Cryo-EM study of Cafeteria roenbergensis virus
Nancy Rondeau1, Gustavo A. Avila1, Chuan Xiao1, Matthias G. Fischer2, Curtis A. Suttle2
1. Department of Chemistry, University of Texas at El Paso, El Paso, Texas, USA
2. Departments of Microbiology & Immunology, Botany, and Earth & Ocean Sciences, University of British Columbia, Vancouver, British Columbia, Canada
Marine viruses play a critical role in the ecosystem of the world’s oceans but have been largely ignored because most of them do not have a direct economic impact on fisheries or other important industries. Nevertheless, marine viruses are significant mortality agents of marine microorganisms and control their abundance and diversity. Cafeteria roenbergensis virus (CroV) is the first well-studied virus infecting a marine phagotrophic flagellate. CroV replicates inside the single-celled zooplankter Cafeteria roenbergensis, which is widespread throughout the world’s oceans.Its genome size is about 730 kbp, making it the second largest viral genome known. Sequence analysis shows that CroV is related to Mimivirus, the world’s largest virus. Initial cryo-EM images of CroV show that CroV has an approximate size of 3,000Å from one vertex to the other. Unlike Mimivirus (approximately 5,000Å in diameter without fiber), CroV does not contain long fibers on its surface but does share a similar hexagonal profile and a multiple layer internal structure.