Structural highlights
Publication Abstract from PubMedDNA methylation plays critical roles in eukaryotic gene silencing, genome imprinting, viral defense, and suppression of transposable elements. In plants, RNA Polymerase V (Pol V)-generated non-coding RNA guides DNA methylation through the RNA-directed DNA methylation (RdDM) pathway; however, how these RNAs are selected is unknown. Here, we show that the 3'-ends of Pol V transcripts are enriched at A-rich template DNA (A-rich-DNA(T)). Arabidopsis RdDM regions possess AT-rich boundaries genome-wide, suggesting that Pol V likely terminates at A-rich-DNA(T), which subsequently defines the DNA methylation landscape in plants. A-rich-DNA(T) successfully stops Pol V transcription in vitro. Structural snapshots of Pol V transcribing A-rich-DNA(T) show that accumulation of unstable rU:dA pairs in the RNA-DNA hybrid promotes transcription bubble collapse and spontaneous transcription termination. These findings identify an intrinsic Pol V termination signal that shapes genomic DNA methylation patterning in plants and reveals a common mechanism for spontaneous transcription termination. A spontaneous termination mechanism of RNA polymerase V shapes the DNA methylation landscape in plants.,Xie G, Du X, Tan Y, Zhou Y, Chi C, Zhou S, Picard CL, Chai S, Wu L, Zhu D, Zhao J, Xue Y, Li S, Jacobsen SE, Wu Z, Du J EMBO J. 2026 Apr 2. doi: 10.1038/s44318-026-00763-7. PMID:41928006[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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