Date of Award
Fall 2023
Document Type
Dissertation
Degree Name
Doctor of Philosophy (PhD)
Department
Genetics
First Advisor
Giraldez, Antonio
Abstract
Nanoscale chromatin organization regulates gene expression. While chromatin is dramatically reprogrammed during zygotic genome activation (ZGA), the organization of chromatin regulatory factors during this universal process remains unclear. Here, 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, where enhancer-promoter contacts are transient and released by transcriptional elongation. Our results demonstrate that ChromExM is broadly applicable to study nanoscale nuclear organization.
Recommended Citation
Pownall, Mark, "Chromatin Expansion Microscopy Reveals Nanoscale Organization of Transcription and Chromatin" (2023). Yale Graduate School of Arts and Sciences Dissertations. 1106.
https://elischolar.library.yale.edu/gsas_dissertations/1106
