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

J Orthop Sci. 2014 Jan;19(1):172-80. doi: 10.1007/s00776-013-0485-z. Epub 2013 Oct 29.


Background: Mohawk (Mkx) is a homeodomain-containing transcription factor that is expressed in various mesoderm-derived tissues, particularly in developing tendons. In this study, we investigate the exact expression pattern and functions of Mkx in forelimbs.

Methods: We analyzed the forelimbs of Mkx knockout mice [from embryonic day (E) 18.5 to postnatal day (P) 28 weeks] by using knocked-in Venus signals, Masson trichrome staining, and hematoxylin and eosin (H&E) staining.

Results: 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.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Animals, Newborn
  • Cell Differentiation
  • Disease Models, Animal
  • Forelimb
  • Gene Expression Regulation, Developmental*
  • Gene Knockout Techniques
  • Homeodomain Proteins / biosynthesis
  • Homeodomain Proteins / genetics*
  • Immunohistochemistry
  • Mice
  • Mice, Knockout
  • Morphogenesis / genetics*
  • Palmar Plate / growth & development*
  • Palmar Plate / pathology
  • Phenotype
  • RNA, Messenger / genetics*
  • Tendons / growth & development*
  • Tendons / pathology
  • Transcription, Genetic


  • Homeodomain Proteins
  • RNA, Messenger
  • mohawk protein, mouse