Functional role of annexins in zebrafish caudal fin regeneration - A gene knockdown approach in regenerating tissue.

Abstract Regeneration is an adaptive phenomenon with wide biological implications spread heterogeneously in almost all the organism including human beings. The ability of regeneration varies from species to species for its complexity. Epimorphic regeneration of zebrafish caudal fin tissue is the most widely studied regeneration mechanism for its discrete and rapid regenerative capability. Several genes and proteins were found to be associated with regenerative mechanisms of zebrafish caudal fin tissue. In this study we have evaluated the functional role of Annexin 2a and 2b genes during zebrafish caudal fin tissue regeneration using inventive electroporation techniques for targeting the gene involving CRISPR-Cas9 technology. The electroporation of the CRISPR was performed on the adult zebrafish caudal fin tissue post amputation. We report retarded growth during the regeneration of caudal fin tissue when Annexin 2a and 2b genes were knocked down, which was validated through gene expression & sequencing analysis and further supported by high-throughput quantitative proteomic analysis of the fin tissue. Annexin family genes such as ANXA13, ANXA1a, ANXA5b were also found to be repressed with their expression. Knocking down of ANXA2a and 2b in regenerating caudal fin tissue compromises regenerating capacity as these genes are involved in cell to cell communication and extracellular matrix growth. This study proves that ANXA2a and 2b plays a significant role in epimorphic regeneration of zebrafish caudal fin tissue.