title: A ribonucleotide reductase gene involved in a p53-dependent cell-cycle checkpoint for DNA damage.
abstract: The p53 gene is frequently inactivated in human cancers. Here we have isolated a p53-inducible gene, p53R2, by using differential display to examine messenger RNAs in a cancer-derived human cell line carrying a highly regulated wild-type p53 expression system. p53R2 contains a p53-binding sequence in intron 1 and encodes a 351-amino-acid peptide with striking similarity to the ribonucleotide reductase small subunit (R2), which is important in DNA synthesis during cell division. Expression of p53R2, but not R2, was induced by ultraviolet and gamma-irradiation and adriamycin treatment in a wild-type p53-dependent manner. Induction of p53R2 in p53-deficient cells caused G2/M arrest and prevented cells from death in response to adriamycin. Inhibition of endogenous p53R2 expression in cells that have an intact p53-dependent DNA damage checkpoint reduced ribonucleotide reductase activity, DNA repair and cell survival after exposure to various genotoxins. Our results indicate that p53R2 encodes a ribonucleotide reductase that is directly involved in the p53 checkpoint for repair of damaged DNA. The discovery of p53R2 clarifies a relationship between a ribonucleotide reductase activity involved in repair of damaged DNA and tumour suppression by p53.
authors.affiliation: Laboratory of Molecular Medicine, Human Genome Center, Institute of Medical Science, The University of Tokyo, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Tanaka
authors.forename: H
authors.initials: H
authors.lastname: Arakawa
authors.forename: T
authors.initials: T
authors.lastname: Yamaguchi
authors.forename: K
authors.initials: K
authors.lastname: Shiraishi
authors.forename: S
authors.initials: S
authors.lastname: Fukuda
authors.forename: K
authors.initials: K
authors.lastname: Matsui
authors.forename: Y
authors.initials: Y
authors.lastname: Takei
authors.forename: Y
authors.initials: Y
authors.lastname: Nakamura
mesh_terms: D000595:Amino Acid Sequence; D002453:Cell Cycle; D018797:Cell Cycle Proteins; D004249:DNA Damage; D004260:DNA Repair; D004790:Enzyme Induction; D015971:Gene Expression Regulation, Enzymologic; D006801:Humans; D008969:Molecular Sequence Data; D009153:Mutagens / Q000494:pharmacology; D012264:Ribonucleotide Reductases / Q000235:genetics*; D017386:Sequence Homology, Amino Acid; D014162:Transfection; D014407:Tumor Cells, Cultured; D016159:Tumor Suppressor Protein p53 / Q000502:physiology*
chemical_list: D018797:Cell Cycle Proteins; D009153:Mutagens; D016159:Tumor Suppressor Protein p53; C405947:RRM2B protein, human; D012264:Ribonucleotide Reductases