Expression pattern, and potential role of DNAJC7 during arm regeneration in the brittle star Ophioderma longicauda

A fragment of the cDNA encoding the DNAJ, subfamily C member 7-like (DNAjC7) protein from regenerating arms (24 hours) of the ophiuroid Ophioderma longicauda has been cloned. This 558 bp cDNA clone matches to the 3`UTR region of a Strongylocentrotus purpuratus DNAJ ortholog (79% identity), a member of the DNAJ heat shock proteins (HSP40) family. Members of the DNAJ/HSP40 family are characterized by two N-terminal tetratricopeptide repeat domains and a C-terminal DNAJ domain. It is a very conserved gene found from bacteria up to humans, also known to be involved in cell cycle control and as an up-regulated gene expression for HSPs, this protein binds the chaperone proteins HSP 70 and 90 in an ATP-dependent manner and may function as a co-chaperone. For Instance, DNAjC7 might regulate incomplete folded polypeptides from Hsp90 onto an Hsp70 protein in Human Liver Regeneration recycling. In zebrafish DnaJ-like protein, has been studied its expression during fin regeneration showing drastically increased in all ray segments beneath the regenerated part, or blastema, in response to caudal fin amputation. The identified DNAJC7 cDNA clone was used to perform in-situ hybridization (ISH) on the whole animal arm, optimizing and modifying the method for the O. longicauda model. Our results showed a clear expression in the radial water canal system (RWC) of both the freshly cut and the regenerating arm at 24h. Based on the above mention evidences we hypothesized a potential involvement of DNAJC7 like in arm regeneration in the ophiuroid O. longicauda.