Speaker: Dipa Sashital, professor in the Department of Biochemistry, Biophysics and Molecular Biology

Title: CRISPR-Cas and beyond — Mechanisms of anti-phage defense through genetic, biochemical and structural approaches

Abstract: Bacteria are under constant threat of predation by viruses, known as bacteriophages (or phages). To counteract these threats, bacteria have evolved defense systems that collectively enable both adaptive and innate immunity against phages. CRISPR-Cas systems allow bacteria to adapt to infection through the creation of molecular memories in the form of spacer sequences within a CRISPR array. Spacers can then be used to program RNA-guided Cas effectors to seek and destroy invading nucleic acids upon subsequent infection. The discovery of CRISPR-Cas defense precipitated a revolution in genome editing, and a renewed interest in understanding the mechanisms of bacterial defense against phage. In the past 10 years, over 100 previously unknown defense systems have been discovered, revealing the diverse mechanisms that underly bacterial immunity. I will present our work elucidating how bacteria memorize infection events during adaptive immunity, as well our recent findings on how innate immunity is triggered in a newly discovered defense system.

Host: Jeff Essner, GDCB professor