BRE-gal reporter activity in the mammary buds and vibrissal follicles of an E13.5 mouse embryo.

A wholemount X-gal stained BRE-gal mouse embryo at E13.5 is shown in a right, lateral view (A). The upper, right dashed box in (A) indicates the area that is magnified in (B1), and a transverse section of a vibrissal follicle is shown in (B2). The lower, left dashed box in (A) indicates the area that is magnified in (C1), and a transverse section of a mammary bud is shown in (C2). Sections are 12 µm thickness. Abbreviations: cms, condensing mesenchyme; fl, forelimb bud; hl, hindlimb bud; mb, mammary buds; mb2, second mammary bud on right side; mb3, third mammary bud on right side; ms, mesenchyme; s, somites; se, surface ectoderm; vf, vibrissal follicles. Scalebar 1 mm.