Fig. 1. Kif3a-deficient cranial bases and synchondroses are abnormal. (A,B,H,I) Skulls from P7 control (Kif3a^fl/fl; A,B) and Kif3a-deficient (Kif3a^fl/fl;Col2-Cre; H,I) mice were analyzed by micro-computed tomography (µCT) and are shown by birds-eye view at low (A,H) and high (B,I) magnification. The location of intrasphenoidal (is), spheno-occipital (so) and intra-occipital (io) synchondroses is indicated in controls (B); arrows point to defects in mutant specimens (I). (C-E,J-L) Parasagittal hematoxylin and Eosin (H&E)-stained sections of control (C-E) and Kif3a-deficient (J-L) cranial bases at P0, P7 and P15 displaying is and so synchondroses as well as intervening endochondral bone. Notice that the histology and organization of mutant synchondroses are markedly abnormal compared with controls, and that the distance between the synchondroses is also reduced (indicated by double-headed arrow). Arrowheads indicate ectopic bone formation. (F,G,M,N) Immunolocalization of acetylated -tubulin in primary cilia (arrowheads) in P0 control (F,G) and Kif3a-deficient (M,N) synchondrosis growth plate and associated perichondrium. Scale bars: 5 mm in H for A,H; 2 mm in I for B,I; 300 µm in J for C-E and J-L; 100 µm in M for F,M; and 35 µm in N for G,N. is, intrasphenoidal; io, intra-occipital; P, postnatal day; so, spheno-occipital.