Fig. 7

DNA binding is necessary for Tbx2 repressor activity. a RT-PCR analysis of animal cap explants injected with Tbx2 DNA binding mutant construct. Embryos were injected with 1 ng myc-tbx2R-A or myc-tbx2 at the two-cell stage; animal caps were explanted at stage 8.5 and incubated in Activin (2.5 ng/ml) where indicated until late gastrula stages. b Smad1 physically associates with Tbx2R-A. Embryos were injected at the two-cell stage with 1 ng of RNA synthesized from Myc-Tbx2R-A. Pull-down of native Smad1 from injected embryos leads to co-immunoprecipitation of exogenous Myc-Tbx2R-A. Normal rabbit IgG antibodies was used in parallel studies as a negative control. c Smad2 physically associates with Myc-Tbx2R-A. Embryos were injected at the two-cell stage with 1 ng myc-tbx2R-A and 1 ng flag-smad2. Pull-down of Flag-Smad2 from injected embryos leads to co-immunoprecipitation of exogenous Myc-Tbx2R-A. Normal rabbit IgG antibodies were used in parallel studies as a negative control