I have investigated the range of chromatin motion in living human cells. I have shown that Lac Operator arrays tagged with GFP-LacI are able to move up to 2-3 µm over the period of two hours and on average, 0.2µm per second. These distances are greater than previously reported and similar to motion observed in yeast. I have also determined whether the position of a locus is conserved from one cell cycle to the next by following cells through mitosis. I concluded that although some aspects of positioning were conserved, loci position was established anew each cell cycle. I have investigated the effect of different epigenetic modifications on the mobility of linker histones. I was able to show that while Su(Var)3-9, responsible for tri-methylation of Lysine 9 on histone 3, and MeCP2, a DNA methylation binding protein, have no effect on linker histone mobility, the methylation of DNA does. In humans it is well established that chromosomes are arranged non-randomly within the cell nucleus. I have mapped the radial position of mouse chromosome territories in ES cells to determine if a similar pattern of non-random positioning also exists in the mouse. My results suggest there may be a loose correlation between chromosome size and position within the mouse genome. Furthermore differentiation of mouse ES cells, induced changes in the position of some, but not all, chromosomes, suggesting that gene expression may have a role in chromosome position. To determine directly if nuclear position can regulate gene expression in the mouse I aimed to artificially tether an active gene to the edge of the mouse nucleus. Transfections with Lac Operator containing plasmids were anchored to the nuclear periphery 6-18hrs after transfection and were able to show directly that the nuclear position can have a large effect on gene expression.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:662904 |
| Date | January 2006 |
| Creators | Thomson, Inga |
| Publisher | University of Edinburgh |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://hdl.handle.net/1842/30841 |
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