A sticky problem for digits

Abstract

Development Cell death during development is important for finger and toe separation, but additional developmental programs are also required for proper digitation. Kashgari et al. show that, after the death of the mesenchyme cells from which digits form, a structure called the interdigital epithelial tongue invaginates into the mesenchyme, allowing the digits to bifurcate. In normal digit formation, the outermost layer of the embryonic epidermis, the periderm, prevents digit adhesion. However, after the digits separate, they sometimes fuse back together, causing a condition known as syndactyly. This occurs when the transcription factor grainyhead-like 3 (GRHL3) is lacking, which results in the usually nonsticky periderm becoming sticky. Dev. Cell. 52 , 764 (2020).