title: A novel function for Egr4 in posterior hindbrain development.
abstract: Segmentation of the vertebrate hindbrain is an evolutionarily conserved process. Here, we identify the transcription factor early growth response 4 (egr4) as a novel regulator of posterior hindbrain development in Xenopus. egr4 is specifically and transiently expressed in rhombomeres 5 and 6 (r5/r6), and Egr4 knockdown causes a loss of mafb/kreisler and krox20/egr2 expression in r5/r6 and r5, respectively. This phenotype can be fully rescued by injection of frog or mouse Egr4 mRNA. Moreover Egr4-depleted embryos exhibit a specific loss of the neural crest stream adjacent to r5, and have inner ear defects. While the homeodomain protein vHnf1/Hnf1b directly activates Mafb and Krox20 expression in the mouse hindbrain to specify r5, we show that in Xenopus this process is indirect through the activation of Egr4. We provide evidence that rearrangements in the regulatory sequences around egr4 and mafb genes may account for this difference.
authors.affiliation: 1] Department of Basic Science &Craniofacial Biology, College of Dentistry, New York University, New York, USA [2] Permanent address: Ministry of Food and Drug Safety, 187 Osongsaengmyeong2(i)-ro, Osong-eup, Cheongwon-gun, Chungcheongbuk-do 363-700, Republic of Korea.
authors.forename: Chang-Joon
authors.initials: CJ
authors.lastname: Bae
authors.affiliation: Department of Basic Science &Craniofacial Biology, College of Dentistry, New York University, New York, USA.
authors.forename: Juhee
authors.initials: J
authors.lastname: Jeong
authors.affiliation: Department of Basic Science &Craniofacial Biology, College of Dentistry, New York University, New York, USA.
authors.forename: Jean-Pierre
authors.initials: JP
authors.lastname: Saint-Jeannet
mesh_terms: D000818:Animals; D001483:Base Sequence; D007758:Ear, Inner / Q000196:embryology / Q000473:pathology; D004625:Embryo, Nonmammalian / Q000378:metabolism; D018507:Gene Expression Regulation, Developmental; D017403:In Situ Hybridization; D051379:Mice; D008954:Models, Biological; D008969:Molecular Sequence Data; D009432:Neural Crest / Q000196:embryology / Q000473:pathology; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D012249:Rhombencephalon / Q000196:embryology* / Q000378:metabolism*; D013997:Time Factors; D014157:Transcription Factors / Q000235:genetics* / Q000378:metabolism; D014981:Xenopus / Q000196:embryology* / Q000235:genetics*; D029867:Xenopus Proteins / Q000235:genetics* / Q000378:metabolism
chemical_list: C000602131:Egr4 protein, Xenopus; D012333:RNA, Messenger; D014157:Transcription Factors; D029867:Xenopus Proteins