Protein extracts from control or Tgif1KO mice (right) were immunoprecipitated using normal IgG, anti-TGIF1 or anti-Twist1 antibody and analyzed by immunoblotting using antibodies to Twist1 or TGIF1 To control for loading, total cell lysates were analyzed by immunoblotting using antibodies to Twist1, TGIF1 or β-Actin. 