DdmABC-dependent death triggered by viral palindromic DNA sequences
William P Robins1, Bradley T Meader1, Jonida Toska1
1Department of Microbiology, Harvard Medical School, 77 Avenue Louis Pasteur, Boston, MA 02115, USA.
Cell Reports
|July 13, 2024
Summary
Researchers identified the Lamassu DdmABC system in Vibrio cholerae, which triggers cell death upon detecting viral DNA. This defense mechanism activates when foreign DNA forms stem-loop structures, offering insights into bacterial immunity.
Area of Science:
- Microbiology
- Bacterial genetics
- Innate immunity
Background:
- Prokaryotic and eukaryotic innate immunity mechanisms are crucial for defense against pathogens.
- Molecular signals activating many defense systems, particularly those involving cell death, remain largely uncharacterized.
- Vibrio cholerae possesses defense systems that respond to foreign genetic elements.
Purpose of the Study:
- To characterize a cell density-dependent death (CDD) system in Vibrio cholerae.
- To identify the molecular signals that activate this defense system.
- To elucidate the role of the Lamassu DdmABC system in bacterial defense.
Main Methods:
- Genetic analysis of Vibrio cholerae strains.
- DNA sequence analysis to identify trigger motifs.
- Experimental validation of DNA structures and their effect on CDD.
Main Results:
- The Lamassu DdmABC system is identified as the key component responsible for CDD.
- Palindromic DNA sequences forming stem-loop hairpins in phages and plasmids trigger CDD.
- DNA-damaging agents also activate DdmABC, inhibiting cell growth.
Conclusions:
- The DdmABC system acts as an anti-phage and anti-plasmid defense mechanism in Vibrio cholerae.
- Foreign DNA structures, specifically stem-loop hairpins, are identified as potent activators.
- This abortive infection system can be triggered by DNA damage during infection or replication, leading to cell death.
Keywords:
CP: Cell biologyCP: Molecular biologyDNA restrictionV. choleraeabortive infectionbacteriophagesphage defensephage restrictionplasmid restrictionviral defenseMore Related Videos
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