The Mohawk homeobox transcription factor regulates the differentiation of tendons and volar plates

We detected Venus signals in forelimb tendons, pulleys, and volar plates (VPs) in P21 mice. In-depth histological analysis showed that compared to the wild-type mice, the Mkx knockout mice showed significant hypoplasia in the flexor digitorum profundus tendons from E18.5. The VPs and pulleys appeared normal until P0; however, by P14, they became increasingly thicker in Mkx-null mice compared to wild-type mice. The fiber alignment was particularly disrupted in VPs of Mkx-null mice. Conclusions These results suggest that Mkx is an important regulator of the differentiation of VPs and pulleys, as well as of tendon differentiation.