Bombyx mori nucleopolyhedrovirus ORF54, a viral desmoplakin gene, is associated with the infectivity of budded virions

• Published in: Archives of virology 2012-07, Vol.157 (7), p.1241-1251
• Main Authors: Zhang, Min-Juan, Tian, Cai-Hong, Fan, Xiao-Ying, Lou, Yi-Han, Cheng, Ruo-Lin, Zhang, Chuan-Xi
• Format: Article
• Language: English
• Subjects: Amino Acid Sequence; Animals; Antibodies; Antibodies, Viral; Autographa californica; Biological and medical sciences; Biomedical and Life Sciences; Biomedicine; Bombyx - cytology; Bombyx - ultrastructure; Bombyx - virology; Bombyx mori NPV; Cell adhesion & migration; Cells, Cultured; Desmoplakins - genetics; Desmoplakins - immunology; Desmoplakins - metabolism; E coli; Escherichia coli; Fundamental and applied biological sciences. Psychology; Gene Expression Regulation, Viral - physiology; Infections; Infectious Diseases; Insecta; Invertebrates; Medical Microbiology; Microbiology; Microscopy; Microscopy, Electron, Transmission; Miscellaneous; Nuclear polyhedrosis virus; Nucleopolyhedrovirus - classification; Nucleopolyhedrovirus - genetics; Nucleopolyhedrovirus - physiology; Nucleopolyhedrovirus - ultrastructure; Original Article; Pathology; Phylogeny; Plasmids; Proteins; Rabbits; Viral Proteins - genetics; Viral Proteins - metabolism; Virology; Virus Replication - physiology; Viruses
• ISSN: 0304-8608; 1432-8798
• DOI: 10.1007/s00705-012-1276-0

Bombyx mori nucleopolyhedrovirus (BmNPV) ORF54 ( Bm54 ), a member of the viral desmoplakin N-terminus superfamily, is homologous to Autographa californica nucleopolyhedrovirus (AcMNPV) ORF66, which is required for the efficient egress of nucleocapsids from the nucleus and occlusion body formation. In this paper, we generated a bacmid with the Bm54 gene deleted via homologous recombination in Escherichia coli and characterized the mutant virus using a transfection-infection assay and transmission electron microscopy analysis. Our results demonstrated that the cells transfected with viral DNA lacking Bm54 produced non-infectious budded viruses (BVs). Electron microscopy showed that although the deletion of Bm54 did not affect assembly and release of nucleocapsids, it severely affected polyhedron formation. In conclusion, deletion of Bm54 resulted in non-infectious BV and defective polyhedra. Although the sequences of Bm54 and Ac66 are very similar, the two genes function quite differently in the regulation of viral life cycle.