Readthrough protein associated with virions of barley yellow dwarf luteovirus and its potential role in regulating the efficiency of aphid transmission.
Purified particles of barley yellow dwarf luteovirus (BYDV) contain a major 22-kDa protein and a minor protein of approximately 58 kDa. The 22-kDa capsid protein is encoded by open reading frame (ORF) 3. ORF 5 is immediately downstream and in frame with ORF 3 and a 72-kDa protein can be translated via a readthrough suppression of the ORF 3 termination codon. Antibodies were produced against two Escherichia coli expressed polypeptides that represent the amino- and carboxyl-terminal halves of a putative 50-kDa protein encoded by ORF 5. Immunological analyses indicated that the 58-kDa protein associated with purified virions contained sequences encoded by ORF 3 and ORF 5. The carboxyl terminal portion of the full-length (72 kDa) readthrough protein was absent from the 58-kDa protein. The full-length readthrough protein was detected in infected oat protoplasts and plant tissue, but was not associated with virus particles purified from plants. The carboxyl-terminal portion of the 72-kDa readthrough protein was not required for aphid transmission; however, virus was transmitted more efficiently from protoplast extracts containing virions and soluble 72-kDa readthrough protein than from mock-inoculated protoplast extracts to which plant purified virus was added. The full-length readthrough protein, although not required for transmission, may increase the transmission efficiency of BYDV by aphids.
Wang
J Y
JY
USDA-ARS, Cornell University, Ithaca, New York 14853.
Chay
C
C
Gildow
F E
FE
Gray
S M
SM
D000818:Animals; D001042:Aphids / Q000821:virology*; D018554:Avena; D001483:Base Sequence; D002213:Capsid / Q000096:biosynthesis / Q000302:isolation & purification / Q000378:metabolism*; D002478:Cells, Cultured; D003001:Cloning, Molecular; D017931:DNA Primers; D004591:Electrophoresis, Polyacrylamide Gel; D004926:Escherichia coli; D001467:Hordeum / Q000821:virology*; D017793:Luteovirus / Q000302:isolation & purification / Q000472:pathogenicity / Q000502:physiology*; D008969:Molecular Sequence Data; D016366:Open Reading Frames; D010935:Plant Diseases; D016133:Polymerase Chain Reaction; D014176:Protein Biosynthesis; D011523:Protoplasts; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000302:isolation & purification / Q000378:metabolism; D014162:Transfection; D014771:Virion / Q000302:isolation & purification / Q000472:pathogenicity / Q000502:physiology*
D017931:DNA Primers; D011994:Recombinant Proteins