Guide RNA Categorization Enables Target Site Choice in Tn7-CRISPR-Cas Transposons.
Cell
; 183(7): 1757-1771.e18, 2020 12 23.
Article
em En
| MEDLINE
| ID: mdl-33271061
ABSTRACT
CRISPR-Cas defense systems have been coopted multiple times in nature for guide RNA-directed transposition by Tn7-like elements. Prototypic Tn7 uses dedicated proteins for two targeting pathways one targeting a neutral and conserved attachment site in the chromosome and a second directing transposition into mobile plasmids facilitating cell-to-cell transfer. We show that Tn7-CRISPR-Cas elements evolved a system of guide RNA categorization to accomplish the same two-pathway lifestyle. Multiple mechanisms allow functionally distinct guide RNAs for transposition a conventional system capable of acquiring guide RNAs to new plasmid and phage targets and a second providing long-term memory for access to chromosomal sites upon entry into a new host. Guide RNAs are privatized to be recognized only by the transposon-adapted system via sequence specialization, mismatch tolerance, and selective regulation to avoid toxic self-targeting by endogenous CRISPR-Cas defense systems. This information reveals promising avenues to engineer guide RNAs for enhanced CRISPR-Cas functionality for genome modification.
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Texto completo:
1
Base de dados:
MEDLINE
Assunto principal:
Elementos de DNA Transponíveis
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RNA Guia de Cinetoplastídeos
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Sistemas CRISPR-Cas
Idioma:
En
Ano de publicação:
2020
Tipo de documento:
Article