Regions of the retinoblastoma gene product required for its interaction with the E2F transcription factor are necessary for E2 promoter repression and pRb-mediated growth suppression.
Studies of naturally occurring mutations of the RB1 tumor suppressor gene have indicated that the E1A/T antigen-binding domain is important for pRb function. Mutations engineered within the C-terminal 135 amino acids of pRb also abrogate its growth-suppressive function during the G1 interval of the cell cycle. Both the pRb E1A/T antigen-binding domain and the C-terminal domain are required for interaction with the E2F transcription factor. A series of mutated pRb proteins has been used to define the C-terminal sequences which determine E2F binding, adenovirus E2 promoter inhibition, and negative growth control. Deletion of the C terminus to residue 870 allowed full pRb function, while further deletion to residue 841 inactivated pRb in each assay. Amino acid sequences immediately C-terminal to the E1A/T antigen-binding domain were absolutely required for pRb activity. Mutations which prevented pRb from interacting with E2F also eliminated pRb-mediated E2 promoter repression and inactivated the ability of pRb to suppress cell growth.
Department of Tumor Cell Biology, St. Jude Children's Research Hospital, Memphis, Tennessee 38101.
S W
SW
Hiebert
D017500:Adenovirus E1A Proteins / Q000235:genetics; D017502:Adenovirus E2 Proteins / Q000235:genetics*; D001665:Binding Sites; D002352:Carrier Proteins; D002453:Cell Cycle / Q000502:physiology; D018797:Cell Cycle Proteins; D002455:Cell Division; D004268:DNA-Binding Proteins; D050684:E2F Transcription Factors; D005260:Female; D016193:G1 Phase; D016161:Genes, Retinoblastoma; D006801:Humans; D011401:Promoter Regions, Genetic; D016160:Retinoblastoma Protein / Q000235:genetics* / Q000378:metabolism*; D056465:Retinoblastoma-Binding Protein 1; D050680:Transcription Factor DP1; D014157:Transcription Factors / Q000378:metabolism*; D014162:Transfection; D014407:Tumor Cells, Cultured; D002583:Uterine Cervical Neoplasms
D017500:Adenovirus E1A Proteins; D017502:Adenovirus E2 Proteins; D002352:Carrier Proteins; D018797:Cell Cycle Proteins; D004268:DNA-Binding Proteins; D050684:E2F Transcription Factors; D016160:Retinoblastoma Protein; D056465:Retinoblastoma-Binding Protein 1; D050680:Transcription Factor DP1; D014157:Transcription Factors