The Chick Scleral Ossicle System: Unravelling the Induction and Patterning of the Conjunctival Papillae

Abstract

The conjunctival papillae (CP) are epithelial thickenings on the surface of the eye and are required for the induction of the underlying neural crest-derived, intramembranous scleral ossicles. However, little research has been conducted on the mechanisms underlying the induction and patterning of the CP. In order to investigate their development, we used both surgical manipulations and a candidate gene approach. Our results show that a single CP, when removed, is able to regenerate and induce the underlying condensation, demonstrating that the developmental window for CP induction is wider than was previously reported. We are also investigating a list of candidate genes to characterize their involvement in the development of the CP, including such genes as gsc, eya1, dlx5, and wnt1. This is the first investigation into the molecular factors controlling the induction and patterning of these CP. This study will further our understanding of the permissive role played by the epithelium in controlling the patterning of intramembranous bone. Additionally, as the CP share many characteristics with non-neurogenic placodes, understanding their development may provide further insights into the factors that may be controlling the development of other non-neurogenic placodes. This research was primarily funded by the Natural Sciences and Engineering Research Council of Canada and the Killam Trusts.