Oct, 2021 - By WMR
Scientists found a new class of enzyme, OMEGAs, that executes same functions as the CRISPR genome-editing system, and may perform even better in some aspects.
CRISPR genome engineering method is amongst the most ground-breaking inventions of the time. It is based on a bacterial defense mechanism that allows scientists to modify gene precisely. Now, a team of scientists at MIT discovered a new type of programmable gene modification systems called OMEGAs (Obligate Mobile Element Guided Activity), which according to the scientists, could naturally perform rearrangement of bits of DNA throughout bacterial genomes.
In 2012, scientists discovered a process to edit DNA, where they selected an enzyme called Cas9 that can cut DNA, and built a guide RNA sequences to lead it to a preferred part of the DNA sequence. This innovation was later adopted for development of new therapies for cancers and HIV. Now, the researchers at MIT found a new type of enzyme outside CRISPR. The IscB proteins that were found, appeared to be DNA-cutting enzymes but were not related to RNA. The researchers further found that RNAs that drive IscB proteins, alter DNA in particular parts. These RNAs were named as OmegaRNAs. After that, the researchers found two more proteins IsrBs and TnpBs, and together three of these proteins (Omega RNAs, IsrBs and TnpBs) are called transposons, which are able to move in the genome. By moving around in genome, these proteins form new guide RNA and allow the enzymes to alter different parts of DNA.
According to the team, natural form of such systems of gene editing would be a beginning for adapting that specific task of cutting DNA. Past evolution of RNA-guided systems is a deep topic of interest for the team. This discovery of new systems shows that systems guided by RNA are progressed throughout the time, however, the origin of RNA-guided activities is not yet clear. Finding these point of origins would aid in the development of other types of programmable tools for gene editing.