STRUCTURAL ANALYSIS OF RIBOSOME BINDING ELEMENTS OF THE 3´ UTR IN TWO POSITIVE-STRAND PLANT RNA VIRUSES

Turnip crinkle virus (TCV) and Pea enation mosaic virus (PEMV) are two positive (+)-strand RNA viruses that are used to investigate the regulation of translation and replication due to their small size and simple genomes. Both viruses contain cap-independent translation elements (CITEs) within their 3´ untranslated regions (UTRs) that fold into tRNA-shaped structures (TSS) according to nuclear magnetic resonance and small angle x-ray scattering analysis (TCV) and computational prediction (PEMV). Specifically, the TCV TSS can directly associate with ribosomes and participates in RNA-dependent RNA polymerase (RdRp) binding. The PEMV kissing-loop TSS (kl-TSS) can simultaneously bind to ribosomes and associate with the 5´ UTR of the viral genome. Mutational analysis and chemical structure probing methods provide great insight into the function and secondary structure of the two 3´ CITEs. However, lack of 3-D structural information has limited our understanding of their functional dynamics. Here, I report the folding dynamics for the TCV TSS using optical tweezers (OT), a single molecule technique. My study of the unfolding/folding pathways for the TCV TSS has provided an unexpected unfolding pathway, confirmed the presence of Ψ3 and hairpin elements, and suggested an interconnection between the hairpins and pseudoknots. In addition, this study has demonstrated the importance of the adjacent upstream adenylate-rich sequence for the formation of H4a/Ψ3 along with the contribution of magnesium to the stability of the TCV TSS. In my second project, I report on the structural analysis of the PEMV kl-TSS using NMR and SAXS. This study has re-confirmed the base-pair pattern for the PEMV kl-TSS and the proposed interaction of the PEMV kl-TSS with its interacting partner, hairpin 5H2. The molecular envelope of the kl-TSS built from SAXS analysis suggests the kl-TSS has two functional conformations, one of which has a different shape from the previously predicted tRNA-shaped form. Along with applying biophysical methods to study the structural folding dynamics of RNAs, I have also developed a technique that improves the production of large quantities of recombinant RNAs in vivo for NMR study. In this project, I report using the wild-type and mutant E.coli strains to produce cost-effective, site-specific labeled, recombinant RNAs. This technique was validated with four representative RNAs of different sizes and complexity to produce milligram amounts of RNAs. The benefit of using site-specific labeled RNAs made from E.coli was demonstrated with several NMR techniques.

THE PERFORMER’S INFLUENCE ON FRANCO-BELGIAN COMPOSITIONS FROM 1870 TO 1930

The turn of the 20th century marked an ascendancy of the Franco-Belgian school of composers. French composers were inspired by the great German composers of the Romantic era, and they created their own defined national style that emerged toward the end of the 19th century. The Franco-Belgian composers’ special emphasis on tone, timbre and color encouraged a more individual, personally interpretative approach. These devices underscore the importance and influence a performer can have on the outcome of a piece. I researched the relationship between composers and violinists at a time when the Franco-Belgian style developed and flourished. The Franco-Belgian school of violin playing emerged from the Paris and Brussels conservatories as well as the symbiotic relationship between the performers and composers. Three recitals in collaboration with pianist David Ballena, which comprise this dissertation project, were performed at the University of Maryland. Each recital featured music for violin and piano from 1870 through 1930. The repertoire was chosen to reflect a performer’s influence on a composer. I examined specific composer/performer relationships that helped shape the birth of a newly defined “French” style of playing. My research focused on the stylistic interactions composers, such as César Franck, his disciple Guillaume Lekeu had with the leading prominent Belgian violinist Eugène Ysaye and between Maurice Ravel and the Hungarian violinist Jelly d’Aranyi. I also looked into the personal relationship between friends who inspired each other: Gabriel Fauré and Paul Viardot, Edouard Lalo and Pablo de Sarasate, Claude Debussy and Arthur Hartmann, and the young Lili Boulanger and Yvonne Astruc. Furthermore, I looked into the unfulfilled love between Maurice Ravel and Hélène Jourdan-Morhange, as well as the marriage of Olivier Messiaen with Claire Delbos, both relationships resulting in masterpieces for violin that have remained a part of the standard violin repertoire. My research led me to understand what type of violin playing each composer had in mind while composing, all of which led me to understand the importance a performer has in preserving national styles. The recitals were recorded on compact discs and archived within the Digital Repository at the University of Maryland (DRUM).

FROM THE AETHIOPICA TO THE RENAISSANCE: RECOVERING A STAGE TRADITION OF POSITIVE REPRESENTATION OF AFRICANS IN EARLY MODERN ENGLAND

This dissertation looks at the connection between Heliodorus's fifth-century prose romance, An Aethiopian History, certain Renaissance texts, and how these texts helped influence an alternate representation of Africans in the early modern world. Through their portrayals of Africans, early modern English playwrights frequently give the impression that Africans, especially black Africans, were people without accomplishments, without culture. Previously, however, this was not the case. Africans were depicted with dignity, as a tradition existed for this kind of representation--and Renaissance Europe had long been acquainted with the achievements of Africans, dating back to antiquity. As the source of several lost plays, the Aethiopica is instrumental in dramatizing Africans favorably, especially on the early modern stage, and helped shape a stage tradition that runs alongside the stereotyping of Africans. This Heliodoran tradition can be seen in works of Greene, Heywood, Jonson, Shakespeare, and others in the motifs of crosscultural and transracial romance, male and female chastity, racial metamorphosis, lost or abandoned babies, wandering heroes, and bold heroines. In Jonson's Masque of Blackness and Masque of Beauty, I establish a connection between these two masques and Heliodorus's Aethiopica and argue for a Heliodoran stage tradition implicit in both masques through the conceit of blanching. In The English Moore, I explore how Richard Brome uses the Heliodoran and Jonsonian materials to create a negative quality of blackness that participates in the dramatic tradition of the degenerate African on the English Renaissance stage. With Othello, I contend that it is a drama that can be seen in the Heliodoran tradition by stressing certain motifs found in the play that derives from the Aethiopica. Reading Othello this way provides us with a more layered and historicized interpretation of Shakespeare's protagonists. Othello's nationality and faith make his exalted position in Venice and the Venetian army credible and logical. His nobility and heroic status become more sharply defined, giving us a fuller understanding of the emphasis he places on chastity--both for himself and for Desdemona. Instead of a traditional, compliant, and submissive Desdemona, a courageous, resourceful, witty, and pure heroine emerges--one who lives by the dictates of her conscience than by the constraints of societal norms. Recovering the tradition of positive portrayal of Africans that originated from the Aethiopica necessitated an examination of eleven plays that I contend helped to frame the dramatic tradition under investigation. Six of these plays are continental dramas, and five are English. Although three of the English plays are lost and the other two are seventeenth-century dramas, their titles and names of their protagonists, like those of the six extant continental plays, share the names of Heliodorus's hero and heroine, making an exploration of the continental plays imperative to facilitate their use as paradigms in reconstructing the three lost English plays. These continental dramas show that plays whose titles derive from the Aethiopica itself or reflect the names of its major characters follow Heliodorus's text closely, enabling an investigation of the Heliodoran tradition on the early modern English stage. Recovering the Heliodoran tradition adds to the exploration of racial politics and the understanding of the dramatic tradition that constrained and enabled Renaissance playwrights' representation of race and gender.