Lucknow: What can save humanity from the deadly coronavirus pandemic is the star molecule called mRNA. It’s the key ingredient in the Pfizer and Moderna COVID-19 vaccines, which provides immunity against the Covid-19. However, mRNA itself is not a new invention from the lab but it evolved billions of years ago and is naturally found in every cell in your body. Scientists think RNA originated in the earliest life forms, even before DNA.
Here are some interesting facts about mRNA and the job it does:
We all probably know about DNA. It’s the molecule that contains all of our genes, spelled out in a four-letter code – A, C, G and T. The information from our genes has to get from the DNA in the nucleus out to the main part of the cell, the cytoplasm, where proteins are assembled. Cells rely on these proteins to carry out the many processes necessary for the body to function. That’s where messenger RNA, or mRNA, comes in the scene.
DNA is found inside the cells of every living being and is protected in a part of the cell called the nucleus. The genes are the details in the DNA blueprint for all the physical characteristics that give us our unique appearance.
Sections of the DNA code are transcribed into shortened genetic messages that are instructions for making proteins. These messages, which are called the mRNA, are transported out to the main part of the cell. Once the mRNA arrives, the cell can produce particular proteins from these instructions.
Interestingly, RNA structure is similar to DNA but has some important differences. Fir example, RNA is a single strand of code letters (nucleotides), while DNA is double-stranded. The RNA code contains a U (uracil) instead of a T (thymine). Both RNA and DNA structures have a backbone made of sugar and phosphate molecules, but RNA’s sugar is ribose and DNA’s is deoxyribose. DNA’s sugar contains one less oxygen atom and this difference is reflected in their names: DNA is the nickname for deoxyribonucleic acid, RNA is ribonucleic acid.
To note, identical copies of DNA reside in every single cell of an organism, from a lung cell to a muscle cell to a neuron. Where, RNA is produced as needed in response to the dynamic cellular environment and the immediate needs of the body, it is mRNA’s job to help fire up the cellular machinery to build the proteins, as encoded by the DNA, that are appropriate for that time and place. The process that converts DNA to mRNA to protein is the foundation for how the cell functions.
mRNA are programmed to self-destruct
The intermediary messenger, mRNA is an important safety mechanism in the cell as it prevents invaders from hijacking the cellular machinery to produce foreign proteins. Any RNA outside of the cell is instantaneously targeted for destruction by enzymes called RNases. When these enzymes recognise the structure and the U in the RNA code, they erase the message, protecting the cell from false instructions.
By turning the blueprints “on” or “off” as needed, mRNA gives the cell a way to control the rate of protein production. No cell wants to produce every protein described in our whole genome all at once. Messenger RNA instructions are timed to self-destruct, like a disappearing text or snapchat message.
Structural features of the mRNA, the U in the code, its single-stranded shape, ribose sugar and its specific sequence, ensure that the mRNA has a short half-life. These features combine to enable the message to be “read,” translated into proteins, and then quickly destroyed – within minutes for certain proteins that need to be tightly controlled, or up to a few hours for others.
It is to be mentioned that once the instructions get erased, protein production stops until the protein factories receive a new message.
How the scientist are harnessing mRNA for Covid-19 or other vaccination
The of characteristics of mRNA make it of great interest to vaccine developers. The goal of a vaccine is to get our immune system to react to a harmless version or part of a germ so that whenever we encounter the real threat we are ready to fight it off.
As of now, researchers have found a way to introduce and protect an mRNA message with the code for a portion of the spike protein on the SARS-CoV-2 virus’s surface. The vaccine provides just enough mRNA to make just enough of the spike protein for a person’s immune system to generate antibodies that protect them if they are later exposed to the virus.
The mRNA in the vaccine is soon destroyed by the cell just as any other mRNA would be, hence, the mRNA cannot get into the cell nucleus and it cannot affect a person’s DNA. As a result, the vaccines have been well tested for safety.
The success of these mRNA vaccines against COVID-19, in terms of safety and efficacy, predicts a bright future for new vaccine therapies that can be quickly tailored to new, emerging threats. Early-stage clinical trials of mRNA containing vaccines have already been conducted for influenza, Zika, rabies, and cytomegalovirus.
It is believed by scientists that the extra immune firepower mRNA vaccines could also yield more durable protection for other infections in the furure.