Baculovirus proteins IE-1, LEF-3, and P143 interact with DNA in vivo: a formaldehyde cross-linking study
- Department of Microbiology and Immunology, Queen's University, Kingston, Ontario, K7L 3N6 (Canada)
- Department of Biology, Universitaet Konstanz, D-78464 Constance (Germany)
IE-1, LEF-3, and P143 are three of six proteins encoded by Autographa californica nucleopolyhedrovirus (AcMNPV) essential for baculovirus DNA replication in transient replication assays. IE-1 is the major baculovirus immediate early transcription regulator. LEF-3 is a single-stranded DNA binding protein (SSB) and P143 is a DNA helicase protein. To investigate their interactions in vivo, we treated AcMNPV-infected Spodoptera frugiperda cells with formaldehyde and separated soluble proteins from chromatin by cell fractionation and cesium chloride equilibrium centrifugation. Up to 70% of the total LEF-3 appeared in the fraction of soluble, probably nucleoplasmic proteins, while almost all P143 and IE-1 were associated with viral chromatin in the nucleus. This suggests that LEF-3 is produced in quantities that are higher than needed for the coverage of single stranded regions that arise during viral DNA replication and is consistent with the hypothesis that LEF-3 has other functions such as the localization of P143 to the nucleus. Using a chromatin immunoprecipitation procedure, we present the first direct evidence of LEF-3, P143, and IE-1 proteins binding to closely linked sites on viral chromatin in vivo, suggesting that they may form replication complexes on viral DNA in infected cells.
- OSTI ID:
- 20637177
- Journal Information:
- Virology, Journal Name: Virology Journal Issue: 2 Vol. 329; ISSN VIRLAX; ISSN 0042-6822
- Country of Publication:
- United States
- Language:
- English
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