CpG WIZ®Oct-4

Principles of the Technique Methylation-specific PCR (MSP), performed using the CpGenome™ DNA Modification Kit and the CpG WIZ® Oct-4 Amplification Kit, permits sensitive detection of altered DNA. Because this is a PCR-based assay, it is extremely sensitive, facilitating the detection of low numbers of methylated alleles and the study of samples containing small amounts of DNA. MSP also allows examination of all CpG sites, not just those with Oct-4 sequences recognized by methylation sensitive restriction enzymes. Increasing the number of such sites that can be assessed allows rapid, fine mapping of methylation patterns throughout CpG regions. In addition, the bisulfite modification is ideally suited for analysis of CpG islands since it converts the majority of cytosines to uracils, making a region of the genome that is CG-rich less difficult to amplify by PCR. MSP employs an initial bisulfite reaction to modify the DNA, followed by a “hot start” PCR amplification with specific primers designed to distinguish methylated DNA from unmethylated DNA. As shown in Figure 1, in the bisulfite reaction, all unmethylated cytosines are converted to uracils while 5-methylcytosines remain unaltered. Thus, the sequence of the treated DNA will differ if the DNA is originally methylated vs. unmethylated. Primers contained in the CpG WIZ® Oct-4 Amplification Kit are designed to specifically amplify each of the sequences based upon these chemically-induced differences. If the sample DNA was originally unmethylated, a product will be generated after PCR using the U primer set. Conversely, a product will be generated using the M primer set if the sample was originally methylated.