Use this URL to cite or link to this record in EThOS: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.659607
Title: Rhox4 : duplication, evolution and thymus organogenesis
Author: Morris, Lucy
Awarding Body: University of Edinburgh
Current Institution: University of Edinburgh
Date of Award: 2006
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Abstract:
The thymus develops from the ventral portion of 3rd pharyngeal pouch endoderm. At E9.5 this region is marked by expression of the transcription factor Rhox4, Rhox4 may therefore have a role in the developing thymic primordia. Rhox4 is a member of the recently described Rhox family of homeobox-containing genes, which are present in 3 clusters on the mouse X chromosome and are primarily expressed in reproductive and extra-embryonic tissues. The expression of Rhox4 in the thymus, in addition to the testis and placenta makes it unique amongst family members. Here we show that there are seven copies of Rhox4 present in a tandem array within the Rhox α  locus. All alleles of Rhox4 are expressed, although preferential expression was observed and differed between tissues. In contrast to reproductive tissues, no evidence of co-linear expression of the Rhox α cluster during thymus development was found. Two other members of the α cluster, Rhox2 and Rhox3 are also present in the duplicated unit, both having 8 copies. The only predicted orthologue of Rhox4 is present in a single copy in the rat; however, no Rhox4 expression was detected in the developing or postnatal rat thymus. Examination of different sub-species of mice showed that all contain multiple copies of Rhox4, suggesting that the duplication event arose at the time of divergence of the rat and mouse lineages. Finally, no changes in Rhox4 expression were detected in mice with defects in thymus organogenesis, placing it upstream or outside of established transcriptional pathways.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID: uk.bl.ethos.659607  DOI: Not available
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