title: GSM8000194: Prime editing of IL2RB Exon1 after activation of IL2RB in K562 (Rep2); Homo sapiens; OTHER
library_construction_protocol: K562 and WTC11 cells were lysed in a lysis buffer [100 mM Tris-HCl pH8.0, 0.05% SDS and 0.04 mg/mL proteinase K(Thermo Scientific)], and incubated at 50 oC 60 min and 80 oC 30 min. T7-assisted reporter mapping: gDNA of K562 cells was purified using the DNeasy Blood & Tissue Kit (QIAGEN) and in vitro transcribed with the HiScribe T7 High Yield RNA Synthesis Kit (New England Biolabs). Briefly, each reaction (20 uL) contained 0.3~1 ug gDNA, NTPs (10 mM each) and 2 ul T7 RNA Polymerase Mix. The reaction mixture was incubated at 37 oC for 16 hours. Then, gDNA was digested with 2.5 uL DNase (Qiagen) in a 100 uL reaction at room temperature for 30 min. RNA was extracted with TRIzol LS Reagent (Invitrogen), and aqueous phase was precipitated with 1 volume of isopropanol and 5 ug Glycogen (Invitrogen) at -80 oC for 1 hour. RNA pellet was collected by centrifugation at 21,000 x g at 4 oC for 1 hour. The pellet was washed with 80% ice-cold ethanol and resuspended in 11.5 uL nuclease-free water. For reverse transcription, RNA was incubated with 0.5 uL 100 uM RT primer p6 (5'-TCGTCGGCAGCGTCAGATGTGTATAAGAGACAGNNNNNNNN-3') and 1 uL 10 mM dNTP at 65 oC for 5 min and cooled on ice. Then, 4 uL 5X RT buffer, 1 uL 100 mM DTT, 1 uL RNaseOUT (40 U/uL) and 1 uL SuperScript IV RT (200 U/uL, Invitrogen) were added and the reaction mixture was incubated at 23 oC for 10 min, 50  oC for 15 min and 80 oC for 10 min. cDNA library was amplified with KAPA2G Robust HotStart polymerase, using primers p7 (5'- GTGACTGGAGTTCAGACGTGTGCTCTTCCGATCTGAAAGGAAGCCCTGCTTCCTCCAGAGGG-3', 0.5 uM) and p8 (5'- TCGTCGGCAGCGTCAGATGTGTATAAGAGACAG-3', 0.5 uM). PCR reaction was performed as follows: 95 oC 3 min; 95 oC 15 s, 65 oC 15 s, 72 oC 30 s, 16~18 cycles; and 72 oC 1 min. The PCR product was subjected to double-sided size selection (0.5X, 0.9X) and cleaned up with AMPure XP beads. The resulting product ranged from 200 to 1000 bp. To prepare Illumina sequencing libraries, 5-10 ng PCR product was re-amplified with the Nextera P5 and TruSeq P7 library index primers for 5 cycles. The final PCR product underwent another round of double-sided size selection (0.5X, 0.9X) and cleaned up with AMPure XP beads. The library was sequenced on an Illumina MiSeq in paired-end mode (Read 1: 254 bp; Read2: 55bp). Amplicon sequencing of synHEK3 reporters: 100~250 ng gDNA or cell lysates were amplified using KAPA2G Robust HotStart ReadyMix with primers p9 (5'-GTGACTGGAGTTCAGACGTGTGCTCTTCCGATCTCTACCCCGACCACATGAAGCAGC-3', 0.5 uM) and p10 (5'-TCGTCGGCAGCGTCAGATGTGTATAAGAGACAGNNNNNNNNNNGACCATGTCATCGCGCTTCTCGT-3', 0.5 uM). PCR reaction was performed as follows: 95 oC 3 min; 95 oC 15 s, 68-N oC 15 s, 72 oC 30 s, for 9 cycles (N was cycle number); 95 oC 15 s, 65 oC 15 s, 72 oC 30 s, for 11 cycles; and 72 oC 1 min. To ensure enough coverage and accurate measurement of editing efficiencies, for the K562 synHEK3 pool, we pooled products from at least 16 PCR reactions. The PCR product was purified with AMPure XP beads. 5 ng PCR product was re-amplified with the Nextera P5 and TruSeq P7 library index primers for 5 cycles.  Other amplicon sequencing: Cell lysates or plasmids were directly used for PCR with the KAPA2G Robust HotStart ReadyMix with primers (0.5 uM each) designed for the endogenous targets. PCR reaction was performed as follows: 95 oC 3 min; 95 oC 15 s, 66-N oC 15 s, 72 oC 40 s, for 8 cycles (N was cycle number); 95 oC 15 s, 60 oC 15 s, 72 oC 40 s, for 11 cycles; and 72 oC 1 min. The PCR product was purified with AMPure XP beads. 5 ng PCR product was re-amplified with the Nextera P5 and TruSeq P7 library index primers for 5 cycles. Amplicon sequencing