Department of Biochemistry, Biophysics and Molecular Biology - Iowa State University

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Host:  Kristen Johansen

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"Mechanisms of CRISPR-Cas Systems: From Adaptive Immunity to Biotechnology"

All forms of life require immune systems to stave off infection from viruses and other pathogens.  In bacteria and archaea, clustered regularly interspaced short palindromic repeats (CRISPR) arrays and CRISPR-associated (Cas) proteins provide adaptive immunity against invading DNA from bacteriophages and plasmids.

During infection, host cells adapt by storing short segments of foreign DNA in CRISPR arrays, providing heritable molecular memories of the infection.  CRISPR-derived RNAs guide Cas complexes to bind and cleave the specific matching region of the foreign nucleic acids, thus neutralizing the infection.  The unique, programmable DNA cleavage activity of CRISPR-Cas systems has been widely adapted for genome editing.  In addition to providing revolutionary biotechnological tools, fundamental research into CRISPR-Cas systems has deepened our understanding of the complex molecular warfare that occurs between bacteria and their invaders.

Research in our lab focuses on understanding the molecular mechanisms of CRISPR-Cas immunity and how these mechanisms can impact biotechnological tools. I will present an overview of our research and highlight recent biochemical and structural results that reveal how bacteria adapt to rapidly evolving viruses.