Acute effect of copper and cadmium exposure on the expression of heat shock protein 70 in the Cyprinidae fish Tanichthys albonubes

Abstract

A full sequence of TaHSP70 (heat shock protein 70 of Tanichthys albonubes) was amplified which was 2398bp, including an open reading frame (ORF) of 1392bp encoding a polypeptide of 643 amino acids with all three HSP70 family signatures and cytosolic motif of EEVD. Genomic DNA structure analysis revealed that the TaHSP70 gene contained one intron in 5′UTR. BLAST analysis revealed that the TaHSP70 gene shared high similarity with other known HSP70 genes. The alignment of inferred amino acid sequences also showed high degrees of similarity among the homologues.There was a basal mRNA expression of TaHSP70 in the different tissues from the non-exposed T. albonubes and the highest expression level in the liver. To investigated the time- and dose-dependent relationship of the expression of TaHSP70 following exposure to heavy metals, T. albonubes were exposed to 2−1 96h-LC50 (0.027mgL−1), 4−1 96h-LC50 (0.0135mgL−1) of copper and 2−1 96h-LC50 (2.31mgL−1), 4−1 96h-LC50 (1.15mgL−1) of cadmium for 96h. Hsp70 expression relative to the control was analyzed by Quantitative real-time PCR and Western blotting. The results indicated that there were a dose-dependent expression pattern and an exposure time effect in the liver responded to heavy metal stress. Interestingly, TaHSP70 gene expressions did not show consistent changes between transcription and translation levels. Taken together, the dynamics of TaHSP70 expression observed provided important insight into heavy metal stress, heat shock protein activity, and the potential ways to monitor the chronic stressors in T. albonubes culture environments.