Calreticulin (CRT) plays pivotal roles in Ca2+ homeostasis, molecular chaperoning, infection, inflammation and innate immunity. In an attempt to study the involvement of CRT in innate immunity, the full‐length cDNA of calreticulin (PxCRT) was cloned from the diamondback moth, Plutella xylostella. It consists of 1674 bp (excluding poly‐A tail) with a longest open reading frame (ORF) of 1197 bp encoding 398 amino acids. In silico analysis of PxCRT ORF reveals that it has various repeat motifs and endoplasmic reticulum retention signal found in all the calreticulin proteins. As expected, high amino acid sequence identities were found from other CRTs identified from Bombyx mori (87%), Galleria mellonella (87%), Apis mellifera (74%), Anopheles gambiae (74%), Tribolium castaneum (73%), Culex quinquefasciatus (73%), Rhodnius prolixus (72%), Nasonia vitripennis (71%), Drosophila melanogaster (71%) and Haemaphysalis qinghaiensis (68%). During development, P. xylostella expressed PxCRT predominantly in the pupal stage. In addition, spatial expression pattern analysis indicates that PxCRT was highly expressed in the silk gland. PxCRT mRNA, furthermore, was strongly induced 3 to 6 h after laminarin treatment, suggesting that PxCRT appears to be involved in immune responses and also plays an important role in the silk gland.

Hemolin has been known to play a key role in insect innate immunity. In an attempt to examine expression pattern of the Hemolin gene in the diamondback moth, Plutellea xylostella, the full-length cDNA of Hemolin was cloned using 5'-RACE PCR technique. The cDNA contained a 5' untranslated region of 48 nucleotides and a 3' untranslated region of 198 nucleotides, including a stop codon (TAA) and a poly (A) tail. It consists of 1,401 bp with an open reading frame of 1,245 bp, encoding 414 amino acids. The deduced amino acid sequence of PxHemolin has relatively low identities (35−42%) to various insect Hemolins. However, it has high three-dimensional structural similarity to Hemolin. Interestingly, analysis of spatial expression pattern of PxHemolin shows that it was highly expressed in the Malpighian tubule and the silk gland although it was also detected in fat body and gut. Furthermore, PxHemolin mRNA was highly induced 3 hr after immune-challenging with lipopolysaccharide and was gradually up-regulated after laminarin treatment. These data suggest that PxHemolin may play a role in innate immune responses although it remains to further elucidate the precise biological R. J. Kim and Y. H. Jo are equally contributed to this work. functions in P. xylostella.