TAF9 explained

TAF9 RNA polymerase II, TATA box binding protein (TBP)-associated factor, 32kDa, also known as TAF9, is a protein that in humans is encoded by the TAF9 gene.^{[1] [2]}

Function

Initiation of transcription by RNA polymerase II requires the activities of more than 70 polypeptides. The protein complex that coordinates these activities is transcription factor IID (TFIID), which binds to the core promoter to position the polymerase properly, serves as the scaffold for assembly of the remainder of the transcription complex, and acts as a channel for regulatory signals. TFIID is composed of the TATA-binding protein (TBP) and a group of evolutionarily conserved proteins known as TBP-associated factors or TAFs. TAFs may participate in basal transcription, serve as coactivators, function in promoter recognition or modify general transcription factors (GTFs) to facilitate complex assembly and transcription initiation. This gene encodes one of the smaller subunits of TFIID that binds to the basal transcription factor GTF2B as well as to several transcriptional activators such as p53 and VP16. A similar but distinct gene (TAF9B) has been found on the X chromosome and a pseudogene has been identified on chromosome 19. Alternative splicing results in multiple transcript variants encoding different isoforms.^[1]

Structure

The 17-amino-acid-long trans-activating domains (TAD) of several transcription factors were reported to bind directly to TAF9: p53, VP16, HSF1, NF-IL6, NFAT1, NF-κB, and ALL1/MLL1.^[3] Inside of these 17 amino acids, a unique Nine-amino-acid transactivation domain (9aaTAD) was identified for each reported transcription factor.^[4] 9aaTAD is a novel domain common to a large superfamily of eukaryotic transcription factors represented by Gal4, Oaf1, Leu3, Rtg3, Pho4, Gln4, Gcn4 in yeast and by p53, NFAT, NF-κB and VP16 in mammals.^[5] TAF9 is supposed to be a universal transactivation cofactor for 9aaTAD transcription factors.^[4]

Interactions

TAF9 has been shown to interact with:

• GCN5L2,^[6]
• Myc,^[7]
• SF3B3,^[6]
• SUPT7L,^[6]
• TADA3L,^[6]
• TAF5,^{[6] [8]}
• TAF6L,^[6]
• TAF10,^[6]
• TAF12,^[6]
• TAF5L,^[6]
• TATA binding protein,^{[6] [9]}
• Transcription initiation protein SPT3 homolog,^[6] and
• Transformation/transcription domain-associated protein.^[6]

