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. Author manuscript; available in PMC: 2012 Apr 1.
Published in final edited form as: Dev Biol. 2011 Jan 22;352(1):83–91. doi: 10.1016/j.ydbio.2011.01.018

Fig. 3.

Fig. 3

Joint defects in Osr1f/fOsr2−/−Prrx1-cre double mutant mice. (A–D) Alizarin red and alcian blue stained skeleton preparations of E17.5 limbs of Osr1f/fPrrx1-cre (A, C) and Osr1f/fOsr2−/−Prrx1-cre mutant (B, D) embryos. The double mutants showed delay in mineralization of phalanges (arrowheads in B and D), fusion of the elbow joints (arrow in B), and fusion between tibia and fibula in both the distal (red arrow in D) and proximal (black arrow in D) regions. (E–H) High magnification views of proximal and distal regions of the tibia and fibula in control (E, G) and mutant (F, H) hindlimbs. Arrows point to the aberrant fusion between these two elements in the mutants and corresponding regions in the control littermates. (I–L) Osr1f/fPrrx1-cre embryo had normal synovial joint development in the elbow (arrows in I and K) while in Osr1f/fOsr2−/−Prrx1-cre mutant embryo humerus is fused to radius (arrow in J) and to ulna (arrow in H). (M, N) Carpal elements are demarcated clearly by the synovial joints in E17.5 Osr1f/fPrrx1-cre littermate (M), while they are fused together in the E17.5 Osr1f/fOsr2−/−Prrx1-cre mutant embryo (N). (O, P) Tarsal elements are separated by synovial joints in the E17.5 Osr1f/fPrrx1-cre embryo (O), while the intermediate cuneiform and lateral cuneiform were fused respectively with the navicular bone in the Osr1f/fOsr2−/−Prrx1-cre mutant (P). In addition, the cuboidal and calcaneus bones were also fused in Osr1f/fOsr2−/−Prrx1-cre mutant embryo (arrowhead in P). (Q–T) Histological sections through the interphalangeal (Q, R) and metacarpophalangeal (S, T) joint regions in the E17.5 forelimbs of control (Q, S) and Osr1f/fOsr2−/−Prrx1-cre mutant (R, T) embryos. Arrowheads in Q and R point to corresponding interphalangeal joints, whereas arrows in S and T point to the corresponding metacarpophalangeal joints in the control and mutant littermates. cal, calcaneus bone; cub, cuboid bone; h, humerus; i.c., intermediate cuneiform; l.c., lateral cuneiform; nc, navicular bone; t, talus bone; r, radius; u, ulna.