title: GSM1474235: ChrRNA_siLuc; Homo sapiens; OTHER
library_construction_protocol: Chromatin RNA fraction was prepared from ~80% confluent HeLa cells in 100mm Dishes. Approximately 7x106 cells were washed with ice-cold PBS twice. The cells were lysed with ice-cold 4 ml of HLB/NP40 buffer (10 mM Tris-Hcl pH 7.5, 10 mM NaCl, 0.5% NP40 and 2.5 mM MgCl2) and incubated on ice for 5 min. After the incubation, 1 ml of ice-cold HLB/NP40/Sucrose buffer (10 mM Tris-HCl pH 7.5, 10 mM NaCl, 0.5% NP40, 2.5 mM MgCl2 and 10 % Sucrose) was under-laid and then the nuclei were collected under 1,400 rpm centrifuge at 40C for 5 min. Isolated nuclei were resuspended in 1.25 ml of NUN1 solution (20 mM Tri-HCl pH 8.0, 75mM NaCl, 0.5 mM EDTA, 50% Glycerol and proteinase inhibitor 1xComplete (Roche)) and added 1.2 ml NUN2 buffer (20 mM HEPES-KOH pH 7.6, 7.5 mM MgCl2, 0.2 mM EDTA, 300 mM NaCl, 1 M Urea, 1% NP40, proteinase inhibitor 1xComplete and phosphatase inhibitor 1xPhosStop (Roche)). 15 min incubation was carried out on ice with mixing by max speed vortex for 5 sec every ~4 min and then chromatin pellets were precipitated under 13,000 rpm centrifuge at 4oC for 10min. Chromatin pellet was resuspended in 200 ml HSB (10mM Tris-HCl pH 7.5, 500 mM NaCl and 10 mM MgCl2) with 0.25 U/ml TURBO DNase (Life technologies) at 37oC for 10 min and then treated with Proteinase K for 10 min. RNA was extracted by Trizol reagent (Life technologies). This extraction steps were repeated three times.