Baculovirus entire ORF1629 is not essential for viral replication

PLoS One. 2019 Aug 22;14(8):e0221594. doi: 10.1371/journal.pone.0221594. eCollection 2019.

Abstract

It is generally accepted that ORF1629 is essential for baculovirus replication, which has enabled isolation of recombinant viruses in a baculovirus expression system using linearized viral DNA. ORF1629-defective viruses cannot replicate in insect cells; only recombinant virus with complete ORF1629 restoration by recombination can propagate, allowing for pure isolation and the development of bacmids for easy selection of recombinant viruses. We inadvertently found proliferation in insect cells of a bacmid lacking a complete ORF1629. PCR indicated no other viruses but a lack of complete ORF1629 in the proliferated bacmid, suggesting that the baculovirus propagated without a complete ORF1629. Lack of ORF1629 decreased the virus growth rate and yield; it also increased the occlusion body (OB) size but decreased its yield. These results were confirmed for Autographa californica multicapsid nucleopolyhedrovirus (AcMNPV) and Bombyx mori NPV (BmNPV). Thus, entire ORF1629 is not essential for viral replication, though it does affect the virus growth rate, yield, and size and OB production.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Baculoviridae / growth & development
  • Baculoviridae / physiology*
  • Inclusion Bodies / metabolism
  • Recombination, Genetic / genetics
  • Reproducibility of Results
  • Viral Proteins / metabolism*
  • Virus Replication / physiology*

Substances

  • Viral Proteins

Grants and funding

This research was supported by Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education (NRF-2017R1D1A1B04036274). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. The authors declare no conflicts of interest. Optipharm Inc. and ImmuneMed Inc. provided support in the form of salary for authors SNL, JBC, BKH and SMB, but did not have any additional role in the study design, data collection and analysis, decision to publish, or preparation of the manuscript. The specific roles of these authors are articulated in the ‘author contributions’ section.