Structural basis of a Tn7-like transposase recruitment and DNA loading to CRISPR-Cas surveillance complex

• 来源期刊: 细胞研究（英文版）
• 年，卷（期）: 2020,（2）
• 页码范围: 185-187
• 页数: 3页
• 语种: 英文

摘要

Dear Editor, Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR) and CRISPR-associated (Cas) systems confer RNA-guided adaptive immunity against invading genetic elements in prokaryotic cells.1 These systems employ CRISPR RNA (crRNA) containing surveillance complexes for sequence-specific recognition and degradation of foreign DNA or RNA.Several nuclease-deficient type I-F,I-B,and V-K systems have been reported to be evolutionarily and functionally associated with Tn7-like transposons lacking a key gene for DNA targeting,implying a new mode of RNA-guided DNA insertion.2,3 Recent studies characterized CRISPR-associated transposase in type I-F and V-K systems and established genome-wide programmable site-specific DNA transposition in E.coli cells,providing the prospect of genome editing strategy without requirement of double-strand breaks and endogenous DNA repair pathways.4,5 All these CRISPR-associated transposons contain transposase subunits,CRISPR effector,and a CRISPR array.Furthermore,subunit TniQ,a homolog of E.coli TnsD,forms a stable complex with Vibrio cholerae Tn6677 type I-F effector Cascade (also called Csy complex) and plays an essential role during DNA insertion.