Transcription-induced active forces suppress chromatin motion

• 成果类型: Article
• 署名作者: Shin, Sucheol; Shi, Guang; Cho, Hyun Woo; Thirumalai, D.
• 署名单位: University of Texas System; University of Texas Austin; University of Illinois System; University of Illinois Urbana-Champaign; Seoul National University of Science & Technology; Seoul National University of Science & Technology; University of Texas System; University of Texas Austin
• 刊物名称: PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
• ISSN/ISSBN: 0027-12132
• DOI: 10.1073/pnas.2307309121
• 发表日期: 2024-03-19
• 关键词: dynamics; interphase; dna; ORGANIZATION; TRANSITION; principles; liquids; STATES; genome

摘要

The organization of interphase chromosomes in a number of species is starting to emerge thanks to advances in a variety of experimental techniques. However, much less is known about the dynamics, especially in the functional states of chromatin. Some experiments have shown that the motility of individual loci in human interphase chromosome decreases during transcription and increases upon inhibiting transcription. This is a counterintuitive finding because it is thought that the active mechanical force (F) on the order of ten piconewtons, generated by RNA polymerase II (RNAPII) that is presumably transmitted to the gene -rich region of the chromatin, would render it more open, thus enhancing the mobility. We developed a minimal active copolymer model for interphase chromosomes to investigate how F affects the dynamical properties of chromatin. The movements of the loci in the gene -rich region are suppressed in an intermediate range of F and are enhanced at small F values, which has also been observed in experiments. In the intermediate F, the bond length between consecutive loci increases, becoming commensurate with the distance at the minimum of the attractive interaction between nonbonded loci. This results in a transient disorder -to -order transition, leading to a decreased mobility during transcription. Strikingly, the F -dependent change in the locus dynamics preserves the organization of the chromosome at F = 0. Transient ordering of the loci, which is not found in the polymers with random epigenetic profiles, in the gene -rich region might be a plausible mechanism for nucleating a dynamic network involving transcription factors, RNAPII, and chromatin.