Disintegration promotes protospacer integration by the Cas1-Cas2 complex.

Content Provider	Europe PMC
Author	Ma, Chien-Hui Javanmardi, Kamyab Finkelstein, Ilya J Jayaram, Makkuni
Editor	Berger, James M Storz, Gisela
Copyright Year	2021
Abstract	‘Disintegration’—the reversal of transposon DNA integration at a target site—is regarded as an abortive off-pathway reaction. Here, we challenge this view with a biochemical investigation of the mechanism of protospacer insertion, which is mechanistically analogous to DNA transposition, by the Streptococcus pyogenes Cas1-Cas2 complex. In supercoiled target sites, the predominant outcome is the disintegration of one-ended insertions that fail to complete the second integration event. In linear target sites, one-ended insertions far outnumber complete protospacer insertions. The second insertion event is most often accompanied by the disintegration of the first, mediated either by the 3′-hydroxyl exposed during integration or by water. One-ended integration intermediates may mature into complete spacer insertions via DNA repair pathways that are also involved in transposon mobility. We propose that disintegration-promoted integration is functionally important in the adaptive phase of CRISPR-mediated bacterial immunity, and perhaps in other analogous transposition reactions.
Journal	eLife
Volume Number	10
PubMed Central reference number	PMC8390005
PubMed reference number	34435949
e-ISSN	2050084X
DOI	10.7554/elife.65763
Language	English
Publisher	eLife Sciences Publications, Ltd
Publisher Date	2021-08-26
Access Restriction	Open
Rights License	This article is distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use and redistribution provided that the original author and source are credited. © 2021, Ma et al
Subject Keyword	CRISPR adaptation transposition E. coli
Content Type	Text
Resource Type	Article
Subject	Immunology and Microbiology Neuroscience Medicine Biochemistry, Genetics and Molecular Biology