Molecular cloning and functional analysis of small heat shock protein 19.1 gene from the Chinese oak silkworm, Antheraea pernyi.

Small heat shock proteins (sHSPs) are a class of highly conserved proteins that are ubiquitously found in all types of organisms, from prokaryotes to eukaryotes. In the current study, we identified and characterized the full-length cDNA encoding sHSP 19.1 from the oak silkworm, Antheraea pernyi. Ap-sHSP is 510 bp in length, and encodes a protein of 169 amino acid residues. The protein contains conserved domains found in insect sHSPs, and it belongs to the α-crystallin-HSPs_p23-like superfamily. Recombinant Ap-sHSP was expressed in Escherichia coli cells, and a rabbit anti-Ap-sHSP 19.1 antibody was generated to confirm the biological functions of Ap-sHSP 19.1 in A. pernyi. Real-time polymerase chain reaction and western blot analysis revealed that Ap-sHSP 19.1 expression was highest in the fat body, followed by the midgut, and the lowest expression was found in the Malpighian tubule. Ap-sHSP 19.1 transcript expression was significantly induced following challenge with microbial pathogens. In addition, the expression of Ap-sHSP 19.1 was strongly induced after heat shock. These results suggest that Ap-sHSP 19.1 plays a crucial role in immune responses and thermal tolerance in A. pernyi.