Scientists discover new error-reducing gene-editing system

Researchers from Broad Institute of MIT, Harvard, and the McGovern Institute for Brain Research at MIT have teamed up to create a new gene-editing system that can precisely and efficiently insert large DNA sequences into a genome. The system that the team developed uses cyanobacteria and is called CRISPR-associated transposase (CAST).

The new method allows for the efficient introduction of DNA and reduced potential for error in the process. The process is one step closer to the goal of precision gene editing. Researchers say that the precision insertion of DNA has the potential to treat large swaths of genetic diseases by integrating new DNA into the genome and disabling the genes associated with the disease.

Normally researchers use CRISPR enzymes to cut the genome at the site where they want to remove genes. The cells own repair machinery stitches the old and new DNA elements together, but that approach has limitations. By harnessing the Escherichia coli bacteria, the researchers have a new CAST that can efficiently insert new DNA at a designated site with minimal editing errors. The system also doesn't rely on the cells own repair machinery.

The researchers are working on applying the editing platform in Eukaryotic organisms, including plant and animal cells for precision and therapeutic applications. The team molecularly characterized and harnessed CAST using two cyanobacteria, Scytonema hofmanni and Anabaena cylindrica. They say that the way some CRISPR systems perform in nature doesn't protect bacteria from viruses, but facilitates the spread of the transposon DNA.

The new CAST process is said to be much more attractive for any situation where people want to insert DNA. The process can also be used to augment healthy cells with therapeutically beneficial elements. This would allow an approach for immunotherapy where a "chimeric antigen receptor" could be inserted into the genome of a T cell to enable the T cell to recognize and destroy cancer cells.