Negative regulation of DNA replication by the retinoblastoma protein is mediated by its association with MCM7.
A yeast two-hybrid screen was employed to identify human proteins that specifically bind the amino-terminal 400 amino acids of the retinoblastoma (Rb) protein. Two independent cDNAs resulting from this screen were found to encode the carboxy-terminal 137 amino acids of MCM7, a member of a family of proteins that comprise replication licensing factor. Full-length Rb and MCM7 form protein complexes in vitro, and the amino termini of two Rb-related proteins, p107 and p130, also bind MCM7. Protein complexes between Rb and MCM7 were also detected in anti-Rb immunoprecipitates prepared from human cells. The amino-termini of Rb and p130 strongly inhibited DNA replication in an MCM7-dependent fashion in a Xenopus in vitro DNA replication assay system. These data provide the first evidence that Rb and Rb-related proteins can directly regulate DNA replication and that components of licensing factor are targets of the products of tumor suppressor genes.
Sterner
J M
JM
Department of Molecular Cancer Biology, Duke University Medical Center, Durham, North Carolina 27710, USA.
Dew-Knight
S
S
Musahl
C
C
Kornbluth
S
S
Horowitz
J M
JM
D000595:Amino Acid Sequence; D000818:Animals; D018797:Cell Cycle Proteins; D004261:DNA Replication; D018076:DNA, Complementary / Q000235:genetics; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D008297:Male; D064168:Minichromosome Maintenance Complex Component 7; D008969:Molecular Sequence Data; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism*; D010063:Ovum; D010446:Peptide Fragments / Q000235:genetics / Q000378:metabolism; D010750:Phosphoproteins / Q000378:metabolism; D011485:Protein Binding; D011506:Proteins; D011994:Recombinant Proteins / Q000378:metabolism; D016160:Retinoblastoma Protein / Q000235:genetics / Q000378:metabolism*; D050720:Retinoblastoma-Like Protein p107; D050717:Retinoblastoma-Like Protein p130; D013094:Spermatozoa; D014981:Xenopus; D029867:Xenopus Proteins
D018797:Cell Cycle Proteins; D018076:DNA, Complementary; D004268:DNA-Binding Proteins; D009687:Nuclear Proteins; D010446:Peptide Fragments; D010750:Phosphoproteins; D011506:Proteins; C493844:RBL1 protein, human; C493837:RBL2 protein, human; D011994:Recombinant Proteins; D016160:Retinoblastoma Protein; D050720:Retinoblastoma-Like Protein p107; D050717:Retinoblastoma-Like Protein p130; D029867:Xenopus Proteins; C101624:MCM7 protein, human; C509836:Mcm7 protein, Xenopus; D064168:Minichromosome Maintenance Complex Component 7