Elsevier

Journal of Biotechnology

Volume 208, 20 August 2015, Pages 44-53
Journal of Biotechnology

Rapid and highly efficient mammalian cell engineering via Cas9 protein transfection

https://doi.org/10.1016/j.jbiotec.2015.04.024Get rights and content
Under a Creative Commons license
open access

Highlights

  • Design to analysis in 3 days with in vitro transcribed gRNA and cas9 protein or mRNA.

  • Effective transfection of Cas9 mRNA or RNPs using Lipofectamine® 3000 or RNAiMax.

  • Electroporation of cas9 RNPs in difficult cell lines (Jurkat, iPSC, CD34+).

  • Cas9 RNPs enables multiple loci to be targeted simultaneously.

  • Process is amenable to high throughput set up and transfection in multi-well plates.

Abstract

CRISPR-Cas9 systems provide a platform for high efficiency genome editing that are enabling innovative applications of mammalian cell engineering. However, the delivery of Cas9 and synthesis of guide RNA (gRNA) remain as steps that can limit overall efficiency and ease of use. Here we describe methods for rapid synthesis of gRNA and for delivery of Cas9 protein/gRNA ribonucleoprotein complexes (Cas9 RNPs) into a variety of mammalian cells through liposome-mediated transfection or electroporation. Using these methods, we report nuclease-mediated indel rates of up to 94% in Jurkat T cells and 87% in induced pluripotent stem cells (iPSC) for a single target. When we used this approach for multigene targeting in Jurkat cells we found that two-locus and three-locus indels were achieved in approximately 93% and 65% of the resulting isolated cell lines, respectively. Further, we found that the off-target cleavage rate is reduced using Cas9 protein when compared to plasmid DNA transfection. Taken together, we present a streamlined cell engineering workflow that enables gRNA design to analysis of edited cells in as little as four days and results in highly efficient genome modulation in hard-to-transfect cells. The reagent preparation and delivery to cells is amenable to high throughput, multiplexed genome-wide cell engineering.

Keywords

CRISPR
Cas9
gRNA
Gene editing
Transfection
Multiplex

Abbreviations

CRISPR
clustered regularly interspaced short palindromic repeats
CAS9
CRISPR associated protein
gRNA
guide RNA
crRNA
CRISPR RNA
tracrRNA
trans-activating crRNA

Cited by (0)

1

Contributed equally to this work.