Cooperative interaction of an initiator-binding transcription initiation factor and the helix-loop-helix activator USF.
Transcription initiation by mammalian RNA polymerase II is effected by multiple common factors interacting through minimal promoter elements and regulated by gene-specific factors interacting with distal control elements. Minimal promoter elements that can function independently or together, depending on the specific promoter, include the upstream TATA box and a pyrimidine-rich initiator (Inr) overlapping the transcription start site. The binding of TFIID to the TATA element promotes the assembly of other factors into a preinitiation complex but factors which function at the Inr have not been defined. We show here that a novel factor (TFII-I) binds specifically to Inr elements, supports basal transcription from the adenovirus major late promoter and is immunologically related to the helix-loop-helix activator USF. We further show that TFII-I also binds to the upstream high-affinity USF site (E box), that USF also binds to the Inr, and that TFII-I and USF interact cooperatively at both Inr and E box sites. Thus, TFII-I represents a novel type of transcription initiation factor whose interactions at multiple promoter elements may aid novel communication mechanisms between upstream regulatory factors and the general transcriptional machinery.
Roy
A L
AL
Laboratory of Biochemistry and Molecular Biology, Rockefeller University, New York, New York 10021.
Meisterernst
M
M
Pognonec
P
P
Roeder
R G
RG
D000818:Animals; D001483:Base Sequence; D001667:Binding, Competitive; D015153:Blotting, Western; D002851:Chromatography, High Pressure Liquid; D004268:DNA-Binding Proteins / Q000502:physiology*; D006801:Humans; D066298:In Vitro Techniques; D008969:Molecular Sequence Data; D011401:Promoter Regions, Genetic / Q000235:genetics / Q000502:physiology; D014157:Transcription Factors / Q000502:physiology*; D014158:Transcription, Genetic / Q000502:physiology*; D051720:Upstream Stimulatory Factors
D004268:DNA-Binding Proteins; D014157:Transcription Factors; C497181:USF1 protein, human; D051720:Upstream Stimulatory Factors