Infection mechanisms of archaeal viruses

We are interested in the infection mechanisms of archaeal viruses. We focus specifically on viruses of halophilic archaea as they offer the exciting possibility to combine genetics with life cell imaging and fluorescent microscopy approaches, allowing the study of dynamics of infection. In nature, halophilic microorganisms are outnumbered 10-100 fold by viruses and consequently in a constant interplay with them. Archaeal viruses are famous for the high diversity of their virion morphologies, but relatively little is known about their infection strategies. We study the infection mechanisms that archaeal viruses employ in order to enter the host cell, establish an successful infection and to redirect the cellular recourses for their own reproduction. The bacterial and archaeal cell envelopes are fundamentally different, and consequently archaeal viruses face different challenges as their bacterial counterparts. For only a handful of these archaeal viruses, entry and egress strategies have been studied. In a few cases, strategies are employed that resemble those of bacterial viruses, while others are unique for archaeal viruses, such as the egress mechanism of some crenarchaeal viruses that relies on the formation of pyramidal shaped structures on the host cell surface. We aim to characterize more infection strategies of archaeal viruses, in order to shed light onto the viral evolutionary history and adaptation to extreme environments.

Pyramidal egress structure induced by the crenarchaeal virus Sulfolobus islandicus rod-shaped virus 2 (SIRV2) in cells of its hyperthermophilic archaeal host. Negative contrast electron micrograph.