title: GSM1634685: leo1_H3K9me2 rep2; Schizosaccharomyces pombe; ChIP-Seq
library_construction_protocol: Immunoprecipitation was done using indicated antibody from chromatin extracts prepared from mid-logarithmic phase cells. Briefly, cells were fixed in 1% formaldehyde for 30 minutes, quenched with 125 mM glycine, and washed twice in PBS. Cells were resuspended in lysis buffer (0.1% SDS, 50 mM Hepes-KOH, 1 % Triton X-100, 0.1 % sodium deoxucholate, 1 mM EDTA and 150 mM NaCl) and lysed with glass beads in a FastPrep homogenizer. The lysate was sonicated and soluble chromatin fragments with an average size of 300 bp were collected. Chromatin was immunoprecipitated with indicated antibody and protein A magnetic beads overnight. The beads were washed. With the immunoprecipitate still on the beads, the DNA was polished, A-tailed, and ligated to an Illumina sequencing library adaptor. Digestion lambda exonuclease (final concentration 2.5U/reaction) removed nucleotides from 5′ ends of double-stranded DNA until blocked by the formaldehyde induced protein-DNA crosslink. The crosslinks were reversed (4h at 65°C) and DNA was eluted from the beads. The single-stranded DNA was subsequently made double-stranded by primer annealing and extension. A second sequencing adaptor was ligated. Using indexing primers, the fragments were PCR amplified and gel purified (Qiagen MinElute). Samples were quantified on using Qubit (HS dsDNA).
attributes.tag: GEO Accession
attributes.value: GSM1634685