This Article Full Text (PDF) Other Versions of this Article: JVI.02510-07v1 82/9/4554    most recent Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Reprints and Permissions Copyright Information Books from ASM Press MicrobeWorld Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Wang, Y. Articles by Chen, X. Search for Related Content PubMed PubMed Citation Articles by Wang, Y. Articles by Chen, X.

 Previous Article  |  Next Article 

J. Virol. doi:10.1128/JVI.02510-07
Copyright (c) 2008, American Society for Microbiology and/or the Listed Authors/Institutions. All Rights Reserved.

Autographa californica multiple nucleopolyhedrovirus nucleocapsid protein BV/ODV-C42 mediates the nuclear entry of P78/83

State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese, Academy of Sciences, Wuhan, 430071, People's Republic of China; Graduate University of the Chinese Academy of Sciences, Beijing, 100039 People's Republic of China

^* To whom correspondence should be addressed. Email: chenxw{at}pentium.whiov.ac.cn.

	Abstract

Autographa californica multiple nucleopolyhedrovirus (AcMNPV) BV/ODV-c42 (orf101; c42), which encodes a 41.5 kDa viral nucleocapsid protein with a putative nuclear localization signal (NLS) motif at the C-terminus is a highly conserved gene among members of baculoviridae family. C42 is demonstrated to be essential for AcMNPV propagation and can bind to nucleocapsid protein P78/83, a viral activator for the actin-related-protein 2/3 (ARP2/3) complex to initiate nuclear actin polymerization, which is essential for viral nucleocapsid morphogenesis during AcMNPV infection. Here, we report the identification of a novel pathway through which c42 functions in nucleocapsid assembly. Co-transfection of Sf9 cells with c42 and p78/83 plasmids demonstrated that C42 was capable of recruiting P78/83 to the nuclei of uninfected cells and the NLS motif of C42 was essential for this process. To validate this nuclear relocation mode in bacmid transfected cells, c42 disrupted bacmid (vAc^c42ko-gfp) and rescued bacmids with wild-type c42 (vAc^c42res-gfp) or with NLS coding sequence mutated c42 (vAc^c42nls-gfp) were prepared. By immuno-staining, P78/83 was found to be localized in the cytoplasm of either vAc^c42ko-gfp or vAc^c42nls-gfp transfected cells, whereas P78/83 was relocated to the nuclei of vAc^c42res-gfp transfected cells. Furthermore, F-actin specific staining confirmed that there was no actin polymerization activity in the nuclei of either vAc^c42ko-gfp or vAc^c42nls-gfp transfected cells, which might be attributed to the absence of nuclear P78/83 for activation of the ARP2/3 complex to initiate nuclear actin polymerization. We therefore hypothesize a mode of action where C42 binds to P78/83 in the cytoplasm to form a protein complex and co-transports to the nucleus under the direction of the NLS motif in C42 during AcMNPV infection.