The intriguing world of archaeal viruses

Abstract

Viruses are among the most abundant biological entities on earth, outnumbering cells in some environments by more than an order of magnitude. Viruses of Archaea (termed archaeal viruses) are some of the most unusual and least understood group of viruses. However, even with our limited knowledge of these remarkable viruses, their characterization has led to major and sometimes startling discoveries. Major questions facing the field include the following (Fig Fig 1. Interesting aspects of archaeal virology. (A) Acidianus tailed spindle virus schematic (and TEM background image) illustrates the unique morphologies that can be found among archaeal viruses. (B) Archaeal viruses and their hosts have no known role in human pathogenesis. (C) Archaeal viruses have revealed novel virus-host interactions, including a novel pyramid-based lysis mechanism. (D) Archaeal viruses are common but not limited to extreme environments. (E) The evolutionary history of archaeal viruses involves two tracts, one unique to Archaea and one with relationships to eukaryotic and bacterial viruses.