Fig. 2
From: Titration-based normalization of antibody amount improves consistency of ChIP-seq experiments
Determination of the optimal antibody titer using DNAchrom. Chromatin input was prepared from 40 million fixed K562 cells and DNAchrom was measured. 0.05 to 10.0 µg of ChIP-validated anti-H3K27ac antibody was incubated with 10 µg of DNAchrom in ChIP reactions. Fold enrichment of H3K27ac-positive PABPC1-TSS and SMARCA4-TSS loci against a negative MYT1-TSS locus was shown in the left y-axis to access the specificity of individual ChIP reaction. The DNA amount obtained after ChIP (ChIP DNA) and ChIP yield were shown in the right Y- axes to access the yield of immunoprecipitation in individual reaction. The optimal titer as the the ratio between antibody and chromatin amounts to yield 1 – 5 ng of ChIP DNA and 5 – 200 fold enrichment in multiple positive over negative loci was highlighted as orange arrow on the top, and the ratio between the antibody amount and DNAchrom at the optimal titer is indicated as titer 1 (T1)