GSM8309020: NKL2_LGIIK9het25-deletion_H3K9me3_rep2; Neurospora crassa; ChIP-Seq
Tissue was added to ChIP lysis buffer (50mM Hepes pH 7.5, 90mM NaCl, 1mM EDTA, 1% triton + proteinase inhibitors) and was disrupted by sonication, which simultaneously sheared chromatin, using a Bioruptor Pico (Diagenode) for 15 min with a cycle of 30 sec on followed by 30 sec off, at high power. Lysates were cleared by centrifugation, 1/20th Input was saved, and histone modification antibody was added (typically 1uL) and samples were nutated overnight at 4oC. The next day, equilibrated protein A/G magnetic agarose beads (Pierce/Thermo Scientific; cat # PI78609) was added to bind the antibody, incubated for 2 hours at 4oC, and washed twice in cold ChIP Lysis buffer, once with ChIP Lysis buffer + 0.5M NaCl, once with LiCl was buffer (10mM Tris pH 8.0, 250mM LiCl, 1mM EDTA, 0.5% NP40), and DNA/protein was eluted with TES buffer (50mM Tris pH 8.0, 10mM EDTA, 1% SDS) and incubated at 65oC. Samples (IP and input) were decrosslinked at 65oC overnight. The next day, samples were RNaseA treated for two hours at 50oC, then proteinase K treated for 2 hours at 50oC, the DNA was extracted with phenol:chloroform:IAA (25:24:1), and DNA was precipitated with ethanol, sodium acetate, and glycogen, and allowed to precipitate overnight at -80oC. The next day, samples were precipitated by centrifugation, washed, dried in a Speedvac and resuspended in 30uL TE. ChIP DNA was quantified with a Qubit 3.0 using the HS method. Approximately 10 ng of DNA was used to generate ChIP-Seq libraries. Each library was prepared using the NEB Next Ultra II Library Preparation Kit (New England Biolabs, #E7645L) with the adapters from the NEBNext® Multiplex Oligos for Illumina®(Index Primers Set 1 [E7335L] or 2 [E7500L]) according to the manufacturer's instructions, except that final libraries were only PCR-amplified using eight cycles for amplification.