Cecília G. Magalhães

Traditionally, the surface ectoderm has been described as a simple cuboidal epithelium. Here we will describe in detail the constant emission of protrusions in periplacodal cells as they move towards the invagination point of the lens placode. We compared in detail the dynamics of protrusions in the surface cells surrounding the lens placode and other regions of the head. Regions where there are no significant changes in tissue shape displayed longer and more stable protrusions than periplacodal cells. Finally, we observed intercellular trafficking of membrane puncta in the protrusions of both chick and mouse embryos in all the regions analyzed. The existence of these protrusions suggests that the surface ectoderm is more dynamic than what is believed. We further propose that these protrusions could contribute to intercellular communication.