Transcription factor II D

Transcription factor II D (TFIID) is one of several general transcription factors that make up the RNA polymerase II preinitiation complex. RNA polymerase II holoenzyme is a form of eukaryotic RNA polymerase II that is recruited to the promoters of protein-coding genes in living cells. It consists of RNA polymerase II, a subset of general transcription factors, and regulatory proteins known as SRB proteins. Before the start of transcription, the transcription Factor II D (TFIID) complex binds to the TATA box in the core promoter of the gene.



TFIID is itself composed of several subunits called TATA-binding protein Associated Factors (TBP-associated factors, or TAFs). In a test tube, only TBP is necessary for transcription at promoters that contain a TATA box.[1] TAFs, however, add promoter selectivity, especially if there is no TATA box sequence for TBP to bind to. TAFs are included in two distinct complexes, TFIID[2] and B-TFIID.[3] The TFIID complex is composed of TBP and more than eight TAFs. But, the majority of TBP is present in the B-TFIID complex, which is composed of TBP and TAFII170 (BTAF1) in a 1:1 ratio.[4] TFIID and B-TFIID are not equivalent, since transcription reactions utilizing TFIID are responsive to gene specific transcription factors such as SP1, while reactions reconstituted with B-TFIID are not.[4]

Subunits in the TFIID complex include:[1]

See also


  1. 1 2 Lee, Tong Ihn; Young, Richard A. (2000). "Transcription of eukaryotic protein-coding genes". Annu. Rev. Genet. 34: 77–137. doi:10.1146/annurev.genet.34.1.77. PMID 11092823.
  2. Dynlacht, Brian David; Hoey, Timothy; Tjian, Robert (Aug 1991). "Isolation of co-activators associated with the TATA-binding protein that mediate transcriptional activation". Cell. 66 (3): 563–576. doi:10.1016/0092-8674(81)90019-2. PMID 1907890.
  3. "NCBI Entrez GeneID: 9044 BTAF1 BTAF1 RNA polymerase II, B-TFIID transcription factor-associated, 170kDa (Mot1 homolog, S. cerevisiae)".
  4. 1 2 Timmers, H.; Meyers, RE; Sharp, PA (Sep 1992). "Composition of transcription factor B-TFIID" (PDF). Proc Natl Acad Sci USA. 89 (17): 8140–4. doi:10.1073/pnas.89.17.8140. PMC 49872Freely accessible. PMID 1387711.

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