Mapping the subgenomic RNA promoter of the Citrus leaf blotch virus coat protein gene by Agrobacterium-mediated inoculation.
Citrus leaf blotch virus has a single-stranded positive-sense genomic RNA (gRNA) of 8747 nt organized in three open reading frames (ORFs). The ORF1, encoding a polyprotein involved in replication, is translated directly from the gRNA, whereas ORFs encoding the movement (MP) and coat (CP) proteins are expressed via 3' coterminal subgenomic RNAs (sgRNAs). We characterized the minimal promoter region critical for the CP-sgRNA expression in infected cells by deletion analyses using Agrobacterium-mediated infection of Nicotiana benthamiana plants. The minimal CP-sgRNA promoter was mapped between nucleotides -67 and +50 nt around the transcription start site. Surprisingly, larger deletions in the region between the CP-sgRNA transcription start site and the CP translation initiation codon resulted in increased CP-sgRNA accumulation, suggesting that this sequence could modulate the CP-sgRNA transcription. Site-specific mutational analysis of the transcription start site revealed that the +1 guanylate and the +2 adenylate are important for CP-sgRNA synthesis.
Renovell
Agueda
A
Instituto Valenciano de Investigaciones Agrarias (IVIA), 46113 Moncada, Valencia, Spain.
Gago
Selma
S
Ruiz-Ruiz
Susana
S
Velázquez
Karelia
K
Navarro
Luis
L
Moreno
Pedro
P
Vives
Mari Carmen
MC
Guerri
José
J
D001483:Base Sequence; D036022:Capsid Proteins / Q000235:genetics* / Q000378:metabolism; D002874:Chromosome Mapping; D005822:Genetic Vectors / Q000235:genetics / Q000378:metabolism; D008969:Molecular Sequence Data; D011401:Promoter Regions, Genetic; D012367:RNA, Viral / Q000235:genetics*; D012231:Rhizobium / Q000235:genetics / Q000378:metabolism; D014026:Nicotiana / Q000821:virology; D046830:Tymoviridae / Q000235:genetics* / Q000378:metabolism
D036022:Capsid Proteins; D012367:RNA, Viral