Figure 1.

BMP1 CUB domains dorsalize ventral half-embryos independently of Chordin. (A) Diagram of the generic Tolloid family metalloproteinase primary structure, BMP1, and the BMP1 CUB1/2/3 construct. (B) Xenopus laevis embryos were bisected into dorsal and ventral halves at late blastula/early gastrula stage using a surgical blade. (C,C′) Bisected wild-type embryos result in the dorsal half-embryo that self-regulates into a relatively normal embryo and a ventral belly piece lacking all neural structures marked by the pan-neural marker Sox2. (D,D′) BMP1 CUB1/2/3 mRNA (1 ng per embryo injected at the two-cell stage) dorsalizes the ventral half-embryo (n = 86, 96% positive for Sox2). (E,E′) Microinjection of morpholino oligos against Chordin (ChdMO) reduced neural structures in the dorsal half. (F,F′) The dorsalizing effect of BMP1 CUB1/2/3 mRNA in the ventral half-embryo is not affected by Chordin depletion (n = 82, 95% positive for Sox2).