title: Immunocytology shows the presence of tobacco etch virus P3 protein in nuclear inclusions.
abstract: Intracellular localization studies of various potyvirus proteins have been made in hope of finding clues to their function(s). Immunocytological studies localized many of the tobacco etch virus (TEV)-encoded proteins in infected cells. We used antiserum against the nonstructural P3 protein of TEV to determine the subcellular location of the P3 protein in ultrathin sections of virus-infected cells. Immunogold labeling with the antiserum showed labels associated with nucleoli, nuclei, or NIs, Absorption of antiserum with purified NIs or P3 protein resulted in no labeling. TEV NIs are known to contain a bifunctional genome-linked protein-viral proteinase (NIa-VPg) and RNA-dependent RNA polymerase (NIb). It appeared that the TEV P3 protein was a third nonstructural viral protein of NIs of TEV if the NIa-VPg is considered one protein. The presence of P3 in NIs was also supported by Western blot assays. P3 protein in the nucleolus and nucleus could indicate that it, too, is involved in early stages of viral replication.
authors.affiliation: U.S. Department of Agriculture, University of Nebraska, Lincoln 68583, USA.
authors.forename: W G
authors.initials: WG
authors.lastname: Langenberg
authors.forename: L
authors.initials: L
authors.lastname: Zhang
mesh_terms: D001483:Base Sequence; D002466:Cell Nucleolus / Q000378:metabolism / Q000648:ultrastructure / Q000821:virology; D002467:Cell Nucleus / Q000378:metabolism / Q000648:ultrastructure / Q000821:virology; D017931:DNA Primers / Q000235:genetics; D010450:Endopeptidases / Q000235:genetics / Q000378:metabolism*; D005814:Genes, Viral / Q000235:genetics; D007150:Immunohistochemistry; D007181:Inclusion Bodies, Viral / Q000378:metabolism* / Q000648:ultrastructure* / Q000821:virology; D016253:Microscopy, Immunoelectron; D010947:Plants, Toxic; D017800:Potyvirus / Q000235:genetics / Q000378:metabolism* / Q000648:ultrastructure; D014026:Nicotiana / Q000648:ultrastructure* / Q000821:virology*; D014764:Viral Proteins / Q000235:genetics / Q000378:metabolism*
chemical_list: D017931:DNA Primers; D014764:Viral Proteins; D010450:Endopeptidases; C059992:nuclear inclusion protein a, mosaic viruses