Cloning, Expression, and Localization of a Molt- Related β-N-Acetylglucosaminidase in the Spruce Budworm, Choristoneura fumiferana

A β-N-acetylglucosaminidase cDNA (Cf GlcNAcase) was cloned from the spruce budworm, Choristoneura fumiferana. Western blotting analysis of developmental Cf GlcNAcase expression revealed high levels of expression of the gene on the last day of the 5th instar larvae and the first day in the 6th instar larvae, followed by a decrease to background levels during the intermolt of the 6th instar. Cf GlcNAcase was detected again from the last day of the 6th instar to day 2 of pupal stage. Cf GlcNAcase expression was induced by tebufenozide at 24 h post treatment and remained at high levels until 72 h. Immunohistochemical localization analysis of Cf GlcNAcase indicated that Cf GlcNAcase was present in the molting fluid, epidermis, trachea, and hemolymph in prepupae during the transformation from larva to pupa. Cf GlcNAcase cDNA was expressed into a recombinant protein in bacterial and baculovirus systems and the protein expressed in the baculovirus system had a higher chitinolytic activity than in the bacterial system and appeared to be secreted. Arch. Insect Biochem. Physiol. 68:49–59, 2008. © 2008 Wiley-Liss, Inc.