Spruce budworm (Choristoneura fumiferana) juvenile hormone esterase: hormonal regulation, developmental expression and cDNA cloning

We have used the differential display of mRNAs technique to identify Choris toneura fumiferana genes that are induced by juvenile hormone I (JH I). Of the six PCR products identified, one bound to a 2.8-kb mRNA from CF-203 cel ls whose abundance increased when the cells were grown in the presence of J H I. The same 2.8-kb mRNA decreased to undetectable levels when the CF-203 cells were grown in the presence of 20-hydroxyecdysone (20E). The PCR fragm ent probe also detected a 2.8-kb mRNA in the C. fumiferana larval tissues. This 2.8-kb mRNA was present on the first day of the first, third, fourth, fifth and sixth larval and pupal stadia, but was conspicuously absent on th e first day of the second larval stadium, as well as during the intermolt p eriods of the first to fifth instar larval stages. In the sixth instar larv ae the 2.8-kb mRNA was detected in the fat body, epidermis and midgut durin g the intermolt period. The PCR fragment was used as a probe to screen a cD NA library. The deduced amino acid sequence of this 2.8-kb cDNA clone showe d similarity with the deduced amino acid sequences of Heliothis virescens j uvenile hormone esterases (HvJHE). The deduced amino acid sequence of the c DNA clone contained all five functional motifs that are present in most of esterases, proteases and lipases. The cDNA clone was expressed in the bacul ovirus expression system, producing a protein that showed JHE activity. (C) 1999 Elsevier Science Ireland Ltd. All rights reserved.