Padilla, Veronica Mercedes Narvaez;
(1996)
Expression and regulation of sex determining genes in the mouse.
Doctoral thesis (Ph.D), UCL (University College London).
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Abstract
The aims of my thesis were to characterize the regulatory elements of the mouse gene Sry, the testes determining factor, and of the mouse gene Dax-1, a candidate for an ovary determining gene; and to analyze their function during development. The first strategy used was to map DNAse I hypersensitive sites (DHSs) in the regions flanking the open reading frame (ORF) of Sry, as it has been found that DHSs often correspond to DNA sequences that function as regulatory regions. No DHSs were found in the first four kb surrounding the ORF. Another strategy for finding regulatory regions was to use transgenic mice harbouring lac-Z reporter constructs with different amounts of flanking genomic sequence. None of the transgenic reporter constructs with Sry sequences were found to be expressed at a high enough level for the detection of β-galactosidase expression by staining with X-gal. The endogenous low levels of expression and the complex genomic structure of Sry might account for this result. Since Sry expression is tightly regulated during development, we attempted to misexpress it to see if it produced an abnormal phenotype. Three lines carrying Sry under the control of a constitutive promoter were produced. No obvious phenotype has been observed to date. Dax-1 has at least two important sites of expression: the developing gonads and the adrenal glands. Reporter constructs with Dax-1 genomic sequences allowed us to define upstream regions responsible for expression in these two tissues. Within 18 kb 5' of the ORF we have found a gonad-specific and an adrenal-specific expression element. In order to study the function of Dax-1 in the sex determining pathway, transgenic animals with extra copies of this gene have been produced. Male to female sex-reversal was expected. Up to now, no sex-reversal has been found in these animals, however the level of expression may be too low.
| Type: | Thesis (Doctoral) |
|---|---|
| Qualification: | Ph.D |
| Title: | Expression and regulation of sex determining genes in the mouse |
| Open access status: | An open access version is available from UCL Discovery |
| Language: | English |
| Additional information: | Thesis digitised by ProQuest. |
| URI: | https://discovery.ucl.ac.uk/id/eprint/10103804 |
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