Genetic suppressors reveal varying methods for improving peroxisome function in Arabidopsis peroxin mutants

dc.contributor.advisorBartel, Bonnieen_US
dc.contributor.advisorMatthews, Kathleenen_US
dc.creatorLlinas, Roxanna J.en_US
dc.date.accessioned2021-12-06T19:46:14Zen_US
dc.date.available2022-12-01T06:01:11Zen_US
dc.date.created2021-12en_US
dc.date.issued2021-12-02en_US
dc.date.submittedDecember 2021en_US
dc.date.updated2021-12-06T19:46:14Zen_US
dc.description.abstractPeroxisomes are eukaryotic organelles that support several metabolic pathways critical to survival and development. These pathways include diverse oxidative reactions with harmful reactive byproducts that are neutralized with enzymes accumulated in peroxisomes. New peroxisomes can be generated via de novo formation from the endoplasmic reticulum or growth and fission of mature peroxisomes with the assistance of proteins called peroxins (PEX proteins). Once formed, peroxisomes acquire necessary enzymes by using other peroxins to import lumenal proteins. Although we have a general framework for understanding peroxisome biogenesis, we lack a complete molecular understanding of the activity and specific sequence of events through which these peroxins function. Unlike in mammals, -oxidation is exclusively peroxisomal in plants, making plants an ideal multicellular system in which to study peroxisomes and peroxisomal metabolism. Germinating Arabidopsis seedlings rely on peroxisomes to catabolize fatty acids stored in lipid droplets, and mutations in peroxin genes confer a range of easily assayed developmental defects that report peroxisome function. I elucidated molecular mechanisms underlying Arabidopsis peroxisomal biogenesis and function by characterizing peroxin mutants and peroxin mutant suppressors. These suppressors carry secondary mutations that restore peroxisomal function to Arabidopsis peroxin mutants. I examined suppressors of pex10-2 and pex12-1, mutants defective in ubiquitin-protein ligases that aid in peroxisome receptor recycling, and pex14-1 and pex14-6, mutants defective in a docking complex peroxin that aids in peroxisomal protein import. I clarified details of how these peroxins function and uncovered novel associations between peroxins by assessing the steps in peroxisomal function that are restored in the suppressors. One pex14-6 suppressor corrects the splicing defect of the original lesion, and I used it to investigate how splicing factors maintain splicing fidelity. One pex12-1 suppressor is defective in a peroxin implicated in peroxisomal membrane protein insertion and pre-peroxisome budding from the endoplasmic reticulum, and I used it to investigate a potential role in protein import. Finally, I examined the role of PEX16, an early-acting peroxisome biogenesis factor, in plants. Together, these studies revealed varying methods for modulating peroxisome function and suggest additional obscure factors in peroxisome competence.en_US
dc.embargo.terms2022-12-01en_US
dc.format.mimetypeapplication/pdfen_US
dc.identifier.citationLlinas, Roxanna J.. "Genetic suppressors reveal varying methods for improving peroxisome function in Arabidopsis peroxin mutants." (2021) Diss., Rice University. <a href="https://hdl.handle.net/1911/111749">https://hdl.handle.net/1911/111749</a>.en_US
dc.identifier.urihttps://hdl.handle.net/1911/111749en_US
dc.language.isoengen_US
dc.rightsCopyright is held by the author, unless otherwise indicated. Permission to reuse, publish, or reproduce the work beyond the bounds of fair use or other exemptions to copyright law must be obtained from the copyright holder.en_US
dc.subjectperoxisomesen_US
dc.subjectsuppression screenen_US
dc.subjectgeneticsen_US
dc.subjectsplicingen_US
dc.subjectspliceosomeen_US
dc.titleGenetic suppressors reveal varying methods for improving peroxisome function in Arabidopsis peroxin mutantsen_US
dc.typeThesisen_US
dc.type.materialTexten_US
thesis.degree.departmentBiochemistry and Cell Biologyen_US
thesis.degree.disciplineNatural Sciencesen_US
thesis.degree.grantorRice Universityen_US
thesis.degree.levelDoctoralen_US
thesis.degree.nameDoctor of Philosophyen_US
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