The vertebrate skeleton provides a variety of important functions including form, strength, flexibility, and protection of vital organs. Establishment of the complex form of the skeleton requires the coordination of growth with the differentiation of bone-forming cells and joint-forming cells. Indeed, much is known about how cells divide and about how relevant cell types differentiate. However, very little is understood about how these events are coordinated to give rise to skeletal elements of the correct size and shape. The gap junction protein Cx43 has been shown to regulate both cell proliferation and joint formation during zebrafish fin regeneration, revealing that Cx43 coordinates growth and patterning concomitantly. To determine how Cx43 mediates these activities, putative target genes were identified using a molecular genetics approach. Validated Cx43-dependent genes from this list of target genes will be placed in an ordered pathway of genes acting downstream of Cx43. Thus, it will be possible to reveal the step-wise molecular pathway(s) regulated by Cx43 during growth and patterning of the fin. The intellectual merit of this proposal is that mechanistic insights into the establishment of skeletal form and patterning will be revealed. Validation of the top 50 target genes will be completed in part during a new inquiry-based laboratory course for undergraduates. Thus, the broader impacts of this proposal include providing a large number of students access to the practice of science while also providing a set of core laboratory skills in Developmental Biology. The intellectual merit and the broader impacts are fully integrated in this proposal, both advancing the field of knowledge of skeletal morphogenesis and providing instruction on how to solve complex biological problems in a laboratory setting.
