CLONING AND EXPRESSION ANALYSIS OF SRBI GENE IN DIFFERENT SHELL-COLOR STRAINS OF MERETRIX MERETRIX

To explore the molecular structure and biological function of SRBI in the process of carotenoids accumulation in Meretrix meretrix, we cloned cDNA of Mm-SRBI by SMART RACE technique and conducted the bioinformatics, expression analysis and intron amplification. The full length cDNA of Mm-SRBI is 1723 bp that contains a complete 1515 bp ORF encoding 504 amino acids with one functional domain of Mm-SRBI protein (CD36). Mm-SRBI is highly homologous with Mimachlamys nobilis and shares 55% similarity in amino acid sequence. It shares 34%—40% similarity with vertebrates. We also amplified 12 introns of Mm-SRBI, which followed the principle of GT-AG. Mm-SRBI gene expressed in all six tested tissues with the highest level in mantle (P<0.01), suggesting thatMm-SRBI gene maybe relate to high carotenoid in mantle. Moreover, the expression of Mm-SRBI gene in red shell strain was significantly higher than that of white shell strain (P<0.05). In conclusion, this study provides helpful foundation to explore the shell colors on this species.