Bacterial Immune Systems: From Molecular Mechanisms to Next-Generation Biotechnology

Immense evolutionary pressure has driven bacteria to innovate a diverse arsenal of immune systems that defend against parasitic mobile genetic elements, including bacteriophages and plasmids. The study of these systems has proven extraordinarily fruitful for biotechnology: CRISPR-Cas9, originally discovered as a bacterial defense mechanism, has revolutionized genome editing and demonstrated the transformative potential of mining bacterial immunity for molecular tools.
Yet the diversity of bacterial defense extends far beyond CRISPR. Bacteria have evolved numerous strategies to recognize and destroy foreign DNA, many of which remain poorly understood at the mechanistic level. A central question is how these systems distinguish self from non-self — and how the underlying molecular logic of DNA targeting is encoded in protein structure and biochemistry. We combine cryo-electron microscopy, quantitative biochemistry, and in vivo genomics to characterize newly discovered defense systems and dissect their targeting mechanisms. This work is revealing unexpected principles of foreign DNA recognition, with implications both for our understanding of bacterial immunity and for the development of next-generation biotechnological tools for genome editing and beyond.