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Published on: February 22, 2018
Comparative studies of lepidopteran baculovirus-specific protein FP25K: development of a novel Bombyx mori
Tadashi Nakanishi1, Chie Goto, Michihiro Kobayashi
1Department of Agricultural and Environmental Biology, Graduate School of Agricultural and Life Sciences, University of Tokyo, Yayoi 1-1-1, Bunkyo-ku, Tokyo 113-8657, Japan.
Abstract:
Lepidopteran baculovirus-specific protein FP25K performs many roles during the infection cycle, including functions in the production of occlusion bodies (OBs) and budded viruses (BVs), oral infection, and postmortem host degradation. To explore the common and specific functions of FP25K proteins among lepidopteran baculoviruses, we performed comparative analyses of FP25K proteins from group I and group II nucleopolyhedroviruses (NPVs) and granulovirus (GV). Using recombinant Bombyx mori NPVs (BmNPVs), we showed that the FP25Ks from NPVs were able to eliminate all the phenotypic defects observed in an infection with a BmNPV mutant lacking functional fp25K but that FP25K from GV did not show abilities to recover oral infectivity and postmortem host degradation. We also observed that introduction of Autographa californica multiple NPV (AcMNPV) fp25K into the BmNPV genome enhanced OB and BV production. According to these results, we generated a novel BmNPV-based expression vector with AcMNPV fp25K and examined its potential in BmN cells and B. mori larvae. Our results showed that the introduction of AcMNPV fp25K significantly increases the expression of foreign gene products in cultured cells and shortens the time for obtaining the secreted recombinant proteins from larval hemolymph.
Insights
Lepidopteran baculovirus protein FP25K is crucial for infection. Nucleopolyhedrovirus FP25K aids viral production and infection, while granulovirus FP25K does not fully restore these functions.
Area of Science:
- Virology
- Molecular Biology
- Insect Pathology
Background:
- The baculovirus FP25K protein is essential for viral replication and infection.
- FP25K plays roles in occlusion body and budded virus production, oral infection, and host degradation.
Purpose of the Study:
- To compare the functions of FP25K proteins across different lepidopteran baculoviruses (NPVs and GVs).
- To develop an enhanced baculovirus expression vector utilizing AcMNPV FP25K.
Main Methods:
- Comparative analysis of FP25K proteins from group I and II NPVs and GVs.
- Utilized recombinant Bombyx mori NPVs (BmNPVs) to test FP25K function.
- Generated a novel BmNPV-based expression vector containing Autographa californica multiple NPV (AcMNPV) fp25K.
Main Results:
- NPV FP25K proteins rescued BmNPV mutants lacking functional fp25K, but GV FP25K did not fully restore oral infectivity or postmortem degradation.
- Introduction of AcMNPV FP25K into BmNPV enhanced OB and BV production.
- The AcMNPV FP25K-enhanced BmNPV vector increased foreign gene product expression in BmN cells and reduced production time in B. mori larvae.
Conclusions:
- Lepidopteran baculovirus FP25K proteins have distinct functions depending on their viral group.
- AcMNPV FP25K can enhance baculovirus replication and foreign gene expression.
- A novel BmNPV-based expression vector with AcMNPV FP25K shows potential for improved bioproduction.
