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Title: Dissecting a novel invertebrate pathway implicated in heavy metal mediated transcriptional control
Author: Hughes, Samantha Louise
ISNI:       0000 0004 2751 8141
Awarding Body: Cardiff University
Current Institution: Cardiff University
Date of Award: 2008
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The genome of Caenorhabditis elegans contains two metallothionein isoforms and a functional phytochelatin synthase. All three proteins have roles in metal detoxification and metal homeostasis. Although a great deal is known with regards to vertebrate metallothioneins and their transcriptional control, little is understood about C. elegans metallothionein. In addition, phytochelatin synthase was only discovered within the last decade and as a consequence little is known about this enzyme and its product, phytochelatins. The use of green fluorescent protein expressing transgenes C. elegans allows the expression pattern for all genes to be investigated. The GFP transgenic strains were also utilised in the RNA mediated knockdown of a selection of transcription factors to identify two candidate genes involved in metallothionein transcription. The generation of a combination of single, double and triple mutants permitted the investigation into the function of metallothioneins and phytochelatins on elevated and depleted levels of essential and non-essential heavy metals via their phenotypic effects. Metabolomic analysis of these mutants provided an indication that cadmium affected the transsulfuration pathway and ultimately suggested that phytochelatins have a significant role in cadmium detoxification. Quantitative PCR analysis showed that there was minimal compensatory up regulation of metallothionein when one isoform is removed. Conversely, the removal of pcs-1 results in significant up regulation of both MT isoforms following exposure to cadmium. In conclusion, this research was able to demonstrate that in C. elegans, phytochelatins play an important and significant role in metal detoxification, possibly more than metallothioneins.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available