Protocol for Methylated DNA Immunoprecipitation (MeDIP) Analysis

DNA methylation is a fundamental epigenetic mechanism for silencing gene expression by either modifying chromatin structure to a repressive state or interfering with the transcription factors' binding. DNA methylation primarily occurs at the position C5 of a cytosine ring mainly in the context of CpG dinucleotides. The modification can be recognized both in vivo and in vitro by the methyl-CpG binding proteins (MBPs) as well as in vitro by an antibody raised against 5-methylcytosine (5mC). This chapter describes different MBPs and introduces a standard methylated DNA immunoprecipitation (MeDIP) method, which is based on using the anti-5mC antibody to isolate methylated DNA fragments for subsequent locus-specific DNA methylation analysis. The MeDIP-generated DNA can be used as well for methylation profiling on a genome scale using array-based (MeDIP-chip) and high-throughput (MeDIP-seq) technologies.