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Differential requirements for baculovirus late expression factor genes in two cell lines
1Department of Entomology, University of Georgia, Athens 30602-2603, USA.
Journal of Virology
|October 1, 1995
Summary
A baculovirus Autographa californica nuclear polyhedrosis virus (AcMNPV) late expression factor (LEF) library requires a novel host cell-specific factor 1 (hcf-1) for optimal gene expression and DNA replication in Trichoplusia ni (TN-368) cells, unlike in Spodoptera frugiperda (SF-21) cells.
Area of Science:
- Molecular Virology
- Insect Cell Culture
- Baculovirus Gene Expression
Background:
- Baculovirus Autographa californica nuclear polyhedrosis virus (AcMNPV) gene expression relies on viral and host factors.
- A library of 18 late expression factor (LEF) genes supports transient expression in Spodoptera frugiperda (SF-21) cells.
Purpose of the Study:
- To identify host cell-specific factors influencing AcMNPV late gene expression.
- To investigate the role of ORF70 in AcMNPV gene expression and DNA replication.
Main Methods:
- Transient expression assays using a baculovirus LEF gene library in SF-21 and Trichoplusia ni (TN-368) cell lines.
- Cotransfection experiments to identify additional factors required for expression in TN-368 cells.
- Plasmid DNA replication assays to assess the role of identified factors.
Main Results:
- A novel host cell-specific factor, hcf-1 (ORF70), was identified as essential for late and very late gene expression in TN-368 cells.
- hcf-1 is involved in AcMNPV origin-specific DNA replication in TN-368 cells.
- Certain LEF genes (ie-2, lef-7, p35) critical for DNA replication/stability in SF-21 cells showed minimal impact in TN-368 cells.
Conclusions:
- Host cell-specific factors are crucial for AcMNPV origin-specific DNA replication and stability.
- The identified hcf-1 plays a significant role in differential baculovirus gene expression between insect cell lines.