Hybrid lentivirus-phiC31-int-NLS vector allows site-specific recombination in murine and human cells but induces DNA damage

PLoS One. 2014 Jun 23;9(6):e99649. doi: 10.1371/journal.pone.0099649. eCollection 2014.

Abstract

Gene transfer allows transient or permanent genetic modifications of cells for experimental or therapeutic purposes. Gene delivery by HIV-derived lentiviral vector (LV) is highly effective but the risk of insertional mutagenesis is important and the random/uncontrollable integration of the DNA vector can deregulate the cell transcriptional activity. Non Integrative Lentiviral Vectors (NILVs) solve this issue in non-dividing cells, but they do not allow long term expression in dividing cells. In this context, obtaining stable expression while avoiding the problems inherent to unpredictable DNA vector integration requires the ability to control the integration site. One possibility is to use the integrase of phage phiC31 (phiC31-int) which catalyzes efficient site-specific recombination between the attP site in the phage genome and the chromosomal attB site of its Streptomyces host. Previous studies showed that phiC31-int is active in many eukaryotic cells, such as murine or human cells, and directs the integration of a DNA substrate into pseudo attP sites (pattP) which are homologous to the native attP site. In this study, we combined the efficiency of NILV for gene delivery and the specificity of phiC31-int for DNA substrate integration to engineer a hybrid tool for gene transfer with the aim of allowing long term expression in dividing and non-dividing cells preventing genotoxicity. We demonstrated the feasibility to target NILV integration in human and murine pattP sites with a dual NILV vectors system: one which delivers phiC31-int, the other which constitute the substrate containing an attB site in its DNA sequence. These promising results are however alleviated by the occurrence of significant DNA damages. Further improvements are thus required to prevent chromosomal rearrangements for a therapeutic use of the system. However, its use as a tool for experimental applications such as transgenesis is already applicable.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Attachment Sites, Microbiological / genetics
  • Bacteriophages / metabolism*
  • Base Sequence
  • Cell Line
  • DNA Damage*
  • Genetic Vectors / metabolism*
  • Humans
  • Hybridization, Genetic*
  • Lentivirus / genetics*
  • Mice
  • Models, Biological
  • Molecular Sequence Data
  • Mutagenesis, Insertional / genetics
  • Nuclear Localization Signals
  • Polymerase Chain Reaction
  • Recombination, Genetic*

Substances

  • Nuclear Localization Signals

Grants and funding

This work was supported by grants from European FP6 (INTEGRA NEST-Adventure contract #29025), AFM (Association Française contre les Myopathies), and Rétina France. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. Co-authors NG, DA, SP, SU and HP are employed by NewVectys SAS. NewVectys SAS provided support in the form of salaries for authors NG, DA, SP, SU and HP, 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.