Efficient gene targeting by homology-directed repair in rat zygotes using TALE nucleases (original) (raw)

  1. Laurent Tesson1,2,7,
  2. Séverine Menoret1,2,
  3. Claire Usal1,2,
  4. Anne De Cian3,
  5. Virginie Thepenier1,2,
  6. Reynald Thinard1,2,
  7. Daniel Baron1,
  8. Marine Charpentier3,
  9. Jean-Baptiste Renaud3,
  10. Roland Buelow4,
  11. Gregory J. Cost5,
  12. Carine Giovannangeli3,
  13. Alexandre Fraichard6,
  14. Jean-Paul Concordet3 and
  15. Ignacio Anegon1,2
  16. 1INSERM UMR 1064-ITUN, CHU de Nantes, Nantes F44093, France;
  17. 2Platform Rat Transgenesis, Nantes F44093, France;
  18. 3INSERM U565, CNRS UMR7196, Museum National d’Histoire Naturelle, F75005 Paris, France;
  19. 4Open Monoclonal Technologies, Palo Alto, California 94303, USA;
  20. 5Sangamo BioSciences, Richmond, California 94804, USA;
  21. 6genOway, Lyon F69007, France
  22. Corresponding author: Ignacio.Anegon{at}univ-nantes.fr
  23. ↵7 These authors contributed equally to this work.

Abstract

The generation of genetically modified animals is important for both research and commercial purposes. The rat is an important model organism that until recently lacked efficient genetic engineering tools. Sequence-specific nucleases, such as ZFNs, TALE nucleases, and CRISPR/Cas9 have allowed the creation of rat knockout models. Genetic engineering by homology-directed repair (HDR) is utilized to create animals expressing transgenes in a controlled way and to introduce precise genetic modifications. We applied TALE nucleases and donor DNA microinjection into zygotes to generate HDR-modified rats with large new sequences introduced into three different loci with high efficiency (0.62%–5.13% of microinjected zygotes). Two of these loci (Rosa26 and Hprt1) are known to allow robust and reproducible transgene expression and were targeted for integration of a GFP expression cassette driven by the CAG promoter. GFP-expressing embryos and four Rosa26 GFP rat lines analyzed showed strong and widespread GFP expression in most cells of all analyzed tissues. The third targeted locus was Ighm, where we performed successful exon exchange of rat exon 2 for the human one. At all three loci we observed HDR only when using linear and not circular donor DNA. Mild hypothermic (30°C) culture of zygotes after microinjection increased HDR efficiency for some loci. Our study demonstrates that TALE nuclease and donor DNA microinjection into rat zygotes results in efficient and reproducible targeted donor integration by HDR. This allowed creation of genetically modified rats in a work-, cost-, and time-effective manner.

Footnotes

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