Time course of expression of Br-cadherin. (a) Br-cadherin is not present during embryonic development and in newborn mice. Protein samples of C57BL/6J mice from adult mouse forebrain and different developmental stages were reacted with anti-Br-cad-EC1. Lanes: 1, adult forebrain; 2, 6-day-old embryos; 3, embryos from a 13-day gestation, trunk segment; 4, embryos from 13-day gestation, head segment; 5, newborns, trunk segment; 7, newborns, head segment. Six-day-old embryos were too small to dissect. (b) Br-cadherin initiates its expression at day 1 postnatally and gradually increases during the 1st week of life. Proteins from forebrains, brainstems, and cerebella were obtained from C57BL/6J mice at different time points postnatally and were immunoblotted with anti-Br-cad-EC1. All loadings were equalized by Comassie blue staining. Size markers are indicated in kilodaltons. P1–P7, postnatal days 1–7; 2wk, 2-week-old embryos.