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dc.contributor.advisorCruz-Reyes, Jorge
dc.creatorMeehan, Joshua Everett
dc.date.accessioned2023-09-19T19:04:51Z
dc.date.created2023-05
dc.date.issued2023-05-11
dc.date.submittedMay 2023
dc.identifier.urihttps://hdl.handle.net/1969.1/199144
dc.description.abstractT. brucei is a protozoan parasite which is the causative agent of African Sleeping Sickness. It undergoes a complex lifecycle as it switches between its insect vector and mammalian hosts. Mitochondrial mRNAs are genomically encoded as cryptogenes and must be post-transcriptionally modified by uridine insertion and deletion (U-indels) along the length of the pre-mRNA. This process is directed by antisense guide RNAs also encoded in the mitochondrial genome and is orchestrated by a ribonuclear protein (RNP) holoenzyme known as the editosome. Editosomes are of dynamic composition and contain multiple subcomplexes, including RESC, RECC, and REH2C. Here, I describe my work at the Cruz-Reyes lab on the essential helicase complex REH2C, which was discovered at TAMU. The REH2C complex consists of three proteins, of which two are known to be relevant to editing: the DExH/RHA RNA helicase (kREH2) and an associated protein with eight Zinc-Finger motifs (kH2F1). Using molecular genetics, we have dissected the role this helicase complex plays in regulating RNA editing in the two major lifecycle stages. Genetic knockdown of REH2C reveals that this helicase complex is essential in both stages for growth and fidelity of canonical editing. LOF of REH2C has substrate specific effects on editing regulation which promote or inhibit canonical editing of transcripts based on their lifecycle stage and association with other editing complexes. We hypothesized that this regulation of RNA editing could be through remodeling secondary structures in the RNAs. With our collaborators at TAMU and Harvard Medical School, we established DMS-MapSeq protocols for Trypanosome mitochondria to uncover these structures and propose how they regulate editing fidelity. With our collaborator at Seattle Children’s hospital, we established the first trypanosome conditional null and expression cell lines that will enable studies of the role of each finger of kH2F1 in editing. Finally, I established cell lines that will enable studies of proximal labeling of editosomes to examine association of these complexes. These cell lines express fusion constructs of TurboID with proteins in editosomes to perform in vivo biotinylation assays. We hope that this work will provide further insights into REH2C’s role in RNA editing regulation throughout development.
dc.format.mimetypeapplication/pdf
dc.language.isoen
dc.subjectRNA biology
dc.subjectTrypanosomes
dc.subjectRNA helicase
dc.subjectRNA editing
dc.subjectParasitology
dc.titleThe Role of the Essential Helicase Complex REH2C in T. brucei Mitochondria RNA Editing
dc.typeThesis
thesis.degree.departmentBiochemistry and Biophysics
thesis.degree.disciplineGenetics and Genomics
thesis.degree.grantorTexas A&M University
thesis.degree.nameDoctor of Philosophy
thesis.degree.levelDoctoral
dc.contributor.committeeMemberZhang, Xiuren
dc.contributor.committeeMemberLeibowitz, Julian
dc.contributor.committeeMemberZhang, Junjie
dc.type.materialtext
dc.date.updated2023-09-19T19:04:52Z
local.embargo.terms2025-05-01
local.embargo.lift2025-05-01
local.etdauthor.orcid0000-0003-1617-2926


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