Binding of TAL1 transcription factor was measured using a ChIP protocol as previously described (Palii, 2011). Chromatin from 0.5x10^8 cells was fragmented to a size range of 100-300 bases with a Bioruptor (Diagenode) at 4°C. Solubilized chromatin was immunoprecipitated with an antibody against TAL1 (C-21, Santa-Cruz) or an isotype IgG control. Antibody-chromatin complexes were pulled-down using Dynabeads-Protein G, washed and eluted. After cross-link reversal and proteinase K treatment, immunoprecipitated DNA was extracted with phenol-chloroform. ChIPed DNA was amplified using the Illumina protocol with modifications described in (Palii, 2011).