Further reading

• Klemm RD, Goodrich JA, Zhou S, Tjian R . Molecular cloning and expression of the 32-kDa subunit of human TFIID reveals interactions with VP16 and TFIIB that mediate transcriptional activation. . Proc. Natl. Acad. Sci. U.S.A. . 92 . 13 . 5788–92 . 1995 . 7597030 . 41586 . 10.1073/pnas.92.13.5788 . 1995PNAS...92.5788K . free .
• Hisatake K, Ohta T, Takada R, Guermah M, Horikoshi M, Nakatani Y, Roeder RG . Evolutionary conservation of human TATA-binding-polypeptide-associated factors TAFII31 and TAFII80 and interactions of TAFII80 with other TAFs and with general transcription factors. . Proc. Natl. Acad. Sci. U.S.A. . 92 . 18 . 8195–9 . 1995 . 7667268 . 41123 . 10.1073/pnas.92.18.8195 . 1995PNAS...92.8195H . free .
• Lu H, Levine AJ . Human TAFII31 protein is a transcriptional coactivator of the p53 protein. . Proc. Natl. Acad. Sci. U.S.A. . 92 . 11 . 5154–8 . 1995 . 7761466 . 41867 . 10.1073/pnas.92.11.5154 . 1995PNAS...92.5154L . free .
• Thut CJ, Chen JL, Klemm R, Tjian R . p53 transcriptional activation mediated by coactivators TAFII40 and TAFII60. . Science . 267 . 5194 . 100–4 . 1995 . 7809597 . 10.1126/science.7809597 .
• Zhou Q, Sharp PA . Novel mechanism and factor for regulation by HIV-1 Tat. . EMBO J. . 14 . 2 . 321–8 . 1995 . 7835343 . 398086 . 10.1002/j.1460-2075.1995.tb07006.x.
• Parada CA, Yoon JB, Roeder RG . A novel LBP-1-mediated restriction of HIV-1 transcription at the level of elongation in vitro. . J. Biol. Chem. . 270 . 5 . 2274–83 . 1995 . 7836461 . 10.1074/jbc.270.5.2274 . free .
• Richard Gaynor. Ou SH, Garcia-Martínez LF, Paulssen EJ, Gaynor RB . Role of flanking E box motifs in human immunodeficiency virus type 1 TATA element function. . J. Virol. . 68 . 11 . 7188–99 . 1994 . 7933101 . 237158 . 10.1128/JVI.68.11.7188-7199.1994.
• Kashanchi F, Piras G, Radonovich MF, Duvall JF, Fattaey A, Chiang CM, Roeder RG, Brady JN . Direct interaction of human TFIID with the HIV-1 transactivator tat. . Nature . 367 . 6460 . 295–9 . 1994 . 8121496 . 10.1038/367295a0 . 1994Natur.367..295K . 4362048 .
• Adams MD, Soares MB, Kerlavage AR, Fields C, Venter JC . Rapid cDNA sequencing (expressed sequence tags) from a directionally cloned human infant brain cDNA library. . Nat. Genet. . 4 . 4 . 373–80 . 1993 . 8401585 . 10.1038/ng0893-373 . 12612300 .
• Wang Z, Morris GF, Rice AP, Xiong W, Morris CB . Wild-type and transactivation-defective mutants of human immunodeficiency virus type 1 Tat protein bind human TATA-binding protein in vitro. . J. Acquir. Immune Defic. Syndr. Hum. Retrovirol. . 12 . 2 . 128–38 . 1996 . 8680883 . 10.1097/00042560-199606010-00005 . free .
• Pendergrast PS, Morrison D, Tansey WP, Hernandez N . Mutations in the carboxy-terminal domain of TBP affect the synthesis of human immunodeficiency virus type 1 full-length and short transcripts similarly. . J. Virol. . 70 . 8 . 5025–34 . 1996 . 8764009 . 190456 . 10.1128/JVI.70.8.5025-5034.1996.
• Kashanchi F, Khleif SN, Duvall JF, Sadaie MR, Radonovich MF, Cho M, Martin MA, Chen SY, Weinmann R, Brady JN . Interaction of human immunodeficiency virus type 1 Tat with a unique site of TFIID inhibits negative cofactor Dr1 and stabilizes the TFIID-TFIIA complex. . J. Virol. . 70 . 8 . 5503–10 . 1996 . 8764062 . 190508 . 10.1128/JVI.70.8.5503-5510.1996.
• Zhou Q, Sharp PA . Tat-SF1: cofactor for stimulation of transcriptional elongation by HIV-1 Tat. . Science . 274 . 5287 . 605–10 . 1996 . 8849451 . 10.1126/science.274.5287.605 . 1996Sci...274..605Z . 13266489 .
• Tao Y, Guermah M, Martinez E, Oelgeschläger T, Hasegawa S, Takada R, Yamamoto T, Horikoshi M, Roeder RG . Specific interactions and potential functions of human TAFII100. . J. Biol. Chem. . 272 . 10 . 6714–21 . 1997 . 9045704 . 10.1074/jbc.272.10.6714 . free .
• García-Martínez LF, Ivanov D, Gaynor RB . Association of Tat with purified HIV-1 and HIV-2 transcription preinitiation complexes. . J. Biol. Chem. . 272 . 11 . 6951–8 . 1997 . 9054383 . 10.1074/jbc.272.11.6951 . free .
• Ogryzko VV, Kotani T, Zhang X, Schiltz RL, Howard T, Yang XJ, Howard BH, Qin J, Nakatani Y . Histone-like TAFs within the PCAF histone acetylase complex. . Cell . 94 . 1 . 35–44 . 1998 . 9674425 . 10.1016/S0092-8674(00)81219-2 . 18942972 . free .
• Vassilev A, Yamauchi J, Kotani T, Prives C, Avantaggiati ML, Qin J, Nakatani Y . The 400 kDa subunit of the PCAF histone acetylase complex belongs to the ATM superfamily. . Mol. Cell . 2 . 6 . 869–75 . 1999 . 9885574 . 10.1016/S1097-2765(00)80301-9 . free .
• Evans SC, Foster CJ, El-Naggar AK, Lozano G . Mapping and mutational analysis of the human TAF2G gene encoding a p53 cofactor. . Genomics . 57 . 1 . 182–3 . 1999 . 10191103 . 10.1006/geno.1999.5745 .
• Lai CH, Chou CY, Ch'ang LY, Liu CS, Lin W . Identification of novel human genes evolutionarily conserved in Caenorhabditis elegans by comparative proteomics. . Genome Res. . 10 . 5 . 703–13 . 2000 . 10810093 . 310876 . 10.1101/gr.10.5.703 .
• Choi Y, Asada S, Uesugi M . Divergent hTAFII31-binding motifs hidden in activation domains. . J. Biol. Chem. . 275 . 21 . 15912–6 . 2000 . 10821850 . 10.1074/jbc.275.21.15912 . free .

