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dc.contributor.authorWoolfson, Kathlyn
dc.date.accessioned2014-09-10T13:28:02Z
dc.date.issued2014-09-10
dc.identifier.urihttp://hdl.handle.net/10464/5686
dc.description.abstractThe various steps of monoterpene indole alkaloid (MIA) biosynthesis are known to occur in specialized cell types and subcellular compartments. Numerous MIAs display powerful biological activities that have led to their use as pharmaceutical treatments for cancer, hypertension and malaria. Many of these compounds accumulate on the leaf surface of medicinally important Apocynaceae plants, which led to the recent discovery and characterization of an ABC transporter (CrTPT2) that was shown to mobilize catharanthine from its site of biosynthesis in epidermal cells to the leaf surface of Catharanthus roseus. Bioinformatic analysis of transcriptomes from several geographically distant MIA-producing species led to the identification of proteins with high amino acid sequence identity to CrTPT2. Molecular cloning of a similar transporter (VmTPT2) from Vinca minor was carried out and expressed in a yeast heterologous system for transport experiments and functional characterization. In planta studies involved transcript expression analysis of the early MIA biosynthetic gene VmTDC and putative transporter VmTPT2, and alkaloid profile analyses. RT-qPCR results showed that VmTPT2 expression increased 15-fold between the first two leaf pairs, and high levels were maintained across older leaves. The alkaloid accumulation profile on leaf surfaces matched that of VmTPT2 expression, especially for the MIAs vincadifformine and vincamine. Gene expression and alkaloid profile analyses suggest that the functional protein may act as a similar transporter to CrTPT2. However, although VmTPT2 had 88.4% identity at the amino acid level to CrTPT2, it displayed an altered expression pattern in planta across developing leaves, and functional characterization using a previously developed yeast heterologous system was unsuccessful due to difficulties with reproducibility of transport assays.en_US
dc.language.isoengen_US
dc.publisherBrock Universityen_US
dc.subjectABC transporteren_US
dc.subjectplant secondary metabolismen_US
dc.subjectmonoterpene indole alkaloidsen_US
dc.subjectVinca minoren_US
dc.subjectApocynaceaeen_US
dc.titlePreliminary characterization of VmTPT2, a putative monoterpene indole alkaloid (MIA) transporter from Vinca minor L. (Apocynaceae)en_US
dc.typeElectronic Thesis or Dissertationen_US
dc.degree.nameM.Sc. Biological Sciencesen_US
dc.degree.levelMastersen_US
dc.contributor.departmentDepartment of Biological Sciencesen_US
dc.degree.disciplineFaculty of Mathematics and Scienceen_US
dc.embargo.lift2015-09-05T13:28:02Z
dc.embargo.terms12 Monthsen_US


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