title: Translation of the shallot virus X TGB3 gene depends on non-AUG initiation and leaky scanning.
abstract: Triple gene block (TGB), a conserved gene module found in the genomes of many filamentous and rod-shaped plant viruses, encodes three proteins, TGB1, TGB2 and TGB3, required for viral cell-to-cell movement through plasmodesmata and systemic transport via the phloem. The genome of Shallot virus X, the type species of the genus Allexivirus, includes TGB1 and TGB2 genes, but contains no canonical ORF for TGB3 protein. However, a TGB3-like protein-encoding sequence lacking an AUG initiator codon has been found in the shallot virus X (ShVX) genome in a position typical for TGB3 genes. This putative TGB3 gene is conserved in all allexiviruses. Here, we carried out sequence analysis to predict possible non-AUG initiator codons in the ShVX TGB3-encoding sequence. We further used an agroinfiltration assay in Nicotiana benthamiana to confirm this prediction. Site-directed mutagenesis was used to demonstrate that the ShVX TGB3 could be translated on a bicistronic mRNA template via a leaky scanning mechanism.
authors: Department of Genetics, Biotechnology, Plant Breeding and Seed Science, Russian State Agrarian University - Moscow Timiryazev Agricultural Academy, Moscow 127550, Russia.
authors: Alexander A
authors: AA
authors: Lezzhov
authors: Department of Virology, Biological Faculty, Moscow State University, Moscow 119992, Russia.|Genetic Department, Russian Center of Forest Health, Pushkino 141207, Russia.
authors: Vladimir A
authors: VA
authors: Gushchin
authors: Department of Virology, Biological Faculty, Moscow State University, Moscow 119992, Russia.
authors: Ekaterina A
authors: EA
authors: Lazareva
authors: Institute of Agricultural Biotechnology, Russian Academy of Agricultural Sciences, Moscow 127550, Russia.
authors: Valery K
authors: VK
authors: Vishnichenko
authors: Department of Virology, Biological Faculty, Moscow State University, Moscow 119992, Russia.|Belozersky Institute of Physico-Chemical Biology, Moscow State University, Moscow 119992, Russia.
authors: Sergey Y
authors: SY
authors: Morozov
authors: Institute of Agricultural Biotechnology, Russian Academy of Agricultural Sciences, Moscow 127550, Russia.|Belozersky Institute of Physico-Chemical Biology, Moscow State University, Moscow 119992, Russia.
authors: Andrey G
authors: AG
authors: Solovyev
mesh_terms: D018387:Codon, Initiator; D052677:Flexiviridae / Q000235:genetics*; D016297:Mutagenesis, Site-Directed; D014176:Protein Biosynthesis; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism*; D012270:Ribosomes / Q000378:metabolism*; D014026:Nicotiana; D014764:Viral Proteins / Q000096:biosynthesis*
chemical_list: D018387:Codon, Initiator; D012333:RNA, Messenger; D014764:Viral Proteins