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What is CRISPR-Cas9?

CRISPR-Cas9 is a powerful genomic tool for gene editing of DNA. CRISPR-Cas9 stands for Clustered Regularly Interspaced Short Palindromic Repeats/CRISPR associated sequence complex and is an important part for the bacterial immune system. CRISPR are short repeated codes in the DNA. Cas9 is a protein that comes from bacteria like streptococcus pyogenes and functions as a defence against viruses.

In total, the CRISPR-Cas9 system consists of two key components. The first component of the CRISPR-Cas9 system is an RNA molecule known as the guide RNA (gRNA), that can identify the sequence of DNA to be edited. The second component of the CRISPR-Cas9 system is a non-specific CRISPR-associated endonuclease Cas9. Bound together, they form a complex. The gRNA is a short pre-designed synthetic RNA located in a scaffold sequence needed for binding of Cas9. The gRNA is located right before a common sequence in the genome called Protospacer Adjacent Motif (PAM).

The entire CRISPR-Cas9 complex is introduced into the target cells. The Cas9 recognizes and binds to its target sequence in front of the PAM sequence. Activated by the PAM sequence, the Cas9 system then acts as a molecular scissor at its target specific location. Cas9 makes a cut across the two strands of the target DNA in the genome, leading to a double strand break (DSB). The cell with a DSB created by the Cas9 nuclease will try to repair it in this step, which can happen in two ways. One, the cells natural repair mechanism will join the two ends of the cut DNA together, called non-homologous end joining. This process is of DNA fixing is error-prone as nucleotides can be inserted or deleted by mistake.  The second option is repairing the break by insertion of a known DNA sequence provided by the scientist. This small DNA sequence can be introduced into the cell by transfection, together with the CRISPR-Cas9 complex.

Where is CRISPR-Cas9 used for?

The CRISPR-Cas9 method makes it possible for scientist to edit the existing genome by either modifying, deleting or inserting new sequences into the DNA very accurately and efficiently. CRISPR-Cas9 is also called “genome editing” or “genetic modification’’. One of the most important advantages of CRISPR-Cas9 over other genomic editing technologies is its simplicity and efficiency. CRISPR-Cas9 reduces the time required to edit target genes. In the future scientist hope to use CRISPR-cas9 to critical advances in patient care of even cure lifelong inherited diseases. On the other hand, there is a discussion about whether CRISPR-Cas9 is ethically justified, the impact can be huge and this can have consequences for the ecosystem.

CleanNA offers an amount of products used for CRIPSR-Cas9, such as the Clean Blood tissue DNA kit, Clean blood LV DNA kit, Clean Plasmid TR DNA kit, the CleanDTR and the CleanNGS.