文摘
Ruditapes philippinarum is an economically important marine bivalve species. Heat shock proteins (HSPs) play significant roles in the immune response of aquatic animals in defending against diverse environmental threats or stresses. In this study, a full length cDNA of HSP70 was cloned from the clam and expression profiles were performed in different color strain of R. philippinarum. The complete HSP70 genes of R. philippinarum were identified and characterized. The complete open reading frame (ORF) fragments of HSP70 were 1875 bp encoding 624 amino acids residues. Based on the amino acid sequence analysis and phylogenetic analysis, the RpHSP70 gene was identified as a member of the cytoplasmic HSP70 family, being the constitutive expression. The mRNA levels of RpHSP70 under acute high temperature and low salinity stresses were analyzed by real-time PCR. The relative expression of RpHSP70 in different color strains were up-regulated after being treated with heat shock in the first 12 h, and reached 7.46-fold compared with the blank at 12 h after challenge in wild R. philippinarum, while reached 3.56, 9.21, and 3.62 for zebra, white, and orange strain, respectively. These results indicate that RpHSP70 expression in gill was inducible under thermal stress and low salinity stress, and the increase of RpHSP70 mRNA presumably reflected the cellular requirement for more HSP70 protein to promote the refolding and renaturation of abnormal proteins. All the findings will contribute to better understanding the biological function of HSPs in defending against environmental challenge and further exploring the innate immune response in R. philippinarum.