Virologica Sinica

, Volume 34, Issue 6, pp 701–711 | Cite as

Functional Characterization of the Group I Alphabaculovirus Specific Gene ac73

  • Wei Shao
  • Lihong He
  • Qingxiu Chen
  • Jiang Li
  • Fei Deng
  • Hualin Wang
  • Zhihong HuEmail author
  • Manli WangEmail author


Baculoviridae is a family of large DNA viruses that specifically infect insects. It contains four genera, Alpha-, Beta-, Gamma-, and Deltabaculovirus. Alphabaculovirus is further divided into Group I and II, and Group I appears to be emerged most recently among all baculoviruses. Interestingly, there are 12 Group I specific genes that are only found in this lineage. Studying these genes is helpful to understand how baculoviruses evolved. Here, we reported the functional analyzing results of ac73, a function unknown Group I specific gene of Autographa californica multiple nucleopolyhedrovirus (AcMNPV) which is the type species of baculovirus. The AC73 protein encoded by ac73 was found to be expressed during the late stage of infection and incorporated into the nucleocapsids of budded virus (BV) and occlusion-derived virus (ODV). In infected cells, AC73 resided mainly in the ring zone region of the nucleus, and appeared to be assembled into occlusion bodies (OBs). The ac73 knockout and repaired viruses were constructed and studied by in vitro and in vivo infection. Although ac73 was not essential for BV and ODV or OB formation, the BV titer and viral infectivity in insect larvae of ac73 knockout AcMNPV decreased by about 5–8 and 3–4 fold compared to those of wild type virus, respectively, suggesting ac73 contributed to infectious BV production and viral infectivity in vivo. This research provides new insight into the function of this Group I specific gene.


Baculovirus AC73 Group I Nucleocapsid Bcl-2-associated athanogene (BAG) domain 



This research was supported by the grants from the Key Research Project of Frontier Science (QYZDJ-SSW-SMC021), the Strategic Priority Research Program (grant No. XDB11030400) from the Chinese Academy of Sciences, and the grants (No. 31621061) from the National Natural Science Foundation of China. We would like to thank Mr. Ding Gao, Ms. Pei Zhang and Ms. An-na Du, Mr. He Zhao, and Ms. Li Li from The Core Facility and Technical Support of Wuhan Institute of Virology for their technical assistance.

Author Contributions

WS, ZH and MW designed the experiments. WS, LH and QC performed the experiments and analyzed the data. WS, ZH and MW wrote the manuscript. JL, FD, HW, ZH and MW edited and commented on the manuscript.

Compliance with Ethical Standards

Conflict of interest

The authors declare that they have no conflict of interest.

Animal and Human Rights Statement

This article does not contain any studies with human or animal subjects performed by any of the authors.


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Copyright information

© Wuhan Institute of Virology, CAS 2019

Authors and Affiliations

  1. 1.State Key Laboratory of Virology, Wuhan Institute of VirologyChinese Academy of SciencesWuhanChina
  2. 2.University of the Chinese Academy of SciencesBeijingChina

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