CRISPR-Cas design tools are computer software platforms and bioinformatics tools used to facilitate the design of guide RNAs (gRNAs) for use with the CRISPR/Cas gene editing system.

CRISPR-Cas

The CRISPR/Cas (clustered regularly interspaced short palindromic repeats/CRISPR associated nucleases) system was originally discovered to be an acquired immune response mechanism used by archaea and bacteria. It has since been adopted for use as a tool in the genetic engineering of higher organisms.

Designing an appropriate gRNA is an important element of genome editing with the CRISPR/Cas system. A gRNA can and at times does have unintended interactions ("off-targets") with other locations of the genome of interest. For a given candidate gRNA, these tools report its list of potential off-targets in the genome thereby allowing the designer to evaluate its suitability prior to embarking on any experiments.

Scientists have also begun exploring the mechanics of the CRISPR/Cas system and what governs how good, or active, a gRNA is at directing the Cas nuclease to a specific location of the genome of interest. As a result of this work, new methods of assessing a gRNA for its 'activity' have been published, and it is now best practice to consider both the unintended interactions of a gRNA as well as the predicted activity of a gRNA at the design stage.

Table

The below table lists available tools and their attributes.

List of CRISPR-Cas design tools
Tool NameProviderSearches whole genome for targetsReturns all targets of genomeSeed span and location can be definedMaximum number of mismatches supportedPredicts gRNA activityAvailable Protospacer adjacent motif (PAM) sequencesAnnotation is reportedgRNA suggestion or scoringRef.
CRISPRon, CRISPRoffYesYesYesAllYesNGG, NGA, NAGYesYes,
Invitrogen TrueDesign Genome EditorYesYesNo3NoNGGYesYes
Breaking-CasSpanish National Center for BiotechnologyYes (over 1000 genomes)YesYes (by weights)4NoUser customizableYesYes
Cas-OFFinderSeoul National UniversityYesYesNo0-10NoNGG, NRG, NNAGAAW, NNNNGMTTNoYes
CASTINGCaagleYesYesNo3NoNGG and NAGNoYes
CRISPyTechnical University of DenmarkYesYesNoAllNoNGGYesYes
CCTopUniversity of HeidelbergYesYesPartial5 (0-5)YesNGG, NRG, NNGRRT, NNNNGATT, NNAGAAW, NAAAACYesYes
CHOPCHOPHarvard UniversityYesYesPartial0, 2NoNGG, NNAGAA, NNNNGANNNoYes
CHOPCHOP v2University of BergenYesYesYes3 (0-3)YesUser customizableYesYes
CRISPORUniversity of California, Santa Cruz TEFORYes (over 200 genomes)YesNo4YesNGG, NGA, NGCG, NNAGAA, NGGNG, NNGRRT, NNNRRT, NNNNGMTT, NNNNACA, TTTNYesYes
CRISPR DesignZhang Lab, MITYesNoNo4NoNGG and NAGmRNA exonsYes
CRISPRdirectDatabase Center for Life Science (DBCLS)Yes (over 200 species)YesNoAny numberNoNNNYesYes
CRISPRscanGiraldez Lab, YaleYesYesNo4YesNGG, TTTV, TTTNYesYes
CRISPRseekBioconductorYesYesNoAny numberNoUser customizablemRNA exonsYes
DESKGENDesktop GeneticsYesYesYesAny numberYesFully user customizableYesYes
GuideScanGuideScanYesYesYes3 on website and customizable with command lineYesNGG/NAG on website and customizable with command lineYesYes
GT-ScanCSIRO & EMBL-ABRYesYesYes3 (0-3)NoUser customizableLinks to Ensembl genome browserYes
Off-SpotterThomas Jefferson UniversityYesYesYes0-5NGG, NAG, NNNNACA, NNGRRT (R is A or G)mRNA exons, unspliced mRNA, mRNA, 5'UTR, CDS, 3'UTR, unspliced lincRNA, lincRNAUser customizable
sgRNA DesignerBroad InstituteNoNoNo0YesNGGCDS (if searching by transcript ID)Yes
Synthego Design ToolSynthegoYes (over 120,000 genomes)No (Optimized for Knockout)Yes3YesNGGYes (RefSeq, Ensembl, Gencode)Yes
TUSCANCSIRONoNoNo0YesNGGNoYes
VARSCOTCSIROYesYesNo0-8YesUser customizableNoYes
CRISPR Targeted Gene Designer[permanent dead link]Yes, Multipleyesyes4YesNGG, NNGRRT, YTTV, otherYesYes(21)
GuideMakerYes, any user supplied genomeYesYes0-5YesAny PAM site and PAM orientationYesYes
WGEWellcome Sanger InstituteYes, human and mouse reference genomesYesYes4 (0-4)NoNGGYesYes