Investigating whether the FGF pathways are involved in scleral ossicle development

Abstract

During animal development, fibroblast growth factors (FGF) play several important roles. Both ‘b’ and ‘c’ isoforms of <i>fibroblast growth factor receptors</i> 1-3 were expressed in the conjunctival papillae, a ring of small epithelial thickenings in the corneal-scleral limbus that induce scleral ossicles, a ring of neural crest derived intramembranous bones in the chick sclera. Whereas, downregulation of the <i>FGFR</i> isoforms was observed during the later stages of scleral ossicle induction. All <i>FGFR</i> isoforms were expressed in the epithelium, however, only <i>FGFR</i>1c, 2c, 3b, and 3c were expressed in the mesenchyme. I also examined the potential role of the FGF pathway during scleral ossicle induction, however, these results were inconclusive. This research provides insight into the expression of another major developmental gene family that could play an important role in the scleral ossicle system and helps to further conceptualize the basic signalling networks involved during scleral ossicle formation.