title: HOXA13 directly regulates EphA6 and EphA7 expression in the genital tubercle vascular endothelia.
abstract: Hypospadias, a common defect affecting the growth and closure of the external genitalia, is often accompanied by gross enlargements of the genital tubercle (GT) vasculature. Because Hoxa13 homozygous mutant mice also exhibit hypospadias and GT vessel expansion, we examined whether genes playing a role in angiogenesis exhibit reduced expression in the GT. From this analysis, reductions in EphA6 and EphA7 were detected. Characterization of EphA6 and EphA7 expression in the GT confirmed colocalization with HOXA13 in the GT vascular endothelia. Analysis of the EphA6 and EphA7 promoter regions revealed a series of highly conserved cis-regulatory elements bound by HOXA13 with high affinity. GT chromatin immunoprecipitation confirmed that HOXA13 binds these gene-regulatory elements in vivo. In vitro, HOXA13 activates gene expression through the EphA6 and EphA7 gene-regulatory elements. Together these findings indicate that HOXA13 directly regulates EphA6 and EphA7 in the developing GT and identifies the GT vascular endothelia as a novel site for HOXA13-dependent expression of EphA6 and EphA7.
authors.affiliation: Department of Molecular and Medical Genetics, Oregon Health and Science University, Portland, Oregon.
authors.forename: Carley A
authors.initials: CA
authors.lastname: Shaut
authors.forename: Chie
authors.initials: C
authors.lastname: Saneyoshi
authors.forename: Emily A
authors.initials: EA
authors.lastname: Morgan
authors.forename: Wendy M
authors.initials: WM
authors.lastname: Knosp
authors.forename: Diane R
authors.initials: DR
authors.lastname: Sexton
authors.forename: H Scott
authors.initials: HS
authors.lastname: Stadler
mesh_terms: D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D002478:Cells, Cultured; D004730:Endothelium, Vascular / Q000196:embryology* / Q000378:metabolism; D018507:Gene Expression Regulation, Developmental; D005835:Genitalia / Q000098:blood supply* / Q000196:embryology* / Q000378:metabolism; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D018398:Homeodomain Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D051379:Mice; D008817:Mice, Mutant Strains; D008969:Molecular Sequence Data; D011401:Promoter Regions, Genetic; D036124:Receptor, EphA6 / Q000235:genetics* / Q000378:metabolism; D036141:Receptor, EphA7 / Q000235:genetics* / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D012689:Sequence Homology, Nucleic Acid; D014162:Transfection
chemical_list: D018398:Homeodomain Proteins; D011993:Recombinant Fusion Proteins; C099959:homeobox protein HOXA13; D049452:Green Fluorescent Proteins; D036124:Receptor, EphA6; D036141:Receptor, EphA7