Analysis Of Retinitis Photoreceptors

CRISPR is a new gene-modifying tool that has the potential to treat numerous medical conditions by editing genes that are responsible for certain diseases. This technology is based on the ability of bacteria to destroy the DNA of invading viruses. Studies have suggested that this new technology can be applied to human cells, although the idea of chopping up regions of the human genome can be unethical and could even be harmful. In order for the treatment to be administered to a patient, a small piece of RNA and an enzyme that makes a cut in the DNA are delivered to the cells. A biotechnology company, known as Editas Medicine, located in Cambridge, MA, is already designing treatments for conditions of the blood and the eye using CRISPR. For

The Cas9 protein is an enzyme that effectively acts as a pair of molecular ‘scissors’, cutting

CRISPR Cas-9 is a system that changes genes and shows a further promise for treatment for Duchenne Muscular Dystrophy (DMD). Doing this will hopefully avoid ethical dilemmas. DMD effects nearly 1 in 5,600-7,700 people between the ages of 5 and 24 for males in the U. S. CRISPR stands for “Clustered Regularly Interspaced Short Palindromic Repeats”. These are DNA segments found in microorganisms that repeat itself in open spaces. CRISPR attacks any virus that comes into your body and cuts the strand of virus on the DNA out. Researchers have tried to cure DMD in mice by getting therapy through the back of the eye, one of the ways CRISPR therapy works, which seems to work best.

Researchers affiliated with the Shanghai Institutes for Biological Sciences, decided to test this up-and-coming editing tool on mice with the dominant blurred vision or cataract-causing mutation in their CRYGC gene, hoping to correct it. The results of their experimentation showed that after the mice with the fixed mutation mated with mice without the mutated genes, their offspring received the correct mutant-free allele from the priorly disease carrying parent. This information provides proof that the CRISPR-Cas9 can be used to correct genetic diseases before they are passed down from one generation to the next (3).

CRISPR Cas9 has many advantages, but it has generated a lot of excitement in the scientific community because it is faster, cheaper, more accurate, and more efficient than other existing genome editing methods. CRISPR reduces the time required to modify targeted genes and has improved bioinformatics tools to identify the best sequences to design guide RNAs. CRISPR Cas9 in embryos works extremely well for the generation

With the use of CRISPR, a specific gene in the genome of a cell can be targeted and mutated to rid of the preexisting mutation. The technique works through the use of an enzyme called Cas9, which acts as the “scissors” to cut two strands of DNA at a specific location in the genome to allow for pieces of DNA to be added or removed. Another molecule of use in the process is a piece of RNA called guide RNA (gRNA). Guide RNA comprises of a small piece of pre-designed RNA sequence located within a longer RNA strand. This longer RNA strand binds to DNA and the pre-designed sequence guides the Cas9 to the correct part of the genome. This occurs for the assurance that the Cas9 enzyme cuts the right part of the genome out. The article provides specific cancers and genetic diseases and the targets for CRISPR/Cas9 that act on these mutations. Amongst the cancers, lung, thyroid, and breast cancer was mentioned. The genetic diseases mentioned were Huntington disease, Alzheimer’s and muscular

A simple but effective method is correctly designing gRNAs. Ideally, the target sequence must be a unique and nearly perfect homology to the gRNA with as little to no homology at other points within the gene sequence. Another potential strategy involves reducing the concentration of gRNA and Cas9 that are expressed in cells. However, this strategy is considered inconclusive due to inconsistent reporting. Some cell lines showed a large decrease in rates of off-target binding while others showed no effect. An increasingly promising method for improving specificity involves using a mutated nickase version of the Cas9 enzyme. This modified version contains only one catatylic domain and is used as a single nickase system capable of cutting a single strand of DNA. This results in a “nick” or single stand break rather then a DSB and is repaired by HDR. To further reduce the risk of off target binding, a double or dual nickase CRISPR system can be implemented. This system uses two nickases which bind to opposite strands of the target gene, generating a DSB. This system closely resembles the Fokl enzyme activation used in TALEN, in that off target effects are reduced because the probability of two off target nicks within the same region is very unlikely. When the DSB is made, activation of NHEJ is initiated; to further increase specificity and reduce off-target effects, the HDR mediated editing is advised for both nickase

