Shocked! Two cells reveal that viral like protein arc may control your memory

According to a new study, a protein involved in cognition and long-term memory looks like a viral protein and functions like a viral protein The protein, called arc, has similar properties to the one used by viruses to infect host cells It originated from an accidental evolutionary event hundreds of millions of years ago The related research results were published in the cell Journal on January 11, 2018, and the paper title is "the neural gene Arc codes a recycled retrotransfer Gag protein that mediates intercellular RNA transfer"   According to Dr Jason shepherd, a neuroscientist at the University of Utah, the virus like protein may become a new form of intercellular communication in the brain, which may change our understanding of how memory is produced When shepherd's colleagues captured images that confirmed that the protein arc was assembled into a larger structure, he first guessed that there were some differences in arc These structures are similar in shape to the lunar lander's capsule and look like the retroviral HIV virus capsid Shepherd studied the protein for 15 years "At that time, we didn't know much about the molecular function and evolutionary history of arc," he said To be honest, I almost lost interest in this protein After observing the capsid structure it forms, we know that we have some interesting ideas " Previous studies have shown that mice lacking arc forget what they learned 24 hours ago Moreover, their brains lack plasticity There is a time window in early life during which the brain, like a sponge, can easily absorb new knowledge and skills Without arc, this time window will never open Scientists have never considered that the mechanism responsible for acquiring knowledge may have an external origin Now, this new study by shepherd and his team raises this interesting possibility Renew vitality The abnormal tendency of arc to form virus like structure was observed, which prompted shepherd to carefully examine the sequence of the protein He found that its coding region was similar to that of the virus capsid As an important tool of virus infection, virus capsid carries the genetic information of virus and transports it between the cells of infected people Since arc looks like a viral protein, shepherd and his colleagues designed a series of experiments to test whether it also works like a viral protein They first identified several copies of arc that self assemble into hollow viral like shells and store their own genetic material, in this case, mRNA When they added the viral capsid to mouse brain cells (neurons) cultured in a dish, arc transferred its genetic material to those cells After the virus invades the host cells, they are ready to be reinfected It seems that arc works in a similar way Shepherd's team collected the protein arc released by mouse neurons and determined that the protein and its cargo could be ingested by another group of neurons Unlike viruses, the activated neuronal transfer protein arc triggers the release of viral like capsid formed by this protein Dr Elissa pastuzyn, the first author and postdoctoral researcher of the paper, said, "we know that arc is special in many aspects when we enter this field, but we are shocked when we find that arc can mediate the intercellular transport of RNA We know that other non viral proteins don't behave like this " Good luck in pairs Throughout the evolution, the story of arc's origin spread through the animal genome Between 350 and 400 million years ago, an accidental event happened to the four limb animals walking on the earth The ancestors of retroviruses, retrotransposons, inserted their genetic material into the DNA of these animals This event led to the production of the mammalian Arc protein as we know it today The significance of this incident lies in the fact that it happened more than once Another paper published in the cell journal at the same time confirmed that the version of Arc protein found in Drosophila also looked like a viral capsid and functioned like a viral capsid Vivian budnik's laboratory at the University of Massachusetts confirmed that the arc protein of Drosophila flies transports RNA from neurons to muscles to control movement Although mammalian Arc protein and Drosophila Arc protein evolved from the same type of retrotransposon, this event occurred about 150 million years later in Drosophila "As an evolutionary biologist, this is the most exciting thing for me," said co-author Dr C é dric feschotte, a professor at Cornell University The fact that it happened at least twice makes us think it happened more times " Shepherd believes that this may mean that there are advantages to having this virus inspired system, and it may represent a new type of intercellular communication This hypothesis has yet to be tested in mammals "Understanding which goods arc vesicles transport in living animals will be crucial to understanding the function of this pathway," he said
Remember when you first learned about this unusual viral protein? It may control your memory.