title: Interferon regulatory factor 6 promotes differentiation of the periderm by activating expression of Grainyhead-like 3.
abstract: IFN regulatory factor 6 (IRF6) is a transcription factor that, in mammals, is required for the differentiation of skin, breast epithelium, and oral epithelium. However, the transcriptional targets that mediate these effects are currently unknown. In zebrafish and frog embryos, Irf6 is necessary for differentiation of the embryonic superficial epithelium, or periderm. Here we use microarrays to identify genes that are expressed in the zebrafish periderm and whose expression is inhibited by a dominant-negative variant of Irf6 (dnIrf6). These methods identify Grainyhead-like 3 (Grhl3), an ancient regulator of the epidermal permeability barrier, as acting downstream of Irf6. In human keratinocytes, IRF6 binds conserved elements near the GRHL3 [corrected] promoter. We show that one of these elements has enhancer activity in human keratinocytes and zebrafish periderm, suggesting that Irf6 directly stimulates Grhl3 expression in these tissues. Simultaneous inhibition of grhl1 and grhl3 disrupts periderm differentiation in zebrafish, and, intriguingly, forced grhl3 expression restores periderm markers in both zebrafish injected with dnIrf6 and frog embryos depleted of Irf6. Finally, in Irf6-deficient mouse embryos, Grhl3 expression in the periderm and oral epithelium is virtually absent. These results indicate that Grhl3 is a key effector of Irf6 in periderm differentiation.
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, University of Iowa, Iowa City, IA, USA.
authors.forename: Gabriel
authors.initials: G
authors.lastname: de la Garza
authors.forename: Jack Robert
authors.initials: JR
authors.lastname: Schleiffarth
authors.forename: Martine
authors.initials: M
authors.lastname: Dunnwald
authors.forename: Anuj
authors.initials: A
authors.lastname: Mankad
authors.forename: Jason L
authors.initials: JL
authors.lastname: Weirather
authors.forename: Gregory
authors.initials: G
authors.lastname: Bonde
authors.forename: Stephen
authors.initials: S
authors.lastname: Butcher
authors.forename: Tamer A
authors.initials: TA
authors.lastname: Mansour
authors.forename: Youssef A
authors.initials: YA
authors.lastname: Kousa
authors.forename: Cindy F
authors.initials: CF
authors.lastname: Fukazawa
authors.forename: Douglas W
authors.initials: DW
authors.lastname: Houston
authors.forename: J Robert
authors.initials: JR
authors.lastname: Manak
authors.forename: Brian C
authors.initials: BC
authors.lastname: Schutte
authors.forename: Daniel S
authors.initials: DS
authors.lastname: Wagner
authors.forename: Robert A
authors.initials: RA
authors.lastname: Cornell
mesh_terms: D000818:Animals; D004268:DNA-Binding Proteins / Q000096:biosynthesis* / Q000235:genetics; D004742:Enhancer Elements, Genetic; D018507:Gene Expression Regulation, Developmental / Q000235:genetics; D020868:Gene Silencing; D005855:Germ Layers / Q000196:embryology / Q000254:growth & development* / Q000378:metabolism*; D006801:Humans; D050835:Interferon Regulatory Factors / Q000378:metabolism*; D015603:Keratinocytes / Q000378:metabolism; D051379:Mice; D011401:Promoter Regions, Genetic; D014157:Transcription Factors / Q000096:biosynthesis* / Q000235:genetics; D015027:Zebrafish / Q000196:embryology / Q000235:genetics; D029961:Zebrafish Proteins / Q000096:biosynthesis* / Q000235:genetics / Q000378:metabolism*
chemical_list: D004268:DNA-Binding Proteins; C473143:GRHL3 protein, human; C579350:GRHL3 protein, zebrafish; C551737:Grhl1 protein, zebrafish; C499942:Grhl3 protein, mouse; C109803:IRF6 protein, human; C504917:IRF6 protein, zebrafish; D050835:Interferon Regulatory Factors; D014157:Transcription Factors; D029961:Zebrafish Proteins