A hapten-sandwich procedure has been used for immunospecific labeling of cell surface antigens with markers visible by scanning electron microscopy. Antihapten antibody was used to link hapten-modified tobacco mosaic virus, bushy stunt virus, or hemocyanin to hapten-modified human erythrocytes. The antihapten antibody bridge was also used to link the hapten-virus marker to hapten-modified antib...

Intracellular membranes are critical for replication of positive-strand RNA viruses. To dissect the roles of various lipids, we have developed an artificial phosphatidylethanolamine (PE) vesicle-based Tomato bushy stunt virus (TBSV) replication assay. We demonstrate that the in vitro assembled viral replicase complexes (VRCs) in artificial PE vesicles can support a complete cycle of replication...

Original publications This thesis is based on the following articles, which are referred to in the text by their Roman numerals. Purification and protein composition of PM2, the first lipid-containing bacterial virus to be isolated. Virology 262, 364-374. PM2 has a protein capsid surrounding a spherical proteinaceous lipid core. The PM2 virion has a novel organization with an internal membrane ...

Of seven plant viruses tested, all except tobacco mosaic showed the phenomenon of photoreactivation, i.e. plants exposed to visible light after inoculation with preparations partially inactivated by ultraviolet radiation produced more local lesions than plants kept in darkness. Five straiIis of tobacco mosaic virus, which differed widely in their pathogenicity and other properties, were tested,...

Tobacco mosaic virus (TMV) forms dense cytoplasmic bodies containing replication-associated proteins (virus replication complexes [VRCs]) upon infection. To identify host proteins that interact with individual viral components of VRCs or VRCs in toto, we isolated viral replicase- and VRC-enriched fractions from TMV-infected Nicotiana tabacum plants. Two host proteins in enriched fractions, ATP-...

Tobacco mosaic virus (TMV) forms dense cytoplasmic bodies containing replication-associated proteins (virus replication complexes [VRCs]) upon infection. To identify host proteins that interact with individual viral components of VRCs or VRCs in toto, we isolated viral replicaseand VRC-enriched fractions from TMV-infected Nicotiana tabacum plants. Two host proteins in enriched fractions, ATP-sy...

Turnip crinkle virus (TCV) can be dissociated under mild conditions, yielding dimers of the protein subunit, as shown by chemical cross-linking and by gel filtration. These dimers have defined regions of proteolytic sensitivity, correDeterminat ion of the complete three-dimensional structure of tomato bushy stunt virus (TBSV) has revealed a number of remarkable features with implications for me...

RNA viruses exploit host cells by co-opting host factors and lipids and escaping host antiviral responses. Previous genome-wide screens with Tomato bushy stunt virus (TBSV) in the model host yeast have identified 18 cellular genes that are part of the actin network. In this paper, we show that the p33 viral replication factor interacts with the cellular cofilin (Cof1p), which is an actin depoly...

BACKGROUND Integrating non-viral vectors based on transposable elements are widely used for genetically engineering mammalian cells in functional genomics and therapeutic gene transfer. For the Sleeping Beauty (SB) transposase system it was demonstrated that convergent transcription driven by the SB transposase inverted repeats (IRs) in eukaryotic cells occurs after somatic integration. This co...

This study on Tomato bushy stunt virus identified and defined three previously unknown regulatory sequences involved in RNA accumulation that are located within the 3'-proximal nested movement protein genes p22 and p19. The first is a 16-nucleotide (nt) element termed III-A that is positioned at the very 3' end of p22 and is essential for RNA accumulation. Approximately 300 nt upstream of III-A...