Georgia Family January 2023 | Page 25

ANCIENT VIRAL DNA IN HUMAN GENOME GUARDS AGAINST INFECTIONS

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VIRAL DNA IN HUMAN genomes , embedded there from ancient infections , serve as antivirals that protect human cells against certain present-day viruses , according to new research .
The paper , " Evolution and Antiviral Activity of a Human Protein of Retroviral Origin ," recently published in Science , provides proof of principle of this effect .
Previous studies have shown that fragments of ancient viral DNA — called endogenous retroviruses — in the genomes of mice , chickens , cats , and sheep provide immunity against modern viruses that originate outside the body by blocking them from entering host cells . Though this study was conducted with human cells in culture in the lab , it shows that the antiviral effect of endogenous retroviruses likely also exists for humans .
The research is important because further inquiry could uncover a pool of natural antiviral proteins that lead to treatments without autoimmune side effects . The work reveals the possibility of a genome defense system that has not been characterized , but could be quite extensive .
In addition , the researchers did reverse experiments , using an embryonic kidney cell line normally susceptible to RD114 . The cells became resistant when the researchers experimentally introduced Suppressyn into these cells . The study shows how one human protein of retroviral origin blocks a cell receptor that allows viral entry and infection by a broad range of retroviruses circulating in many non-human species . In this way , Feschotte said , ancient retroviruses integrated into the human genome provide a mechanism for protecting the developing embryo against infection by related viruses .
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