Single-nucleotide resolution mapping of DNA abasic sites by snAP-seq

Abasic (AP) sites are one of the most common forms of DNA damage which can lead to polymerase stalling, strand breaks and mutations. We developed snA-seq, a mapping method that reveals the location of abasic sites at base-resolution. Using synthetic DNA, we show that high selectivity for AP DNA is achieved. We use this method to explore the distribution of thymine modifications in the Leishmania major genome, by converting these into abasic sites using a glycosylase enzyme. We also apply snAP-seq to the human genome to study the distribution of endogenous AP sites, in both APE1 knockdown and control cells.