Experts Enhance Editing Rates of CRISPR-Cas12a

Scientists from the University of Massachusetts Chan Medical School reported the increased gene editing rate of Cas12a nucleases to almost 100%. Their findings, published in GEN Biotechnology journal, could improve the use of Cas12a to uncover functions of new genes and design new CRISPR-based treatments.

Cas12a nucleases, commonly isolated from Acidaminococcus and Lachnospiraceae bacteria, have promising attributes that are not present in SpyCas9 nucleases and these include: greater editing precision, recognize a thymine-rich PAM, use of a single CRISPR-RNA to identify the target, cut DNA in a staggered fashion, process CRISPR arrays, and function in a variety of plants and animals. However, the downside of Cas12a is that it has lower editing rates than SpyCas9 in primary cells. Thus, the researchers searched for strategies to address this disadvantage.

In their initial investigation, Prof. Scot Wolfe and his team optimized the sequence composition and number of Cas12a's nuclear localization signal (NLS). However, the efficiency was still below SpyCas9's record. In their latest study, they developed three NLS C-terminus variants of Cas12a where they substituted the previously used NLS with a more efficient one. They also added a third NLS to the carboxy end to achieve an editing platform similar with SpyCas9 in editing efficiency.

Read the news release and research article for more details.