GROUP QUAX / Project QU 496/2-1

Molecular mechanisms of viral egress in haloarchaea

Archaea are ubiquitous in the environment and thrive in diverse habitats ranging from the ocean to the human digestive tract. In archaea-dominated environments, more than half of the cells may be infected by viruses, which represent an important evolutionary pressure. The viruses of archaea are distinct from other viruses, as they display an unusually high morphological diversity. Currently, only a hand-full of release mechanisms archaeal viruses are known. Specifically, the egress mechanisms of viruses infecting euryarchaea are still mysterious.
This project aims to address how viruses egress from euryarchaeal cells using the euryarchaeon Haloferax gibbonsii LR2-5 and the virus HFTV1 as a model.
The findings from this project will help to gain insight into infection strategies of the relatively unexplored archaeal viruses, and might allow for the identification of new virus lysis proteins targeted at archaea.

Principal Investigator(s)

Dr. Tessa E.F. Quax
University of Freiburg
Faculty of Biology, Microbiology, Archaeal virus-host interactions
Schaenzlestrasse  1,  79104 Freiburg


PhD student(s)



  • Tittes C, Schwarzer S, Pfeiffer F, Dyall-Smith M, Rodriguez-Franco M, Oksanen H.M., Quax T.E.F. *(2021) Cellular and genomic properties of Haloferax gibbonsii LR2-5, the host of euryarchaeal virus HFTV1. Frontiers in Microbiology, 16;12:625599.