Regulatory roles of epithelial-mesenchymal interaction (EMI) during early and androgen dependent external genitalia development.

摘要: Development of external genitalia (ExG) has been a topic long mystery in the field organogenesis research. Early stage male and female mouse embryos develop common genital tubercle (GT) perineum whose outgrowth extends distally from posterior cloacal regions. Concomitant with GT outgrowth, cloaca is divided into urogenital sinus anorectum by urorectal septum (URS) internally. The associated formation endodermal epithelial urethral plate (UP) attached to ventral epidermis GT. Such developmental phase observed until around embryonic day 15.5 (E15.5) morphologically embryogenesis. Various growth factor genes, such as Fibroblast (Fgf) Wnt genes are expressed function during formation. Since discovery key signals several regulatory molecules, elucidation their functions achieved utilizing models, conditional gene knockout vitro culture. Analyses on phenotypes models have revealed that families play fundamental roles ExG based epithelial-mesenchymal interaction (EMI). More recently, EMI between developing epithelia its bilateral mesenchyme later stages also reported subsequent androgen-dependent male-type embryo. Mafb, belonging AP-1 family androgen-responsive mesenchymal gene, identified starts be E14.5 when masculinization urethra initiated. Mesenchymal cell condensation migration, which regulated nonmuscle myosin, shown essential process for masculinization. Hence, studies at various important not only early but urethra. In this review, dynamic mode both late phases development discussed.