Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.2.1.23 (beta-galactosidase)
 14,648 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The REV1 gene of Saccharomyces cerevisiae is required for normal induction of mutations by physical and chemical agents. We have determined the sequence of a 3,485-base-pair segment of DNA that complements the rev1-1 mutant. Gene disruption was used to confirm that this DNA contained the REV1 gene. The sequenced segment contains a single long open reading frame, which can encode a polypeptide of 985 amino acid residues. The REV1 transcript is 3.1 kilobase pairs in length. Frameshift mutations introduced into the open reading frame yielded a Rev-phenotype. A base substitution, encoding Gly-193 to Arg-193, was found in this open reading frame in rev1-1. Deletion mutants, lacking segments of the 5' region of REV1, had intermediate mutability relative to REV1 and rev1-1; a complete deletion exhibited lower mutability than rev1-1. REV1 is not an essential gene. An in-frame fusion of the 5' end of the REV1 open reading frame to the lacZ gene produced beta-galactosidase activity constitutively. The predicted REV1 protein is hydrophilic, with a predicted pI of 9.82. No homologies to RAD1, RAD2, RAD3, RAD7, or RAD10 proteins were noted. A 152-residue internal segment displayed 25% identity with UMUC protein.
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PMID:The REV1 gene of Saccharomyces cerevisiae: isolation, sequence, and functional analysis. 249 97

Plasmids containing various RAD-lacZ gene fusions were integrated into the chromosome of haploid yeast cells. These integrant strains were tested for expression of Escherichia coli beta-galactosidase after treatment with agents that damage DNA or interfere with normal DNA replication. We did not observe induction of single-copy RAD1-lacZ or RAD3-lacZ fusion genes under the experimental conditions used. However, exposure of cells containing an integrated RAD2-lacZ fusion gene to UV-radiation, gamma-radiation, 4-nitroquinoline 1-oxide, or nalidixic acid resulted in 4- to 6-fold enhanced expression of beta-galactosidase. Induction of the RAD2 gene after treatment of untransformed cells with 4-nitroquinoline 1-oxide was confirmed by direct examination of RAD2 mRNA. Lower levels of induction (approximately equal to 50%) were observed after treatment of cells with other chemicals. Induction of the RAD2-lacZ fusion gene was also observed in cells transformed with single-copy and multicopy autonomously replicating plasmids.
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PMID:A yeast excision-repair gene is inducible by DNA damaging agents. 308 3

The RAD1 and RAD3 genes of Saccharomyces cerevisiae are required for excision repair of UV damaged DNA. In addition, the RAD3 gene is essential since rad3 deletions are recessive lethals. We have examined the induction of the RAD1 and RAD3 genes by DNA damage and during the cell division cycle. We have made fusions of the RAD1 and RAD3 genes with the Escherichia coli lacZ gene encoding beta-galactosidase. Beta-galactosidase activity was measured in a Rad+ yeast strain containing the RAD1-lacZ or the RAD3-lacZ fusion, either in a multicopy replicating plasmid or as a single copy integrant resulting from transformation with an integrating plasmid which transforms yeast by homologous recombination in the yeast genome. No induction of beta-galactosidase activity occurred after ultraviolet light (UV) or 4-nitroquinoline-1-oxide (NQO) treatment. Haploid cells of mating type a were synchronized by treatment with alpha factor and beta-galactosidase activity was determined during different cell cycle stages. No change in beta-galactosidase activity was observed in the strain containing the RAD1-lacZ or the RAD3-lacZ fusion integrated in the yeast genome.
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PMID:Expression of the RAD1 and RAD3 genes of Saccharomyces cerevisiae is not affected by DNA damage or during the cell division cycle. 392 99