Department of Biological Sciences
The zebrafish fin is composed of multiple bony fin rays. Each fin ray is comprised of multiple segments separated by joints. Regulatory mechanisms that control joint morphogenesis and ray segment length in zebrafish fins are not fully understood. We found that the semaphorin3d (sema3d) gene is expressed during fin regeneration in a cx43-dependent manner. Semaphorins are signaling molecules involved in different signaling pathways, especially in axon guidance cues during pattering of the central nervous system. Interestingly, sema3d is found at the lateral compartment of the regenerating fin consistent with the location of precursor cells for bones and joints. Moreover, sema3d knock-down recapitulates the cx43 phenotype including reduced in growth and reduced in segments. Studies show that depending on the cell-type, Sema3s interact with neurophilin receptors (Nrps) either physically or indirectly via other receptor complexes. During fin regeneration, we found expression of only nrp2a. Interestingly, nrp2a is expressed in the skeletal precursors where sema3d expression was identified. We hypothesize that sema3d signaling through nrp2a regulates cell proliferation and inhibits joint formation.
Quynh Ton is a 3rd year graduate student majoring in Cellular/Molecular Biology in the Department of Biological Sciences. Quynh earned her Associate degree in Health Sciences from North Shore Community College, MA and a Bacherlor's degree in Biology from Bard College, NY. Currently, she works under the supervision of Dr. Mary Kathryn Iovine. Quynh's research focuses on joint development in fin regeneration using zebrafish as her research model. After Lehigh, Quynh plans to seek for a posdoctoral position that will allow her to continue expand her interest in cellular/molecular biology for a career in the biotechnology industry.