Dynamic Polycomb-CBC crosstalk orchestrates mRNA production at transcriptionally active loci in plants

• 成果类型: Article
• 署名作者: Xie, Yuanyuan; Du, Lifeng; Chen, Zhijuan; Li, Xiaoyi; Jiang, Danhua; Zhao, Fangqing; Li, Zicong
• 署名单位: Shandong University; Chinese Academy of Sciences; Nanjing Institute of Geology & Paleontology, CAS; Institute of Zoology, CAS; Shanxi Normal University; National University of Singapore
• 刊物名称: PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
• ISSN/ISSBN: 0027-8424; 1091-6490
• DOI: 10.1073/pnas.2607481123
• 发表日期: 2026-09-22
• 页码: e2607481123
• 关键词: Polycomb repression; transcriptionally active loci; mRNA cap-binding complex; pre-mRNA binding; Arabidopsis thaliana; CAP-BINDING PROTEIN; gene; arabidopsis; prc2; methylation; RECRUITMENT; WUSCHEL; determinants; maintenance; elongation

摘要

Histone modifications and cotranscriptional processing play fundamental roles in regulating eukaryotic gene transcription. Active histone modifications and efficient cotranscriptional mRNA processing act in concert to promote transcription, whereas repressive histone marks are normally depleted from active genes. However, the localization of repressive histone marks at transcribing genes and the regulatory mechanism in mRNA transcription are largely unclear. Here, we show that in Arabidopsis thaliana, the chromodomain H3K27me3 reader LIKE HETEROCHROMATIN PROTEIN1 binds nascent precursor mRNA through its middle intrinsically disordered region at H3K27me3-coated chromatin loci, thereby attenuating transcription efficiency. This interaction is subsequently disrupted by mRNA cap-binding complex to complete transcription. We illustrate how this interplay fine-tunes WUSCHEL transcription in the shoot apical meristem region to maintain stem cell homeostasis. Our findings uncover a distinct mechanism implemented by Polycomb repression and elucidates an interdependent crosstalk linking repressive histone modification and cotranscriptional mRNA processing to transcription regulation.