Transcription factor AP-2 alpha (Activating enhancer binding Protein 2alpha), also known as TFAP2A, is a protein that in humans is encoded by the TFAP2Agene.[1]
The AP-2 alpha protein acts as a sequence-specific DNA-binding transcription factor recognizing and binding to the specific DNA sequence and recruiting transcription machinery. Its binding site is a GC-rich sequence that is present in the cis-regulatory regions of several viral and cellular genes.[2] AP2-alpha is a 52-kD retinoic acid-inducible and developmentally regulated activator of transcription that binds to a consensus DNA-binding sequence GCCNNNGGC in the SV40 and metallothionein promoters.[1]
AP-2 alpha is expressed in neural crest cell lineages with the highest levels of expression corresponding to early neural crest cells, suggesting that AP-2 alpha plays a role in their differentiation and development. Transcription factor AP-2 alpha is expressed in ectoderm and in neural-crest cells migrating from the cranial folds during closure of the neural tube in the mouse. Cranial neural crest cell provides patterning information for craniofacialmorphogenesis and generate most of the skull bones and the cranial ganglia.[2][3][4][5]
AP-2 alpha knockout mice die perinatally with cranio-abdominoschisis and severe dysmorphogenesis of the face, skull, sensory organs, and cranial ganglia.[6]Homozygous knockout mice also have neural tube defects followed by craniofacial and body wall abnormalities.[7] In vivo gene delivery of AP-2 alpha suppressed spontaneous intestinal polyps in the Apc(Min/+) mouse.[8] AP-2 alpha also functions as a master regulator of multiple transcription factors in the mouse liver.[9]
Mutations in the TFAP2A gene cause Branchio-oculo-facial syndrome often with a midline cleft lip.[11] In a family with branchio-oculo-facial syndrome (BOFS),[12] a 3.2-Mb deletion at chromosome 6p24.3 was detected.[13] Sequencing of candidate genes in that region in 4 additional unrelated BOFS patients revealed 4 different de novo missense mutations in the exons 4 and 5 of the TFAP2A gene.
A disruption of an AP-2 alpha binding site in an IRF6 enhancer is associated with cleft lip.[14] Mutations in IRF6 gene cause Van der Woude syndrome (VWS)[15] that is a rare mendelian clefting autossomal dominant disorder with lower lip pits in 85% of affected individuals.[16] The remaining 15% of individuals with Van der Woude syndrome show only cleft lip and/or cleft palate (CL/P) and are clinically indistinguishable from the common non syndromic CL/P. NSCL/P occur in approximately 1/700 live births and is one of the most common form of congenital abnormalities. A previous association study between SNPs in and around IRF6 and NSCL/P have shown significant results in different populations[17] and was independently replicated.[18][19][20][21]
A search of NSCL/P cases for potential regulatory elements for IRF6 gene was made aligning genomic sequences to a 500 Kb region encompassing IRF6 from 17 vertebrate species. Human sequence as reference and searched for multispecies conserved sequences (MCSs). Regions contained in introns 5’ and 3’ flanking IRF6 were screened by direct sequencing for potential causative variants in 184 NSCL/P cases. The rare allele of the SNP rs642961 showed a significant association with cleft lip cases. Analysis of transcription factor binding site analysis showed that the risk allele disrupt a binding site for AP-2 alpha.[14]
Mutations in the AP-2 alpha gene also cause branchio-oculo-facial syndrome,[13] which has overlapping features with Van der Woude syndrome such as orofacial clefting and occasional lip pits what make rs642961 a good candidate for an etiological variant. These findings show that IRF6 and AP-2 alpha are in the same developmental pathway and identify a variant in a regulatory region that contributes substantially to a common complex disorder.
↑ 2.02.1Williams T, Tjian R (Apr 1991). "Analysis of the DNA-binding and activation properties of the human transcription factor AP-2". Genes & Development. 5 (4): 670–82. doi:10.1101/gad.5.4.670. PMID2010091.
↑Mitchell PJ, Wang C, Tjian R (Sep 1987). "Positive and negative regulation of transcription in vitro: enhancer-binding protein AP-2 is inhibited by SV40 T antigen". Cell. 50 (6): 847–61. doi:10.1016/0092-8674(87)90512-5. PMID3040262.
↑Williams T, Admon A, Lüscher B, Tjian R (Dec 1988). "Cloning and expression of AP-2, a cell-type-specific transcription factor that activates inducible enhancer elements". Genes & Development. 2 (12A): 1557–69. doi:10.1101/gad.2.12a.1557. PMID3063603.
↑Le Douarin NM, Ziller C, Couly GF (Sep 1993). "Patterning of neural crest derivatives in the avian embryo: in vivo and in vitro studies". Developmental Biology. 159 (1): 24–49. doi:10.1006/dbio.1993.1219. PMID8365563.
