Cysteines 128 and 250 are essential for the functions of the baculovirus core gene ac109

Yao Chen; Hang Wu; Jiang Li; Zhihong Hu; Manli Wang; Huanyu Zhang

doi:10.1016/j.virol.2023.109857

Cysteines 128 and 250 are essential for the functions of the baculovirus core gene ac109

Virology. 2023 Oct:587:109857. doi: 10.1016/j.virol.2023.109857. Epub 2023 Aug 4.

Authors

Yao Chen¹, Hang Wu¹, Jiang Li², Zhihong Hu², Manli Wang², Huanyu Zhang³

Affiliations

¹ School of Bioengineering and Food, Key Laboratory of Fermentation Engineering (Ministry of Education), Key Laboratory of Industrial Microbiology in Hubei, National '111' Center for Cellular Regulation and Molecular Pharmaceutics, Hubei University of Technology, Wuhan, 430068, PR China.
² State Key Laboratory of Virology, Wuhan Institute of Virology, Center for Biosafety Mega-Science, Chinese Academy of Sciences, Wuhan, 430071, PR China.
³ State Key Laboratory of Virology, Wuhan Institute of Virology, Center for Biosafety Mega-Science, Chinese Academy of Sciences, Wuhan, 430071, PR China. Electronic address: zhanghy@wh.iov.cn.

PMID: 37562288
DOI: 10.1016/j.virol.2023.109857

Abstract

The open reading frame 109 (ac109) of Autographa californica multiple nucleopolyhedrovirus (AcMNPV) is one of the 38 core baculovirus genes. Ac109 was shown to be essential for the production of infectious budded virions (BV), envelopment of the nucleocapsid, and embedding of occlusion-derived virions (ODVs) into occlusion bodies (OBs). Herein, the roles of five cysteines with high conservation (C3, C116, C128, C250, and C325) in Ac109 function were investigated. AcMNPV bacmids lacking ac109 or containing single-mutated ac109 were generated. Transfection/infection assays showed that C128 and C250 in Ac109 were important for infectious BV production. Electron microscopy analysis further confirmed that these two cysteines played critical roles in nucleocapsid assembly, ODV envelopment, and embedding of ODVs into OBs. Altogether, these results demonstrate that the conserved residues Ac109 C128 and C250 are critical for baculovirus infection.

Keywords: Ac109; Autograph californica multiple nucleopolyhedrovirus; BV production; Conserved cysteine; Nucleocapsid assembly.