DamIP: using mutant DNA adenine methyltransferase to study DNA-protein interactions in vivo

DamIP is a new method for studying DNA-protein interaction in vivo. A mutant form of DNA adenine methyltransferase (DamK9A) from E. coli is fused to the protein of interest and expressed. The fusion protein will bind to target binding sites and introduce N(6)-adenine methylation in nearby sites in the genomic DNA. Methylated DNA fragments are enriched by immunopreciptation with an antibody that recognizes N(6)-methyladenine, and can then be used for further analysis, e.g., real-time PCR, microarray, or high-throughput sequencing. This method is simple and does not require protein-DNA crosslinking or a specific antibody to the protein of interest. This unit describes the application of this method for identification of DNA binding sites in vivo.