“Shredder” CRISPR Technique Goes Beyond Normal Snipping Mechanism
An international team of scientists has developed a new gene editing tool which goes beyond the usual mechanisms of CRISPR, acting instead as a “shredder” which can delete large stretches of DNA with programmable targeting. The technology was also shown to work in human cells for the first time.
The researchers’ study was published in Molecular Cell journal, and details how the new technology could be used to understand disease mechanisms and possibly treat certain diseases tied to long sections of DNA.
The tool uses Type I CRISPR-Case3, more common in bacteria than the type used in the popular CRISPR-Cas9. Type I CRISPR has never been used in eukaryotic cells, and uses a riboprotein complex for finding its target and Cas3 to shred the DNA.
The team worked to deliver CRISPR components into both human embryonic stem cells and into HAP1 cells. Eventually they succeeded in deleting targeted DNA sections from just a few hundred base pairs to 100 kilobases.
According to lead researcher Yan Zhang of the University of Michigan, the new tool: “goes where you want it, travels along the chromosome, and makes a spectrum of deletions tens of kilobases long. This could make it a powerful screening tool to determine what large areas of DNA are most important for a particular disease.”
The research was not without problems. The scientists had to get the stem cells to show whether DNA had been deleted, since most of their reporter lines developed for research involving CRISPR-Cas9 were not sensitive enough if the shredding activity is low. They also needed to find out what the shredder had actually accomplished using next-generation DNA sequencing and creating new methods to check the edits.