I thought this was a super intriguing paper.
What the authors show is that there is a neuronal gene, Arc, that forms virus-like capsids. In the body, endogenous Arc protein forms capsules that contain mRNA, and these capsules are transferred to nearby neurons. This mRNA actually gets turned into protein in the receiving cells.
Why this is happening is unclear. But this pathway appears to be conserved across a wide range of species. And the Arc protein itself appears to trace its evolutionary lineage back to an old retroviral protein.
Things I wonder about:
- We know that dysfunction in the production of Arc protein has been implicated in various neurological conditions including: amnesia, Alzheimer's disease, autism spectrum disorders, and Fragile X syndrome. Is this related to the RNA-transferring activity of the protein?
- What sort of mRNA messages are being transported? How dynamic is this process? Is it important to the biology of the system?
- What is the point of transferring mRNA this way? Presumably the receiving cells have the same genome and could make the mRNA themselves. And protein-based transduction signals are far better characterized methods for cell-cell signaling. Is there anything special about transferring information this way?
- What about other organ systems? Are there similar examples of this type of cell-cell communication? The closest I could think of was the example of mutant EGFRvIII protein, which can form membrane-based blebs and transfer from one cancerous cell to nearby cells, and inform oncogenic signaling. But this mostly happens in the brain too (glioblastoma).
The full research paper, [The Neuronal Gene Arc Encodes a Repurposed Retrotransposon Gag Protein that Mediates Intercellular RNA Transfer
) was published in the journal *Cell*.
From the paper, a gene that has virus like properties and encodes a protein called Arc (activity-regulated cytoskeleton-associated protein) is involved in the transfer of vesicles which contain mRNA from one neuron to another. The mRNA contained in the vesicles could be modulating the transcription activity of neighboring neurons - which is similar to viral activity.
"back-boned animals"... you mean vertebrates?
Could this be used to improve the effectiveness of gene therapy?
This is super cool! Another example of how capable evolution is. Could this be the mechanism for biologically coded memory? I've only read a little bit of the article, but the concept of viruses that store memory data and transfer it by replicating is super interesting. The article states that Arc genes exist in plenty of different kinds of animals, and that without it, animals are incapable of forming memories. Very cool stuff.
DUDE! Geoffrey Hinton (computer scientist) has a talk in which he claims that human brains must be using backpropagation (way to update/modify internal weights) just like a neural network does, even though neuroscientists haven't found evidence that such a process is going on. Could it be that the brain is sending asynchronous update packets which are used by the receiving neurons to update their structure?
Very interesting. I wonder if something like this comes completely unforseen and strange or if maybe it makes sense because, say, it could explain some mechanisms about memory foeming scientists had not yet fully understood.
This is all really fascinating to me. Can someone explain what is (or what was until now) the current theory about how memories are formed and stored in our brains?
Reminds me of the nanovirus in Adrian Tchaikovsky's Children of Time
I’m currently prepping for my Microbiology final and this is fascinating!!
That is very interesting. As an analogy, consider moving data between computers: we have an internet and can send it via satellite or fiber optic cable, but the fastest way to move huge quantities of data remains loading it on to high-density drives and shipping the drives.
RNA and DNA are fantastically dense ways of packaging information. I bet if we took the information in one of these ARC capsules, and measured the 5mm or whatever it might move before attaching to another neuron, it would be an *extremely* fast method of transmission.
Considering that neurons use electrochemical signaling normally, which is much slower than the electrical signals we use in computers, I would not be surprised if ARC capsules proved to be the majority of total information transmission in the brain.
Ha-Ha! We are walking fermenting bags of skin used by "ideas" viruses to spread memes around. And technology is just another step of evolution of these viruses :P
...probably parkinsons and alzheimers, I'd wager. One wonders what the evolutionary pressure behind this trait would have been.