Identification, Characterization and Expression of Heat Shock Protein 70 in Scapharca broughtonii

As one crucial member of heat shock proteins (HSPs) family, HSP70s play many important roles in a large amount of physiological processes including immune response. However, information regarding HSP70 in ark shell Scapharca broughtonii is still rather limited. Here the full-length cDNA of HSP70 gene (named SbHSP70) of S. broughtonii was identified by using reverse transcription PCR (RT-PCR) and rapid amplification ends (RACE) methods. The SbHSP70 cDNA was 2423 bp in length containing a 5′ untranslated region (UTR) of 131 bp, 3′-UTR of 330 bp, and an open reading frame (ORF) of 1962 bp which encodes a peptide of 653 amino acids.The multiple alignment and phylogeny analysis showed that the SbHSP70 shared high homology sequence with other mollusk species, and clustered together with gastropods to form a sister group. The mRNA expression profiles of SbHSP70 in tissues of foot, gill, mantle, adductor muscle, haemocytes and hepatopancreas analyzed by quantitative real-time PCR (qRT-PCR) suggested the mRNA transcripts of SbHSP70 distributed in all the examined tissues, and the highest expression level was observed in foot, and a significant difference could be detected between gill and adductor muscle (p<0.05), no significant difference among the gill, mantle and hemocytes (p > 0.05). Its dynamic change during the early stage of larvae showed that it could be transferred from parent and may be involved in some key developmental process. What’s more, Vibrio anguillarum challenge resulted in regular change of expression of SbHSP70 mRNA, indicating SbHSP70 actively participated in the immune response process.