Fig. 1. Inhibition of SHP-2 activity results in loss of MHC expression. Tissue explants show identical cardiac expression profiles as intact Xenopus embryos. (A) Whole-mount antibody staining of cardiac differentiation with tropomyosin (Tmy; red) or myosin heavy chain (MHC; red) antibodies as indicated, in whole embryos and cardiac explants at stages 22 (neurula), 29 (tailbud) and 37 (tadpole). (B) Whole-mount in situ hybridization for early heart markers Tbx5, Tbx20, Nkx2.5 in whole embryos and cardiac explants at stage 22, 29 and 37, as indicated. (C) MHC expression is dependent on SHP-2 activity. Whole-mount antibody staining for MHC (red) in cardiac explants taken from uninjected (control) embryos or embryos injected with Shp-2 N308D and treated with either buffer or DMSO carrier as controls or with NSC-87877 as indicated. BF, bright field.