[{"key":"dc.contributor.author","value":"Finnen, Rene\u0301e Louise","language":null},{"key":"dc.date.accessioned","value":"2009-02-19T00:00:00","language":null},{"key":"dc.date.available","value":"2009-02-19T00:00:00","language":null},{"key":"dc.date.issued","value":"1996","language":null},{"key":"dc.identifier.uri","value":"http:\/\/hdl.handle.net\/2429\/4798","language":null},{"key":"dc.description.abstract","value":"In this thesis, the molecular biology of defective interfering (DI) RNAs\r\nassociated with cucumber necrosis virus (CNV), a simple, well characterized plant\r\nRNA virus, was examined to gain insight into CNV RNA replication. Seven\r\ndifferent cDNA clones of DI RNAs associated with either a laboratory strain of CNV\r\nor nucleic acid extracts from serially-passaged CNV infections (de now-generated DI\r\nRNAs) were constructed using reverse transcription followed by the polymerase\r\nchain reaction (RT-PCR). The sequence of each clone was determined and RNA\r\ntranscripts generated by T7 RNA polymerase were assessed for biological activity by\r\ncoinfecting with CNV. This analysis demonstrated that three or four large sequence\r\nblocks of the CNV genome are retained in CNV DI RNAs. These sequence blocks\r\ntherefore likely represent essential c\/s-acting elements involved in viral RNA\r\nreplication. The presence of DI RNAs in CNV infected plants interfered with the\r\ndevelopment of the severe necrosis typical of CNV infections. Total nucleic acid\r\nextracts from coinfections were also found to contain RNAs which were twice the\r\nsize of the DI RNA used in the coinfection. Using RT-PCR analyses and direct\r\nsequencing of RNA templates, these RNAs were established to be linear, head-to-tail\r\nrepeats of DI RNA sequence, the first described in association with tombusvirus DI\r\nRNAs. Further characterization revealed that DI RNA dimers are likely generated\r\nfrom monomers by RNA recombination. Individual DI RNAs were found to vary\r\nin the amount of dimer which they accumulate during coinfection. Dimer\r\naccumulation was examined by coinfecting a series of chimeric and mutated DI\r\nRNAs constructed from a DI RNA which accumulated primarily as monomer and\r\none which accumulated primarily as dimer. These analyses identified two distinct\r\ntracts of sequence in the 3' terminal region which correlate with increased dimer\r\naccumulation. The results of these investigations are discussed in terms of the\r\ninsights they provide into CNV replication and recombination. A model for the\r\ngeneration of DI RNA dimers is also proposed.","language":"en"},{"key":"dc.format.extent","value":"10888163 bytes","language":null},{"key":"dc.format.mimetype","value":"application\/pdf","language":null},{"key":"dc.language.iso","value":"eng","language":"en"},{"key":"dc.publisher","value":"University of British Columbia","language":null},{"key":"dc.rights","value":"For non-commercial purposes only, such as research, private study and education. Additional conditions apply, see Terms of Use https:\/\/open.library.ubc.ca\/terms_of_use.","language":null},{"key":"dc.title","value":"Molecular analysis of defective interfering RNAs associated with cucumber necrosis virus infections","language":"en"},{"key":"dc.type","value":"Text","language":null},{"key":"dc.degree.name","value":"Doctor of Philosophy - PhD","language":"en"},{"key":"dc.degree.discipline","value":"Microbiology and Immunology","language":"en"},{"key":"dc.degree.grantor","value":"University of British Columbia","language":null},{"key":"dc.date.graduation","value":"1996-05","language":"en"},{"key":"dc.type.text","value":"Thesis\/Dissertation","language":"en"},{"key":"dc.description.affiliation","value":"Science, Faculty of","language":null},{"key":"dc.description.affiliation","value":"Microbiology and Immunology, Department of","language":null},{"key":"dc.degree.campus","value":"UBCV","language":"en"},{"key":"dc.description.scholarlevel","value":"Graduate","language":"en"}]