An international collaboration among researchers from Denmark and New Zealand has identified a novel genetic mechanism that enables certain viruses to bypass the bacterial immune system. The findings were published in Nature.
Bacteria defend themselves against viral invaders with CRISPR-Cas, a system that captures fragments of bacteriophage DNA and integrates them into the microbial genome. This creates a memory archive that helps bacteria recognize and neutralize future attacks.
According to Dr. David Mayo-Muñoz, a microbiologist at the University of Otago in New Zealand, the memory bank is activated when a virus’s DNA is incorporated and transformed into RNA. Each RNA segment then serves as a guide, directing the CRISPR-Cas apparatus to identify and destroy the invading phage with precision.
Recent work shows that some viruses have evolved strategies to subvert CRISPR-Cas by incorporating components of the system into their own genomes. These molecular mimics can interfere with, or partly disable, the bacterial defense mechanism, allowing the virus to evade detection.
Experts say this discovery could inform safer gene-editing approaches and spur the development of alternatives to traditional antibiotics, potentially improving treatments in microbial infections and biotechnology applications.
Earlier research has highlighted two major classes of phages that interact with CRISPR-Cas systems, underscoring the ongoing evolutionary arms race between bacteria and viruses. This new insight adds a layer of complexity to how microbial communities adapt to immune pressure and how scientists might harness or modulate these interactions for biomedical purposes. (Attribution: Nature, 2024)