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Title: Directing gene expression to cerebellar granule cells
Author: Bahn, S.
Awarding Body: University of Cambridge
Current Institution: University of Cambridge
Date of Award: 1998
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The aim of this thesis was to investigate mechanisms involved in activating gene expression in a distinct neuronal sub-population. As a model system, I have chosen the GABAA receptor α6 subunit gene. Within the whole brain, α6 gene expression is restricted to differentiated cereballar granule cells and the lineage-related granule cells in the cochlear nucleus. I searched for regulatory elements using constructs derived from regions within the α6 gene in a transgenic mouse assay, linking these regions to the β-galactosidase reporter gene to assay for transcriptional activity. A 7.2 kb DNA fragment containing a 1 kb portion upstream of the start site(s), together with exons 1-8, directs cerebellar granule cell-specific reporter gene expression. Truncated versions of this 7.2 kb transgene were analysed; none of these smaller transgenes gave consistent granule cell-specific expression. As an adjunct to identify cerebellar granule cell-specific DNA elements, a comparative approach was employed. If the expression pattern of the α6 gene is conserved in evolutionary distant species, then sequences involved in spatially regulating this gene expression may also be conserved. I cloned α6 cDNA homologues in distant species (goldfish and chicken) and showed that α6 expression was restricted to cerebellar granule cells. Comparative genome sequencing was used to look for conserved DNA regions outside the coding region of the α6 gene. The chicken and pufferfish α6 gene structures were mapped and the corresponding regions of the mouse, chicken and pufferfish genomic clones were sequenced. Two small regions of sequence identity were identified in the 5' proximal area in all three species. These regions could be binding sites for transcription factors. Cerebellar granule cell precursors can switch on the α6 gene ectopically. This implies that α6 gene expression is cell-intrinsically regulated.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available