Practical method for targeted disruption of cilia-related genes by using CRISPR/Cas9-mediated, homology-independent knock-in system.
The CRISPR/Cas9 system has revolutionized genome editing in virtually all organisms. Although the CRISPR/Cas9 system enables the targeted cleavage of genomic DNA, its use for gene knock-in remains challenging because levels of homologous recombination activity vary among various cells. In contrast, the efficiency of homology-independent DNA repair is relatively high in most cell types. Therefore the use of a homology-independent repair mechanism is a possible alternative for efficient genome editing. Here we constructed a donor knock-in vector optimized for the CRISPR/Cas9 system and developed a practical system that enables efficient disruption of target genes by exploiting homology-independent repair. Using this practical knock-in system, we successfully disrupted genes encoding proteins involved in ciliary protein trafficking, including IFT88 and IFT20, in hTERT-RPE1 cells, which have low homologous recombination activity. The most critical concern using the CRISPR/Cas9 system is off-target cleavage. To reduce the off-target cleavage frequency and increase the versatility of our knock-in system, we constructed a universal donor vector and an expression vector containing Cas9 with enhanced specificity and tandem sgRNA expression cassettes. We demonstrated that the second version of our system has improved usability.
Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan ykatoh@pharm.kyoto-u.ac.jp kazunaka@pharm.kyoto-u.ac.jp.
Yohei
Y
Katoh
Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan.
Saki
S
Michisaka
Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan.
Shohei
S
Nozaki
Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan.
Teruki
T
Funabashi
Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan.
Tomoaki
T
Hirano
Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan.
Ryota
R
Takei
Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan ykatoh@pharm.kyoto-u.ac.jp kazunaka@pharm.kyoto-u.ac.jp.
Kazuhisa
K
Nakayama
D064113:CRISPR-Cas Systems; D002923:Cilia / Q000235:genetics*; D064112:Clustered Regularly Interspaced Short Palindromic Repeats; D004247:DNA; D004260:DNA Repair; D055879:Gene Knock-In Techniques / Q000379:methods*; D018390:Gene Targeting; D059765:Homologous Recombination
D004247:DNA