CRISPR/Cas9 Gene Editing System
Crispr/Cas9: The Process
Background
The Clustered repeats that make up Crispr were discovered in 1987 in the bacteria, Escherrichia coli but at the time, the function was unknown. Jennifer Doudna and Emmanuelle Charpentier recently combined the Crispr RNA guide and Cas9 protein into a gene editing system which could target and correct sequences in the genome. There is an enormous potential for the Crispr/Cas9 system in the area of genetic diseases, but work still needs to be done on the process of editing a human's genome. Despit the numerous benefits, there are also problems that could arise if we exploit the Crispr/Cas9 editing tool. One such exploitation of the system includes designer babies. (#42)
Applications to HIV
The Crispr/Cas9 editing system presents the possibility of editing the HIV-1 genome and thus blocking its expression. A study was done to experiment on the effectiveness of using the Crispr/Cas9 method on infected T-cells by editingout the HIV-1 proviral DNA spanning between the 5' and 3' LTRs. Results showed that the entire proviral genome between the LTRs were eliminated which shows that the Crispr/Cas9 eliminated the HIV-1 genome in host cells. Overall the study demonstrated that Crispr/Cas9 can eradicate the HIV-1 genome from CD4+ T-cells but before the editing system can be used on humans, there are still many important issues that must be addressed with regards to its specificity and efficiency. (#44)
Cas stands for Crispr Associated Proteins which are enqymes that can cut DNA dns slice invading viruses. As a result, the genes for Cas are near the Crispr sequence. The best known Cas protein is Cas9, which comes from Streptococcus pyrogenes, a bacteria that causes strep throat. Cas9 can recognize sequences up to 20 base pairs long so it is used in accordance with Crispr to target specific genes. (#43)
Crispr, which stands for clustered regular interspaced short palindromic repeats, is a new genome editing tool which has the potential to transform the world of science. Crispr allows scientists to edit genomes with precision, ifficiency and flexibility. Crispr was discovered in bacteria, acting as a defense mechanism. Crispr were the unique sequences stranded in between repeats which matched the DNA of viruses. Scientists discovered that Crispr was an important part of the bacteria's immune system because it kept small parts of viruses around, so that the bacteria could recognize and defend against those viruses the next time they attack. (#43)
Cas9
Crispr
