title: Retinoblastoma binding factor 1 site in the core promoter region of the human RB gene is activated by hGABP/E4TF1.
abstract: We previously reported two oncogenic point mutations present in the RB (retinoblastoma) gene promoter region, found at consensus Sp1 and ATF sites, respectively, and in two separate hereditary RB families. However, Sp1 protein was shown not to bind to the Sp1 site; this indicated that the Sp1 consensus site mutation was blocking the action of an alternative transcription factor, which we called RBF-1 (retinoblastoma binding factor 1). Subsequent purification of RBF-1 revealed it to be hGABP/E4TF1, a transactivator from the adenovirus early-region 4 promoter. In this study, we directly examined the effects of hGABP/E4TF1 on transactivation of the RB gene promoter through the RBF-1 site. As expected, hGABP/E4TF1 enhanced the core RB promoter activity, whereas it did not stimulate a mutant RBF-1 site. We therefore conclude that the most essential transcription factor in the human RB gene is likely to be hGABP/E4TF1.
authors.affiliation: Department of Preventive Medicine, Kyoto Prefectural University of Medicine, Kamigyo-ku, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Sowa
authors.forename: Y
authors.initials: Y
authors.lastname: Shiio
authors.forename: T
authors.initials: T
authors.lastname: Fujita
authors.forename: T
authors.initials: T
authors.lastname: Matsumoto
authors.forename: Y
authors.initials: Y
authors.lastname: Okuyama
authors.forename: D
authors.initials: D
authors.lastname: Kato
authors.forename: J
authors.initials: J
authors.lastname: Inoue
authors.forename: J
authors.initials: J
authors.lastname: Sawada
authors.forename: M
authors.initials: M
authors.lastname: Goto
authors.forename: H
authors.initials: H
authors.lastname: Watanabe
authors.forename: H
authors.initials: H
authors.lastname: Handa
authors.forename: T
authors.initials: T
authors.lastname: Sakai
mesh_terms: D000818:Animals; D002352:Carrier Proteins / Q000235:genetics*; D004268:DNA-Binding Proteins / Q000378:metabolism*; D004330:Drosophila; D051268:GA-Binding Protein Transcription Factor; D017930:Genes, Reporter; D016161:Genes, Retinoblastoma / Q000235:genetics*; D006801:Humans; D017354:Point Mutation; D011401:Promoter Regions, Genetic / Q000502:physiology*; D014157:Transcription Factors / Q000378:metabolism*; D014162:Transfection
chemical_list: D002352:Carrier Proteins; D004268:DNA-Binding Proteins; D051268:GA-Binding Protein Transcription Factor; D014157:Transcription Factors