Zinc Uptake by HIV-1 Viral Particles: An Isotopic Study

Zinc, an essential trace element that serves as a cofactor for numerous cellular and viral proteins, plays a central role in the dynamics of HIV-1 infection. Among the viral proteins, the nucleocapsid NCp7, which contains two zinc finger motifs, is abundantly present viral particles and plays a crucial role in coating HIV-1 genomic RNA, thus concentrating zinc within virions. In this study, we investigated whether HIV-1 virus production impacts cellular zinc homeostasis and whether isotopic fractionation occurs between the growth medium, the producing cells, and the viral particles. We found that HIV-1 captures a significant proportion of cellular zinc in the neo-produced particles. Furthermore, as cells grow, they accumulate lighter zinc isotopes from the medium, resulting in a concentration of heavier isotopes in the media, and the viruses exhibit a similar isotopic fractionation to the producing cells. Moreover, we generated HIV-1 particles in HEK293T cells enriched with each of the five zinc isotopes to assess the potential effects on the structure and infectivity of the viruses. As no strong difference was observed between the HIV-1 particles produced in the various conditions, we have demonstrated that enriched isotopes can be accurately used in future studies to trace the fate of zinc in cells infected by HIV-1 particles. Comprehending the mechanisms underlying zinc absorption by HIV-1 viral particles offers the potential to provide insights for developing future treatments aimed at addressing this specific facet of the virus's life cycle.