Regulated nuclear targeting of cauliflower mosaic virus.
The mature cauliflower mosaic virus (CaMV) capsid protein (CP), if expressed in the absence of other viral proteins, is transported into the plant cell nucleus by the action of a nuclear localization signal (NLS) close to the N terminus. In contrast, virus particles do not enter the nucleus, but dock at the nuclear membrane, a process inhibited by anti-NLS antibodies or by GTP gamma S, and apparently mediated by interaction of CP with host importin alpha. The very acidic N-terminal extension of the viral CP precursor inhibits nuclear targeting of the protein and hence the precursor is localized in the cytoplasm. We hypothesize that this provides a control mechanism which ensures that the CP precursor is used for virus assembly in the cytoplasm and that only mature virus particles reach the nuclear pore.
Karsies
Aletta
A
Friedrich Miescher Institute, PO Box 2543,CH-4002 Basel, Switzerland1.
Merkle
Thomas
T
Institut für Biologie II, Zellbiologie, Universität Freiburg, 79104 Freiburg, Germany2.
Szurek
Boris
B
Institute of Genetics, Martin-Luther University, 06120 Halle, Germany3.
Bonas
Ulla
U
Institute of Genetics, Martin-Luther University, 06120 Halle, Germany3.
Hohn
Thomas
T
Friedrich Miescher Institute, PO Box 2543,CH-4002 Basel, Switzerland1.
Leclerc
Denis
D
Centre de Recherche en Infectiologie, Université Laval, Ste-Foy, Qc, G1V 4G2, Canada4.
D000595:Amino Acid Sequence; D000906:Antibodies / Q000494:pharmacology; D015153:Blotting, Western; D002213:Capsid / Q000235:genetics / Q000378:metabolism / Q000494:pharmacology; D017796:Caulimovirus / Q000302:isolation & purification / Q000378:metabolism*; D002467:Cell Nucleus / Q000378:metabolism; D016244:Guanosine 5'-O-(3-Thiotriphosphate) / Q000378:metabolism; D028884:Karyopherins / Q000378:metabolism; D008969:Molecular Sequence Data; D009154:Mutation; D009685:Nuclear Envelope / Q000821:virology; D019913:Nuclear Localization Signals; D011485:Protein Binding; D020079:Terminal Repeat Sequences; D014026:Nicotiana / Q000235:genetics; D014162:Transfection; D019065:Virus Assembly
D000906:Antibodies; D028884:Karyopherins; D019913:Nuclear Localization Signals; D016244:Guanosine 5'-O-(3-Thiotriphosphate)