Characterization of the human RB1 promoter and of elements involved in transcriptional regulation.
The retinoblastoma gene (RB1) is a recessive oncogene implicated in a number of human tumors. Although the RB1 gene is expressed in most proliferating cells, there is considerable evidence for the transcriptional regulation of this gene. Therefore, we have performed a detailed analysis of the regulatory elements in the promoter of the human RB1 gene. Deletion analysis of the 5' upstream region determined the location of the basal promoter to be between -208 and -179 nucleotides relative to the translational start. This region contains essential binding sites for the transcription elements ATF and SP1 and potentially important sites for E2F and steroid hormone responsiveness but no TATA or CAAT boxes. Primer extension and RNase protection analysis identified two initiation sites at -176 and -128 base pairs, both downstream of the promoter. Cotransfection experiments revealed repression of the RB1 promoter by its protein product p110RB1. This repression has been mapped to the core promoter region containing the E2F-binding site; however, this site is not required for autorepression.
Gill
R M
RM
Division of Immunology and Cancer Research, Hospital for Sick Children, Toronto, Ontario, Canada.
Hamel
P A
PA
Zhe
J
J
Zacksenhaus
E
E
Gallie
B L
BL
Phillips
R A
RA
D051696:Activating Transcription Factors; D001483:Base Sequence; D001665:Binding Sites; D001798:Blood Proteins / Q000378:metabolism; D004247:DNA / Q000378:metabolism; D016161:Genes, Retinoblastoma / Q000235:genetics*; D006801:Humans; D008969:Molecular Sequence Data; D009363:Neoplasm Proteins / Q000378:metabolism; D020652:Peptide Elongation Factor 2; D010445:Peptide Elongation Factors / Q000378:metabolism; D011401:Promoter Regions, Genetic / Q000235:genetics*; D012333:RNA, Messenger / Q000096:biosynthesis; D016160:Retinoblastoma Protein / Q000235:genetics* / Q000502:physiology; D017384:Sequence Deletion / Q000502:physiology; D016329:Sp1 Transcription Factor / Q000378:metabolism; D014157:Transcription Factors / Q000378:metabolism; D014158:Transcription, Genetic / Q000235:genetics*; D014407:Tumor Cells, Cultured
D051696:Activating Transcription Factors; D001798:Blood Proteins; D009363:Neoplasm Proteins; D020652:Peptide Elongation Factor 2; D010445:Peptide Elongation Factors; D012333:RNA, Messenger; D016160:Retinoblastoma Protein; D016329:Sp1 Transcription Factor; D014157:Transcription Factors; D004247:DNA