Switch from capsid protein import to adenovirus assembly by cleavage of nuclear transport signals.
Replication and assembly of adenovirus occurs in the nucleus of infected cells, requiring the nuclear import of all viral structural proteins. In this report we show that nuclear import of the major capsid protein, hexon, is mediated by protein VI, a structural protein located underneath the 12 vertices of the adenoviral capsid. Our data indicate that protein VI shuttles between the nucleus and the cytoplasm and that it links hexon to the nuclear import machinery via an importin alpha/beta-dependent mechanism. Key nuclear import and export signals of protein VI are located in a short C-terminal segment, which is proteolytically removed during virus maturation. The removal of these C-terminal transport signals appears to trigger a functional transition in protein VI, from a role in supporting hexon nuclear import to a structural role in virus assembly.
Wodrich
Harald
H
Department of Cell Biology, The Scripps Research Institute, 10550 N. Torrey Pines Road, La Jolla, CA 92037, USA.
Guan
Tinglu
T
Cingolani
Gino
G
Von Seggern
Dan
D
Nemerow
Glen
G
Gerace
Larry
L
D000818:Animals; D001483:Base Sequence; D036022:Capsid Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D002460:Cell Line; D002463:Cell Membrane Permeability; D002467:Cell Nucleus / Q000378:metabolism*; D017931:DNA Primers; D017930:Genes, Reporter; D049452:Green Fluorescent Proteins; D006367:HeLa Cells; D006801:Humans; D008164:Luminescent Proteins / Q000235:genetics / Q000378:metabolism; D008969:Molecular Sequence Data; D016366:Open Reading Frames; D021381:Protein Transport; D051381:Rats; D011994:Recombinant Proteins / Q000737:chemistry / Q000378:metabolism; D014162:Transfection; D015678:Viral Structural Proteins / Q000378:metabolism
D036022:Capsid Proteins; D017931:DNA Primers; D008164:Luminescent Proteins; D011994:Recombinant Proteins; D015678:Viral Structural Proteins; C018315:hexon capsid protein, Adenovirus; D049452:Green Fluorescent Proteins