteins that regulate the Saccharomyces cerevisiae DNA repair gene PHR1. Deleting these proteins enhances DNA repair capacity by increasing PHR1 expression.
Area of Science:
- Molecular Biology
- Genetics
- Biochemistry
Background:
- The Saccharomyces cerevisiae DNA repair gene PHR1 encodes a photolyase crucial for light-dependent pyrimidine dimer repair.
- PHR1 expression is transcriptionally induced by DNA-damaging agents, regulated by the URS(PHR1) sequence bound by the damage-responsive repressor PRP.
Purpose of the Study:
- To identify the proteins constituting the PRP complex that regulates PHR1 expression.
- To elucidate the mechanism by which Rph1p and Gis1p control PHR1 transcription in response to DNA damage.
Main Methods:
- Protein identification and characterization.
- Gene deletion studies in Saccharomyces cerevisiae.
- In vitro DNA binding and footprinting assays.
Main Results:
- Two proteins, Rph1p and Gis1p, were identified as regulators of PHR1 expression via URS(PHR1).
- Both Rph1p and Gis1p possess identical DNA-binding zinc finger domains.
- Complete derepression of PHR1 requires deletion of both RPH1 and GIS1 genes.
- In vitro studies pinpoint the AG(4)(C(4)T) sequence within URS(PHR1) as the binding site for Rph1p and Gis1p.
- Evidence suggests the presence of additional DNA-binding components within the PRP complex.
Conclusions:
- Rph1p and Gis1p are key components of the PRP complex that represses PHR1 expression.
- The PHR1 damage response, mediated by Rph1p and Gis1p, enhances cellular DNA repair capacity through increased photoreactivation.
- Further investigation is needed to identify the complete PRP complex composition.
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