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研究揭示RNA依赖性DNA转座系统的靶点选择机制
作者:小柯机器人 发布时间:2021/7/18 14:48:48

美国康奈尔大学Elizabeth H. Kellogg及其团揭示了在RNA依赖的DNA转座系统中其靶点选择的结构基础 。这一研究成果于2021年7月15日发表在国际学术期刊《科学》上。

研究人员利用冷冻电镜 (cryo-EM) 在V-K型CRISPR转座酶系统中利用转座调节因子TnsC来解释这一过程发生的机制。结合ATP的TnsC 螺旋丝聚合可以解释极性信息如何传递给转座酶。TniQ掩盖了TnsC细丝,这为Tn7/Tn7样元件中目标信息的传输建立了通用机制。转座酶诱导的解聚仅在非靶标原型间隔区建立元件传递。

最后,ADP、AlF3的模拟过渡态结构揭示了TnsC如何完成固定位点的插入。这些结果为研究和治疗相关CRISPR转座系统的研发提供了基础。

据悉,CRISPR相关转座系统可以在目标编辑序列固定距离的单向上完成引导RNA依赖的单个DNA序列整合。

附:英文原文

Title: Structural basis for target-site selection in RNA-guided DNA transposition systems

Author: Jung-Un Park, Amy Tsai, Eshan Mehrotra, Michael T. Petassi, Shan-Chi Hsieh, Ailong Ke, Joseph E. Peters, Elizabeth H. Kellogg

Issue&Volume: 2021/07/15

Abstract: CRISPR-associated transposition systems allow guide RNA-directed integration of a single DNA cargo in one orientation at a fixed distance from a programmable target sequence. We define the mechanism explaining this process by characterizing the transposition regulator, TnsC, from a type V-K CRISPR-transposase system using cryo-electron microscopy (cryo-EM). Polymerization of ATP-bound TnsC helical filaments could explain how polarity information is passed to the transposase. TniQ caps the TnsC filament, establishing a universal mechanism for target information transfer in Tn7/Tn7-like elements. Transposase-driven disassembly establishes delivery of the element only to unused protospacers. Finally, structures with the transition state mimic, ADPAlF3, reveals how TnsC transitions to define the fixed point of insertion. These mechanistic findings provide the underpinnings for engineering CRISPR-associated transposition systems for research and therapeutic applications.

DOI: 10.1126/science.abi8976

Source: https://science.sciencemag.org/content/early/2021/07/14/science.abi8976

期刊信息
Science:《科学》,创刊于1880年。隶属于美国科学促进会,最新IF:41.037