CpGV-MMP characterization, activity, and effects on AcMNPV replication in cultured cells
Bacterially purified CpGV-MMP had MMP activity in vitro that was abolished with MMP and metal chelator inhibitors (Fig. 2B). HA-tagged CpGV-MMP expressed in a recombinant AcMNPV was detected in the extracellular media of infected Sf9 NS 6180 (Fig. 4A), confirming that CpGV-MMP is a secreted protein. MMP secretion is also predicted in most baculovirus MMPs, implying a common extracellular function. The molecular mass of CpGV-MMP was significantly reduced after treatment with PNGase F, indicating that CpGV-MMP was N-glycosylated (Fig. 4B). Whether N-glycosylation is a requirement for function was not investigated. Finally, CpGV-MMP does not appear to have any obvious effect on AcMNPV BV production or occlusion body formation in vitro (Fig. 5A and B).
Effects of CpGV-MMP on larval mortality
The XcGV-MMP has been previously characterized (Ko et al., 2000). It is important to note that in contrast to CpGV-MMP, XcGV-MMP does not have a signal peptide and, as indicated by Ko et al., it is likely that XcGV-MMP is released after lysis of infected cells. This implies that XcGV-MMP, in contrast to CpGV-MMP, may function at later stages of infection (e.g., after lysis of infected cells) or it may be playing a role intracellularly, although intracellular regulation of an active XcGV-MMP is not well known.
Bacterially purified CpGV-MMP had MMP activity in vitro that was abolished with MMP and metal chelator inhibitors (Fig. 2B). HA-tagged CpGV-MMP expressed in a recombinant AcMNPV was detected in the extracellular media of infected Sf9 NS 6180 (Fig. 4A), confirming that CpGV-MMP is a secreted protein. MMP secretion is also predicted in most baculovirus MMPs, implying a common extracellular function. The molecular mass of CpGV-MMP was significantly reduced after treatment with PNGase F, indicating that CpGV-MMP was N-glycosylated (Fig. 4B). Whether N-glycosylation is a requirement for function was not investigated. Finally, CpGV-MMP does not appear to have any obvious effect on AcMNPV BV production or occlusion body formation in vitro (Fig. 5A and B).
Effects of CpGV-MMP on larval mortality
The XcGV-MMP has been previously characterized (Ko et al., 2000). It is important to note that in contrast to CpGV-MMP, XcGV-MMP does not have a signal peptide and, as indicated by Ko et al., it is likely that XcGV-MMP is released after lysis of infected cells. This implies that XcGV-MMP, in contrast to CpGV-MMP, may function at later stages of infection (e.g., after lysis of infected cells) or it may be playing a role intracellularly, although intracellular regulation of an active XcGV-MMP is not well known.