PUBLICATION Mammalian Cell Designers’ Laboratory

MISSION

Our mission is to engineer next-generation mammalian cell factories
for the production of complex biotherapeutics.
By integrating synthetic biology, genome engineering, and autonomous experimentation,
we aim to transform cell line development from empirical optimization into a predictive engineering discipline.

Journal Articles

One-step generation of triple knockout CHO cell lines using CRISPR/Cas9 and fluorescent enrichment
Author
Lise Marie Grav*, Jae Seong Lee*, Signe Gerling, Thomas Beuchert Kallehauge, Anders Holmgaard Hansen, Stefan Kol, Gyun Min Lee, Lasse Ebdrup Pedersen, Helene Faustrup Kildegaard‡
Journal
Biotechnology Journal
Vol
10(9)
Page
1446-1456
Year
2017~

The CRISPR/Cas9 genome editing technology has previously been shown to be a highly efficient tool for generating gene disruptions in CHO cells. In this study we further demonstrate the applicability and efficiency of CRISPR/Cas9 genome editing by disrupting FUT8, BAK and BAX simultaneously in a multiplexing setup in CHO cells. To isolate Cas9-expressing cells from transfected cell pools, GFP was linked to the Cas9 nuclease via a 2A peptide. With this method, the average indel frequencies generated at the three genomic loci were increased from 11% before enrichment to 68% after enrichment. Despite the high number of genome editing events in the enriched cell pools, no significant off-target effects were observed from off-target prediction followed by deep sequencing. Single cell sorting of enriched multiplexed cells and deep sequencing of 97 clones revealed the presence of four single, 23 double and 34 triple gene-disrupted cell lines. Further characterization of selected potential triple knockout clones confirmed the removal of Bak and Bax protein and disrupted fucosylation activity as expected. The knockout cell lines showed improved resistance to apoptosis compared to wild-type CHO-S cells. Taken together, multiplexing with CRISPR/Cas9 can accelerate genome engineering efforts in CHO cells even further.