CRISPR-Cas9 is a gene editing tool that cuts out, replaces, and alters unwanted pieces of DNA. This process starts by scientists creating a synthetic RNA guide with a specific sequence. Upon entering the cell, the RNA guide meets up with the enzyme Cas9. The RNA then leads the Cas9 to a predetermined section of DNA. The Cas9 unzips the DNA which allows the RNA

One of the challenges with this therapy is to determine how late in the disease process one can therapeutically intervene. Though mutations in the RPE65 gene lead to critical vision loss, the retina’s structure remains undamaged for a time period, which is unknown. Too soon the retinal cells would soon begin to die and at some point the disease will no longer be treatable with gene therapy.

CRISPR cas9 should continue to advance in the science world because “UC Berkeley researchers have made a major improvement in CRISPR-Cas9 technology that achieves an unprecedented success rate of 60 percent when replacing a short stretch of DNA with another”(Antonio Carusillo, PhD Candidate in Genetic Engineering (Marie Curie) at University of Freiburg (2018-present). This statistic shows that there is more of a chance to success but there is a chance to fail 40 percent but overall it will succeed which is why people are lenient about will it actually work or not, but as technology get better so will treatments to cure hard to pinpoint disease such as cancer, zika, or leukemia. Genome editing (also called gene editing) is a group of technologies that give scientists the ability to change an organism's DNA. These technologies allow genetic material to be added, removed, or altered at particular locations in the genome. Several approaches to genome editing have been developed. A recent one is known as CRISPR-Cas9, which is short for clustered regularly interspaced short palindromic repeats and CRISPR-associated protein. The CRISPR-Cas9 system has generated a lot of excitement in the scientific community because it is faster, cheaper, more accurate, and more efficient than other existing genome editing methods (yin, steph.What Is CRISPR/Cas9 and Why Is It Suddenly Everywhere? published april 30,

This easy-to-use technique will facilitate understanding genome functions and their relationships. It has sparked a revolution in genome engineering field since 2012. Below we review the history of CRISPR-Cas9 system development, reveal its underlying molecular mechanism and discuss its applications, challenges and future avenues of this novel

Hsu, P., Lander, E., & Zhang, F. (2014). Development and Applications of CRISPR-Cas9 for Genome Engineering. Cell, 157(6), 1262-1278. http://dx.doi.org/10.1016/j.cell.2014.05.010

Currently, one of the most exciting applications for CRISPR/Cas9 systems is that it has the potential to cure hereditary diseases. A significant amount of current medical research is heading in that direction with hopes that scientists can develop a

They improved the NHEJ machinery to collaborate with the CRISPR system, allowing DNA to be inserted at precise locations in the genome, and then inserted “an inert virus to deliver HITI’s package of genetic instructions to neurons derived from human embryonic stem cells” (…). The innovation allows the cells to glue the ends of cut targeted DNA back together, with the extra addition of the DNA template in-between the cut targeted DNA, via NHEJ. In the case of the cell re-joining without the added insertion or mutation, the CRISPR system would reform and repeat the process. Likewise, donor DNA was designed to recreate the cut site, for the situation of the insertion gluing back together in the wrong orientation.

In the studies of Lee’s, “The Neisseria meningitidis CRISPR-Cas9 System Enables Specific Genome Editing in Mammalian Cells.” the CRISPR-Cas9 frameworks utilized 24 and 20 nucleotides long RNA. Since CRISPR-Cas9 RNA with truncations caused diminished off-target action, Lee’s research team, efficiently tried Cas9 RNAs extending from 24 to 20 nucleotides to decide the ideal RNA length for high CRISPR-Cas9 movement for both the local crRNA and tracrRNA framework where the crRNA and tracrRNA are independent and communicated from various U6 promoters, and an illusory single guide RNA framework with crRNA and tracrRNA combined and communicated from a solitary U6 promoter . Lee’s team also found that the CRISPR-Cas9 frameworks had non-homologous end joining-prompted small insertions and erasure rates. Past research has demonstrated that CRISPR-Cas9 frameworks can endure genomic targeting containing single-base DNA inclusions and single-base DNA cancellations, which have noteworthy