Fig. 9. p15Ink4b is ectopically expressed in the perichondrium, on forming cartilage, and in the ventricular zone of the lateral ventricle in Zeb1-null mice. (A,C) Immunostaining for p15Ink4b on forming cartilage. (B,D) Overlay of the immunostaining in A and C with a Nomarski image. (E,F) Immunostaining for p15Ink4b in the ventricular zone of the lateral ventricle. (G,H) Immunostaining for BrdU and p15Ink4b, respectively, in the ventricular zone of the lateral ventricle. (I) Overlay of G and H. Immunostaining of E15.5 embryos is shown. Scale bars: 50 µm.