A new method for simultaneously capturing the chromosome conformation and DNA methylome in a cell is reported in Nature Methods this week. Called Methyl-HiC, the technique combines in situ Hi-C and whole-genome bisulfite sequencing. Its developers say it can be used to reveal coordinated DNA methylation status between distal genomic segments that are in spatial proximity in the nucleus, as well as to delineate heterogeneity of both the chromatin architecture and DNA methylome in a mixed population. Methyl-HiC, they write, "enables simultaneous characterization of cell-type-specific chromatin organization and epigenome in complex tissues."
Step defects can be used to precisely guide the transport of DNA to and from graphene nanopores, according to a paper appearing in Nature Nanotechnology this week. The study's authors write that adsorbed DNA moves "much faster down a step defect than up, and even faster along the defect edge, regardless of whether the motion was produced by a mechanical force or a solvent flow." They take advantage of this direction dependency to demonstrate a mechanical analogue of an electric diode and a system for delivering DNA molecules to a nanopore, and write that this approach "can be of use in a diverse range of technological processes from lab-on-chip sorting and synthesis of biomolecules to single-molecule nanopore sequencing."
A new sequencing technique for the rapid high-quality sequencing of entire messenger RNAs is detailed in Nature Methods this week. Called FLAM-seq — short for full-length poly(A) and mRNA sequencing — the method is used to deliver high-quality full-length mRNA sequences for thousands of different genes per sample in human cell lines, brain organoids, and Caenorhabditis elegans. "We find that 3' untranslated region length is correlated with poly(A) tail length, that alternative polyadenylation sites and alternative promoters for the same gene are linked to different tail lengths, and that tails contain a substantial number of cytosines," the paper's authors write of their experiments with the technique.