An investigation of nutrition-dependent mRNA translation in Drosophila larvae

atmire.migration.oldid2927
dc.contributor.advisorGrewal, Savraj
dc.contributor.authorNagarajan, Sabarish
dc.date.accessioned2015-01-28T22:43:48Z
dc.date.available2015-02-23T08:00:38Z
dc.date.issued2015-01-28
dc.date.submitted2015en
dc.description.abstractDietary nutrients promote organismal growth via activation of cellular pathways that are necessary for cellular growth and division. However, upon conditions of nutrient scarcity, organisms ranging from yeast to mammals alter their metabolism to conserve nutrients and energy. One of the key cellular events required for sustained growth downstream of nutrition is mRNA translation. In order to coordinate cellular and organismal growth with nutrient availability, organisms have devised several control checkpoints to limit the energy consuming process of translation under starvation. Work on mammalian cell lines have shown that mRNA translation is inhibited in response to a multitude of stresses including nutritional stress, DNA damage, viral stress, hypoxia and oxidative stress. However, it is unclear as to how an organism in general responds to starvation in terms of mRNA translation. I have used polysome gradient analysis in developing Drosophila larvae to show that starvation led to a rapid decrease in translation, seen as early as 30 minutes after removal of larvae from food. A maximal decrease in translation was observed after 6-18 hours of starvation. Using qRT-PCR I have looked at the translation profile of 18 individual genes and observed that starvation led to a general decrease in translation, irrespective of the starvation-mediated change in total transcript levels. Sugars and amino acids have been shown to be important regulators of translation in animal cells. I have determined that neither sugars nor amino acids were sufficient to maintain translation in larvae removed from food. However, a complex diet such as yeast was sufficient to maintain translation in larvae removed from food. The majority of work in the field of translation suggest three main signaling pathways functioning downstream of nutrition to regulate translation - insulin signaling,TOR signaling and eIF2α signaling. I have shown that TOR signaling is required for translation in fed conditions. On the other hand, genetic activation of TOR and/or insulin signaling was not sufficient to prevent the starvation-mediated inhibition of translation. I have also shown that the eiF2α kinases - GCN2 and PERK were not required for starvation-mediated suppression of translation.en_US
dc.identifier.citationNagarajan, S. (2015). An investigation of nutrition-dependent mRNA translation in Drosophila larvae (Doctoral thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca. doi:10.11575/PRISM/24913en_US
dc.identifier.doihttp://dx.doi.org/10.11575/PRISM/24913
dc.identifier.urihttp://hdl.handle.net/11023/2035
dc.language.isoeng
dc.publisher.facultyGraduate Studies
dc.publisher.facultyMedicine
dc.publisher.institutionUniversity of Calgaryen
dc.publisher.placeCalgaryen
dc.rightsUniversity of Calgary graduate students retain copyright ownership and moral rights for their thesis. You may use this material in any way that is permitted by the Copyright Act or through licensing that has been assigned to the document. For uses that are not allowable under copyright legislation or licensing, you are required to seek permission.
dc.subjectGenetics
dc.subjectBiology--Molecular
dc.subject.classificationPolysome analysisen_US
dc.subject.classificationTranslationen_US
dc.subject.classificationDrosophilaen_US
dc.titleAn investigation of nutrition-dependent mRNA translation in Drosophila larvae
dc.typedoctoral thesis
thesis.degree.disciplineBiochemistry and Molecular Biology
thesis.degree.grantorUniversity of Calgary
thesis.degree.nameDoctor of Philosophy (PhD)
ucalgary.item.requestcopytrue
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