A comprehensive analysis of viral classical nuclear localization signals

Identification of new viral nuclear proteins and characterization of their nuclear import pathway would not only enable a better understanding of virus-host interaction but also, pave the way to the development of new antivirals preventing the accumulation of viral protein in the nucleus. Keeping this in mind, our lab previously performed a bioinformatic analysis to identify about 200 novel viral proteins potentially translocated into the nucleus of infected cells via IMPa/b pathway due to their putative cNLSs. In this study, we began the functional validation of such hypothetical nuclear proteins with two different approaches. First, we focused on viral proteins which were already known to be nuclear in some species. but were not characterized as nuclear protein in their orthologous belonging to the same viral family. This approach was used to study the nuclear import process of LTAs from all Human Polyomaviruses (HPyVs). By combining phylogenetic and bioinformatic analyses, we identified at least one putative cNLS that could be responsible for the nuclear import of each LTA.Secondly, we functionally validated the 26 top ranking newly identified viral nuclear proteins based on their cNLS strength.