CRISPRCasjärjestelmäs

The CRISPR-Cas system is a revolutionary gene-editing technology derived from a natural defense mechanism found in bacteria and archaea. This system allows for precise modification of DNA sequences. It consists of two main components: CRISPR (Clustered Regularly Interspaced Short Palindromic Repeats) and Cas (CRISPR-associated) proteins. The CRISPR array is a region of bacterial DNA containing short, repeated sequences interspersed with unique "spacer" sequences. These spacers are derived from the DNA of invading viruses or plasmids.

When a virus infects a bacterium, the cell can capture a piece of the viral DNA and integrate it as a new spacer into its CRISPR array. This genetic memory is then transcribed into a small RNA molecule. This RNA molecule, along with a Cas protein (often Cas9), forms a complex that can recognize and bind to complementary DNA sequences. If the same virus attempts to infect the cell again, the CRISPR-RNA guides the Cas protein to the matching viral DNA. The Cas protein then acts like molecular scissors, cutting the viral DNA at a specific location, thereby neutralizing the threat.

Scientists have adapted this system for gene editing in various organisms. By designing a synthetic guide RNA that matches a target DNA sequence in any organism, and delivering it along with a Cas protein (most commonly Cas9), researchers can precisely cleave DNA at that specific site. This break can then be repaired by the cell's own DNA repair machinery, which can be harnessed to introduce specific changes, such as deleting a gene, inserting a new sequence, or correcting a mutation. The simplicity and precision of CRISPR-Cas have made it an indispensable tool in biological research, with potential applications in medicine, agriculture, and biotechnology.