Journal: Nucleic Acids Research
Article Title: Single-stranded DNA with internal base modifications mediates highly efficient knock-in in primary cells using CRISPR-Cas9
doi: 10.1093/nar/gkae1069
Figure Lengend Snippet: Knocking out TREX1 improved mutational KI without chemically modifying ssDNA. ( A ) Western blot shows TREX1 expression in ABCs and HUVECs but not iPSCs. ABCs with TREX1 KO show reduced TREX1 expression. ( B ) HDR using unmodified ssDNA templates (800 nM) was improved when TREX1 was knocked out in non-CF ABCs. Knocking out TREX1 did not improve HDR by esDNA templates ( n = 4 biological replicates). ( C ) Mutational KI with ssDNA using combinations of chemical modifications in ABCs. Both esDNA OM (40 ± 21%) and esDNA PS (34 ± 16%) showed improved mutational KI relative to unmodified (3 ± 3%), end-modified (11 ± 6%) and Alt-R HDR modified ssDNA (23 ± 9%). All other combinations did not improve on esDNA OM (40 ± 21%) and esDNA PS (34 (± 16%) ( n = 4–6 biological replicates). ( D ) Modifying the 3′ half of the template alone with PS improved mutational KI compared to end modification ( n = 3 biological replicates). Including PS chemical modifications throughout the template improved editing slightly but the improvement was not statistically significant compared to templates in which only the 3′ half was modified. ( E ) Templates with PS modified internal bases spread throughout the template resulted in more consistent HDR compared to template with PS modified bases in just the last 20 bases ( n = 4 biological replicates). ( F ) Mutational KI in the HBB locus was significantly higher in ABCs using esDNA-6-PS templates (53 ± 14%) compared with Alt-R HDR templates (13 ± 12%) ( n = 4 biological replicates). G ) Mutational KI in the HBB locus was also significantly higher in CD34 + cells using esDNA-6-PS templates (66 ± 2%) compared with Alt-R HDR templates (17 ± 1%) ( n = 4 biological replicates). ( H ) Modification of every 10th base with PS groups also improved mutational KI compared to unmodified or end-modified ssDNA. Mutational KI was reduced when every fourth base was modified. Statistical comparison was made using one-way ANOVA. Multiple comparisons were performed using Tukey’s test. ***, ** and * represent P < 0.005, P < 0.01, P < and P < 0.05 respectively in all panels. All experiments used 800 nM template.
Article Snippet: Cells were resuspended in StemSpanTM SFEM II supplemented with StemSpanTM CD34 + Expansion Supplement (10X) (StemCell Technologies, Catalog #09605 and #02691).
Techniques: Western Blot, Expressing, Modification, Comparison