Cryo-electron tomography of porcine reproductive and respiratory syndrome virus: organization of the nucleocapsid.
Porcine reproductive and respiratory virus (PRRSV) is an enveloped positive-sense RNA virus of the family Arteriviridae that causes severe and persistent disease in pigs worldwide. The PRRSV virion consists of a lipid envelope that contains several envelope proteins surrounding a nucleocapsid core that encapsidates the RNA genome. To provide a better understanding of the structure and assembly of PRRSV, we have carried out cryo-electron microscopy and tomographic reconstruction of virions grown in MARC-145 cells. The virions are pleomorphic, round to egg-shaped particles with an average diameter of 58 nm. The particles display a smooth outer surface with only a few protruding features, presumably corresponding to the envelope protein complexes. The virions contain a double-layered, hollow core with an average diameter of 39 nm, which is separated from the envelope by a 2-3 nm gap. Analysis of the three-dimensional structure suggests that the core is composed of a double-layered chain of nucleocapsid proteins bundled into a hollow ball.
Spilman
Michael S
MS
Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL 35294, USA.
Welbon
Craig
C
Department of Veterinary Science, South Dakota State University, Brookings, SD 57007, USA.
Nelson
Eric
E
Department of Veterinary Science, South Dakota State University, Brookings, SD 57007, USA.
Dokland
Terje
T
Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL 35294, USA.
D000818:Animals; D002460:Cell Line; D020285:Cryoelectron Microscopy / Q000379:methods*; D055032:Electron Microscope Tomography / Q000379:methods*; D007668:Kidney / Q000166:cytology / Q000821:virology; D008958:Models, Molecular; D019251:Nucleocapsid / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D019590:Nucleocapsid Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D019316:Porcine respiratory and reproductive syndrome virus / Q000235:genetics / Q000254:growth & development / Q000378:metabolism / Q000648:ultrastructure*; D019065:Virus Assembly
D019590:Nucleocapsid Proteins