During mammalian development, eyelid growth, fusion and subsequent reopening involve cellular proliferation, shape changes, migration and death. On , Tao et al. report that fibroblast growth factor 10 (FGF10) controls the proliferation and coordinated migration of epithelial cells during eyelid development. The researchers investigate eyelid development in Fgf10-deficient mice,which are born with open instead of shut eyelids. They show, for example, that activin βB and transforming growth factor α, both of which are critical for eyelid development, are downregulated in the leading epithelial edge of the developing mutant eyelid, but are upregulated in explanted cultures of normal eyelid primordia after FGF10 treatment. Overall, their results indicate that FGF10 signalling is required early in eyelid development for cell shape changes and proliferation of the prospective eyelid epithelium,and later for the cellular changes underlying epithelial cell migration during eyelid closure, a process that resembles wound healing.
