title: Retinoblastoma susceptibility protein, Rb, possesses multiple BRCT-Ws, BRCA1 carboxyl-terminus-related W regions with DNA break-binding activity.
abstract: The BRCT region, the carboxyl-terminus of BRCA1 (the breast cancer susceptibility gene 1 product), is ubiquitous in several proteins that participate in cell cycle checkpoints and DNA repair. We have previously shown that the BRCT regions of TopBP1 (DNA topoisomerase II binding protein 1) and BRCA1 bound DNA breaks. A BRCT-related region, BRCT-W1, in the retinoblastoma susceptibility gene product (Rb) also could bind DNA fragments, independently of DNA sequences. Five BRCT-W regions were found in the Rb family. All BRCT-Ws of Rb bound DNA fragments. Electron microscopy and treatment with an exonuclease showed that BRCT-Ws bound double-strand DNA breaks. Since some BRCTs are exceptional common relating elements in tumor suppression, our findings reveal novel aspects of the tumor suppression mechanism.
authors.affiliation: Laboratory of Biomedical Research, Institute of Molecular and Cellular Biosciences, The University of Tokyo, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Yamane
authors.forename: E
authors.initials: E
authors.lastname: Katayama
authors.forename: K
authors.initials: K
authors.lastname: Sugasawa
authors.forename: T
authors.initials: T
authors.lastname: Tsuruo
mesh_terms: D000595:Amino Acid Sequence; D000957:Antigens, Viral, Tumor / Q000378:metabolism; D019313:BRCA1 Protein / Q000378:metabolism*; D002352:Carrier Proteins / Q000378:metabolism; D004247:DNA / Q000737:chemistry / Q000378:metabolism; D004249:DNA Damage; D004268:DNA-Binding Proteins; D004706:Endodeoxyribonucleases / Q000378:metabolism; D004926:Escherichia coli / Q000235:genetics; D008854:Microscopy, Electron; D008969:Molecular Sequence Data; D009687:Nuclear Proteins; D010446:Peptide Fragments / Q000378:metabolism; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D016160:Retinoblastoma Protein / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D017386:Sequence Homology, Amino Acid
chemical_list: D000957:Antigens, Viral, Tumor; D019313:BRCA1 Protein; D002352:Carrier Proteins; D004268:DNA-Binding Proteins; D009687:Nuclear Proteins; D010446:Peptide Fragments; D011994:Recombinant Proteins; D016160:Retinoblastoma Protein; C110513:TOPBP1 protein, human; D004247:DNA; D004706:Endodeoxyribonucleases; C038407:exonuclease Bal 31