A new study by Dr. Bill Metcalfe, G. William Arends Professor of Microbiology at the University of Illinois, and his postdoctoral Fellow Dr. Dipti Nayak, has documented the use of CRISPR-Cas9-mediated genome editing in the third domain of life, Archaea, for the first time. The ground-breaking work, reported online on March 6, 2017 in PNAS, has the potential to vastly accelerate future studies of these organisms, with implications for research including global climate change. Dr. Metcalf and Dr. Nayak are members of the Carl R. Woese Institute for Genomic Biology at Illinois. The PNAS article is titled “Cas9-Mediated Genome Editing in the Methanogenic Archaeon Methanosarcina acetivorans.” "Under most circumstances, our model archaeon, Methanosarcina acetivorans, has a doubling time of 8 to 10 hours, as compared to E. coli, which can double in about 30 minutes. What that means is that doing genetics, getting a mutant, can take months--the same thing would take three days in E. coli," explains Dr. Nayak. "What CRISPR-Cas9 enables us to do, at a very basic level, is speed up the whole process. It removes a major bottleneck... in doing genetics research with this archaeon.” "Even more," continues Dr. Nayak, "with our previous techniques, mutations had to be introduced one step at a time. Using this new technology, we can introduce multiple mutations at the same time. We can scale up the process of mutant generation exponentially with CRISPR." CRISPR, short for Clustered Regularly Interspaced Short Palindromic Repeats, began as an immune defense system in archaea and bacteria. By identifying and storing short fragments of foreign DNA, Cas (CRISPR-associated system) proteins are able to quickly identify that DNA in the future, so that it can then quickly be destroyed, protecting the organism from viral invasion.
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