JVI Figure table search 04
Home Help [Feedback] [For Subscribers] [Archive] [Search] [Contents]
This Article
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrowReprints and Permissions
Right arrow Copyright Information
Right arrow Books from ASM Press
Right arrow MicrobeWorld
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Okano, K.
Right arrow Articles by Maeda, S.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Okano, K.
Right arrow Articles by Maeda, S.

 Previous Article  |  Next Article 

Journal of Virology, January 1999, p. 110-119, Vol. 73, No. 1
0022-538X/99/$04.00+0
Copyright © 1999, American Society for Microbiology. All rights reserved.

Colocalization of Baculovirus IE-1 and Two DNA-Binding Proteins, DBP and LEF-3, to Viral Replication Factoriesdagger

Keiju Okano,1,2,* Victor S. Mikhailov,1,3 and Susumu Maeda1,2,4

Laboratory of Molecular Entomology and Baculovirology, The Institute of Physical and Chemical Research (RIKEN), Wako, Saitama,1 and Core Research for Evolutional Science and Technology (CREST) Project, Japan Science and Technology Corporation (JST), Kawaguchi, Saitama,2 Japan; N. K. Koltzov Institute of Developmental Biology, Moscow, Russia3; and Department of Entomology, University of California, Davis, California4

Received 11 May 1998/Accepted 23 September 1998

We have recently identified a DNA-binding protein (DBP) from the baculovirus Bombyx mori nucleopolyhedrovirus (BmNPV) which can destabilize double-stranded DNA (V. S. Mikhailov, A. L. Mikhailova, M. Iwanaga, S. Gomi, and S. Maeda, J. Virol. 72:3107-3116, 1998). DBP was found to be an early gene product that was not present in budded or occlusion-derived virions. In order to characterize the localization of DBP during viral replication, BmNPV-infected BmN cells were examined by immunostaining and confocal microscopy with DBP antibodies. DBP first appeared as diffuse nuclear staining at 4 to 6 h postinfection (p.i.) and then localized to several specific foci within the nucleus at 6 to 8 h p.i. After the onset of viral DNA replication at around 8 h p.i., these foci began to enlarge and eventually occupied more than half of the nucleus by 14 h p.i. After the termination of viral DNA replication at about 20 h p.i., the DBP-stained regions appeared to break down into approximately 100 small foci within the nucleus. At 8 h p.i., the distribution of DBP as well as that of IE-1 or LEF-3 (two proteins involved in baculovirus DNA replication) overlapped well with that of DNA replication sites labeled with bromodeoxyuridine incorporation. Double-staining experiments with IE-1 and DBP or IE-1 and LEF-3 further confirmed that, between 8 and 14 h p.i., the distribution of IE-1 and LEF-3 overlapped with that of DBP. However, IE-1 localized to the specific foci prior to DBP or LEF-3 at 4 h p.i. In the presence of aphidicolin, an inhibitor of DNA synthesis, immature foci containing IE-1, LEF-3, and DBP were observed by 8 h p.i. However, the subsequent enlargement of these foci was completely suppressed, suggesting that the enlargement depended upon viral DNA replication. At 4 h p.i., the number of IE-1 foci correlated with the multiplicity of infection (MOI) between 0.4 and 10. At higher MOIs (e.g., 50), the number of foci plateaued at around 15. These results suggested that there are about 15 preexisting sites per nucleus which are associated with the initiation of viral DNA replication and assembly of viral DNA replication factories.

* Corresponding author. Mailing address: Laboratory of Molecular Entomology and Baculovirology, The Institute of Physical and Chemical Research (RIKEN), 2-1 Hirosawa, Wako-shi, Saitama 351-0198, Japan. Phone: 81-48-467-9521. Fax: 81-48-462-4678. E-mail: keijuo{at}postman.riken.go.jp.

dagger K.O. and V.S.M. dedicate this paper to the memory and achievements of Susumu Maeda, who died unexpectedly on 26 March 1998.

Journal of Virology, January 1999, p. 110-119, Vol. 73, No. 1
0022-538X/99/$04.00+0
Copyright © 1999, American Society for Microbiology. All rights reserved.


This article has been cited by other articles:



Home Help [Feedback] [For Subscribers] [Archive] [Search] [Contents]
J. Bacteriol. Mol. Cell. Biol. Microbiol. Mol. Biol. Rev.
Clin. Vaccine Immunol. ALL ASM JOURNALS

Copyright © 1999 by the American Society for Microbiology. All rights reserved.