The current method employed to analyse CGI methylation are cumbersome, time-consuming, use toxic reagents, and can damage template DNA. Given the importance of CGI methylation in influencing the expression of genes, a new method is required for faster analysis free of DNA damaging chemicals.
Using the CxxC domain, which specifically binds non-methylated CGIs, in a column format, it is possible to generate a complete library of non-methylated CGIs from tissues or cells of interest. Complete isolation of all CGIs is facilitated through the combined use of CxxC and MBD domains, the latter binding specifically to methylated CGIs. Isolation of CGIs using CxxC domain followed by downstream array- or PCR-based analysis allows fast and accurate identification of non-methylated CGIs from the sample of interest.
This method has successfully been applied to various human tissues, available as an array of non-methylated CGIs. The CxxC domain column provides a >50-fold enrichment of non-methylated CGIs from bulk DNA, validating the use of this domain.
Patent on CxxC domain, CGI library, and CxxC domain based reagents has been granted in USA, UK, and EU