Fig. 2. Mutation of Zeb1 leads to ectopic expression of E-cadherin, loss of vimentin, and defective proliferation in the perichondrial region of forming cartilage. (A) Immunostaining showing expression of Zeb1 in the perichondrium. (B) Immunostaining for vimentin in the perichondrium. (C) E-cadherin immunostaining is seen in the skin (arrow) but not in underlying mesenchymal cells. (D) Immunostaining for BrdU incorporation into the perichondrium. (E,F) Double immunolabeling for Zeb1 and BrdU in the perichondrium. (G) Overlay of E and F. (H) Diminished immunostaining for vimentin in the perichondrium of Zeb1-null mice. (I) Ectopic immunostaining of E-cadherin in the perichondrium of Zeb1-null mice. Arrow indicates skin. (J) Loss of BrdU immunostaining in the perichondrium of Zeb1-null mice. Sections of mice at E15.5 are shown. C, cartilage. Scale bars: 50 µm.