Molecular Cloning And Expression Profiling Of Calbin And Tyrosinase In Larval Growth Of Pacific Oyster (Crassostrea Gigas)

Bivalve culture is one of most widely aquaculture in China. Early larvae have greatinfluence on larval metamorphosis and growth rate after metamorphosis. If the early larvaehave normal growth, it can bring great production efficiency. Larval development is a keyphase in large scale bivalve culture industry. So investigation of molecular mechanism inlarval development is very important for production practice.As an important economic bivalve, Crassostrea gigas distributes in the coastal areasand it is the main breeding species for the southern coast. In this paper, we studied CgCalbingene which is a EF-hand Calcium-binding protein and CgTyrosinase gene which is relatedto the formation of prodissconchâ… . We obtained sequences of the two genes, and analyzedtemporal and spatial expression in C. gigas larvae and possible functions of CgCalbin generespectively.CgCalbin sequence was obtained from larvae cDNA library of oyster. Sequence wasthen analyzed and phylogenetic tree was constructed. The real time PCR analysis revealedthat CgCalbin has the highest mRNA expression level in trochophore, and then theD-shaped larvae, the spat, and has the lowest level in veliger. The different tissue analysisshowed that CgCalbin has a very high mRNA expression level in liver, gonad and gill, andhas a very low level in mantle and muscle. The result of whole mount in situ hybridizationshowed that CgCalbin was located at the position of ganglion in trochophore stage,indicating CgCalbin may plays a role in neuromodulation.EST sequence was selected from the subtranctive library of D-shape larvae and the spat.The full-length of CgTyrosinase was cloned by genome walking and RACE method. Thesequence of CgTyrosinase was analysed, and the real time PCR revealed that the mRNAlevel is highest in the spat. This indicates that the gene plays an important role in themetamorphosis and formation of shell in larvae.In conclusion, the two genes (CgCalbin, CgTyrosinase) associated withneuromodulation and prodissconchâ… formation, have been characterized and analyzed respectively. The investigation will be helpful for studying the molecular mechanism ofgrowth and development in bivalve larvae.