The interaction of RB with E2F coincides with an inhibition of the transcriptional activity of E2F.
Recent experiments have shown that the E2F transcription factor is in a complex with the RB1 gene product. The E2F-pRB complex can be reconstituted in an in vitro assay using a GST-RB fusion protein isolated from Escherichia coli. This interaction is dependent on pRB sequences involved in E1A/T-antigen binding as well as carboxy-terminal pRB sequences that are not necessary for E1A/T binding. Moreover, reconstitution assays reveal a requirement for an accessory factor, in addition to E2F and pRB, for formation of the E2F-pRB complex. Assays of transcription from the adenovirus E2 promoter in transfection experiments demonstrate that formation of the complex containing pRB and E2F coincides with an inhibition of E2F-dependent transcriptional activity. A mutant pRB protein that does not associate with E2F does not inhibit transcription. We conclude that as a consequence of its interaction with E2F, pRB may regulate the transcriptional function of the E2F factor.
Hiebert
S W
SW
Howard Hughes Medical Institute, Duke University Medical Center, Durham, North Carolina 27710.
Chellappan
S P
SP
Horowitz
J M
JM
Nevins
J R
JR
D017456:Adenovirus Early Proteins; D000957:Antigens, Viral, Tumor / Q000235:genetics / Q000378:metabolism; D002352:Carrier Proteins; D018797:Cell Cycle Proteins; D015500:Chloramphenicol O-Acetyltransferase / Q000235:genetics / Q000378:metabolism; D004268:DNA-Binding Proteins; D050684:E2F Transcription Factors; D016161:Genes, Retinoblastoma; D006367:HeLa Cells; D006801:Humans; D009154:Mutation / Q000235:genetics; D009856:Oncogene Proteins, Viral / Q000235:genetics / Q000378:metabolism; D011233:Precipitin Tests; D011401:Promoter Regions, Genetic; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D016160:Retinoblastoma Protein / Q000235:genetics / Q000378:metabolism*; D056465:Retinoblastoma-Binding Protein 1; D050680:Transcription Factor DP1; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*; D014158:Transcription, Genetic / Q000502:physiology*
D017456:Adenovirus Early Proteins; D000957:Antigens, Viral, Tumor; D002352:Carrier Proteins; D018797:Cell Cycle Proteins; D004268:DNA-Binding Proteins; D050684:E2F Transcription Factors; D009856:Oncogene Proteins, Viral; D011993:Recombinant Fusion Proteins; D016160:Retinoblastoma Protein; D056465:Retinoblastoma-Binding Protein 1; D050680:Transcription Factor DP1; D014157:Transcription Factors; D015500:Chloramphenicol O-Acetyltransferase