A more detailed understanding of the immune mechanisms involved in anti-inflammatory events in fish is required for effective disease control in aquaculture. Significant expansion of immune genes, often resulting from whole genome duplication events in teleost fish, adds complexity to their potentially anti-inflammatory pathways. This thesis contributes to a more complete insight into the suppressor of cytokine signalling (SOCS) and transforming growth factor-β1 (TGF-β1) gene system in fish by the discovery of paralogues and reporting of ways in which these potential negative regulators of immune responses can be induced in the the commercially valuable rainbow trout (Oncorhynchus mykiss). Gene expression analysis, revealed that a novel trout TGF-β1 paralogue (TGF-β1b) was more inducible by immune stimulants than the known TGF-β1a and likely represents an important intrinsic factor in macrophages. Both trout TGF-β type I and type II receptor (TGFBR1 and TGFBR2) genes identified encode highly conserved serine/threonine kinases and they are modulated during immune responses. Counter-regulation of the two receptor transcripts in immune stimulated macrophages may indicate regulatory mechanisms operating at the receptor level. Thorough phylogenetic and synteny analysis of the lower vertebrate SOCS system led to further paralogue discovery and uncovered that the proposed teleost-specific SOCS-8 and SOCS-9 members are more likely paralogues of cytokine inducible SH2-containing protein (CISH) and SOCS-5. The trout SOCS-2 subfamily was expanded to three members by cloning SOCS-2b and SOCS-2bRel in addition to SOCS-2a. I revealed for the first time that four paralogues in a SOCS subfamily exist in a teleost by cloning trout CISHa2, CISHb1 and CISHb2 in addition to the known CISHa1. In vivo and in vitro expression of the CISH paralogues suggest possible subfunctionalisation in immunity and development. Attempts to produce trout recombinant proteins of potentially anti-inflammatory cytokines in transiently transfected mammalian cells primed exploitation of these molecules in functional studies.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:577665 |
| Date | January 2013 |
| Creators | Maehr, Tanja |
| Publisher | University of Aberdeen |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://digitool.abdn.ac.uk:80/webclient/DeliveryManager?pid=201702 |
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