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dc.contributor.advisorPrice, Jeffrey L.eng
dc.contributor.authorVenkatesan, Anandakrishnaneng
dc.date.issued2012-10-01eng
dc.date.submitted2012 Summereng
dc.descriptionTitle from PDF of title page, viewed on October 1, 2012eng
dc.descriptionDissertation advisor: Jeffrey L. Priceeng
dc.descriptionVitaeng
dc.descriptionIncludes bibliographic references (p. 143-150)eng
dc.descriptionThesis (Ph.D.)--School of Biological Sciences. University of Missouri--Kansas City, 2012eng
dc.description.abstractIn this dissertation, I used the GAL4-UAS binary expression method to overexpress mutant and wild type forms of the circadian protein kinase DBT in order to address several basic questions about DBT's biological functions. Different dbt mutations either shorten or lengthen the circadian period, although they all possess lower kinase activity in vitro. Therefore, I first addressed whether these period-altering mutations of DBT act independently of any effects on DBT's intrinsic kinase activity by analyzing them in a kinase inactive background (DBTK/R) in cis. All three double mutants shortened the DBTK/R period in cis and enhanced PER oscillations, supporting our hypothesis. Next, I addressed whether DBT has different roles in the cytoplasm and the nucleus with opposite effects in these two compartments (lengthening period in the cytoplasm and shortening it in the nucleus). I mutated the putative nuclear localization sequence (DBTWTNLS-) and added a strong NLS (DBTWT stNLS) to make DBT cytoplasmic or nuclear, respectively. In contrast to my predictions, the DBTWTNLS- shortened period, while DBTWT stNLS did not alter period. The NLS- mutation affected amino acids that are part of a proposed phosphate-binding domain. Additional mutations in the vicinity of the NLS shortened period, while mutations that were not close lengthened period. The shortening of period by some mutations suggests that they affect a TAU-like domain involved in a protein-protein interaction that lengthens period. A third question addressed was whether DBT has specific roles in the brain morning and evening oscillator cells. I investigated these cellular interactions by expression of DBTK/R in different subsets of cells to damp just one oscillator. Our experiments suggest the evening oscillator is necessary for suppressing the morning startle response, in addition to its role in production of evening activity. The final part of my thesis employed a fly eye model for tauopathy to investigate whether DBT might have a role in neurodegeneration. Overexpression of the dominant negative DBTK/R enhanced the eye neurodegeneration produced by expression of human TAU in the fly eye. Our investigation suggests that DBT phosphorylates a caspase (DRONC), thereby preventing it from cleaving TAU and thus preventing its toxicity.eng
dc.description.tableofcontentsBackground and significance -- Materials and methods -- Drosophila DBT period altering mutants in-cis shorten periods produces by expression of a kinase inactive DBT -- A mutaational analysis of DBT reveals a unique domain that produces short periods -- Expression of DBT [super K/R] in the clock cells affects per in a cell-autonomous manner but reveals a need for a functional circadian clock in the evening cells to produce high levels of evening activity and suppress the morning activity -- A role of DBT in TAU processing and toxicity -- BDBT is necessary for the destabilization of per in the lateral neurons of adult brainseng
dc.format.extentx, 151 pageseng
dc.identifier.urihttp://hdl.handle.net/10355/15542eng
dc.publisherUniversity of Missouri--Kansas Cityeng
dc.subject.lcshProtein kinaseseng
dc.subject.lcshDrosophilaeng
dc.subject.lcshCircadian rhythmseng
dc.subject.otherDissertation -- University of Missouri--Kansas City -- Biologyeng
dc.titleThe role of drosophila protein kinase doubletime in circadian period determination, morning and evening oscillators and tauopathyeng
dc.typeThesiseng
thesis.degree.disciplineMolecular Biology and Biochemistry and Cell Biology and Biophysics (UMKC)eng
thesis.degree.grantorUniversity of Missouri--Kansas Cityeng
thesis.degree.levelDoctoraleng
thesis.degree.namePh.D.eng


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