All About Crispr Cas 9
In June of 2012, UC Berkeley graduate student, Jennifer Dounda, discovered a gene editing tool that would revolutionize the biotechnology industry. Today, the tool is known as CRISPR-CAS 9. CRISPR CAS-9, which stands for Clustered regularly-interspaced short palindromic repeats, is a protein complex used to “cut out” DNA sequences in the genome turning off specific genes. Scientists across the globe are using the new gene editing tool to alter agriculture, cure diseases, and fix genetic mutations. The tool may one day also be used to genetically modify human embryos, but at the moment scientists have not experimented with the concept due to ethical issues. But while CRISPR is a huge concept in the science community, the average consumer has never heard of the tool. Though CRISPR could potentially have a huge effect on all of our future lives, we as a society are unaware of what it does and how it will work to change our lives.
What is CRISPR?
To start, we must understand how the gene editing tool works. The Cas-9 protein complex was first discovered in e coli bacteria, used as a way to defend themselves from viral attacks. CRISPR is formed by small clusters of DNA, each cluster containing 20-40 nucleotides. Nucleotides are molecules that build DNA and create our cells genetic code. As stated in the name, CRISPR is made up of palindromic repeats- meaning each DNA cluster is identical to one another, and contains the exact same nucleotides in the exact same order. Spacer DNA links all the clusters together to create a long chain. Pieces of spacer DNA are found to be unique, and do not resemble one another, often belonging to old viruses and bacteriophages. At the end of the long chain of DNA clusters sits the CAS 9 genes. These CAS genes code for proteins such as helicases and cut mechanisms that allow CRISPR to cut out specific parts of an organism's genetic code.
* This long chain represents the CRISPR DNA clusters attached by spacer DNA as stated above. The CAS genes located at the end of the CRISPR DNA Structure code for the protein seen on the right, and create the CAS-9 complex. This complex was originally used in ecoli to cut and deactivate viral DNA using the spacer DNA.
CRISPR genes
CAS-9 Protein Complex
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The CAS-9 protein complex contains a small section of guide RNA (Tracr RNA) and a specific RNA sequence that matches with a specific part of the genome. The CAS-9 protein travels through the genome and locates a specific area of DNA to cut out and replace.
How does the CAS-9 Protein alter the genome?
* The CAS-9 protein complex travels through a cells genome until it locates the specific part of DNA that matches the sequence it carries.
*Once the CAS-9 Protein complex locates the correct sequence, it inserts the matching RNA it carried, during DNA replication.
*After the matching sequence is inserted, the CAS-9 protein uses its endonucleases to cut out a part of the DNA sequence.
Once the DNA is cut, the CAS-9 protein may insert a new sequence of DNA to correct the mutation.
After the DNA is cut the cell may try to repair the cut and add new DNA containg many mistakes. This disables the gene.
Learn More
Agriculture
CRISPR is also changing our agriculture and poultry. Learn more about how scientist use the gene editing tool to enhance flavors, create weather resistant plants, and change GMOs.
Gene Therapy
CRISPR is also being used to cure different diseases and conditions. such as sickle cell anemia, Cystic Fibrosis and hemophilia. One day CRISPR could also be used to cure cancer, heart disease and HIV along with many resistant bacterial infections.