Biophysical regulation of early limb bud morphogenesis

- Morphogenesis of the early limb bud involves oriented mesodermal and ectodermal cell behaviours.
- Increased mesenchymal cohesion might contribute to phase separation of the initial limb field from the flank.
- The surface ectoderm might help to maintain a narrow dorsoventral axis by moulding the underlying mesoderm at initial stages.
- Other physical properties such as endogenous electrical fields might promote oriented cell behaviours.
- Quantitative biophysical data combined with modelling will likely advance this field.

The physical basis of morphogenesis is a fascinating concern that has been a longstanding interest of developmental biologists. In this review, I attempt to incorporate earlier and recent biophysical concepts and data to explain basic features of early limb bud morphogenesis. In particular, I discuss the influence of mesenchymal cohesion and physical properties that might contribute to phase separation of the bud from the lateral plate, the possibility that the early dorsoventral limb bud axis is moulded by the surface ectoderm, and endogenous electric fields that might contribute to oriented cell movements which generate the early limb bud. A combination of quantitative biophysical experimentation and modelling will likely advance this field.