FIG. 10.

Expression of Tppp3 mRNA marks the tendon sheath and provides an outline of the tendon circumference for measurements of tendon size and tendon cell numbers. (A and B) In situ hybridization with a Tppp3 probe on transverse sections of limbs from wild-type (A) and Mkx^−/− mutant (B) embryos. Tppp3 mRNA signals were detected as a blue color. The arrows point to the flexor profundus tendon tissues. (C and D) DAPI staining (shown in red) following in situ hybridization detection of Tppp3 revealed more densely packed tendon cells in the flexor profundus tendon in the Mkx^−/− mutant (D) than in the wild-type littermate (C).