title: Acidianus Tailed Spindle Virus: a New Archaeal Large Tailed Spindle Virus Discovered by Culture-Independent Methods.
abstract: The field of viral metagenomics has expanded our understanding of viral diversity from all three domains of life (Archaea, Bacteria, and Eukarya). Traditionally, viral metagenomic studies provide information about viral gene content but rarely provide knowledge about virion morphology and/or cellular host identity. Here we describe a new virus, Acidianus tailed spindle virus (ATSV), initially identified by bioinformatic analysis of viral metagenomic data sets from a high-temperature (80°C) acidic (pH 2) hot spring located in Yellowstone National Park, followed by more detailed characterization using only environmental samples without dependency on culturing. Characterization included the identification of the large tailed spindle virion morphology, determination of the complete 70.8-kb circular double-stranded DNA (dsDNA) viral genome content, and identification of its cellular host. Annotation of the ATSV genome revealed a potential three-domain gene product containing an N-terminal leucine-rich repeat domain, followed by a likely posttranslation regulatory region consisting of high serine and threonine content, and a C-terminal ESCRT-III domain, suggesting interplay with the host ESCRT system. The host of ATSV, which is most closely related to Acidianus hospitalis, was determined by a combination of analysis of cellular clustered regularly interspaced short palindromic repeat (CRISPR)/Cas loci and dual viral and cellular fluorescence in situ hybridization (viral FISH) analysis of environmental samples and confirmed by culture-based infection studies. This work provides an expanded pathway for the discovery, isolation, and characterization of new viruses using culture-independent approaches and provides a platform for predicting and confirming virus hosts.
  
  
  OBJECTIVE
  Virus discovery and characterization have been traditionally accomplished by using culture-based methods. While a valuable approach, it is limited by the availability of culturable hosts. In this research, we report a virus-centered approach to virus discovery and characterization, linking viral metagenomic sequences to a virus particle, its sequenced genome, and its host directly in environmental samples, without using culture-dependent methods. This approach provides a pathway for the discovery, isolation, and characterization of new viruses. While this study used an acidic hot spring environment to characterize a new archaeal virus, Acidianus tailed spindle virus (ATSV), the approach can be generally applied to any environment to expand knowledge of virus diversity in all three domains of life.
authors.affiliation: Department of Microbiology and Immunology, Montana State University, Bozeman, Montana, USA Thermal Biology Institute, Montana State University, Bozeman, Montana, USA.
authors.forename: Rebecca A
authors.initials: RA
authors.lastname: Hochstein
authors.affiliation: Department of Microbiology and Immunology, Montana State University, Bozeman, Montana, USA Thermal Biology Institute, Montana State University, Bozeman, Montana, USA.
authors.forename: Maximiliano J
authors.initials: MJ
authors.lastname: Amenabar
authors.affiliation: Department of Microbiology and Immunology, Montana State University, Bozeman, Montana, USA Thermal Biology Institute, Montana State University, Bozeman, Montana, USA.
authors.forename: Jacob H
authors.initials: JH
authors.lastname: Munson-McGee
authors.affiliation: Department of Microbiology and Immunology, Montana State University, Bozeman, Montana, USA Thermal Biology Institute, Montana State University, Bozeman, Montana, USA NASA Astrobiology Institute, Montana State University, Bozeman, Montana, USA.
authors.forename: Eric S
authors.initials: ES
authors.lastname: Boyd
authors.affiliation: Department of Plant Sciences and Plant Pathology, Montana State University, Bozeman, Montana, USA Thermal Biology Institute, Montana State University, Bozeman, Montana, USA myoung@montana.edu.
authors.forename: Mark J
authors.initials: MJ
authors.lastname: Young
mesh_terms: D041541:Acidianus / Q000821:virology*; D023641:Archaeal Viruses / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification; D001483:Base Sequence; D036022:Capsid Proteins / Q000235:genetics*; D002874:Chromosome Mapping; D064112:Clustered Regularly Interspaced Short Palindromic Repeats; D004270:DNA, Circular / Q000235:genetics; D004279:DNA, Viral / Q000235:genetics; D016679:Genome, Viral / Q000235:genetics*; D045482:Hot Springs / Q000821:virology*; D006358:Hot Temperature; D017404:In Situ Hybridization, Fluorescence; D056186:Metagenomics; D017422:Sequence Analysis, DNA
chemical_list: D036022:Capsid Proteins; D004270:DNA, Circular; D004279:DNA, Viral