Figure 2.

Bone morphogenetic protein (BMP) ligands and receptors are not expressed in first digits of fore‐ and hind limbs after conditional knockout (cKO) of Acvr1. Whole‐mount in situ hybridization (WISH) of forelimb (FL) and hind limb (HL) was performed in WT mice and Prx1‐Cre‐Acvr1(fl/fl) mice (cKO) in developmental stages E11.5, E12.5 and E13.5. Magnifications of digit 1 are provided for E13.5. Expression of BMP ligands Bmp2, Bmp4, BMP6, and Bmp7 and expression of BMP type I receptors Bmpr1a and Bmpr1b were not altered by Acvr1 cKO, except for digit 1. Interestingly, at E13.5, in digit 1 there was no expression of Bmp ligands or receptors seen in Acvr1 cKO mice. These changes are marked with arrows