An internal ribosome entry site located upstream of the crucifer-infecting tobamovirus coat protein (CP) gene can be used for CP synthesis in vivo.
It was previously shown that, unlike the type member of the genus Tobamovirus (TMV U1), a crucifer-infecting tobamovirus (crTMV) contains a 148 nt internal ribosome entry site (IRES)(CP,148)(CR) upstream of the coat protein (CP) gene. Here, viral vectors with substitutions in the stem-loop (SL) region of CP subgenomic promoters (TMV U1-CP-GFP/SL-mut and crTMV-CP-GFP/SL-mut) were constructed and the levels of CP synthesis in agroinoculation experiments were compared. No CP-GFP (green fluorescent protein) synthesis was detected in Nicotiana benthamiana leaves inoculated with TMV U1-CP-GFP/SL-mut, whereas a small amount of CP-GFP synthesis was obtained in crTMV-CP-GFP/SL-mut-injected leaves. Northern blots proved that both promoters were inactive. It could be hypothesized that IRES-mediated early production of the CP by crTMV is needed for realization of its crucifer-infecting capacity.
Dorokhov
Yu L
YL
A. N. Belozersky Institute of Physico-Chemical Biology, Moscow State University, Leninsky Gory 1, Laboratory Building A, Moscow 119992, Russia.
Ivanov
P A
PA
Department of Virology, Moscow State University, Leninsky Gory 1, Laboratory Building A, Moscow 119992, Russia.
Komarova
T V
TV
A. N. Belozersky Institute of Physico-Chemical Biology, Moscow State University, Leninsky Gory 1, Laboratory Building A, Moscow 119992, Russia.
Skulachev
M V
MV
Department of Virology, Moscow State University, Leninsky Gory 1, Laboratory Building A, Moscow 119992, Russia.
Atabekov
J G
JG
Department of Virology, Moscow State University, Leninsky Gory 1, Laboratory Building A, Moscow 119992, Russia.
D001483:Base Sequence; D019607:Brassicaceae / Q000821:virology; D036022:Capsid Proteins / Q000096:biosynthesis / Q000235:genetics*; D005814:Genes, Viral; D049452:Green Fluorescent Proteins / Q000096:biosynthesis / Q000235:genetics; D016297:Mutagenesis, Site-Directed; D009690:Nucleic Acid Conformation; D011401:Promoter Regions, Genetic; D012367:RNA, Viral / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis / Q000235:genetics; D014026:Nicotiana / Q000821:virology; D017898:Tobamovirus / Q000235:genetics* / Q000378:metabolism / Q000472:pathogenicity; D014774:Virulence / Q000235:genetics
D036022:Capsid Proteins; D012367:RNA, Viral; D011993:Recombinant Fusion Proteins; D049452:Green Fluorescent Proteins