Characterization of Myelin P2 and Slitrk Echinoderm Genes and Their Expression During Enteric Nervous System Regeneration

Abstract

Holuthuria glaberrima is an echinoderm known for its ability to regenerate its internal organs including its enteric nervous system (ENS). Unfortunately, there is a limited amount of nervous component markers and many of the molecular events that occur during the regeneration of this system in the sea cucumber are still unknown. New insights into the regeneration of the holothurian ENS may be provided by determining the genes involved and differentially expressed in this process. Using a database generated by Next Generation Sequencing (NGS), we identified two genes that might be associated with regeneration: Slitrk and the gene that encodes Myelin P2 protein. Slitrk proteins have been shown to modulate neurite outgrowth in vertebrate animals. Myelin P2 protein is one of the components of the myelin sheath in vertebrate glial cells, and holothurian glia has been shown to play an important role in the regeneration of the holothurian CNS. We have shown that these genes are present and expressed in normal and regenerating sea cucumber by using various bioinformatic tools, sqPCR and immunohistochemistry. We established a gene expression profile of various tissues and at different stages of intestinal regeneration. To view the spatial localization of Myelin P2 protein, we developed an antibody and localized its expression to the ceolomic epithelium of the intestine and muscle. Finally, our work also explores the evolution of myelin‐related proteins, an interesting development from our findings, since myelin is not found in invertebrate nervous systems. In conclusion, we believe that understanding the role of these genes may aid in the elucidation of possible patterns of ENS regeneration of H. glaberrima.