Sub-cellular localization of the 25-kDa protein encoded in the triple gene block of potato virus X.
The 25-kDa protein of potato virus X (PVX) is encoded by the 5' open reading frame of the overlapping triple gene block, has a GKS sequence motif characteristic of nucleotide binding proteins, and is thought to play a role in movement between cells. We have produced a polyclonal antibody to the 25-kDa protein to investigate its synthesis and intracellular location. On Western blots of infected tissue extracts this antibody detected a single major protein of the expected mobility, produced earlier than the viral coat protein in infected protoplasts and located predominantly in the 1000 g pellet fraction of infected cells. Immunogold labeling of thin sections of infected tissue revealed that the 25-kDa protein is associated with the cytoplasmic inclusion bodies characteristic of PVX infections, but not with the cell wall or plasmodesmata. Therefore, although mutational studies indicate a role for the 25-kDa protein in the cell to cell movement of viral infection it is unlikely to act in precisely the same manner as the other well-characterized movement proteins of tobacco mosaic and cowpea mosaic viruses.
Davies
C
C
Sainsbury Laboratory, Norwich Research Park, Colney, United Kingdom.
Hills
G
G
Baulcombe
D C
DC
D000595:Amino Acid Sequence; D000906:Antibodies; D001483:Base Sequence; D015153:Blotting, Western; D002213:Capsid / Q000032:analysis / Q000096:biosynthesis; D003001:Cloning, Molecular; D005814:Genes, Viral; D016253:Microscopy, Immunoelectron; D008969:Molecular Sequence Data; D008970:Molecular Weight; D009838:Oligodeoxyribonucleotides; D016366:Open Reading Frames; D010947:Plants, Toxic; D017863:Potexvirus / Q000235:genetics* / Q000378:metabolism / Q000648:ultrastructure; D011523:Protoplasts / Q000382:microbiology / Q000648:ultrastructure; D012367:RNA, Viral / Q000096:biosynthesis; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis; D014026:Nicotiana; D014764:Viral Proteins / Q000032:analysis / Q000096:biosynthesis*
D000906:Antibodies; D009838:Oligodeoxyribonucleotides; D012367:RNA, Viral; D011993:Recombinant Fusion Proteins; D014764:Viral Proteins