With Redesigning Of Protein, CRISPR Gene Editing Becomes More Accurate

Apr, 2022 - By SMI

Researchers identified a structure of the protein causing mistakes in gene editing, and tweaking this structure reduces the chances of off-target mutation by 4,000 times

CRISPR-based gene editing comes with challenges and one of the major challenge of this method is that sometimes it tends to make wrong editing to the wrong DNA sections. Now, a team of scientists at University of Texas found an already known structure of the protein that causes these challenges, and redesigning this structure reduces chances of off-target mutation by 4,000 times.

CRISPR tools utilize specific proteins, mostly Cas9 for making edits to particular sequences of DNA in living cells. However, sometimes this tool tends to make errors by making changes to the wrong parts that potentially triggers various other health problems. The researchers now found how these error occur. Normally, the Cas9 protein hunts for particular sequence of 20 letters in the DNA code. However, when it finds the sequence where 18 letters out of 20 match the target, it tend to make edits there anyway. Now, in order to find why this happens, the team using cryo-electron microscopy observed the activity of Cas9 when it interacted with as mismatched sequence of DNA.

Surprisingly, the team found a unnatural finger-like structure that was never before observed. This structured stabilized the DNA sequence for the protein to make its edits. The team them redesigned this finger-like structure to stop it from stabilizing the DNA and instead push itself away from the DNA. This prevented the editing of that sequence by Cas9, which reduced the chances of off-target mutation by 4,000 times. The scientists named the new protein as SuperFi-Cas9. Moreover, the team also created various other versions of Cas9 for making more accurate, however, these tend to slow down the editing. As per the team, the SuperFi-Cas9 makes its normal edits at the similar speed as usual.