CONICET | Buscador de Institutos y Recursos Humanos

Junín virus, agent of the Argentine hemorrhagic fever, belongs to the Arenaviridae. The virion genome is composed of two ambisense single-stranded RNA segments, encoding the nucleocapsid, the glycoprotein precursor that is processed into the mature glycoproteins, the viral RNA polymerase, and the Z protein that serves as a matrix protein. In our previous studies we reported the inhibitory action against arenaviruses of some antiretroviral Zn finger compounds provided by the National Cancer Institute (USA). These compounds were able to inactivate virions by direct contact as well as to reduce virus yields from infected Vero cells. The target of these compounds is the Z RING finger motif. In the present study, we have characterized purified inactivated particles under the electron microscope, showing an electrodense labeling around the matrix Z protein, suggesting some protein modification. To understand which step in the viral cycle is blocked by the inactivated particles we performed a nucleocapsid penetration assay. Using labeled viral proteins we verified that the inactivated particles are retained in endosomes and are not able to enter the cytoplasm. This inactivation mechanism seems to involve irreversible structural changes in the Z matrix protein that inhibit uncoating, indicating that the Z protein might play a role in this step.Moreover the reactivity of these compounds with the Z protein inside the cell was confirmed using a recombinant fusion protein Z-eGFP. After 48 h, transfected and treated cells were fixed and Z-eGFP was located by fluorescence microscopy. Z aggregates close to the endoplasmic reticulum indicated that Z structure was destabilized. Thus, these compounds can be potential anti-arenaviral agents and can be used as tools for biological studies.

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