Present address: Centro Nacional de Investigaciones Cardiovasculares, Melchor Fernández Almagro, 3, 28029 Madrid, Spain.Email: firstname.lastname@example.org
Digit morphogenesis: Is the tip different?
Article first published online: 27 JUL 2007
Development, Growth & Differentiation
Volume 49, Issue 6, pages 479–491, August 2007
How to Cite
Casanova, J. C. and Sanz-Ezquerro, J. J. (2007), Digit morphogenesis: Is the tip different?. Development, Growth & Differentiation, 49: 479–491. doi: 10.1111/j.1440-169X.2007.00951.x
- Issue published online: 27 JUL 2007
- Article first published online: 27 JUL 2007
- Received 15 March 2007; revised 7 May 2007; accepted 17 May 2007.
- bone morphogenetic protein;
- digit morphogenesis;
- Sonic hedgehog;
Digit formation is the last step in the skeletal patterning of developing limbs. This process involves important aspects such as determination of chondrogenic versus interdigital areas; growth of digital rays with periodic segmentation to form joints and thus phalanges, and finally tip formation. Traditionally it was believed that the properties of digital rays were fixed at earlier stages, but recently a surprising plasticity of digit primordia at the time of condensation has been demonstrated. This implies the presence of local interactions that are able to modulate the particular programs that make a given digit, but we don't fully understand how they operate. An involvement of signaling from the interdigital spaces and from the apical ectodermal ridge has been proposed. Another interesting question is the formation of the last limb structure, digit tips, which may involve a specific molecular and cellular program. Indeed, the expression of several developmentally important genes is restricted to digit tips at late stages of limb development. Understanding the molecular and cellular interactions that lead to digit morphogenesis has important implications not only in the context of embryonic development (for example, how early cues received by cells are translated into anatomy or what are the mechanisms that control the cease of activity of signaling regions) but also in terms of limb diversification during evolution.