My channel also press bell icon for future video notifications, thanks in a series of experiments with laboratory cultured bacteria johns hopkins scientists have found evidence that there is a second role for the widely used gene cutting system crispr sauce 9. As a genetic dimmer switch for sauce 9 genes, its role of dialing down or dimming crispr sauce 9 activity may help scientists develop new ways to genetically engineer cells for research purposes. A summary of the findings was published january 8 in cell first identified in the genome of gut bacteria in 1987 crispr sauce 9 as a naturally occurring, but unusual group of genes with a potential for cutting dna sequences in other types of cells. That was realized 25 years later. Its value in genetic engineering, programmable gene alteration in living cells, including human cells, was rapidly appreciated and its widespread use as a genome editor in thousands of laboratories worldwide, was recognized in the awarding of the nobel prize in chemistry last year. To its aim, crispr stands for clustered regularly. Interspaced short palindromic repeats size 9, which refers to crispr associated protein 9 is the name of the enzyme that makes the dna slice bacteria naturally use crispr, sauce, 9 to cut viral or other potentially harmful dna and disable. The threat says: joshua modale ph.d assistant, professor of molecular biology and genetics at the johns hopkins university school of medicine. In this role, modal says: crispr is not only an immune system, it’s, an adaptive immune system, one that can remember threats it has previously encountered by holding on to a short piece of their dna, which is akin to a mug shot.

These mug shots are then copied into guide rnas that tell saws 9. scientists have long worked to unravel the precise steps of crispr sawz9’s mechanism and how its activity in bacteria is dialed up or down. Looking for genes that ignite or inhibit the crispr saw’s 9 gene cutting system for the common strep throat, causing bacterium streptococcus pyogenes, the johns hopkins scientists found a clue regarding how that aspect of the system works. Specifically, the scientists found a gene in the crispr sauce 9 system that, when deactivated led to a dramatic increase in the activity of the system in bacteria, the product of this gene appeared to reprogram sauz 9 to act as a break rather than as a scissor to Dial down the crispr system from an immunity perspective, bacteria need to ramp up crispr sauce 9 activity to identify and rid the cell of threats, but they also need to dial it down to avoid autoimmunity when the immune system, mistakenly attacks, components of the bacteria themselves says Graduate student rachel workman to further nail down the particulars of the break. The team’s next step was to better understand the product of the deactivated gene tracher rna rna is a genetic cousin to dna and is vital to carrying out dna instructions for making proteins. Tracher rn has belonged to a unique family of rnas that do not make proteins. Instead, they act as a kind of scaffold that allows the saus 9 enzyme to carry the guide rna that contains the mug shot and cut matching dna sequences in invading viruses.

Tracher rna comes in two sizes, long and short, most of the modern gene cuttings crispr saw’s nine tools use the short form. However, the research team found that the deactivated gene product was the long form of tracher rna, the function of which has been entirely unknown. The long and short forms of tracher rna are similar in structure and have in common the ability to bind to sauz 9. The short form tracher rna also binds to the guide rna. However, the long form tracher rna doesn’t need to bind to the guide rna because it contains a segment that mimics the guide, rna, essentially long form tracher rn, as have combined the function of the short form, tracher, rna and guide rna says modal. In addition, the researchers found that, while guide rnas normally seek out viral dna sequences, long form tracher rn as target the crispr sas 9 system itself. The long form tracher rna tends to sit on dna rather than cut it. When this happens in a particular area of a gene, it prevents that gene from expressing or becoming functional to confirm this. The researchers used genetic engineering to alter the length of a certain region in long form, tracher rna, to make the tracher rna appear more. Like a guide rna, they found that, with the altered, long form, tracher rna saws 9 once again behaved more like a scissor. Other experiments showed that in lab grown bacteria with a plentiful amount of long form, trach or rna levels of all crispr related genes were very low when the long form tracher rna was removed.

From bacteria, however, expression of crispr saw’s nine genes increased a hundredfold bacterial cells lacking the long form trachea rna were cultured in the laboratory for three days and compared with similarly cultured cells containing the long form tracher rna by the end of the experiment. Bacteria. Without the long form, trachea rna had completely died off, suggesting that long form, tracher rna, normally protects cells from the sickness and death that happen when crispr sawz9 activity is very high. We started to get the idea that the long form was repressing but not eliminating its own crispr related activity says workman to see if the long form, trach or rna could be reprogrammed to repress other bacterial genes. The research team altered the long form tracher rn as spacer region, to let it sit on a gene that produces green fluorescence bacteria, with this mutated version of long form, tracher rna, glowed, less green than bacteria containing the normal long form tracher rna, suggesting that the long Form tracher rna can be genetically engineered to dial down other bacterial genes. Another research team from emory university found that in the parasitic bacteria, francisella navicida saas9 behaves as a dimmer switch for a gene outside the crispr sauce 9 region. The crispr sauce 9 system in the johns hopkins study is more widely used by scientists as a gene cutting tool and the johns hopkins team’s findings provide evidence that the dimmer action controls the cri spr saws 9 system. In addition to other genes, the researchers also found the genetic components of long form, tracher rna and about 40 percent of the streptococcus group of bacteria.

Further study of bacterial strains that don’t have the long form tracher rna says workman will potentially reveal whether their crispr 9 systems are intact and other ways that bacteria may dial back the crispr saws 9 system, the dimmer capability that the experiments uncovered says modale offers opportunities To design new or better crispr saws, 9 tools aimed at regulating gene activity for research purposes. Please support my channel to grow by pressing, subscribe button and the bell icon. We will notify you technological news.