Trans complementation of virus-encoded replicase components of tobacco mosaic virus.
ABSTRACT We examined whether the 130K and 180K proteins of tobacco mosaic virus (TMV), the putative virus-encoded replicase components, produced by a replication-competent TMV mutant could complement a replication-defective mutant in a single cell. The replication-competent mutant (LDCS29) had a deletion in the coat protein gene and the replication-defective mutant (LDR28) had a large deletion in the gene encoding the 130K and 180K proteins. Neither the replication of LDR28 nor the production of the coat protein from LDR28 or LDCS29 was detected when the mutants were inoculated separately into tobacco protoplasts. However, when the two mutants were co-inoculated, the production of the LDR28 genomic RNA and the subgenomic RNA for the coat protein and accumulation of the coat protein were observed. These results show that the virus-encoded replicase components of TMV complemented the replication-defective mutant in trans.
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ABSTRACT: Chronic obstructive pulmonary disease and asthma are both highly prevalent inflammatory diseases characterized by airway obstruction with distinct pathogenic mechanisms and different degrees of response to antiinflammatory therapy. However, forms of presentation that show overlap between both diseases and which are not clearly represented in clinical trials are frequently encountered in clinical practice. These patients may show accelerated loss of pulmonary function and have a worse prognosis. Therefore their early identification is essential. Biomarkers such as bronchial hyperreactivity or nitric oxide in exhaled air have yielded discrepant results. Phenotypic characterization will allow treatment with inhaled corticosteroids to be individually tailored and optimized.Archivos De Bronconeumologia - ARCH BRONCONEUMOL. 01/2010; 46:2-7.
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ABSTRACT: Plant viruses, in particular Tobacco mosaic virus (TMV), are model systems to study RNA and protein trafficking in plants. Although TMV cell-to-cell transport controlled by the 30-kDa movement protein (MP) has been intensively studied, it was only recently demonstrated that the 126/183-kDa replicase proteins are also involved in cell-to-cell movement. Elucidating the role(s) of 126/183-kDa proteins in movement is complicated because these proteins have multiple functions associated with replication and gene expression. To overcome these difficulties we developed a TMV helper virus-defective RNA (dRNA) system to study the role of replicase protein sequences in dRNA cell-to-cell movement. Artificially constructed dRNAs lacking sequences encoding the helicase and polymerase domains of the replicase proteins and portions of the MP were viable in protoplasts and plants in the presence of helper virus. Expression of at least approximately 50% of the methyl transferase (MT) domain was required for efficient dRNA movement in Nicotiana benthamiana. dRNAs that encoded the N-terminal 64 replicase amino acids or lacked a translatable MT domain failed to move or moved poorly. TMV dRNAs expressing 258 amino acids of the replicase protein moved into all specialized non-vascular tissues, whereas dRNAs expressing replicase sequences beyond amino acid 258 were restricted to the epidermis and palisade mesophyll tissues. Furthermore, second-site mutations within the dRNA-encoded truncated replicase protein altered efficiency in dRNA cell-to-cell movement.Virology 11/2005; 341(1):47-58. · 3.37 Impact Factor
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ABSTRACT: Several strains of soybean mosaic virus (SMV) can be differentiated on the basis of the phenotypic response of various soybean cultivars (e.g., the soybean line Williams ‘82 is susceptible to all SMV strains, whereas the lines P. I. 96983, L78-379, and Davis are functionally immune to SMV strain G2 but susceptible to strains G7 and G7a). Inoculation of the immune lines with G2, followed 2 days later by inoculation with G7 or G7a, resulted in systemic spread of the avirulent SMV G2. Further evidence, suggests that complementation groups of SMV strains may exist.Journal of Phytopathology 06/2008; 143(4):247 - 250. · 1.00 Impact Factor