Genetics instability of wtAAV2 genome and AAV promoter activities in the Baculovirus/Sf9 cells system

PLoS One. 2018 Jul 5;13(7):e0199866. doi: 10.1371/journal.pone.0199866. eCollection 2018.

Abstract

The human Adeno-Associated Virus serotype 2 (wtAAV2) is a common non-pathological virus and its recombinant form (rAAV) is widely used as gene therapy vector. Although rAAVs are routinely produced in the Baculovirus/Sf9 cell system, wtAAV2 has never been studied in this context. We tried to produce wtAAV2 in the baculovirus/Sf9 cell system hypothesizing that the wtAAV2 may be considered as a normal recombinant AAV transgene. Through our attempts to produce wtAAV2 in Baculovirus/Sf9, we found that wtAAV2 p5 promoter, which controls the expression of large Rep proteins in mammalian cells, was active in this system. p5 promoter activity in the baculovirus/Sf9 cell system leads to the expression of Rep78 that finally excises wtAAV2 genome from the baculovirus genome during the earliest phases of baculovirus stock production. Via p5 promoter expression kinetics and strand specific RNA-Seq analysis of wtAAV2, rAAV and Rep2/Cap2 cassettes in the baculovirus context we could demonstrate that wtAAV2 native promoters, p5, p19 and p40 are all active in the context of the baculovirus system and lead to the expression of different proteins and peptides. In addition, this study has proven that the baculovirus brings at least some of the helper functions needed in the AAV replication/life cycle.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Baculoviridae / genetics*
  • DNA Replication
  • DNA, Viral / genetics
  • DNA, Viral / isolation & purification
  • DNA, Viral / metabolism
  • DNA-Binding Proteins / genetics
  • DNA-Binding Proteins / metabolism
  • Dependovirus / genetics*
  • Gene Expression Regulation, Viral*
  • Gene Transfer Techniques
  • Genetic Vectors / genetics
  • Genetic Vectors / metabolism*
  • Genome, Viral*
  • Genomic Instability*
  • Humans
  • Promoter Regions, Genetic*
  • Sf9 Cells
  • Virus Replication

Substances

  • DNA, Viral
  • DNA-Binding Proteins

Grants and funding

M.U.K. was supported by grants from Academy of Finland, Sigrid Jusélius Foundation and Jane and Aatos Erkko Foundation.