title: Gata6-Dependent GLI3 Repressor Function is Essential in Anterior Limb Progenitor Cells for Proper Limb Development.
abstract: Gli3 is a major regulator of Hedgehog signaling during limb development. In the anterior mesenchyme, GLI3 is proteolytically processed into GLI3R, a truncated repressor form that inhibits Hedgehog signaling. Although numerous studies have identified mechanisms that regulate Gli3 function in vitro, it is not completely understood how Gli3 function is regulated in vivo. In this study, we show a novel mechanism of regulation of GLI3R activities in limb buds by Gata6, a member of the GATA transcription factor family. We show that conditional inactivation of Gata6 prior to limb outgrowth by the Tcre deleter causes preaxial polydactyly, the formation of an anterior extra digit, in hindlimbs. A recent study suggested that Gata6 represses Shh transcription in hindlimb buds. However, we found that ectopic Hedgehog signaling precedes ectopic Shh expression. In conjunction, we observed Gata6 and Gli3 genetically interact, and compound heterozygous mutants develop preaxial polydactyly without ectopic Shh expression, indicating an additional prior mechanism to prevent polydactyly. These results support the idea that Gata6 possesses dual roles during limb development: enhancement of Gli3 repressor function to repress Hedgehog signaling in the anterior limb bud, and negative regulation of Shh expression. Our in vitro and in vivo studies identified that GATA6 physically interacts with GLI3R to facilitate nuclear localization of GLI3R and repressor activities of GLI3R. Both the genetic and biochemical data elucidates a novel mechanism by Gata6 to regulate GLI3R activities in the anterior limb progenitor cells to prevent polydactyly and attain proper development of the mammalian autopod.
authors.affiliation: Department of Genetics, Cell Biology and Development, University of Minnesota, Minneapolis, Minnesota, United States of America.|Stem Cell Institute, University of Minnesota, Minneapolis, Minnesota, United States of America.
authors.forename: Shinichi
authors.initials: S
authors.lastname: Hayashi
authors.affiliation: Department of Genetics, Cell Biology and Development, University of Minnesota, Minneapolis, Minnesota, United States of America.|Stem Cell Institute, University of Minnesota, Minneapolis, Minnesota, United States of America.
authors.forename: Ryutaro
authors.initials: R
authors.lastname: Akiyama
authors.affiliation: Department of Genetics, Cell Biology and Development, University of Minnesota, Minneapolis, Minnesota, United States of America.
authors.forename: Julia
authors.initials: J
authors.lastname: Wong
authors.affiliation: Department of Genetics, Cell Biology and Development, University of Minnesota, Minneapolis, Minnesota, United States of America.|Stem Cell Institute, University of Minnesota, Minneapolis, Minnesota, United States of America.
authors.forename: Naoyuki
authors.initials: N
authors.lastname: Tahara
authors.affiliation: Department of Genetics, Cell Biology and Development, University of Minnesota, Minneapolis, Minnesota, United States of America.|Stem Cell Institute, University of Minnesota, Minneapolis, Minnesota, United States of America.
authors.forename: Hiroko
authors.initials: H
authors.lastname: Kawakami
authors.affiliation: Department of Genetics, Cell Biology and Development, University of Minnesota, Minneapolis, Minnesota, United States of America.|Stem Cell Institute, University of Minnesota, Minneapolis, Minnesota, United States of America.
authors.forename: Yasuhiko
authors.initials: Y
authors.lastname: Kawakami
mesh_terms: D000818:Animals; D019521:Body Patterning / Q000235:genetics; D002460:Cell Line; D005121:Extremities / Q000254:growth & development*; D050993:GATA6 Transcription Factor / Q000235:genetics*; D018507:Gene Expression Regulation, Developmental / Q000235:genetics*; D057809:HEK293 Cells; D053823:Hedgehog Proteins / Q000235:genetics; D006801:Humans; D051741:Kruppel-Like Transcription Factors / Q000235:genetics*; D018878:Limb Buds / Q000254:growth & development / Q000378:metabolism; D051379:Mice; D041681:NIH 3T3 Cells; D009419:Nerve Tissue Proteins / Q000235:genetics*; D038081:Organogenesis / Q000235:genetics*; D017689:Polydactyly / Q000235:genetics; D015398:Signal Transduction / Q000235:genetics; D013234:Stem Cells / Q000378:metabolism*; D014157:Transcription Factors / Q000235:genetics; D014158:Transcription, Genetic / Q000235:genetics; D000074290:Zinc Finger Protein Gli3
chemical_list: D050993:GATA6 Transcription Factor; C494759:GATA6 protein, human; C065683:GLI3 protein, human; D053823:Hedgehog Proteins; D051741:Kruppel-Like Transcription Factors; D009419:Nerve Tissue Proteins; D014157:Transcription Factors; D000074290:Zinc Finger Protein Gli3