Notes and References

1. Web site: Entrez Gene: TAF9 TAF9 RNA polymerase II, TATA box binding protein (TBP)-associated factor, 32kDa.
2. Evans SC, Foster CJ, El-Naggar AK, Lozano G . Mapping and mutational analysis of the human TAF2G gene encoding a p53 cofactor . Genomics . 57 . 1 . 182–3 . April 1999 . 10191103 . 10.1006/geno.1999.5745 .
3. . Induced alpha helix in the VP16 activation domain upon binding to a human TAF . Science . 277 . 5330 . 1310–3 . August 1997 . 9271577 . 10.1126/science.277.5330.1310 . Uesugi M, Verdine GL . The alpha-helical FXXPhiPhi motif in p53: TAF interaction and discrimination by MDM2 . Proc. Natl. Acad. Sci. U.S.A. . 96 . 26 . 14801–6 . December 1999 . 10611293 . 24728 . 10.1073/pnas.96.26.14801 . 1999PNAS...9614801U . free . Choi Y, Asada S, Uesugi M . Divergent hTAFII31-binding motifs hidden in activation domains . J. Biol. Chem. . 275 . 21 . 15912–6 . May 2000 . 10821850 . 10.1074/jbc.275.21.15912 . free . Venot C, Maratrat M, Sierra V, Conseiller E, Debussche L . Definition of a p53 transactivation function-deficient mutant and characterization of two independent p53 transactivation subdomains . Oncogene . 18 . 14 . 2405–10 . April 1999 . 10327062 . 10.1038/sj.onc.1202539 . free . Lin J, Chen J, Elenbaas B, Levine AJ . Several hydrophobic amino acids in the p53 amino-terminal domain are required for transcriptional activation, binding to mdm-2 and the adenovirus 5 E1B 55-kD protein . Genes Dev. . 8 . 10 . 1235–46 . May 1994 . 7926727 . 10.1101/gad.8.10.1235 . free .
4. Piskacek S, Gregor M, Nemethova M, Grabner M, Kovarik P, Piskacek M . Nine-amino-acid transactivation domain: establishment and prediction utilities . Genomics . 89 . 6 . 756–68 . June 2007 . 17467953 . 10.1016/j.ygeno.2007.02.003 . free .
5. The prediction for 9aa TADs (for both acidic and hydrophilic transactivation domains) is available online from National EMBnet-Node Austria (Web site: 9aaTAD Prediction Webtool. EMBnet AUSTRIA. https://web.archive.org/web/20070701165648/https://emb1.bcc.univie.ac.at/toolbox/9aatad/webtool.htm. 2007-07-01. 2009-01-10. dead.)
6. Martinez E, Palhan VB, Tjernberg A, Lymar ES, Gamper AM, Kundu TK, Chait BT, Roeder RG . Human STAGA complex is a chromatin-acetylating transcription coactivator that interacts with pre-mRNA splicing and DNA damage-binding factors in vivo . Mol. Cell. Biol. . 21 . 20 . 6782–95 . Oct 2001 . 11564863 . 99856 . 10.1128/MCB.21.20.6782-6795.2001 .
7. Liu X, Tesfai J, Evrard YA, Dent SY, Martinez E . c-Myc transformation domain recruits the human STAGA complex and requires TRRAP and GCN5 acetylase activity for transcription activation . J. Biol. Chem. . 278 . 22 . 20405–12 . May 2003 . 12660246 . 4031917 . 10.1074/jbc.M211795200 . free .
8. Tao Y, Guermah M, Martinez E, Oelgeschläger T, Hasegawa S, Takada R, Yamamoto T, Horikoshi M, Roeder RG . Specific interactions and potential functions of human TAFII100 . J. Biol. Chem. . 272 . 10 . 6714–21 . Mar 1997 . 9045704 . 10.1074/jbc.272.10.6714. free .
9. Bellorini M, Lee DK, Dantonel JC, Zemzoumi K, Roeder RG, Tora L, Mantovani R . CCAAT binding NF-Y-TBP interactions: NF-YB and NF-YC require short domains adjacent to their histone fold motifs for association with TBP basic residues . Nucleic Acids Res. . 25 . 11 . 2174–81 . Jun 1997 . 9153318 . 146709 . 10.1093/nar/25.11.2174.