CRISPRon/off: CRISPR/Cas9 on- and off-target gRNA design

Bioinformatics. 2022 Dec 13;38(24):5437-5439. doi: 10.1093/bioinformatics/btac697.


Summary: The effectiveness of CRISPR/Cas9-mediated genome editing experiments largely depends on the guide RNA (gRNA) used by the CRISPR/Cas9 system for target recognition and cleavage activation. Careful design is necessary to select a gRNA with high editing efficiency at the on-target site and with minimum off-target potential. Here, we present our webserver for gRNA design with a user-friendly graphical interface, which provides interoperability between our on- and off-target prediction tools, CRISPRon and CRISPRoff, for a complete and streamlined gRNA selection.

Availability and implementation: The graphical interface uses the Integrative Genomic Viewer (IGV) JavaScript plugin. The backend tools are implemented in Python and C. The CRISPRon and CRISPRoff webservers and command-line tools are freely available at

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • CRISPR-Cas Systems* / genetics
  • Gene Editing
  • RNA, Guide, CRISPR-Cas Systems*


  • RNA, Guide, CRISPR-Cas Systems