Author(s)

Gaku Matsunaga, Syuuji Karasuda, Ryo Nishino, Hideto Fukushima, Masahiro Matsumiya

Department of Marine Science and Resources, College of Bioresource Sciences, Nihon University, Kanagawa, Japan.

In this study, we report that we successfully cloned and sequenced a chitinase gene from the ovotestis of Kuroda’s sea hare Aplysia kurodai. By using reverse transcription-polymerase chain reaction (RT-PCR) and a system for the 5’ and 3’ rapid amplification of cDNA ends, we obtained a 1352 bp chitinase gene (AkChi) from the ovotestis of A. kurodai. AkChi contains a 1263 bp open reading frame that encodes 421 amino acids. The domain structure predicted from the deduced amino acid sequence was an N-terminal signal peptide and a catalytic domain of glycoside hydrolase (GH) family 18 chitinase. A comparative analysis of the deduced amino acid sequences of AkChi with those of the acidic mammalian chitinase of the California sea hare Aplysia californica revealed the highest homology at 83%. The purified chitinase from the ovotestis was digested by trypsin, and 119 residues of digested peptides were consistent with the deduced amino acid sequence of AkChi. We used RT-PCR to evaluate the expression of AkChi in various tissues of A. kurodai, and we observed that AkChi was expressed only in the ovotestis. A phylogenetic tree analysis, performed using the amino acid sequences of AkChi and known GH family 18 chitinases, showed that AkChi was separated from the molluscan chitinases with a chitin binding domain. To our knowledge, this is the first study demonstrating the cDNA cloning of an ovotestis chitinase from a sea hare.

Chitinase, Molecular Cloning, Kuroda’s Sea Hare Aplysia kurodai, Mollusc, Ovotestis, Phylogenetic Tree Analysis

Matsunaga, G. , Karasuda, S. , Nishino, R. , Fukushima, H. and Matsumiya, M. (2016) Molecular Cloning of a Chitinase Gene from the Ovotestis of Kuroda’s Sea Hare Aplysia kurodai. Advances in Bioscience and Biotechnology, 7, 38-46. doi: 10.4236/abb.2016.71005.