GSM7743483: Cas9-g5; Homo sapiens; OTHER
Genomic DNA was extracted using the ReliaPrep™ Blood gDNA Miniprep System kit (Promega) according to the manufacturer's protocol Library construction was essentially performed as described by Turchiano et. al (Cell Stem Cell, 2021). Briefly, gDNA was fragmented by enzymatic digestion using the NEBNext® Ultra™ II FS DNA Library Prep (NEB) to obtain average fragment lengths of 350 bp. The DNA was end repaired and a protruding 3'-A nucleotide was added according to the manufacturer's instructions  in order to enable the ligation of a linker sequence with a protruding 3'-T. After linker ligation, fragments were purified using the QIAquick PCR Purification Kit (NEB). The region of interest (on-target site) was amplified in two rounds of PCR using Q5® Hot Start High-Fidelity DNA Polymerase (NEB). PCR conditions were: 20 cycles at 95°C for 15 s, 63°C (first reaction) or 68°C (second reaction) for 20 s, 72°C for 20 s. The first reaction was performed with primers complementary to the linker sequence and to a sequence in close proximity to the on-target site (bait primer). Two decoy primers were introduced to reduce full-length amplification of the fragments which contain the on-target sequence without a chromosomal aberration event. The second PCR utilized nested primers to reduce the amount of mis-amplified fragments and to introduce a binding platform for barcoding primers. DNA fragments from the second PCR were purified using the QIAquick® PCR purification kit (Qiagen) and barcoded. Third PCR introduced the barcoded Illumina adapter for sequencing (NEBNext® Multiplex Oligos for Illumina; Index Primers Sets 1-4). Sequencing was outsourced to service NGS provider Genewiz (part of Azenta Life Sciences) where it was performed on a Illumina NovaSeq6000 device collecting 2x150 bp paired-end reads.