Refining the timeline of conjunctival papillae induction in the chick scleral ossicle system

Abstract

The conjunctival papillae, epithelial thickenings on the surface of the eye, are required for the induction of the underlying neural crest‐derived, intramembranous bones (the scleral ossicles). However, very little research has been conducted in the past 50 years on the mechanisms underlying the induction and patterning of these papillae. In order to further investigate this question, single papillae were surgically removed using fine tungsten needles at various time points during their development and the embryos were cultured for 1 to 5 days post‐surgery. Our results show that papilla removal had no effect on the patterning of the adjacent conjunctival papillae, and surprisingly, a normal patterned scleral ossicle develops under the site of surgery. This research demonstrates that the developmental timeline of the conjunctival papillae is much more flexible than previously noted. Our results also suggest that there is some compensatory mechanism taking place at the epithelial level for the induction of a complete ring of scleral ossicles. Thus, this study provides new insights into the mechanisms patterning the epithelium involved in epithelial‐mesenchymal induction of intramembranous bones. This research was primarily funded by the Natural Sciences and Engineering Research Council of Canada.Grant Funding Source: Natural Sciences and Engineering Research Council of Canada