What is CRISPR?

CRISPR Cas9 Schematic

Definition: Clustered Regularly Interspaced Short Palindromic Repeat or CRISPR was identified in a bacterial defence system. CRISPR are sections of genetic code containing short repetitions of base sequences followed by spacer DNA segments.

CRISPR Gene Editing

The bacteria are able to capture short nucleic acid sequences from invading pathogens and integrate them in the CRISPR loci amidst the repeats. Small RNAs, produced by transcription of these loci, can then guide a set of bacterial endonucleases to cleave the genomes of invading pathogens.

The CRISPR Cas9 gene editing system has since been adapted into a powerful tool that puts genome editing into the mainstream.

What is CRISPR/Cas9?

Definition: CRISPR/Cas9 is an RNA-guided gene-editing platform derived from streptococcus pyogenes that makes use of a endonuclease (Cas9) and a synthetic guide RNA to introduce a double strand break at a specific location within the genome.

In the lab editing is achieved by transfecting a cell with the Cas9 protein along with a specially designed guide RNA (gRNA) that directs the cut through hybridization with its matching genomic sequence. When the cell repairs that break, errors can occur to generate a knockout of that gene or additional modifications can be introduced. Our CRISPR technology is particularly good for the efficient generation of complete knockout of genes on multiple alleles.

Use of wild-type Cas9 has been shown to lead to off-target cleavage, but a modified version introduces only single strand “nicks” to the DNA, which in pairs still stimulate the repair mechanisms while significantly decreasing the risk of off-target cutting.

Horizon has licensed IP from Harvard University, the Broad Institute and ERS Genomics with the goal of being able to ensure that we will be able to offer uninterrupted use of this technology to our customers.

CRISPR gene editing: How it works

The team at Horizon Discovery can provide a range of services based around this genome editing technology including:

Cell Lines BioproductionReference StandardsKnockout Mice & RatsResearch Services

Other Cas9 Proteins

Horizon's CRISPR editing knowledge includes the widely used S. Pyogenes (spCas9), and also supporting those utilising CRISPR Cas9 protocol for S. Aureus (scCas9), Cpf1, HiFi Cas9, Nickase Cas9, Nuclease Cas9, NgAgo gDNA and even synthetic spCas9 with alternative PAM sites. Contact us for more information on the molecular biology and benefits of each Cas9 structure.

CRISPR Cas9 Gene Editing

Continue your research with our gene editing webinars:

An introduction to CRISPR Cas9 gene editing

A starter's guide to CRISPR Cas9 gene editing

Planning a CRISPR genome editing experiment

Maximise your chances of success with this planning guide

Modifying human cell lines with CRISPR

Human cell lines, genomic modification and editing efficiencies


Barrangou R, Fremaux C, Deveau H, Richards M, Boyaval P, Moineau S, Romero DA, Horvath P. 2007. CRISPR provides acquired resistance against viruses in prokaryotes. Science 315(5819): 1709-1712.

Jinek M, Chylinski K, Fonfara I, Hauer M, Doudna JA, Charpentier E. 2012. A programmable dual-RNA-guided DNA endonuclease in adaptive bacterial immunity. Science 337(6096): 816-821.