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Ask HN: How Does MRNA Work?
I did not study biology in the university. I studied computer engineering.
I just would like a to understand how mRNA works.
Is it like a trojan horse that transports another virus code to reprogram your cells? Is this the correct way to understand it?
If this is correct, what would unit tests and acceptance tests look like for this? Does it leave any technical debt in what it reprograms in your cells?
- Balgair 6y agomRNA is 'messenger' RNA. DNA is transcribed into mRNA. That mRNA then goes to a ribosome to be turned into proteins. The mRNA is the 'message' to other cellular machinery of how to make proteins. This is the 'central dogma' of molecular biology: DNA > RNA > Protein. The viral part is that some viruses will just be mRNA in a little molecular capsule. When the virus docks with a cell, it injects the mRNA. This free floating mRNA may get picked up by the cell and then turned into the proteins that it codes for. In the case of a virus, that will be proteins to make more viruses. I'm unsure what you mean by a unit test in terms of biology. If you are asking if the ribosome complexes will check to see if some mRNA is a viral one, then no, they do not. These proteins are too small and chaotic to really have those kinds of things. I'm also unsure of what you mean by tech debt here. The virus, once successfully copying itself, will almost always cause cell death and lysis. To be clear, this process is very complicated and caveats abound to everything I've told you. But this is a HN comment section, not a full four year set of courses on virology. https://en.wikipedia.org/wiki/Messenger_RNA https://en.wikipedia.org/wiki/Messenger_RNA
- tmaly 6y agoThank you for the explanation. I was just trying to understand the news I heard on the radio this morning regarding the Covid vaccine. I was trying to see if there was some analogy that could be made between software and biology to better understand how the process works, that is why I mentioned unit tests and technical debt.
- Balgair 6y agoAhh, yes, ModeRNA's vaccine is some very clever stuff. The way that one works is a bit complex. Essentially, they still want your immune system to recognize that the virus is bad and then make antibodies against it. Usually, you inject broken up bits of a dead virus into a person. The immune system sees the foreign objects, and makes antibodies against it. Withe ModeRNA's vaccine, we go inside out. You have the body produce inactive parts of the virus itself. In this case, the 'spike' proteins of the viral capsid. They do this by injecting mRNA into you. Through some complex bio-chem, the mRNA that codes for the spike protein gets into your cells and makes the ribosome complexes produce the spike protein. These then get out of the cells, again via some complex bio-chem, and the immune system sees these spike proteins. The immune system then builds antibodies to the spike proteins, just like with a regular vaccine. Basically, you skip a few steps in the antibody creation process. I want to stress the mRNA injection part. This method skips the DNA, meaning that you are not editing the genetic code of the cell. The real magic here is the potential such a method has. With this method, you can have much better targeted cancer cures, much broader flu vaccines, and time limited protein production. Think time-limited genetic engineering, minus the actual gene editing. Want to glow green for a few days? No problem. Want to mitigate diseases caused by missing DNA? Just take this.
- tmaly 6y agoThat is fascinating. How does the time limit part actually work?
- Balgair 6y agoIn that once mRNA is read it is destroyed by the cell's machinery. This takes time, but should be a exponentially decaying curve. Thus you'd need to keep injecting mRNA to maintain the effects. With the ModeRNA vaccine, due to the nuances of the immune system, antibodies will stick around. But with other therapies it may be very limited in time. Again, super big caveats to most of what I've been saying, as it's a large overview and there are exceptions to everything here.