BioQuakes

AP Biology class blog for discussing current research in Biology

Tag: #transcription #gene #DNA #RNA #cells

CRISPR Gene Editing: The Future of Food?

Biology class has taught me a lot about genes and DNA – I know genes code for certain traits, DNA is the code that makes up genes, and that genes are found on chromosomes. I could even tell two parents, with enough information, the probabilities of different eye colors in their children! However, even with all this information, when I first heard “gene editing technology,” I thought, “parents editing what their children will look like,” and while this may be encapsulated in the CRISPR gene editing technology, it is far from its purpose! So, if you’re like me when I first started my CRISPR research, you have a lot to learn! Let’s dive right in!

CRISPR

Firstly, what is CRISPR Gene Editing? It is a genetic engineering technique that “edits genes by precisely cutting DNA and then letting natural DNA repair processes to take over” (http://www.crisprtx.com/gene-editing/crispr-cas9).  Depending on the cut of DNA, three different genetic edits can occur: if a single cut in the DNA is made, a gene can be inactivated; if two separate DNA sites are cut, the middle part of DNA will be deleted, and the separate cuts will join together; and if the same two separate pieces of DNA are cut, but a DNA template is added, the middle part of DNA that would have been deleted can either be corrected or completely replaced. This technology allows for endless possibilities of advancements, from reducing toxic protein to fighting cancer, due to the countless ways it can be applied. Check out this link for some other incredible ways to apply CRISPR technology!

In this blog post however, we will focus on my favorite topic, food! Just a few months ago, the first CRISPR gene-edited food went on the market! In Japan, Sicilian Rouge tomatoes are now being sold after the Tokyo-based company, Sanatech Seed, edited them to contain an increased amount of y-aminobutyric acid (GABA). “GABA is an amino acid and neurotransmitter that blocks impulses between nerve cells in the brain” (https://www.scientificamerican.com/article/crispr-edited-tomatoes-are-supposed-to-help-you-chill-out/). It supposedly (there is scarce scientific evidence of its role as a health supplement) lowers blood pressure and promotes relaxation. In the past, bioengineers have used CRISPR technology to “develop non-browning mushrooms, drought-tolerant soybeans and a host of other creative traits in plants,” but this is the first time the creation is being sold to consumers on the market (https://www.scientificamerican.com/article/crispr-edited-tomatoes-are-supposed-to-help-you-chill-out/)!

Tomatoes

So, how did Sanatech Seed do it? They took the gene editing approach of disabling a gene with the first method described above, making a single cut in the DNA. By doing so, Sanatech’s researchers inactivated the gene that “encodes calmodulin-binding domain (CaMBD)” in order to increase the “activity of the enzyme glutamic acid decarboxylase, which catalyzes the decarboxylation of glutamate to GABA, thus raising levels of the molecule” (https://www.scientificamerican.com/article/crispr-edited-tomatoes-are-supposed-to-help-you-chill-out/). These may seem like big words, but we know from biology that enzymes speed up reactions and decarboxylation is the removal of carbon dioxide from organic acids so you are already familiar with most of the vocabulary! Essentially, bioengineers made a single cut in DNA inside of the GABA shunt (a metabolic pathway) using CRISPR technology. They were therefore able to disable the gene that encodes the protein CaMBD, and by disabling this gene a certain enzyme (glutamic acid decarboxylase) that helps create GABA from glutamate, was stimulated. Thus, more activity of the enzyme that catalyzes the reaction of glutamate to GABA means more GABA! If you are still a little confused, check out this article to read more about how glutamate becomes GABA which will help you better understand this whole process – I know it can be hard to grasp!

After reading all of this research, I am sure you are wondering if you will soon see more CRISPR-edited food come onto the market! The answer is, it depends on where you are asking from! Bioengineered crops are already hard to sell – many countries have regulations against such food and restrictions about what traits can actually be altered in food. Currently, there are some nutritionally enhanced food on the market like soybeans and canola, and many genetically modified organisms (GMOs), but no other genome-edited ones! The US, Brazil, Argentina, and Australia have “repeatedly ruled that genome-edited crops fall outside of its purview” and “Europe has essentially banned genome-edited foods” (https://www.scientificamerican.com/article/crispr-edited-tomatoes-are-supposed-to-help-you-chill-out/). However, if you are in Japan, where the tomatoes are currently being sold, expect to see many more genome edited foods! I know I am now hoping to take a trip to Japan soon!

Thank you so much for reading! If you have any questions, please ask them below!

We Have Finally Seen Gene Transcription…LIVE

For the past fifty years, scientists and researchers have studied the RNA polymerase enzyme and gene transcription. Until only a few months ago, researchers had been deconstructing cells and then separating the different parts of cells. They examined the reaction of removing one of the individual parts of the now-separated cell, or the reaction of adding an individual part. Basically, in order to examine the functions of RNA polymerase, researchers could never really observe RNA polymerase in action and how it interacts within a live cell. However, at the Sloan Kettering Institute, researchers have finally discovered a way to observe the gene transcription process in real-time.

The role of RNA polymerase is to synthesize an mRNA template from a strand of DNA. That mRNA will go on to determine how a specific protein is made and define the characteristics of that cell. This process is called gene transcription. For example, a kidney cell will produce proteins that the kidney cell needs to function. This is thanks to gene transcription and RNA polymerase’s role in the specialization of cells.

“DNA transcription and the production of mRNA via RNA polymerase.”

Author: Dovelike

In July 2019, researchers developed a method called “single-molecule nanoscopy” in which the researchers use a “highly specialized optical microscope” to examine the relationship between RNA polymerase and synthesized mRNA and genes. This was the first time in history that scientists were able to observe RNA polymerase within the nucleus of a cell and how the enzyme functions.

While studying organic compounds and molecules in class, I frequently wondered how scientists were able to make conclusions about molecular behavior or cellular processes, assuming that they saw everything under a powerful microscope. But when I read this article’s title, “Scientists Watch Single Cell Transcription in a Living Cell,” I was curious to find out why this was “groundbreaking.” However, I realized that in class, when we use simple microscopes to observe relatively larger organisms like paramecium, we struggle to keep track when they are constantly moving. After reading this article, I learned that observing processes within the cell or an organelle is an even greater challenge due to the dynamic movements of molecules and their minuscule size. I thought that this was a very cool discovery. I also wondered about what this means for future research. How could this help people? What are the negative effects of this process? How practical is it for labs to use?

Dr. Pertsinidis, the structural biologist (a researcher that takes pictures of extremely small things) whose lab was used to found the single-molecule nanoscopy method, mentions that this new discovery in molecular observation could be used for more than just gene transcription, such as DNA repair or protein synthesis.

 

 

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