Dual modes of CRISPR-associated transposon homing.
Cell
; 184(9): 2441-2453.e18, 2021 04 29.
Article
in En
| MEDLINE
| ID: mdl-33770501
ABSTRACT
Tn7-like transposons have co-opted CRISPR systems, including class 1 type I-F, I-B, and class 2 type V-K. Intriguingly, although these CRISPR-associated transposases (CASTs) undergo robust CRISPR RNA (crRNA)-guided transposition, they are almost never found in sites targeted by the crRNAs encoded by the cognate CRISPR array. To understand this paradox, we investigated CAST V-K and I-B systems and found two distinct modes of transposition (1) crRNA-guided transposition and (2) CRISPR array-independent homing. We show distinct CAST systems utilize different molecular mechanisms to target their homing site. Type V-K CAST systems use a short, delocalized crRNA for RNA-guided homing, whereas type I-B CAST systems, which contain two distinct target selector proteins, use TniQ for RNA-guided DNA transposition and TnsD for homing to an attachment site. These observations illuminate a key step in the life cycle of CAST systems and highlight the diversity of molecular mechanisms mediating transposon homing.
Key words
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Bacteria
/
Bacterial Proteins
/
DNA, Bacterial
/
DNA Transposable Elements
/
RNA, Guide, Kinetoplastida
/
Transposases
/
CRISPR-Associated Proteins
Type of study:
Risk_factors_studies
Language:
En
Journal:
Cell
Year:
2021
Document type:
Article