In a recent study, researchers led by Edward Chung, a computational biologist at the University of Utah explored whether ERVs (Endogenous Retroviruses) help us fend off invaders. ERVs are “endogenous” meaning they are sometimes passed down from generation to generation and “retrovirus” which are types of viruses that infect a cell and convert its RNA to DNA and then become part of a human chromosome. Interestingly enough, ERVs are unable to produce new viruses, which led scientists to believe they were harmless genetic fossils with no apparent function. As a matter of fact, 100,000 pieces of ancient viral DNA live among our genes making us 8% virus. This new study brings up a reason to believe this foreign material may boost our immune system, even protecting us from other viruses. The researchers focused on the innate immune system, which is preprogrammed to launch immediate attacks against entire classes of foreigners instead of the adaptive immune system, which learns to recognize specific invaders and prepare an attack strategy. First off, they scanned 3 different human cell lines for ERVs in their DNA that could bind with the innate immunity transcription factors and found thousands. These were especially important because they turn on genes that launch attacks against pathogens. With this in mind, researchers predicted that if they removed viral DNA from the cell, transcription factors would not function properly, potentially disrupting previously mentioned genes. Using a special gene-editing tool called, “CRISPR”, they snipped out several endogenous viruses from the cell’s DNA. The last step was to infect ERV depleted cells with a virus. In this case they chose the vaccinia virus, which has possible ties to the smallpox. As a result, these cells had a much weaker innate immune system response than unedited normal cells. The reason for this was because an important immune protein wasn’t produced thus not fighting the virus. Later on, scientists added the genes back into the cells and immune function was restored. Harmit Malik, an evolutionary biologist suggests these viral fossils probably played a key role in the evolution of our species.
This article was interesting because it gives great detail about our ancestral genes and how our body has evolved over time. The fact scientists can do these kinds of experiments to prove what these viral fossils play a role in is fascinating and hopefully they continue to build off this.