New programmable gene editing proteins found outside of CRISPR systems
Within the last decade, scientists have adapted CRISPR systems from microbes into gene editing technology, a precise and programmable system for modifying DNA. Now, scientists at MIT's McGovern Institute for Brain Research and the Broad Institute of MIT and Harvard have discovered a new class of programmable DNA modifying systems called OMEGAs, which may naturally be involved in shuffling small bits of DNA throughout bacterial genomes. These ancient DNA-cutting enzymes are guided to their targets by small pieces of RNA. While they originated in bacteria, they have now been engineered to work in human cells, suggesting they could be useful in the development of gene editing therapies, particularly as they are small, making them easier to deliver to cells than bulkier enzymes. The discovery, reported Sept. 9 in the journal Science, provides evidence that natural RNA-guided enzymes are among the most abundant proteins on Earth, pointing toward a vast new area of biology that is poised to drive the next revolution in genome editing technology. Zhang's team has been exploring natural diversity in search of new molecular systems that can be rationally programmed. "These results suggest the tantalizing possibility that there are many more programmable systems that await discovery and development as useful technologies." If hosts can "Co-opt" these systems and repurpose them, hosts may gain new abilities, as with CRISPR systems that confer adaptive immunity. "Finding all these new systems sheds light on how RNA-guided systems have evolved, but we don't know where RNA-guided activity itself comes from," Altae-Tran says.