Skip to Main Content
 

Global Search Box

 
 
 
 

Files

File List


Dissertation FINAL pdf.pdf (7.38 MB)

ETD Abstract Container

Abstract Header

Characterization of T box riboswitch gene regulation in the phylum Actinobacteria

Belyaevskaya, Anna V
http://orcid.org/0000-0003-2859-7243
http://rave.ohiolink.edu/etdc/view?acc_num=osu1437725058

Abstract Details

2015, Doctor of Philosophy, Ohio State University, Molecular, Cellular and Developmental Biology.
Riboswitches are cis-acting RNA regulatory elements located in the 5' untranslated region of a gene. These elements modulate gene expression by structural rearrangements in response to an array of physiological signals. T box riboswitches regulate expression of amino acid-related genes by responding to the aminoacylation status of a specific tRNA that matches the amino acid identity of the regulated gene. Most T box RNAs function at the level of transcription attenuation. A terminator that prevents transcription of the downstream gene forms when aminoacylation of the cognate tRNA is high, whereas uncharged tRNA promotes stabilization of an antiterminator that prevents termination and therefore increases gene expression. T box riboswitches are typically composed of three conserved helical domains, designated Stem I, II, III, the Stem IIA/B pseudoknot, and the competing terminator and antiterminator elements; these domains include conserved primary sequence and several secondary structure elements. However, the predicted structure of many T box riboswitches from the phylum Actinobacteria differ from those found in other phyla. A major goal of this research was to characterize the unusual T box RNAs found in Actinobacteria. These riboswitches are present in ileS genes, and were divided into three groups based on the arrangement of the Stem I domain: canonical Stem I; Ultrashort Stem I (US); and Unusually Structured Stem I Region (USSR). The US and USSR domains lack conserved elements in the canonical Stem I that were previously thought to be essential for T box riboswitch regulation. In addition, most of T box riboswitches in Actinobacteria are predicted to regulate gene expression at the level of translation initiation instead of transcription attenuation. In the current study, we demonstrated that several T box RNAs from Actinobacteria are functional in vitro and undergo structural rearrangements and changes in ribosomal binding in response to uncharged tRNAIle that are consistent with regulation at the level of translation initiation. Results from fluorescence assays demonstrated that the US domain binds the cognate tRNAIle in the absence of other riboswitch sequences, and nuclear magnetic resonance spectroscopy revealed structural rearrangements in this unusual domain in response to interaction with the anticodon stem-loop of the cognate tRNAIle. The US riboswitch variant also was used to identify a novel tRNA interaction site between the conserved nts of the Loop E motif in the Stem II domain and the T arm of the tRNA. This work has investigated the molecular details of T box riboswitch gene regulation, explored the codon-anticodon interaction in the context of unusual RNA structures, and identified tRNA elements important for tRNA noncanonical role in gene regulation. Overall, the obtained information increased our understanding of RNA as a regulatory element.
Tina Henkin (Advisor)
Irina Artsimovitch (Committee Member)
Venkat Gopalan (Committee Member)
Anita Hopper (Committee Member)
133 p.
Microbiology
Riboswitch, Gene Regulation, Actinobacteria

Recommended Citations

Citations

  • Belyaevskaya, A. V. (2015). Characterization of T box riboswitch gene regulation in the phylum Actinobacteria [Doctoral dissertation, Ohio State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=osu1437725058

    APA Style (7th edition)

  • Belyaevskaya, Anna. Characterization of T box riboswitch gene regulation in the phylum Actinobacteria. 2015. Ohio State University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=osu1437725058.

    MLA Style (8th edition)

  • Belyaevskaya, Anna. "Characterization of T box riboswitch gene regulation in the phylum Actinobacteria." Doctoral dissertation, Ohio State University, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=osu1437725058

    Chicago Manual of Style (17th edition)

osu1437725058
51
© 2015, some rights reserved.Creative Commons License Characterization of T box riboswitch gene regulation in the phylum Actinobacteria by Anna V Belyaevskaya is licensed under a Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported License. Based on a work at etd.ohiolink.edu.
This open access ETD is published by The Ohio State University and OhioLINK.