title: Translation, modification and cellular distribution of two AC4 variants of African cassava mosaic virus in yeast and their pathogenic potential in plants.
abstract: Plant infecting geminiviruses encode a small (A)C4 protein within the open reading frame of the replication-initiator protein. In African cassava mosaic virus, two in-frame start codons may be used for the translation of a longer and a shorter AC4 variant. Both were fused to green fluorescent protein or glutathione-S-transferase genes and expressed in fission yeast. The longer variant accumulated in discrete spots in the cytoplasm, whereas the shorter variant localized to the plasma membrane. A similar expression pattern was found in plants. A myristoylation motif may promote a targeting of the shorter variant to the plasma membrane. Mass spectrometry analysis of the yeast-expressed shorter variant detected the corresponding myristoylation. The biological relevance of the second start codon was confirmed using mutated infectious clones. Whereas mutating the first start codon had no effect on the infectivity in Nicotiana benthamiana plants, the second start codon proved to be essential.
authors: University of Stuttgart, Institute of Biomaterials and biomolecular Systems, Department of Molecular Biology and Plant Virology, Pfaffenwaldring 57, 70550 Stuttgart, Germany. Electronic address: katharina.hipp@bio.uni-stuttgart.de.
authors: Katharina
authors: K
authors: Hipp
authors: University of Stuttgart, Institute of Biomaterials and biomolecular Systems, Department of Molecular Biology and Plant Virology, Pfaffenwaldring 57, 70550 Stuttgart, Germany.
authors: Peter
authors: P
authors: Rau
authors: University of Stuttgart, Institute of Biomaterials and biomolecular Systems, Department of Molecular Biology and Plant Virology, Pfaffenwaldring 57, 70550 Stuttgart, Germany.
authors: Benjamin
authors: B
authors: Schäfer
authors: University of Hohenheim, Mass Spectrometry Core Facility, August-von-Hartmann-Straße 3, 70599 Stuttgart, Germany.
authors: Jens
authors: J
authors: Pfannstiel
authors: University of Stuttgart, Institute of Biomaterials and biomolecular Systems, Department of Molecular Biology and Plant Virology, Pfaffenwaldring 57, 70550 Stuttgart, Germany.
authors: Holger
authors: H
authors: Jeske
mesh_terms: D000595:Amino Acid Sequence; D053839:Begomovirus / Q000502:physiology*; D015870:Gene Expression; D017930:Genes, Reporter; D016679:Genome, Viral; D018613:Microscopy, Confocal; D010641:Phenotype; D010935:Plant Diseases / Q000821:virology*; D014176:Protein Biosynthesis; D021381:Protein Transport; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000235:genetics; D012568:Schizosaccharomyces / Q000378:metabolism / Q000648:ultrastructure / Q000821:virology; D014764:Viral Proteins / Q000096:biosynthesis* / Q000737:chemistry / Q000235:genetics; D015003:Yeasts / Q000378:metabolism / Q000648:ultrastructure / Q000821:virology*
chemical_list: D011993:Recombinant Fusion Proteins; D014764:Viral Proteins
keywords: AC4; Begomovirus; Confocal laser scanning microscopy; Fission yeast; Freeze fracture immunolabelling; Geminivirus; Virulence