The Role of Endogenous Retroviruses in Placental Gene Expression
The Role of Endogenous Retroviruses in Placental Gene Expression
By: Anna Harnsberger
The role of integrated or “endogenous” retroviruses (ERVs) is extensive. ERVs contribute both positively and negatively toward the health of humans and other taxonomic groups. The functionality of these viruses relies heavily on the process of retrotransposition. This process involves the reverse-transcription of the retrovirus genome into the DNA of the host cell. Though some ERVs are detrimental to human health, such as HIV-1, others are “domesticated” and do not pose a threat. Domesticated ERVs, likely inactivated by mutations over millions of years, serve in adaptive functions of the host. Specifically, the presence of ERVs are essential during human pregnancy. The placenta, a vital organ developed during gestation, is affected by the presence of ERVs. ERVs, acting as non-coding regulatory elements, are key contributors to placental evolution. Absence or mis-expression of specific ERVs in the placenta during pregnancy, results in pre- and or post- defects such as pre-eclampsia. Despite what is known about the importance of ERVs in placental gene expression, there is still much research to be done to fully understand the impacts of these retroviruses on the placenta.
