Ancient Viral DNA Creates Unknown Protein

Viral DNA makes up about 8% of the human genome. And yet, there is still much of it that is left unexplained and mysterious. A recent study identified an unknown protein, called Hemo, in the blood of a mother that appears to be coded for in ancient viral DNA from the fetus and placenta. Scientists are referring to the viral infection that may have caused the creation of this protein "endogenous retroviruses". Retroviruses have the potential to be passed down through generations and can essentially hide within a host. A this point, they are identified as endogenous retroviruses. They can infect many cells and even after this ability is impaired, they can sometimes continue to make proteins and reproduce. Because of this, they have the potential to replicate many times after just one infection so that they can have hundreds of copies in the host's DNA.

Endogenous retroviruses have been found to be present in our ancestors about 450 million years ago. Dr. Odile Heidmann was able to identify the protein Hemo in viral DNA. This very protein was also identified in primates and has supposedly remained unchanged for many thousands of years. Dr. Heidmann explains that this protein "isn't simply a relic" because it is found in many different species over time. It likely has an important role that we simply don't understand currently.

Hemo is produced within the placenta and could potentially act as a communication between the fetus and mother so that the mother's immune system recognizes the fetus as non-foreign. It also may be involved in creating important tissues. From a viral standpoint, the fetus appears to be a brilliant place to infect. For, as the host grows, they can remain in the new child's cells and then be passed on to the next generation. While a lot of this discussion is simply speculation, it is an exciting new area of research in which we have a lot to learn.

-Alexandra

Source: https://www.nytimes.com/2017/10/04/science/ancient-viruses-dna-genome.html?rref=collection%2Ftimestopic%2FViruses&action=click&contentCollection=health&region=stream&module=stream_unit&version=latest&contentPlacement=2&pgtype=collection