Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:6.5.1.2 (DNA ligase)
 2,749 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The PHR1 gene of Saccharomyces cerevisiae encodes the DNA repair enzyme photolyase. Transcription of PHR1 increases in response to treatment of cells with 254-nm radiation and chemical agents that damage DNA. We report here the identification of a damage-responsive DNA binding protein, termed photolyase regulatory protein (PRP), and its cognate binding site, termed the PHR1 upstream repression sequence, that together regulate induction of PHR1 transcription after DNA damage. PRP activity, monitored by electrophoretic-mobility-shift assay, was detected in cells during normal growth but disappeared within 30 min after irradiation. Copper-phenanthroline footprinting of PRP-DNA complexes revealed that PRP protects a 39-base-pair region of PHR1 5' flanking sequence beginning 40 base pairs upstream from the coding sequence. A prominent feature of the foot-printed region is a 22-base-pair palindrome. Deletion of the PHR1 upstream repression sequence increased the basal level expression of PHR1 in vivo and decreased induction after exposure of cells to UV radiation or methyl methanesulfonate, whereas insertion of the PRP binding site between the CYC1 upstream activation sequence and "TATA" sequence reduced basal level expression and conferred damage responsiveness upon a reporter gene. Thus these observations establish that PRP is a damage-responsive repressor of PHR1 transcription.
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PMID:A damage-responsive DNA binding protein regulates transcription of the yeast DNA repair gene PHR1. 176 39

The PHR1 gene of Saccharomyces cerevisiae encodes the apoenzyme for the DNA repair enzyme photolyase. PHR1 transcription is induced in response to 254 nm radiation and a variety of chemical damaging agents. We report here the identification of promoter elements required for PHR1 expression. Transcription is regulated primarily through three sequence elements clustered within a 120 bp region immediately upstream of the translational start site. A 20 bp interrupted palindrome comprises UASPHR1 and is responsible for 80-90% of basal and induced expression. UASPHR1 alone can activate transcription of a CYC1 minimal promoter but does not confer damage responsiveness. In the intact PHR1 promoter UAS function is dependent upon an upstream essential sequence (UES). URSPHR1 contains a binding site for the damage-responsive repressor Prp; consistent with this role, deletion or specific mutations of the URS increase basal level expression and decrease the induction ratio. Deletion of URSPHR1 also eliminates the requirement for UESPHR1 for promoter activation, indicating that the UES attenuates Prp-mediated repression. Sequences within UASPHR1 are similar to regulatory sequences found upstream of both damage responsive and nonresponsive genes involved in DNA repair and metabolism.
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PMID:Promoter elements of the PHR1 gene of Saccharomyces cerevisiae and their roles in the response to DNA damage. 750 52

Photolyase is a DNA repair enzyme that can absorb blue/ultraviolet A light as energy and split a pyrimidine dimer induced by ultraviolet radiation. We isolated and characterized PHR1, a gene encoding photolyase, from the phytopathogenic fungus Bipolaris oryzae. Sequence analysis showed that PHR1 encodes a putative protein that has 634 amino acids, a molecular mass of 72.6 kDa, and 51.3-55.5% sequence identity to other fungal photolyases. Complementation of the photoreactivation-deficient Escherichia coli mutant by PHR1 cDNA demonstrated that the PHR1 gene from B. oryzae encodes a functional photolyase. Real-time PCR analysis showed that the PHR1 transcripts were specifically enhanced by near-ultraviolet radiation (300-400 nm) and by sunlight.
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PMID:Cloning, functional characterization, and near-ultraviolet radiation-enhanced expression of a photolyase gene (PHR1) from the phytopathogenic fungus Bipolaris oryzae. 1513 97