Fig. 4.
Mice expressing a dominant active BMPR1A transgene display precocious hair follicle differentiation. Bitransgenic mice harboring a Dox-regulatable, superactive BMPR1A (dTg), and noninducible CON mice were treated with Dox at P19, after shaving the lower back skin areas (brackets). Analyses of mice were performed at P35, following a 4-h pulse with BrdU. (A) Transgene schematics. (B) Phenotypic abnormalities in the regrowth of the hair coat of dTgDox-treated mice. (C–I) P35 skin sections subjected to either H&E staining or immunofluorescence with the antibodies indicated. Color-coding is according to the fluorescent tag of the secondary antibodies. AE15 recognizes trichohyalin, an IRS marker. Note that following BMPR1A superactivation, dTgDox hair follicles develop cysts of terminally differentiated cells located just below the bulge (Bu, bracket). Dotted lines demarcate dermo–epidermal boundaries. Mx, matrix cells. Boxed areas are magnified in Insets.