Publication Date

1992

Document Type

Dissertation/Thesis

First Advisor

Altschuler, Mitchell

Degree Name

M.S. (Master of Science)

Legacy Department

Department of Biological Sciences

LCSH

Tobacco mosaic virus; Viral genetics; Catalytic RNA

Abstract

In vitro studies suggest that catalytic RNA may down regulate gene expression through cleavage of target RNA. This application is being evaluated by using a "hairpin" ribozyme derived from the negative strand of the satellite RNA of tobacco ringspot virus. This synthesized ribozyme targets the 542 position of the tobacco mosaic virus (TMV) replicase gene. As a control to verify catalysis as opposed to antisense binding, the ribozyme will be compared to a mutant ribozyme containing a substitution in the hairpin which destroys cleavage activity while retaining the target complement. All constructions are expressed by the CaMV 35S promoter and have been mobilized into the binary vector pBI 121. These vectors have been used in Agrobacterium mediated stable transformations of two Nicotiana tabacum cultivars: Xanthi and Xanthi-nc. These cultivars respond differently to TMV infection and were used to evaluate ribozyme activity by monitoring changes in systemic spread and local lesion response, respectively. Two generations of tobacco expressing the ribozyme were tested for their ability to inhibit TMV. Both the active and mutant ribozymes showed protection when compared to non-transformed plants. There was no statistical difference in viral inhibition between the active or mutant ribozymes in either transformant generation. This suggests that protection is probably occurring through an antisense mechanism.

Comments

Includes bibliographical references (pages 78-85)

Extent

v, 97 pages

Language

eng

Publisher

Northern Illinois University

Rights Statement

In Copyright

Rights Statement 2

NIU theses are protected by copyright. They may be viewed from Huskie Commons for any purpose, but reproduction or distribution in any format is prohibited without the written permission of the authors.

Media Type

Text

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