Chromatin expansion microscopy reveals nanoscale organization of transcription and chromatin

• 成果类型: Article
• 署名作者: Pownall, Mark E.; Miao, Liyun; Vejnar, Charles E.; M'Saad, Ons; Sherrard, Alice; Frederick, Megan A.; Benitez, Maria D. J.; Boswell, Curtis W.; Zaret, Kenneth S.; Bewersdorf, Joerg; Giraldez, Antonio J.
• 署名单位: Yale University; Yale University; Yale University; University of Pennsylvania; Yale University; Yale University; Yale University; Yale University; Yale University; Yale New Haven Hospital
• 刊物名称: SCIENCE
• ISSN/ISSBN: 0036-9265
• DOI: 10.1126/science.ade5308
• 发表日期: 2023-07-07
• 页码: 92-99
• 关键词: rna-polymerase-ii; c-terminal domain; general-method; image-analysis; in-vivo; activation; DYNAMICS; nanog; cell; fluorophores

摘要

Nanoscale chromatin organization regulates gene expression. Although chromatin is notably reprogrammed during zygotic genome activation (ZGA), the organization of chromatin regulatory factors during this universal process remains unclear. In this work, we developed chromatin expansion microscopy (ChromExM) to visualize chromatin, transcription, and transcription factors in vivo. ChromExM of embryos during ZGA revealed how the pioneer factor Nanog interacts with nucleosomes and RNA polymerase II (Pol II), providing direct visualization of transcriptional elongation as string-like nanostructures. Blocking elongation led to more Pol II particles clustered around Nanog, with Pol II stalled at promoters and Nanog-bound enhancers. This led to a new model termed kiss and kick, in which enhancer-promoter contacts are transient and released by transcriptional elongation. Our results demonstrate that ChromExM is broadly applicable to study nanoscale nuclear organization.