Extended Data Fig. 3. Installation of a 38-bp Bxb1 attB site at CCR5 with twinPE.

Spacer pairs targeting the CCR5 locus were designed for twinPE-mediated insertion of the Bxb1 attB attachment site. For each spacer, three pegRNAs were designed having three different PBS lengths and a fixed RT template that encodes the full-length Bxb1 attB sequence (38 bp). Sequences of pegRNAs are listed in Supplementary Table 1. For each spacer pair, a three-by-three matrix of pegRNA combinations was tested by plasmid DNA co-transfection with PE2 in HEK293T cells. Each pegRNA pair is specified below the x-axis. Values reflect single biological replicates.