生物
转座因子
清脆的
转座酶
反式激活crRNA
核糖核酸
遗传学
换位(逻辑)
Cas9
转座子突变
细胞生物学
计算生物学
突变体
基因
语言学
哲学
作者
M. Lienhard Schmitz,Irma Querques,Seraina Oberli,Christelle Chanez,Martin Jínek
出处
期刊:Cell
[Elsevier]
日期:2022-12-01
卷期号:185 (26): 4999-5010.e17
被引量:29
标识
DOI:10.1016/j.cell.2022.11.009
摘要
CRISPR-Cas systems have been co-opted by Tn7-like transposable elements to direct RNA-guided transposition. Type V-K CRISPR-associated transposons rely on the concerted activities of the pseudonuclease Cas12k, the AAA+ ATPase TnsC, the Zn-finger protein TniQ, and the transposase TnsB. Here we present a cryo-electron microscopic structure of a target DNA-bound Cas12k-transposon recruitment complex comprised of RNA-guided Cas12k, TniQ, a polymeric TnsC filament and, unexpectedly, the ribosomal protein S15. Complex assembly, mediated by a network of interactions involving the guide RNA, TniQ, and S15, results in R-loop completion. TniQ contacts two TnsC protomers at the Cas12k-proximal filament end, likely nucleating its polymerization. Transposition activity assays corroborate our structural findings, implying that S15 is a bona fide component of the type V crRNA-guided transposon machinery. Altogether, our work uncovers key mechanistic aspects underpinning RNA-mediated assembly of CRISPR-associated transposons to guide their development as programmable tools for site-specific insertion of large DNA payloads.
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