CRISPR/Cas9-mediated genome engineering of CHO cell factories: application and perspectives

Chinese hamster ovary (CHO) cells are the most widely used production host for therapeutic proteins.With the recent emergence of CHO genome sequences, CHO cell line engineering has takenon a new aspect through targeted genome editing. The bacterial clustered regularly interspacedshort palindromic repeat (CRISPR)/CRISPR-associated protein 9 (Cas9) system enables rapid,easy and efficient engineering of mammalian genomes. It has a wide range of applications frommodification of individual genes to genome-wide screening or regulation of genes. Facile genomeediting using CRISPR/Cas9 empowers researchers in the CHO community to elucidate the mechanisticbasis behind high level production of proteins and product quality attributes of interest. Inthis review, we describe the basis of CRISPR/Cas9-mediated genome editing and its applicationfor development of next generation CHO cell factories while highlighting both future perspectivesand challenges. As one of the main drivers for the CHO systems biology era, genome engineeringwith CRISPR/Cas9 will pave the way for rational design of CHO cell factories.