Methylation and hydroxylation of cytosine are two of the most prominent epigenetic modifications in mammalian genes and have important implications for many biological processes. The ability to detect these modifications in an accurate, efficient, and sensitive manner is key to understanding such processes, in both physiological and pathological conditions.
Work carried out by Haiqi Xu and colleagues in the Song lab, and recently published in the Journal of the American Chemical Society, has established a new method enabling improved detection of epigenetic modifications to cytosine residues in double stranded DNA: the CAPS+ method involves two chemical reactions for the sequential transformation of 5hmC to 5fC and then to 5caC. These reactions take place under mild conditions, are selective, efficient, and compatible with double-stranded DNA. Combined, these advantages make CAPS+ an attractive method compared to current enzymatic and chemical alternatives, which do not offer the same level of selectivity and double-stranded DNA compatibility. This work also demonstrates the use of CAPS+ on clinical samples, enabling to map the levels of modified cytosine base 5hmC in genomic DNA from both normal human brain tissue and glioblastoma tissue.
Read the full paper in the Journal of the American Chemical Society.