DNA methylation and nucleosome arrangement work together to exert epigenetic control of gene expression. Precisely tracking the effects of these two processes has traditionally relied on assembling separate snapshots of DNA methylation and nucleosome occupancy, the position of nucleosomes in the genome. But a new technique from Active Motif called NOMe-Seq (Nucleosome Occupancy and Methylome Sequencing) will allow scientists “to look at both DNA methylation and nucleosome positioning within the same DNA molecule,” according to Terry Kelly, the project’s R&D manager.
At the start of the NOMe-Seq process, fixed chromatin is artificially methylated at GpC residues not packaged in a nucleosome. Then the cross-links are reversed, releasing the nucleosomes and any bound proteins such as transcription factors, and the DNA is subjected to bisulfite conversion, which converts unmethylated cytosines to uracil. The DNA can then be sequenced, revealing both the DNA’s methylation profile and the footprint of nucleosome occupancy where DNA was protected from GpC methylation. Introduced last November, the kits cost $650 apiece and include reagents for 10 sample reactions.
NOMe-Seq “was a very attractive technology from the beginning because it allowed us, on a genome-wide scale, to be able to directly determine the nucleosome positioning with the DNA methylation status,” says Sue Clark, acting director of the cancer division at the Garvan Institute of Biomedical Research in Australia. “Previously, you could only infer by association what the relationship was between DNA methylation and nucleosome positioning,” she says. Phillippa Taberlay, a group leader in the epigenetics program at the Garvan Institute, adds that NOMe-Seq “can be applied to almost any type of epigenetic question.”
GIDDINGS: If this performs as advertised, it could add a valuable tool to the analysts’ kit and shine light in some shadowed but very important places.
MUKHOPADHYAY: Allows multitiered epigenetics analysis by combining high-resolution footprint of nucleosome occupancy with DNA methylation profile.
GIDDINGS: If this performs as advertised, it could add a valuable tool to the analysts’ kit and shine light in some shadowed but very important places.
MUKHOPADHYAY: Allows multitiered epigenetics analysis by combining high-resolution footprint of nucleosome occupancy with DNA methylation profile.
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