What is CRISPR/Cas9?
CRISPR/Cas9 is a powerful tool for the precise modification of gene sequences and the control and detection of gene expression. “CRISPR” refers to clustered regularly interspaced short palindromic repeats.
The CRISPR platform technology utilizes a molecular complex comprised of the protein Cas9, together with one or more guide RNAs, which can be targeted to a desired DNA sequence.
How CRISPR/CAS9 is used?
By this method, researchers use CRISPR as a “molecular word processor” to specifically alter the DNA sequence at the targeted sites (DNA deletion, insertion or replacement), alter regulation of the target locus, or tag the locus with markers.
- Double strand break repair by NHEJ, whereby the gene is cleaved by Cas9 then repaired by error prone non homologous end joining
- Base editing, in which catalytically impaired Cas9 is fused to a nucleobase deaminase and can convert one base into another without cleaving the DNA
- Double strand break repair by HDR, whereby the gene is cleaved by Cas9 then repaired precisely by homology directed repair in the presence of a repair template DNA
- Prime editing, whereby catalytically impaired Cas9 is fused to a reverse transcriptase that uses an extended guide RNA as a repair template for precise gene modification
- Activation (CRISPRa) Catalytically inactive Cas9 fused to a transcription activation domain upregulates gene expression
- Gene Repression (CRISPRi) Catalytically inactive Cas9 fused to a transcription repression domain downregulates gene expression
- Diagnostics and imaging: catalytically inactive Cas9 fused to a flourophore can identify the presence and location of a target sequence
- Novel strains can be created for use in research, food, textiles, and manufacturing