Human nuclear ribomes reveal DNA-embedded ribonucleotides as epigenetic modulators of transcription-associated DNA supercoiling.

Embedded rNMPs in the human genome are linked to DNA supercoiling regulation and transcription, with over 1 million rNMPs mapped per genome.

• Why it matters: Understanding the distribution and function of non-canonical nucleotides like rNMPs is crucial because their roles in genome regulation and stability remain unclear, especially in human cells.
• What they did: High-resolution mapping of rNMPs was performed across diverse human cells, revealing their enrichment in GC-rich regions, regulatory elements, and near transcription start sites, with analyses of RNase H2 and Top1 effects.
• The result: Embedded rNMPs act as epigenetic modulators of DNA supercoiling linked to transcription and DNA sequence, suggesting a connection between ribonucleotide processing and DNA topology regulation in human cells.