Semaphorin3d mediates Cx43-dependent phenotypes during fin regeneration

Area of Science:

• Cell Biology
• Developmental Biology
• Molecular Biology

Background:

• Gap junctions, formed by connexin proteins, facilitate intercellular communication.
• Connexin 43 (Cx43) is essential for zebrafish fin regeneration, impacting cell proliferation and joint formation.
• Semaphorins are signaling molecules involved in various cellular processes.

Purpose of the Study:

• To investigate the role of semaphorin3d (Sema3d) in Cx43-dependent fin regeneration.
• To determine if Sema3d acts downstream of Cx43 and mediates its functions.
• To identify potential receptors for Sema3d in the fin regeneration pathway.

Main Methods:

• In situ hybridization and quantitative RT-PCR to assess sema3d expression.
• Morpholino-mediated knockdown of Cx43, Sema3d, nrp2a, plxna1, and plxna3 in zebrafish.
• Phenotypic analysis of fin regeneration, cell proliferation, and joint formation.

Main Results:

• Sema3d expression is dependent on Cx43 activity.
• Knockdown of Sema3d phenocopies Cx43 knockdown, confirming its downstream role.
• Knockdown of nrp2a led to fin overgrowth and increased proliferation, while plxna3 knockdown affected joint formation.
• Cx43-dependent cell proliferation and joint formation appear to be mediated by independent Sema3d receptors.

Conclusions:

• Sema3d functions downstream of Cx43 in a common molecular pathway during fin regeneration.
• Cx43 regulates cell proliferation and joint formation through distinct Sema3d receptor pathways.