Molecular genetic and biochemical studies of cis-prenyltransferase and small rubber particle protein for natural rubber biosynthesis in lettuce (Lactuca saliva)

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atmire.migration.oldid1433
dc.contributor.advisorRo, Dae-Kyun
dc.contributor.authorQu, Yang
dc.date.accessioned2013-09-24T22:47:28Z
dc.date.available2014-03-24T07:00:12Z
dc.date.embargolift2016-03-24T07:00:12Z
dc.date.issued2013-09-24
dc.date.submitted2013en
dc.description.abstractPlant derived metabolites have been extensively implicated in medication and industry. Natural rubber (cis-1,4-polyisoprene) has become one of the most important raw materials since the rise of automotive industry due to its elastic characteristics. Despite the invention of synthetic elastomers, the demand and production of natural rubber has been increasing because it has higher polymer properties such as elasticity, resilience, abrasion and heat dispersion. Natural rubber belongs to the metabolites family termed isoprenoid that is synthesized from the same precursor isopentenyl pyrophosphate (IPP). Natural rubber is classified in a subgroup of linear molecules condensed from various IPP in cis-stereochemistry called cis- polyisoprenoids. The responsible enzyme is termed cis-prenyltransferase (CPT). Bacterial CPTs have been extensively studied in both biochemistry and 3D structure. Eukaryotic CPTs are not studied in such detail. They are not enzymatically active when purified, and the activity requires biomembrane and/or other undetermined membrane associated proteins. Based on natural rubber structure, CPT is suggested in the biosynthesis of this extremely long-chain cis-polyisoprenoid. However, there had not been convincing experimental evidence at the beginning of this study. Using proteomics, next-generation-sequencing, RNAi-silencing, and protein-protein interaction study, we identified two key proteins directly involved in the natural rubber biosynthesis in rubber producing plant lettuce (Lactuca sativa). RNAi silencing of CPT-like gene CPT Scaffold protein 2 (CSF2) resulted in robust decrease of natural rubber in planta. CSF2 interacts with a regular CPT (CPT3), and this interaction mutually influences the subcellular localization of both proteins. In agreement with the recently reported human dolichol synthase comprising both CSF and CPT partners, our data suggests the previously unknown heterodimeric synthase infrastructure may be conserved in eukaryotic long-chain cis-polyisoprenoid synthesis. Rubber Elongation Factor (REF) and its closely related homolog Small Rubber Particle Protein (SRPP) have also been implicated in natural rubber synthesis, despite the lack of convincing evidence. RNAi-silencing of their orthologs (lettuce SRPPs) in planta instead suggests that they are not crucial in the natural rubber synthesis. For the first time, CPT-like gene CSF is shown indispensible in natural rubber synthesis. The discovery of the interaction between CSF and CPT has built the molecular base for future improvement of natural rubber production and the eventual reconstitution of natural rubber synthesis in other organism at industrial scale.en_US
dc.description.embargoterms18 monthsen_US
dc.identifier.citationQu, Y. (2013). Molecular genetic and biochemical studies of cis-prenyltransferase and small rubber particle protein for natural rubber biosynthesis in lettuce (Lactuca saliva) (Doctoral thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca. doi:10.11575/PRISM/26987en_US
dc.identifier.doihttp://dx.doi.org/10.11575/PRISM/26987
dc.identifier.urihttp://hdl.handle.net/11023/1024
dc.language.isoeng
dc.publisher.facultyGraduate Studies
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.subjectGeneral
dc.subject.classificationnatural rubberen_US
dc.subject.classificationcis-prenyltransferaseen_US
dc.subject.classificationsmall rubber particle proteinen_US
dc.titleMolecular genetic and biochemical studies of cis-prenyltransferase and small rubber particle protein for natural rubber biosynthesis in lettuce (Lactuca saliva)
dc.typedoctoral thesis
thesis.degree.disciplineBiological Sciences
thesis.degree.grantorUniversity of Calgary
thesis.degree.nameDoctor of Philosophy (PhD)
ucalgary.item.requestcopytrue
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