Researchers from the University of Illinois Chicago (UIC) have discovered a new gene-editing technique that allows for the programming of sequential cuts — or edits — over time.
The new process developed by UIC's Bradley Merrill, lead author of the paper published in Molecular Cell, involves using special molecules called guide RNA that ferry the Cas9 enzyme within the cell and determine the precise DNA sequence at which Cas9 will cut. They call their specially engineered guide RNA molecules "proGuides," and the molecules allow for the programmed sequential editing of DNA using Cas9.
Merrill said that a drawback of currently available CRISPR-based editing systems is that all the edits or cuts are made all at once and there is no way to guide them so that they take place in a sequential fashion, which proGuides allows. While proGuide is still in the prototype phase, Merrill's team plans to further develop their concept and hopes that researchers will be able to use the technique soon.
(Source: Crop Biotech Update, International Service for Acquisition of Agri-Biotech Applications.

Specially engineered guide RNA molecules called “proGuides” may allow scientists to program sequential gene edits over time.