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Project Progress

In recent years it has become evident that viruses have been and continue to be major drivers of evolution of life on earth. Viruses are the most abundant life-like entities on the planet and are likely a major reservoir of genetic diversity for all life on the planet. We also hypothesize that this will be the case anywhere life exists on Earth or on non-Earth like bodies. We are investigating the role of archaeal viruses present in high temperature acidic environments found in Yellowstone National Park. The specific objectives of this project are to (1) to isolate and characterize new archaeal viruses in high temperature environments and (2) to understand the role these viruses play in determining the evolution and ecology of microbial communities. This project involves extensive tool development, such as virus isolation procedures from extreme environments, extremophile virus propagation techniques, and development of genetic and biochemical assays, for the discovery and characterization of these unusual viruses. We have developed a new method of detecting previously unknown viruses in the environment. By using a CRISPR-spacer microarray, we can monitor virus dynamics over time and have the potential to discover previously unidentified viruses from any environment. The viruses discovered to date are novel and form founding members of new virus families. We have begun genetic and structural analyses of these viruses and we are gaining insights into the evolution of viruses on Earth. We have begun to make evolutionary links between viruses infecting the archaeal and the eukaryal domains of life. We have determined that viruses infecting hosts from both domains utilize the same cellular proteins for assembly and trafficking to the membrane prior to lysis. These results indicate that these cellular proteins were present before the split of the domains of life and viruses utilizing these proteins during their replication cycle is ancient. We hope to gain insights into the role that viruses might have played in the formation of suspected protocells of early life, and the enormous diversity of viruses present on the planet.