Functional domains of transcription factor TFIIB.
Transcription factor TFIIB is an essential component of the RNA polymerase II initiation complex. TFIIB carries out at least two functions: it interacts directly with the TATA-binding protein (TBP) and helps to recruit RNA polymerase II into the initiation complex. The sequence of TFIIB reveals a potential zinc-binding domain and an imperfect duplication of approximately 70 amino acids. Mutagenesis of cysteine codons within the putative zinc finger results in mutant proteins that bind normally to TBP but are unable to recruit RNA polymerase II-TFIIF into the initiation complex. Changing the two most highly conserved amino acids in the TFIIB repeats reduces the ability of TFIIB to interact with TBP. Therefore, the two functions of TFIIB can be assigned to two separable functional domains of the protein.
Whitehead Institute for Biomedical Research, Cambridge, MA 02142.
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D000595:Amino Acid Sequence; D000818:Animals; D017124:Conserved Sequence; D004268:DNA-Binding Proteins / Q000378:metabolism; D004331:Drosophila melanogaster / Q000235:genetics; D006801:Humans; D008969:Molecular Sequence Data; D005810:Multigene Family; D016297:Mutagenesis, Site-Directed; D012319:RNA Polymerase II / Q000378:metabolism; D051381:Rats; D011994:Recombinant Proteins / Q000302:isolation & purification / Q000378:metabolism; D015183:Restriction Mapping; D012441:Saccharomyces cerevisiae / Q000235:genetics; D017386:Sequence Homology, Amino Acid; D035181:TATA-Box Binding Protein; D035581:Transcription Factor TFIIB; D014157:Transcription Factors / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism*; D014982:Xenopus laevis; D016335:Zinc Fingers / Q000235:genetics
D004268:DNA-Binding Proteins; D011994:Recombinant Proteins; D035181:TATA-Box Binding Protein; D035581:Transcription Factor TFIIB; D014157:Transcription Factors; D012319:RNA Polymerase II