David Burstein is co-author of “Two distinct Rnase activities of CRISPR-C2c2 enable guide-RNA processing and RNA detection.” The letter was published on 10 October 2016 in the journal Nature.
Bacterial adaptive immune systems use CRISPRs (clustered regularly interspaced short palindromic repeats) and CRISPR-associated (Cas) proteins for RNA-guided nucleic acid cleavage. Although most prokaryotic adaptive immune systems generally target DNA substrates, type III and VI CRISPR systems direct interference complexes against single-stranded RNA substrates. In type VI systems, the single-subunit C2c2 protein functions as an RNA-guided RNA endonuclease (RNase). How this enzyme acquires mature CRISPR RNAs (crRNAs) that are essential for immune surveillance and how it carries out crRNA-mediated RNA cleavage remain unclear. Here we show that bacterial C2c2 possesses a unique RNase activity responsible for CRISPR RNA maturation that is distinct from its RNA-activated single-stranded RNA degradation activity. These dual RNase functions are chemically and mechanistically different from each other and from the crRNA-processing behaviour of the evolutionarily unrelated CRISPR enzyme Cpf1. The two RNase activities of C2c2 enable multiplexed processing and loading of guide RNAs that in turn allow sensitive detection of cellular transcripts.
David Burstein is currently a joint postdoctoral researcher with Professors Jill Banfield and Jennifer Doudna. He received his doctoral degree at Tel Aviv University, with a dissertation on machine-learning approaches for the identification of pathogenic determinants.
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