(ORDO NEWS) — Scientists have discovered that in the early stages of human embryonic development, it can defend itself against viruses using the SUPYN protein, which is itself a remnant of an ancient virus that persists in our DNA.
Retroviruses are able to integrate their own genetic material into the DNA of the host organism. Once there, the viral genome can randomly mutate and “deactivate”, remaining unnoticed in the cells.
And if it got into the germ cells, then such a DNA fragment will be inherited from generation to generation. It is estimated that about eight percent of the human genome is made up of such endogenous retroviruses (ERVs), remnants of infections that entered the body of our ancestors many millions of years ago.
Some ERVs can change over time and acquire new functions, starting to play an important role in the life of the whole organism. You may recall that one of them is necessary to protect the brain from new infections. Another useful ERV was discovered by scientists from Cornell University.
Cedric Feschotte and colleagues have analyzed the human genome in search of ERVs that can code for proteins that work in the body.
They found more than 1,500 such fragments, including the SUPYN gene, which is active in the early stages of embryonic development, as well as in placental tissues. The protein it encodes binds to ASCT2 receptors on the cell surface.
Another protein, syncytin, interacts with the same receptors, the gene of which is also a remnant of an ancient virus. It once penetrated into cells through the ASCT2 receptor, and now it is involved in the formation of intercellular bonds in the embryo.
Thanks to the same ASCT2, cells also infect some other retroviruses that infect primates, although not from the group of anthropoids. Apparently, our distant ancestors received protection from such infections.
According to Feshhott and his co-authors, the former viral gene SUPYN plays the role of such protection . The body activates it in response to the appearance of new viruses. The gene produces a protein that binds to ASCT2 receptors and blocks them, making them inaccessible to infection.
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