Abstract:

Heat shock protein 70 (HSP70) is one of the most conservative and important proteins in heat shock protein family. Overexpression of HSP70 may obviously improve the survivability of cells, and enhance their tolerance to stress. To investigate the effects of heat stress on HSP70 expression in Chilo suppressalis larvae, RT-PCR and RACE methods were used for cloning the full length cDNA encoding HSP70 from haemocytes of C.suppressalis in this study. The cDNA obtained is 2 102 bp in length, containing an ORF of 1 959 bp, encoding 652 amino acid residues, with a 5′UTR of 81 bp and a 3′UTR of 62 bp．Cluster analysis confirmed that the deduced amino acid sequence shared high identity with the reported homologous sequences from other insects (73%-97%). Real-time quantitative PCR showed that HSP70 gene expression could be induced by heat stress. The maximal induction of HSP70 gene expression in larval haemocytes of C.suppressalis was achieved at 36℃. HSP70 protein expression was observed by using flow cytometry. The results revealed that the expression profiles of HSP70 at both the mRNA level and the protein level are highly in agreement with each other.

Key words: Chilo suppressalis, heat shock protein (HSP), HSP70, RACE, expression, heat stress