Ultrastructural localization of nonstructural and coat proteins of 19 potyviruses using antisera to bacterially expressed proteins of plum pox potyvirus

• Published in: Archives of virology 1998-01, Vol.143 (11), p.2133-2158
• Main Authors: Riedel, D, Lesemann, D.E, Maiss, E
• Format: Article
• Language: English
• Subjects: Antisera; Biological and medical sciences; Capsid - genetics; Capsid - immunology; Capsid - ultrastructure; CI protein; Coat protein; Cytoplasm; cytoplasmic inclusions; Electron microscopy; Escherichia coli - genetics; Filaments; Fundamental and applied biological sciences. Psychology; Genetic Vectors - biosynthesis; Immune Sera - metabolism; Inclusion bodies; Inclusion Bodies, Viral - chemistry; Inclusion Bodies, Viral - ultrastructure; Localization; Microbiology; Morphology, structure, chemical composition, physicochemical properties; Nonstructural proteins; nuclear inclusions; Phytopathology. Animal pests. Plant and forest protection; Plant Extracts - immunology; Plant viruses; Plant viruses and viroids; Plum pox; Plum Pox Virus - genetics; Plum Pox Virus - immunology; Potyvirus - chemistry; Potyvirus - immunology; Potyvirus - ultrastructure; Proteins; Systematics. Structure, properties and multiplication. Genetics; Viral Nonstructural Proteins - genetics; Viral Nonstructural Proteins - immunology; Viral Nonstructural Proteins - ultrastructure; viral proteins; Virions; Virology
• ISSN: 0304-8608; 1432-8798
• DOI: 10.1007/s007050050448

Antisera to the bacterially expressed nonstructural proteins (NSP) HC-Pro, CI, NIa, and NIb and the coat protein (CP) of plum pox potyvirus (PPV) were used for analysing the composition of virus-induced cytoplasmic and nuclear inclusions by electron microscopy. The antisera reacted with NSP and CP of PPV on immunogold-labelled ultrathin sections. Antiserum to CP reacted with virions of seven out of 18 other potyviruses. CP was distributed throughout the cytoplasm of infected cells. Antisera to PPV NSP specifically reacted with virus-specific cytoplasmic and/or nuclear inclusions induced by 17 different potyviruses. NSP were furthermore localized in confined cytoplasmic areas in between complex accumulations of virus-specific inclusions. Cylindrical inclusions induced by the potyviruses were proven to consist of CI protein. Most other cytoplasmic or nuclear inclusions were shown to be composed of two or more NSP. An unexpected composition of virus-induced inclusions was observed for the crystalline nuclear inclusions of tobacco etch virus. Here, in addition to the expected presence of NIa and NIb, HC-Pro could be demonstrated. Furthermore, amorphous cytoplasmic inclusions induced by papaya ringspot virus contained the expected HC-Pro but additionally NIa, NIb and CI. Beet mosaic virus-induced nuclear inclusions ('satellite bodies') contained in their electron-dense matrix NIa, NIb, Hc-Pro and CI and in their lacunae CP in bundles of virion-like filaments. The results indicate that all cytoplasmic or nuclear inclusions of potyviruses have to be regarded as deposition sites of excessively produced viral NSP.