Illustration of the Illumina-adapted ChIP-exo strategy. To carry out ChIP-exo, the P5 adapter is ligated upstream and downstream of the exonuclease digestion-protected region. The ChIP-exo library is sequenced with single-end reads from the P5 adapter. The reads are mapped on the reference genome. The overlap between the reads mapped on the top and the bottom strands is considered as the exonuclease digestion-protected region. The index sequence is underlined. The P7 flow cell capture sequence is in green. The P5 flow cell capture sequence is in purple. The P5/P7 complementary sequence is in blue.