Characterization of VPg and the polyprotein processing of cocksfoot mottle virus (genus Sobemovirus).
The polyprotein of Cocksfoot mottle virus (CfMV; genus SOBEMOVIRUS:) is translated from two overlapping open reading frames (ORFs) 2a and 2b by a -1 ribosomal frameshifting mechanism. In this study, a 12 kDa protein was purified from viral RNA-derived samples that appears to correspond to the CfMV genome-linked protein (VPg). According to the determined N-terminal amino acid sequence, the VPg domain is located between the serine proteinase and replicase motifs and the N terminus of VPg is cleaved from the polyprotein between glutamic acid and asparagine residues. Western blot analysis of infected plant material showed that the polyprotein is processed at several additional sites. An antiserum against the ORF 2a product recognized six distinct proteins, whereas, of these, the VPg antiserum clearly recognized only a 24 kDa protein. This indicates that the fully processed 12 kDa VPg detected in viral RNA-derived samples is a minor product in infected plants. An antiserum against the ORF 2b product recognized a 58 kDa protein, which indicates that the fully processed replicase is entirely or almost entirely encoded by ORF 2b. The origin of the detected cleavage products and a proposed polyprotein processing model are discussed.
Mäkinen
Kristiina
K
Institute of Biotechnology, Program for Plant Molecular Biology, Viikki Biocenter, PO Box 56, FIN-00014 University of Helsinki, Finland1.
Mäkeläinen
Katri
K
Institute of Biotechnology, Program for Plant Molecular Biology, Viikki Biocenter, PO Box 56, FIN-00014 University of Helsinki, Finland1.
Arshava
Natalya
N
Institute of Agricultural Biotechnology, Timiryazevskaya st. 42, Moscow 127550, Russia2.
Tamm
Tiina
T
National Institute of Chemical Physics and Biophysics3 and Gene Technology Center, Tallinn Technical University4, Akadeemia tee 23, EE12618 Tallinn, Estonia.
Merits
Andres
A
Institute of Biotechnology, Program for Plant Molecular Biology, Viikki Biocenter, PO Box 56, FIN-00014 University of Helsinki, Finland1.
Truve
Erkki
E
National Institute of Chemical Physics and Biophysics3 and Gene Technology Center, Tallinn Technical University4, Akadeemia tee 23, EE12618 Tallinn, Estonia.
Zavriev
Sergei
S
Institute of Agricultural Biotechnology, Timiryazevskaya st. 42, Moscow 127550, Russia2.
Saarma
Mart
M
Institute of Biotechnology, Program for Plant Molecular Biology, Viikki Biocenter, PO Box 56, FIN-00014 University of Helsinki, Finland1.
D002874:Chromosome Mapping; D016679:Genome, Viral; D016366:Open Reading Frames / Q000235:genetics; D010942:Plant Viruses / Q000378:metabolism*; D014764:Viral Proteins / Q000235:genetics / Q000378:metabolism*
D014764:Viral Proteins