Fig. 6. Impaired hypertrophic differentiation but normal proliferation in coll2a1-Cre, Fosl2^f/f mice. (A,B) In situ hybridization of femoral growth plates of P5, P10 and P23 coll2a1-Cre, Fosl2^f/f mice and littermate controls using type X collagen (A) and type II collagen (B) antisense probes. Arrowheads indicate size of proliferating zone. (C) Ki67-positive cells in femoral growth plates of Fosl2^–/–, coll2a1-Cre, Fosl2^f/f and control mice at P2, P5 and P10. Bars represent mean value±s.e.m.; n=3. (D) Immunohistochemical detection of Ki67 in P23 coll2a1-Cre, Fosl2^f/f mice and P23 coll2a1-Cre, Fosl2^f/+ controls. Pictures were taken at 50x (col X, P10 and P23; col II, P5 and P10) and 100x (col X, P5; col II, P23; Ki67) magnification.