Genome methylation represents an important source of regulation of gene expression. To date, custom molecular tools for studying targeted regions of the genome are restricted to several megabases. We developed a protocol to epigenotype differentially methylated CpGs in specific regions of the genome. The protocol describes a targeted methylation library preparation upstream short read sequencing with an Illumina instrument. The protocol includes the New England Biolabs Next Enzymatic Methyl-seq Library Preparation workflow combined with the Twist Bioscience Targeted Methylation Sequencing workflow. The protocol is divided into eight steps: fragmentation, library preparation, enzymatic conversion, indexing, pooling, hybridization, capture, and amplification. Main advantages are (a) a lower amount of DNA (100 and 50 ng) than other technologies, (b) the limitation of DNA degradation using enzymatic conversion instead of chemical bisulfite, (c) the pooling of samples into 8-plex reducing handling time, and (d) the significant reduction of the panel quantity divided by 20 for saving experimental costs. This protocol was carried out on 96 samples simultaneously in a standard molecular biology laboratory, and the multiplexing can be run up to 384 samples for methylation experiments. We developed a high-throughput epigenotyping method as an alternative of methylation arrays. This approach can be adapted to any interesting regions using a custom panel for agronomic species and model organisms.
Iannuccelli et al. (Wed,) studied this question.