title: Preaxial polydactyly: interactions among ETV, TWIST1 and HAND2 control anterior-posterior patterning of the limb.
abstract: Preaxial polydactyly (PPD) is a common limb-associated birth defect characterized by extra digit(s) in the anterior autopod. It often results from ectopic sonic hedgehog (Shh) expression in the anterior limb bud. Although several transcription factors are known to restrict Shh expression to the posterior limb bud, how they function together remains unclear. Here we provide evidence from mouse conditional knockout limb buds that the bHLH family transcription factor gene Twist1 is required to inhibit Shh expression in the anterior limb bud mesenchyme. More importantly, we uncovered genetic synergism between Twist1 and the ETS family transcription factor genes Etv4 and Etv5 (collectively Etv), which also inhibit Shh expression. Biochemical data suggest that this genetic interaction is a result of direct association between TWIST1 and ETV proteins. Previous studies have shown that TWIST1 functions by forming homodimers or heterodimers with other bHLH factors including HAND2, a key positive regulator of Shh expression. We found that the PPD phenotype observed in Etv mutants is suppressed by a mutation in Hand2, indicative of genetic antagonism. Furthermore, overexpression of ETV proteins influences the dimerization of these bHLH factors. Together, our data suggest that through biochemical interactions, the Shh expression regulators ETV, TWIST1 and HAND2 attain a precise balance to establish anterior-posterior patterning of the limb.
authors.affiliation: Laboratory of Genetics, University of Wisconsin-Madison, Madison, WI 53706, USA.
authors.forename: Zhen
authors.initials: Z
authors.lastname: Zhang
authors.forename: Pengfei
authors.initials: P
authors.lastname: Sui
authors.forename: Aiwu
authors.initials: A
authors.lastname: Dong
authors.forename: John
authors.initials: J
authors.lastname: Hassell
authors.forename: Peter
authors.initials: P
authors.lastname: Cserjesi
authors.forename: You-Tzung
authors.initials: YT
authors.lastname: Chen
authors.forename: Richard R
authors.initials: RR
authors.lastname: Behringer
authors.forename: Xin
authors.initials: X
authors.lastname: Sun
mesh_terms: D000818:Animals; D051792:Basic Helix-Loop-Helix Proteins / Q000378:metabolism*; D015153:Blotting, Western; D019521:Body Patterning / Q000502:physiology*; D004268:DNA-Binding Proteins / Q000378:metabolism*; D019281:Dimerization; D053823:Hedgehog Proteins / Q000378:metabolism; D047468:Immunoprecipitation; D051379:Mice; D018345:Mice, Knockout; D009687:Nuclear Proteins / Q000378:metabolism*; D017689:Polydactyly / Q000196:embryology*; D050783:Proto-Oncogene Proteins c-ets / Q000378:metabolism*; D014157:Transcription Factors / Q000378:metabolism*; D051879:Twist-Related Protein 1 / Q000378:metabolism*; D020798:Two-Hybrid System Techniques; D034941:Upper Extremity / Q000196:embryology*
chemical_list: D051792:Basic Helix-Loop-Helix Proteins; D004268:DNA-Binding Proteins; D053823:Hedgehog Proteins; D009687:Nuclear Proteins; D050783:Proto-Oncogene Proteins c-ets; D014157:Transcription Factors; D051879:Twist-Related Protein 1; C540571:Etv4 protein, mouse; C513242:Etv5 protein, mouse; C498766:Hand2 protein, mouse; C465570:Shh protein, mouse; C067250:Twist1 protein, mouse
references.citation: Mol Cell Biol. 2004 Nov;24(22):9835-47
references.pmid: 15509787
references.citation: Mech Dev. 2001 Oct;108(1-2):191-5
references.pmid: 11578874
references.citation: Dev Biol. 2002 Aug 1;248(1):143-56
references.pmid: 12142027
references.citation: J Biol Chem. 2002 Mar 15;277(11):9118-26
references.pmid: 11756408
references.citation: Dev Cell. 2009 Apr;16(4):607-13
references.pmid: 19386269
references.citation: Development. 2000 May;127(10):2133-42
references.pmid: 10769237
references.citation: Genesis. 2002 Jun;33(2):77-80
references.pmid: 12112875
references.citation: Mech Dev. 1996 May;56(1-2):93-101
