The neuregulins (NRGs) are ligands for receptor tyrosine kinases of the ErbB family. The NRG gene family consists of four members, NRG 1- 4 encoding different isoforms due to alternative splicing. NRG signalling has been implicated in normal development and in the pathology of many diseases. Using immunohistochemical staining of tissue arrays, we detected that NRG 1 a and 1 ~ localised to the cell nuclei of a range of normal and human cancer tissues. The ~3 isoform of NRG 1 localised to two subnuclear compartments: nucleoli and spliceosomes. We tagged NRG 1 ~3 with photoactivateable GFP and demonstrated that the fusion protein re-Iocalised from nucleoli to spliceosomes over a ninety minute period. Using wild type NRG 1 ~3 and its two mutants which localised exclusively to spliceosomes or to nuc1eoH, we explored the possible functions of intranuclear NRG 1 ~3 in each of these compartments separately. We showed using an array capable of detecting 42 receptor tyrosine kinases that wild type NRG 1 and a mutant exclusively local ising to spliceosomes increased phosphorylation and/or expression of the ErbB4 and ErbB2 receptors. Using a transcriptomic analysis the same two constructs induced expression of messenger RNA of Heat Shock Protein 70B' and we confirmed its increased expression at the protein level using western blot analysis. This data supports the hypothesis that intranuclear NRGs could activate receptor signalling and alter gene expression when localised in spliceosomes.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:544047 |
| Date | January 2011 |
| Creators | Wang, Ming |
| Publisher | University of Kent |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
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