The Crispr System : A Series Of Short Direct Repeats

CRISPR has been garnishing a lot of media attention recently and it is not just popular among the scientific community but also the general public. Several online news outlets and scientific journals have been talking about the significance CRISPR-Cas could have for the field of genetics and science as a whole. I even came across a Youtube video from The Verge, a tech channel that normally does reviews on new smartphones and laptops talking about CRISPR [15]. So why is CRISPR gaining so much attention both from the scientific community and the general public? The answer lies in the potential this technology possesses.

For many years biomedical researchers like myself have been trying to create more proactive ways to amend the genome for living cells. In more recent fieldwork studies there has been a new state of the art instrument based on bacterial CRISP in close works with protein 9 often referred to as CAS9 from the streptococcus progenies have possibly unlocked new data. The CRISP/CAS9 tries to manipulate the function of the gene using homologous recombination and RNA interference, but is set back because it can only provide short term restriction of the genes function and it’s iffy off- target effects.

CRISPR stands for Clustered Regularly Interspaced Short Palindromic Repeat, referring to the repeating DNA sequences found in the genomes of microorganisms. CRISPR technology allows scientists to make precise changes in genes by splicing and replacing these DNA sequences with new ones. Through these changes, the biology of the cell is altered and possibly affects the health of an organism. The possibilities are endless as this offers opportunities in curing deadly diseases, modifying genes, and changing humanity as we know it. Although bioengineering has been around since the 1960s, CRISPR is significant because of the comparative low costs and the ease of the procedure to

The author gives a brief history of past genome editing but thoroughly explains the history and mechanism of the CRISPR technology. She elaborates on how the technology has already been used to cure diseases and speculates on its future uses and regulation.

CRISPR is a technology that allows DNA sequence to be altered in a precised manner in order to avoid genetic mutations that may lead to different diseases. It works by the action of the protein called Cas9 that acts as a molecular scalpel. Cas9 has the ability to detect which parts of the DNA are defective. After it determines where that part is, it attaches itself to it and after a series of chemical reactions, it cuts it right at the spot of the malfunctioned DNA. Sometimes, a new DNA can be attached to it so that the cell can work properly again.

Genetic diseases and illnesses have been of much concern for many years, leaving many deceased or with a poor quality of life. Due to the implication of modern medicine and other techniques used for treatments, mortality rates have decreased and the average life expectancy has increased. Unfortunately, every individual responds differently to the type of treatment they need, which is why the implication of personalized medicine is forthcoming. A certain technique that has been distinguished and commended by researchers today is known as clustered regulatory interspaced short palindromic repeats, or CRISPR. CRISPR is associated with Cas9, and it is a popular genome editing technique which can be programmed to target specific areas of DNA and

CRISPR stands for Clustered Regularly Interspaced Short Palindromic Repeats, which are the trademark of a bacterial defense system that forms the basis for CRISPR-Cas9 genome editing technology. If you have already heard of CRISPR-Cas9 technology, great. If not, I’ll explain it. CRISPR-Cas9 is a unique technology that enables geneticists and medical researchers to edit parts of the genome removing, adding or altering sections of the DNA sequence. This allows scientists to take away an illness or disease from someone’s DNA. CRISPR-Cas9 technology has been a polarizing topic due to ethical reasons. Some people believe that CRISPR is great technology that could and should be used for health reasons and even cosmetic reasons. This would mean

(2012) introduced a new genetic technique that was derived from the defense mechanisms of bacteria. Some bacteria use a CRISPR-Cas system to defend against foreign viral and plasmid genetic material. Once foreign targets enter the system, the bacteria will integrate its CRISPR array to parts of the nucleotide sequences on the invading sequence. The bacteria will then produce a precursor CRISPR-RNA that complements the invading sequence, and is used to find all foreign sequences that match it. These precursor RNAs will work with Cas proteins to cleave the foreign sequence, thus effectively silencing it. There are multiple types of CRISPR-Cas systems that bacteria use. Type 2 systems, paired with Cas-9, use another RNA sequence, tracrRNA (trRNA), as a complement to precursor CRISPR-RNA. These systems used both trRNA and precursor CRISPR-RNA to induce a double stranded cleave. After this discovery, a Cas9 protein was purified and tested to see if it would be able to cleave DNA. It was discovered that if both a trRNA and a precursor CRISPR RNA were present with complementary sequences to a sequence in a DNA strand, the result would be a double strand cleave in the DNA. Cas9 also contains two domains, each of which only cleave either the complementary or the non-complementary strand of the target DNA. After looking at both the trRNA and the precursor CRISPR RNA, researchers theorized that they could engineer a chimera RNA that combined certain sequences of both

The Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR) and CRISPR Associated System (CAS) is an advancement in technology that transformed a previous protein-based targeting (TALEN and Zinc Finger) process used to target and splice genes or DNA sequences. CRISPR-Cas9 was discovered in 2013 by Feng Zhang from the Broad Institute and MIT. CRISPR-Cas9 targets specific base pairs using small RNA that can be easily swapped for many different RNA targeting sites. This allowed CRISPR-Cas9 to surpass the previously used splicing methods such as, Transcription Activator-Like Effector (TALE) and zinc fingers. TALEs and zinc fingers are banded to DNA through a direct protein-DNA interaction. This was a long and tedious process that required proteins to be redesigned for each new target DNA site. CRISPR-Cas9 made the process of genome editing more efficient, effective, and precise by using RNA and proteins (“CRISPR”). CRISPR-Cas9 is a natural system that helps bacteria defend against attacking viruses known as bacteriophages. This process begins with the “CRISPR sequences [bookending] short stretches of DNA that bacteria have copied from invading phages, preserving a memory of the viruses that have attacked them in the past” (“CRISPR”). These sequences are then transcribed into short RNAs that guide the Cas proteins to match the viral sequences. The Cas proteins destroy the matching viral DNA by cutting it from the strand.

Imagine a world where eyesight can be restored, incurable illness can be cured, and genetic conditions can be treated before they are even developed. This is the world that is possible using CRISPR. CRISPR is a gene editing tool that functions through the use of two types of molecules, enzymes and guide RNA. CRISPR was discovered by two major research teams and has since been found to have numerous applications, but it is plagued by controversy.

First discovered in 1987, the CRISPR-Cas system is a prokaryotic adaptive immunity defense system that confers resistance against invading nucleic acids, either viral or plasmid. In other words, if an intracellular parasite (such as a phage or a plasmid) invades the bacterial or achaeal host cell, the host cell is capable of storing short fragments of the foreign nucleic acid originating from the parasite within its own genome (Wiedenheft et al. 2012). The Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR) and the CRISPR associated (Cas) genes are found in approximately 40% of bacterial genomes and in nearly 90% of sequenced archaeal genomes (Zhang and al. 2014).

Even though CRISPR/Cas9 was just discovered around 4 years ago, the CRISPR/Cas system itself was first observed in bacteria (E.coli). It was what CRISPR was doing in the bacteria that makes it so unique. CRISPR stands for, “clustered regularly interspaced short palindromic repeats”. This means that there are going to be short sequences of DNA bases that will read the same forward and backwards. In-between these short sequences will be spacer DNA. Unlike the palindromic sequences, the spacer DNA will have sequences

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

CRISPR-cas9 allows researchers to edit part of the genome by inserting, deleting, or altering sections of the DNA sequence. The CRISPR-cas9 system consists of two key molecules: Cas9 and single-guide RNA (sgRNA). The enzyme Cas9 is ‘guided’ by sgRNA to the DNA sequences where it cuts the two strands of DNA at the specific location in the genome. Endogenous DNA repair mechanisms try to repair the breaks in both strands which then leads to indels that can cause mutation in the target gene. This process is shown in Figure 1.1. To determine whether CRISPR–Cas9 can be used to understand gene function in human preimplantation development, the POU5F1 gene that encodes the development regulator OCT4 was selected as the target. It was predicted that

What is CRISPR? As mentioned above it is the clustered regularly interspaced short palindromic repeats, which are segments of DNA that have short repetitions of base sequences. Each repetition is followed by short segment, which is referred to as spacer DNA. CRISPR is actually found in bacteria and archaea and occurs naturally. Turns out CRISPR is part of the immune systems for bacteria, in those spacer DNAs are store genetic information of viruses that have attacked the bacteria. CRISPR has the ability to capture and store genetic information from invading viruses and use it as template in order to fight off the virus. Along with CRISPR, they have enzymes called CRISPR-associated (Cas) that aid CRISPR in destroying any recognizable virus. The mechanism for CRISPR/Cas goes through this