Objective Gene associated with the calmodulin-dependent protein kinases (CaMKs) from Pseudocohnilembus persalinus was cloned to study its protein structure and function as well as genetic relation and evolutionary characteristics for the development of treatment for the parasitic scuticociliatosis in aquaculture species.

Method Based on the RNA-seq of P. persalinus, the full-length cDNA sequence of PpCaMK1 was obtained using the Rapid Amplification of cDNA Ends (RACE) technique. Bioinformatic methods were employed to analyze the features, structure, physicochemical properties, domains and phylogenetic relationships with other ciliates of the gene.

Result PpCaMK1 contained 9 exons and 8 introns. The full cDNA length was 1 737 bp (GenBank accession number: PQ278249) including a 5'-UTR of 56 bp, a 3'-UTR of 307 bp, and an ORF of 1 374 bp and encoded 457 amino acids. It was a hydrophilic and unstable protein with an average overall hydrophilicity of −0.802 and an instability index of 54.78. Distributed within the cytoplasm and nucleus, PpCaMK1 notably lacked the transmembrane domains and signal peptides and had a secondary structure composed of a significant proportion (i.e., 50.33%) of random coils. P. persalinus closely related to other ciliates in the class Oligohymenophorea.

Conclusion The full-length cDNA of PpCaMK1 was successfully cloned and the basic biological and physicochemical characteristics studied paving the way for further research on the development of an effective treatment of the devastating disease on marine lives in aquacultural environment caused by the parasite P. persalinus.