1. Transcription-mediated supercoiling regulates genome folding and loop formation.
- Author
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Neguembor MV, Martin L, Castells-García Á, Gómez-García PA, Vicario C, Carnevali D, AlHaj Abed J, Granados A, Sebastian-Perez R, Sottile F, Solon J, Wu CT, Lakadamyali M, and Cosma MP
- Subjects
- Cell Cycle Proteins chemistry, Cell Cycle Proteins genetics, Cell Line, Cell Nucleus genetics, Chondroitin Sulfate Proteoglycans genetics, Chondroitin Sulfate Proteoglycans metabolism, Chromatin metabolism, Chromosomal Proteins, Non-Histone chemistry, Chromosomal Proteins, Non-Histone genetics, DNA Topoisomerases, Type I genetics, DNA Topoisomerases, Type I metabolism, DNA-Binding Proteins genetics, DNA-Binding Proteins metabolism, Female, Humans, Lamins genetics, Lamins metabolism, RNA Polymerase II metabolism, Single Molecule Imaging methods, Cohesins, Cell Cycle Proteins metabolism, Chromatin chemistry, Chromatin genetics, Chromosomal Proteins, Non-Histone metabolism, Transcription, Genetic physiology
- Abstract
The chromatin fiber folds into loops, but the mechanisms controlling loop extrusion are still poorly understood. Using super-resolution microscopy, we visualize that loops in intact nuclei are formed by a scaffold of cohesin complexes from which the DNA protrudes. RNA polymerase II decorates the top of the loops and is physically segregated from cohesin. Augmented looping upon increased loading of cohesin on chromosomes causes disruption of Lamin at the nuclear rim and chromatin blending, a homogeneous distribution of chromatin within the nucleus. Altering supercoiling via either transcription or topoisomerase inhibition counteracts chromatin blending, increases chromatin condensation, disrupts loop formation, and leads to altered cohesin distribution and mobility on chromatin. Overall, negative supercoiling generated by transcription is an important regulator of loop formation in vivo., Competing Interests: Declaration of interests C.t.W. holds or has patent filings pertaining to Oligopaints and related technologies, including other oligo-based methods for imaging. Her laboratory also has active collaborations with industry for the development of Oligopaint technologies and holds a sponsored research agreement with Bruker Inc. She is also a non-equity-holding co-founder and member of the scientific advisory board of Acuity Spatial Genomics and, through personal connections to George Church, has equity in companies associated with him (https://arep.med.harvard.edu/gmc/tech.html/), including 10x Genomics and Twist., (Copyright © 2021 Elsevier Inc. All rights reserved.)
- Published
- 2021
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