Input Strategy for Improving Analysis of ChIP-exo Data and Beyond [RNA-Seq]

Several recently emerging ChIP-seq (chromatin immunoprecipitation followed by sequencing) based methods perform chemical steps on bead-bound immunoprecipitated chromatin, posing a challenge for generating similarly treated input controls required for bioinformatics and data quality analyses. Here we present a versatile method for producing technique-specific input controls for ChIP-based methods that utilize additional bead-bound processing steps. Application of this method allowed for discovery of a novel CTCF binding motif from ChIP-exo data. Overall design: HeLa cells were transfected with either a scrambled siRNA or one of two CTCF siRNAs (Thermo Fisher Scientific ? Life technologies) using Lipofectamine RNAiMAX (Thermo Fisher Scientific - Life technologies) and incubated for 24 hr.