↑Schorle H, Meier P, Buchert M, Jaenisch R, Mitchell PJ (May 1996). "Transcription factor AP-2 essential for cranial closure and craniofacial development". Nature. 381 (6579): 235–8. doi:10.1038/381235a0. PMID8622765.
↑Zhang J, Hagopian-Donaldson S, Serbedzija G, Elsemore J, Plehn-Dujowich D, McMahon AP, Flavell RA, Williams T (May 1996). "Neural tube, skeletal and body wall defects in mice lacking transcription factor AP-2". Nature. 381 (6579): 238–41. doi:10.1038/381238a0. PMID8622766.
↑Li Q, Luo C, Löhr CV, Dashwood RH (Aug 2011). "Activator protein-2α functions as a master regulator of multiple transcription factors in the mouse liver". Hepatology Research. 41 (8): 776–83. doi:10.1111/j.1872-034X.2011.00827.x. PMID21682828.
↑Hoek KS, Schlegel NC, Eichhoff OM, Widmer DS, Praetorius C, Einarsson SO, Valgeirsdottir S, Bergsteinsdottir K, Schepsky A, Dummer R, Steingrimsson E (Dec 2008). "Novel MITF targets identified using a two-step DNA microarray strategy". Pigment Cell & Melanoma Research. 21 (6): 665–76. doi:10.1111/j.1755-148X.2008.00505.x. PMID19067971.
↑Kondo S, Schutte BC, Richardson RJ, Bjork BC, Knight AS, Watanabe Y, Howard E, de Lima RL, Daack-Hirsch S, Sander A, McDonald-McGinn DM, Zackai EH, Lammer EJ, Aylsworth AS, Ardinger HH, Lidral AC, Pober BR, Moreno L, Arcos-Burgos M, Valencia C, Houdayer C, Bahuau M, Moretti-Ferreira D, Richieri-Costa A, Dixon MJ, Murray JC (Oct 2002). "Mutations in IRF6 cause Van der Woude and popliteal pterygium syndromes". Nature Genetics. 32 (2): 285–9. doi:10.1038/ng985. PMC3169431. PMID12219090.
↑Zucchero TM, Cooper ME, Maher BS, Daack-Hirsch S, Nepomuceno B, Ribeiro L, Caprau D, Christensen K, Suzuki Y, Machida J, Natsume N, Yoshiura K, Vieira AR, Orioli IM, Castilla EE, Moreno L, Arcos-Burgos M, Lidral AC, Field LL, Liu YE, Ray A, Goldstein TH, Schultz RE, Shi M, Johnson MK, Kondo S, Schutte BC, Marazita ML, Murray JC (Aug 2004). "Interferon regulatory factor 6 (IRF6) gene variants and the risk of isolated cleft lip or palate". The New England Journal of Medicine. 351 (8): 769–80. doi:10.1056/NEJMoa032909. PMID15317890.
↑Blanton SH, Cortez A, Stal S, Mulliken JB, Finnell RH, Hecht JT (Sep 2005). "Variation in IRF6 contributes to nonsyndromic cleft lip and palate". American Journal of Medical Genetics Part A. 137A (3): 259–62. doi:10.1002/ajmg.a.30887. PMID16096995.
↑Ghassibé M, Bayet B, Revencu N, Verellen-Dumoulin C, Gillerot Y, Vanwijck R, Vikkula M (Nov 2005). "Interferon regulatory factor-6: a gene predisposing to isolated cleft lip with or without cleft palate in the Belgian population". European Journal of Human Genetics. 13 (11): 1239–42. doi:10.1038/sj.ejhg.5201486. PMID16132054.
↑ 23.023.1Bragança J, Eloranta JJ, Bamforth SD, Ibbitt JC, Hurst HC, Bhattacharya S (May 2003). "Physical and functional interactions among AP-2 transcription factors, p300/CREB-binding protein, and CITED2". The Journal of Biological Chemistry. 278 (18): 16021–9. doi:10.1074/jbc.M208144200. PMID12586840.
↑Bragança J, Swingler T, Marques FI, Jones T, Eloranta JJ, Hurst HC, Shioda T, Bhattacharya S (Mar 2002). "Human CREB-binding protein/p300-interacting transactivator with ED-rich tail (CITED) 4, a new member of the CITED family, functions as a co-activator for transcription factor AP-2". The Journal of Biological Chemistry. 277 (10): 8559–65. doi:10.1074/jbc.M110850200. PMID11744733.
↑McPherson LA, Loktev AV, Weigel RJ (Nov 2002). "Tumor suppressor activity of AP2alpha mediated through a direct interaction with p53". The Journal of Biological Chemistry. 277 (47): 45028–33. doi:10.1074/jbc.M208924200. PMID12226108.
