Patent ID: 8344208

Claim:
A viral vector system comprising: 1) a functionally crippled viral vector carried on a binary vector, wherein the viral vector is expressed via a constitutively expressed or inducible viral vector promoter, with expression terminating via a viral vector polyA signal/transcription terminator at the 3′ end of the viral vector, and the viral vector comprises a modified foxtail mosaic virus (FoMV) full length cDNA and a heterologous gene; wherein the modified FoMV full length cDNA is a modified wildtype FoMV full length cDNA such that the triple gene block 2 (TGB2) and triple gene block 3 (TGB3) genes are deleted, all bases except the beginning of the triple gene block 1 (TGB1) gene are deleted, all bases except the 3′ end of the coat protein (CP) gene are deleted, the subgenomic promoter of subgenomic RNA 1 is retained, and the start codon of the TGB1 open reading frame has been mutated to be non-functional; wherein the beginning of the TGB1 gene open reading frame is 30% or less of the initial sequence of the open reading frame of TGB 1; and wherein the 3′ end of the CP gene is 30% or less of the 3′ terminal sequence of the CP FoMV gene; and wherein the heterologous gene is inserted into restriction sites at the 3′ end of the subgenomic promoter of subgenomic RNA 1; and 2) a second binary vector carrying a gene for a p19 or a helper-component proteinase (HcPro) silencing suppressor, driven by a constitutively expressed or inducible silencing suppressor promoter; wherein expression of the heterologous gene is dependent on the presence of the p19 or the HcPro silencing suppressor.