RSC和ISW2染色质重塑因子的动态一维搜索与连续性核小体易位

Dynamic 1D Search and Processive Nucleosome Translocations by RSC and ISW2 Chromatin Remodelers.

作者信息

Kim Jee Min, Carcamo Claudia C, Jazani Sina, Xie Zepei, Feng Xinyu A, Yamadi Maryam, Poyton Matthew, Holland Katie L, Grimm Jonathan B, Lavis Luke D, Ha Taekjip, Wu Carl

机构信息

Department of Biology, Johns Hopkins University, Baltimore, MD 21218, USA.

Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD, USA.

出版信息

bioRxiv. 2024 Jan 15:2023.06.13.544671. doi: 10.1101/2023.06.13.544671.

DOI:10.1101/2023.06.13.544671

PMID:38293098

原文链接:https://pmc.ncbi.nlm.nih.gov/articles/PMC10827135/

Abstract

Eukaryotic gene expression is linked to chromatin structure and nucleosome positioning by ATP-dependent chromatin remodelers that establish and maintain nucleosome-depleted regions (NDRs) near transcription start-sites. Conserved yeast RSC and ISW2 remodelers exert antagonistic effects on nucleosomes flanking NDRs, but the temporal dynamics of remodeler search, engagement and directional nucleosome mobilization for promoter accessibility are unknown. Using optical tweezers and 2-color single-particle imaging, we investigated the Brownian diffusion of RSC and ISW2 on free DNA and sparse nucleosome arrays. RSC and ISW2 rapidly scan DNA by one-dimensional hopping and sliding respectively, with dynamic collisions between remodelers followed by recoil or apparent co-diffusion. Static nucleosomes block remodeler diffusion resulting in remodeler recoil or sequestration. Remarkably, both RSC and ISW2 use ATP hydrolysis to translocate mono-nucleosomes processively at ~30 bp/sec on extended linear DNA under tension. Processivity and opposing push-pull directionalities of nucleosome translocation shown by RSC and ISW2 shape the distinctive landscape of promoter chromatin.

摘要

真核基因表达与染色质结构及核小体定位相关联，这一过程由依赖ATP的染色质重塑因子介导，这些因子在转录起始位点附近建立并维持无核小体区域（NDRs）。保守的酵母RSC和ISW2重塑因子对NDRs侧翼的核小体发挥拮抗作用，但重塑因子搜索、结合以及促进启动子可及性的定向核小体移动的时间动态尚不清楚。利用光镊和双色单粒子成像技术，我们研究了RSC和ISW2在游离DNA和稀疏核小体阵列上的布朗扩散。RSC和ISW2分别通过一维跳跃和滑动快速扫描DNA，重塑因子之间发生动态碰撞，随后产生反冲或明显的共同扩散。静态核小体阻碍重塑因子扩散，导致重塑因子反冲或被隔离。值得注意的是，在张力作用下，RSC和ISW2均利用ATP水解在延伸的线性DNA上以约30 bp/秒的速度连续移动单核小体。RSC和ISW2所表现出的核小体移动的持续性和相反的推挽方向性塑造了启动子染色质的独特格局。