Higher organisms can regulate gene expression through changes in epigenetic marks present on the genome. However, how this regulation takes place in organisms with highly repetitive/complex genomes is not well understood. The acquisition of de novo DNA methylation in plants is mediated by siRNAs through the RNAdirected DNA methylation (RdDM) pathway. The targeted deposition of DNA methylation by this pathway allows for the transcriptional silencing of transposable elements and repeat sequences within the genome, as well as regulating gene expression. In addition, it has been hypothesized that mobile siRNAs may be involved in the epigenetic communication between different seed components. Thus the mobility of non-coding RNAs from extra-embryonic tissues could contribute to epigenetic modifications that could be transmitted to the offspring. The aim of my thesis is to characterise the mechanisms involved in epigenetic gene silencing in maize through the use of a novel transgenic reporter. My work has identified components of the RdDM pathway to be involved in maintenance of gene silencing and show that imprinting and paramutation could be recapitulated using synthetic transgenes. In addition, I developed a novel grafting technique to demonstrate that epigenetic gene silencing could be efficiently transmitted between different seed components. Collectively, this work provides an insight into the complex mechanisms that regulate gene expression in the highly repetitive/complex genome of maize.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:606126 |
| Date | January 2013 |
| Creators | Schafer, David Gerald |
| Publisher | University of Warwick |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://wrap.warwick.ac.uk/60414/ |
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