Measuring the Formation and Repair of DNA Damage by Ligation-Mediated PCR

There is a need to analyze the formation of DNA lesions in specific sequence contexts. The formation and repair of DNA damage at specific locations in the genome is modulated by the DNA sequence, by DNA methylation patterns, by the transcriptional status of the locus, and by chromatin proteins associated with the DNA. The only method currently available to allow a precise sequence mapping of DNA lesions in mammalian cells is the ligation-mediated polymerase chain reaction (LM-PCR). I describe the technical details of LM-PCR as exemplified by the mapping of DNA damage products in ultraviolet (UV) light-irradiated cells.