Functional characterization of chitinase from Cydia pomonella granulovirus
SummaryBaculovirus chitinases (V CHIAs) play a crucial role in the terminal liquefaction of virus infected larvae after death. Although v chiAs from nucleopolyhedroviruses (NPVs) have been well characterized, little is known about v chiAs from granuloviruses (GVs) We characterized the v chiA of Cydia pomonella GV (CpGV) by constructing a recombinant Bombyx mori NPV (BmNPV) in which BmNPV v chiA was replaced by CpGV v chiA (103CpGV virus) CpGV v chiA encoded an approximately 70 kDa chitinase with an exo type substrate preference. CpGV V CHIA lacked a C terminal KDEL endoplasmic reticulum retention motif and was suggested to be a secretory protein. Terminal host liquefaction of B. mori larvae and proper folding of BmNPV encoded cysteine protease (BmNPV V CATH) were observed following infection with 103CpGV, indicating that CpGV v chiA is able to compensate for the absence of its BmNPV counterpart. Our data suggest that the molecular interaction between V CHIA and V CATH may be conserved across a broad range of lepidopteran GVs and NPVs.
Archives of Virology