title: Expression patterns of Fgf8 and Shh in the developing external genitalia of Suncus murinus.
abstract: Reciprocal epithelial-mesenchymal interactions and several signalling pathways regulate the development of the genital tubercle (GT), an embryonic primordium of external genitalia. The morphology of the adult male external genitalia of the Asian house musk shrew Suncus murinus (hereafter, laboratory name: suncus) belonging to the order Eulipotyphla (the former order Insectivora or Soricomorpha) differs from those of mice and humans. However, the developmental process of the suncus GT and its regulatory genes are unknown. In the present study, we explored the morphological changes and gene expression patterns during the development of the suncus GT. Morphological observations suggested the presence of common (during the initial outgrowth) and species-specific (during the sexual differentiation of GT) developmental processes of the suncus GT. In gene expression analysis, fibroblast growth factor 8 (Fgf8) and sonic hedgehog (Shh), an indicator and regulator of GT development in mice respectively, were found to be expressed in the cloacal epithelium and the developing urethral epithelium of the suncus GT. This pattern of expression specifically in GT epithelium is similar to that observed in the developing mouse GT. Our results indicate that the mechanism of GT formation regulated by the FGF and SHH signalling pathways is widely conserved in mammals.
authors.affiliation: Department of Molecular Endocrinology miyado-m@ncchd.go.jp.
authors.forename: Mami
authors.initials: M
authors.lastname: Miyado
authors.affiliation: Department of Reproductive BiologyNational Research Institute for Child Health and Development, Setagaya, Tokyo, Japan.
authors.forename: Kenji
authors.initials: K
authors.lastname: Miyado
authors.affiliation: Department of Reproductive BiologyNational Research Institute for Child Health and Development, Setagaya, Tokyo, Japan.
authors.forename: Akihiro
authors.initials: A
authors.lastname: Nakamura
authors.affiliation: Department of Molecular Endocrinology.
authors.forename: Maki
authors.initials: M
authors.lastname: Fukami
authors.affiliation: Department of Developmental GeneticsInstitute of Advanced Medicine, Wakayama Medical University, Wakayama, Japan.
authors.forename: Gen
authors.initials: G
authors.lastname: Yamada
authors.affiliation: Laboratory of Animal Management and ResourcesDepartment of Zoology, Okayama University of Science, Okayama, Japan.
authors.forename: Sen-Ichi
authors.initials: SI
authors.lastname: Oda
mesh_terms: D000818:Animals; D002988:Cloaca / Q000196:embryology / Q000378:metabolism; D004848:Epithelium / Q000196:embryology / Q000378:metabolism; D005260:Female; D051524:Fibroblast Growth Factor 8 / Q000235:genetics* / Q000502:physiology; D015870:Gene Expression; D020869:Gene Expression Profiling; D005835:Genitalia / Q000196:embryology / Q000254:growth & development* / Q000378:metabolism*; D005836:Genitalia, Female / Q000196:embryology / Q000254:growth & development / Q000378:metabolism; D005837:Genitalia, Male / Q000196:embryology / Q000254:growth & development / Q000378:metabolism; D053823:Hedgehog Proteins / Q000235:genetics* / Q000502:physiology; D006801:Humans; D008297:Male; D051379:Mice; D008855:Microscopy, Electron, Scanning; D012727:Sex Characteristics; D012788:Shrews / Q000254:growth & development*; D015398:Signal Transduction / Q000502:physiology; D014521:Urethra / Q000196:embryology / Q000378:metabolism
chemical_list: D053823:Hedgehog Proteins; C465570:Shh protein, mouse; D051524:Fibroblast Growth Factor 8