(A) Editing efficacy plotted as percentage of green fluorescent protein (GFP+) (precise) HEK293T traffic light reporter (TLR) cells at different amounts of unmodified and 2′-O-methyl (2′OMe)-RNA::triethylene glycol (TEG)-modified long single-stranded DNA (ssDNA) donors (800 nt). (B) Editing efficacy of GFP-to-blue fluorescent protein (BFP) reporter conversion in K562 cells using different amounts of unmodified and 2′OMe-RNA::TEG-modified 66 nt single-stranded oligodeoxynucleotide (ssODN) donors plotted as percentage of BFP+ cells (homology-directed repair [HDR]). (C). Editing efficacy of GFP-to-BFP conversion in K562 cells using 0.5 pmol of ssODN donors modified at the 5′-end alone, the 3′-end alone, or at both the 5′- and 3′-ends, with phosphorothioate (PS), TEG, 2′OMe-RNA, or 2′OMe-RNA::TEG, plotted as percentage of BFP+ cells (precise). Complete figure of panel C is shown, along with other modifications, in Figure 3—figure supplement 2. Mean ± s.d. for at least three independent replicates are plotted. p-Values were calculated using one-way ANOVA and in all cases end-modified donors were compared to unmodified donor unless indicated otherwise (Tukey’s multiple comparisons test; ****p < 0.0001; ***p < 0.001; **p < 0.01; *p < 0.05; ns, not significant).