Further reading
Murphy JE, Keen JH (May 1992). "Recognition sites for clathrin-associated proteins AP-2 and AP-3 on clathrin triskelia". The Journal of Biological Chemistry. 267 (15): 10850–5. PMID1587861.
Gaynor RB, Muchardt C, Xia YR, Klisak I, Mohandas T, Sparkes RS, Lusis AJ (Aug 1991). "Localization of the gene for the DNA-binding protein AP-2 to human chromosome 6p22.3-pter". Genomics. 10 (4): 1100–2. doi:10.1016/0888-7543(91)90209-W. PMID1916817.
Williams T, Tjian R (Mar 1991). "Characterization of a dimerization motif in AP-2 and its function in heterologous DNA-binding proteins". Science. 251 (4997): 1067–71. doi:10.1126/science.1998122. PMID1998122.
Williams T, Tjian R (Apr 1991). "Analysis of the DNA-binding and activation properties of the human transcription factor AP-2". Genes & Development. 5 (4): 670–82. doi:10.1101/gad.5.4.670. PMID2010091.
Williams T, Admon A, Lüscher B, Tjian R (Dec 1988). "Cloning and expression of AP-2, a cell-type-specific transcription factor that activates inducible enhancer elements". Genes & Development. 2 (12A): 1557–69. doi:10.1101/gad.2.12a.1557. PMID3063603.
Williamson JA, Bosher JM, Skinner A, Sheer D, Williams T, Hurst HC (Jul 1996). "Chromosomal mapping of the human and mouse homologues of two new members of the AP-2 family of transcription factors". Genomics. 35 (1): 262–4. doi:10.1006/geno.1996.0351. PMID8661133.
Pirozzi G, McConnell SJ, Uveges AJ, Carter JM, Sparks AB, Kay BK, Fowlkes DM (Jun 1997). "Identification of novel human WW domain-containing proteins by cloning of ligand targets". The Journal of Biological Chemistry. 272 (23): 14611–6. doi:10.1074/jbc.272.23.14611. PMID9169421.
Mertens PR, Alfonso-Jaume MA, Steinmann K, Lovett DH (Dec 1998). "A synergistic interaction of transcription factors AP2 and YB-1 regulates gelatinase A enhancer-dependent transcription". The Journal of Biological Chemistry. 273 (49): 32957–65. doi:10.1074/jbc.273.49.32957. PMID9830047.
García MA, Campillos M, Marina A, Valdivieso F, Vázquez J (Feb 1999). "Transcription factor AP-2 activity is modulated by protein kinase A-mediated phosphorylation". FEBS Letters. 444 (1): 27–31. doi:10.1016/S0014-5793(99)00021-6. PMID10037142.
Rosenthal JA, Chen H, Slepnev VI, Pellegrini L, Salcini AE, Di Fiore PP, De Camilli P (Nov 1999). "The epsins define a family of proteins that interact with components of the clathrin coat and contain a new protein module". The Journal of Biological Chemistry. 274 (48): 33959–65. doi:10.1074/jbc.274.48.33959. PMID10567358.
Heicklen-Klein A, Ginzburg I (Oct 2000). "Tau promoter confers neuronal specificity and binds Sp1 and AP-2". Journal of Neurochemistry. 75 (4): 1408–18. doi:10.1046/j.1471-4159.2000.0751408.x. PMID10987820.
Bragança J, Swingler T, Marques FI, Jones T, Eloranta JJ, Hurst HC, Shioda T, Bhattacharya S (Mar 2002). "Human CREB-binding protein/p300-interacting transactivator with ED-rich tail (CITED) 4, a new member of the CITED family, functions as a co-activator for transcription factor AP-2". The Journal of Biological Chemistry. 277 (10): 8559–65. doi:10.1074/jbc.M110850200. PMID11744733.
Mertens PR, Steinmann K, Alfonso-Jaume MA, En-Nia A, Sun Y, Lovett DH (Jul 2002). "Combinatorial interactions of p53, activating protein-2, and YB-1 with a single enhancer element regulate gelatinase A expression in neoplastic cells". The Journal of Biological Chemistry. 277 (28): 24875–82. doi:10.1074/jbc.M200445200. PMID11973333.
Eloranta JJ, Hurst HC (Aug 2002). "Transcription factor AP-2 interacts with the SUMO-conjugating enzyme UBC9 and is sumolated in vivo". The Journal of Biological Chemistry. 277 (34): 30798–804. doi:10.1074/jbc.M202780200. PMID12072434.
Ben-Zimra M, Koler M, Orly J (Aug 2002). "Transcription of cholesterol side-chain cleavage cytochrome P450 in the placenta: activating protein-2 assumes the role of steroidogenic factor-1 by binding to an overlapping promoter element". Molecular Endocrinology. 16 (8): 1864–80. doi:10.1210/me.2002-0056. PMID12145340.