references.pmid: 8798150
references.citation: Genes Dev. 2002 Feb 15;16(4):421-6
references.pmid: 11850405
references.citation: Mech Dev. 2002 Jun;114(1-2):51-9
references.pmid: 12175489
references.citation: Curr Opin Genet Dev. 2006 Aug;16(4):426-32
references.pmid: 16806898
references.citation: Dev Biol. 2008 Aug 1;320(1):131-9
references.pmid: 18539270
references.citation: Development. 2002 Jul;129(13):3077-88
references.pmid: 12070084
references.citation: Dev Biol. 2001 Aug 15;236(2):421-35
references.pmid: 11476582
references.citation: Nat Genet. 2005 Apr;37(4):373-81
references.pmid: 15735646
references.citation: Nat Rev Mol Cell Biol. 2001 Nov;2(11):827-37
references.pmid: 11715049
references.citation: Genesis. 2007 Sep;45(9):588-92
references.pmid: 17868088
references.citation: Genes Dev. 1995 Mar 15;9(6):686-99
references.pmid: 7729687
references.citation: Dev Dyn. 2006 May;235(5):1345-57
references.pmid: 16502419
references.citation: Curr Opin Genet Dev. 2007 Aug;17(4):359-66
references.pmid: 17644373
references.citation: Dev Biol. 1997 Aug 15;188(2):235-47
references.pmid: 9268572
references.citation: Development. 2005 Feb;132(4):797-803
references.pmid: 15677727
references.citation: Am J Med Genet A. 2007 Jan 1;143A(1):27-32
references.pmid: 17152067
references.citation: Development. 1998 Jul;125(14):2711-21
references.pmid: 9636085
references.citation: Development. 1997 Oct;124(20):3999-4008
references.pmid: 9374397
references.citation: Dev Biol. 2007 Jul 1;307(1):114-26
references.pmid: 17531968
references.citation: Hum Mol Genet. 2003 Jul 15;12(14):1725-35
references.pmid: 12837695
references.citation: Mech Dev. 1997 Mar;62(2):175-82
references.pmid: 9152009
references.citation: Dev Cell. 2009 Apr;16(4):600-6
references.pmid: 19386268
references.citation: Development. 2005 Sep;132(17):3859-71
references.pmid: 16049111
references.citation: Development. 2006 Jun;133(11):2263-73
references.pmid: 16672333
references.citation: Genes Dev. 2008 Oct 1;22(19):2651-63
references.pmid: 18832070
references.citation: Mech Dev. 2001 Jan;100(1):45-58
references.pmid: 11118883
references.citation: Dev Dyn. 2005 Feb;232(2):345-8
references.pmid: 15637698
references.citation: Development. 2004 Aug;131(16):3885-96
references.pmid: 15253939
references.citation: Int J Dev Biol. 2005;49(4):443-8
references.pmid: 15968591
references.citation: Nat Rev Genet. 2009 Dec;10(12):845-58
references.pmid: 19920852
references.citation: Hum Mol Genet. 1998 Jun;7(6):945-57
references.pmid: 9580658
references.citation: Int J Dev Biol. 2002;46(7):877-81
references.pmid: 12455624
references.citation: Dev Biol. 1997 Feb 1;182(1):42-51
references.pmid: 9073443
references.citation: Nature. 2006 Oct 26;443(7114):985-8
references.pmid: 17066034
references.citation: Mamm Genome. 2004 Jan;15(1):23-34
references.pmid: 14727139
references.citation: PLoS Genet. 2010 Apr 08;6(4):e1000901
references.pmid: 20386744
references.citation: Cell. 1997 Jul 25;90(2):247-55
references.pmid: 9244299
references.citation: Cell. 2004 Jun 25;117(7):927-39
references.pmid: 15210113
references.citation: Dev Dyn. 1995 Nov;204(3):316-22
references.pmid: 8573722
references.citation: Development. 2003 May;130(10):2263-73
references.pmid: 12668638
references.citation: Int J Cancer. 1997 Mar 4;70(5):590-7
references.pmid: 9052761
references.citation: Development. 2004 May;131(10):2339-47
references.pmid: 15102708
references.citation: Neuron. 2002 Aug 29;35(5):877-92
references.pmid: 12372283
references.citation: Hum Mol Genet. 2008 Aug 15;17(16):2417-23
references.pmid: 18463159
references.citation: Dev Cell. 2004 Mar;6(3):423-35
references.pmid: 15030764
references.citation: J Biol Chem. 2007 Sep 14;282(37):27536-27546
references.pmid: 17652084
references.citation: Cell. 2001 Jun 1;105(5):599-612
references.pmid: 11389830
references.citation: Development. 2000 Jun;127(11):2461-70
references.pmid: 10804186