The arms race between bacteria CBASS and bacteriophages

Area of Science:

• Microbiology
• Immunology
• Virology

Background:

• The Bacterial Cyclic oligonucleotide-Based Anti-phage Signaling System (CBASS) is a key bacterial innate immune system.
• CBASS utilizes cyclic oligonucleotides (cOs) synthesized by CD-NTase enzymes to trigger cell death, inhibiting phage replication.
• Phages have evolved sophisticated mechanisms to evade CBASS-mediated immunity.

Purpose of the Study:

• To provide a comprehensive review of the CBASS innate immune system.
• To elucidate the intricate interplay between CBASS and phage anti-immune strategies.
• To explore conserved viral immune evasion mechanisms across prokaryotic and eukaryotic systems.

Main Methods:

• Literature review and synthesis of existing research on CBASS and phage-bacteria interactions.
• Comparative analysis of bacterial immune systems and viral evasion tactics.
• Exploration of molecular mechanisms underlying CBASS activation and phage counter-defense.

Main Results:

• CBASS functions by synthesizing cOs and activating effector proteins (Caps) that induce DNA cleavage, membrane damage, and NAD depletion.
• Ancillary proteins are crucial for cO synthesis and priming CD-NTase for activation.
• Phages employ immune evasion proteins to disrupt Cap recognition of cOs, ensuring their own propagation.

Conclusions:

• CBASS represents a potent bacterial defense against phage infection, characterized by programmed cell death.
• The co-evolutionary battle between CBASS and phages drives the development of diverse immune evasion strategies.
• Understanding these interactions offers insights into broader viral-host dynamics and potential therapeutic targets.