Calicivirus Non-structural Proteins: Potential Functions in Replication and Host Cell Manipulation

Frontiers in Microbiology, vol. 12, pp. 712710

Abstract

TheCaliciviridaeare a family of viruses with a single-stranded, non-segmented RNA genome of positive polarity. The ongoing discovery of caliciviruses has increased the number of genera in this family to 11 (Norovirus,Nebovirus,Sapovirus,Lagovirus,Vesivirus,Nacovirus,Bavovirus,Recovirus,Salovirus,Minovirus, andValovirus). Caliciviruses infect a wide range of hosts that include fishes, amphibians, reptiles, birds, and marine and land mammals. All caliciviruses have a genome that encodes a major and a minor capsid protein, a genome-linked viral protein, and several non-structural proteins. Of these non-structural proteins, only the helicase, protease, and RNA-dependent RNA polymerase share clear sequence and structural similarities with proteins from other virus families. In addition, all caliciviruses express two or three non-structural proteins for which functions have not been clearly defined. The sequence diversity of these non-structural proteins and a multitude of processing strategies suggest that at least some have evolved independently, possibly to counteract innate and adaptive immune responses in a host-specific manner. Studying these proteins is often difficult as many caliciviruses cannot be grown in cell culture. Nevertheless, the study of recombinant proteins has revealed many of their properties, such as intracellular localization, capacity to oligomerize, and ability to interact with viral and/or cellular proteins; the release of non-structural proteins from transfected cells has also been investigated. Here, we will summarize these findings and discuss recentin silicostudies that identified previously overlooked putative functional domains and structural features, including transmembrane domains that suggest the presence of viroporins.

Authors 5

1. Elena Smertina

   Commonwealth Scientific and Industrial Research Organisation · University of Canberra

   Affiliation as printed

   Commonwealth Scientific and Industrial Research Organization, Health and Biosecurity, Canberra, ACT, Australia

   Faculty of Science and Technology, University of Canberra, Canberra, ACT, Australia

2. Robyn N. Hall

   Commonwealth Scientific and Industrial Research Organisation · Centre for Invasive Species Solution

   Affiliation as printed

   Centre for Invasive Species Solutions, Canberra, ACT, Australia

   Commonwealth Scientific and Industrial Research Organization, Health and Biosecurity, Canberra, ACT, Australia

3. Nadya Urakova Aachen Department of Medical Microbiology

   Leiden University Medical Center

   Affiliation as printed

   Department of Medical Microbiology, Leiden University Medical Center, Leiden, Netherlands

4. Tanja Strive

   Commonwealth Scientific and Industrial Research Organisation · Centre for Invasive Species Solution

   Affiliation as printed

   Centre for Invasive Species Solutions, Canberra, ACT, Australia

   Commonwealth Scientific and Industrial Research Organization, Health and Biosecurity, Canberra, ACT, Australia

5. Michael Frese corresponding

   Commonwealth Scientific and Industrial Research Organisation · University of Canberra

   Affiliation as printed

   Commonwealth Scientific and Industrial Research Organization, Health and Biosecurity, Canberra, ACT, Australia

   Faculty of Science and Technology, University of Canberra, Canberra, ACT, Australia