Browsing by Author "Dresser, David W."

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    Interaction between the Wilms tumour factor-1 element in the promoter of Amh and a downstream enhancer is required for a strong expression of the gene in pre-pubertal sertoli cells
    (Scientific Research Publishing, 2013-07) Dresser, David W.
    Amh (anti-Müllerian hormone) is a single copy gene which is expressed strongly in Sertoli cells in the foetal testis and participates in the onset of sexual differentiation. Its promoter driving the expression of a reporter gene (d2EGFP) has been used to analyse the role of certain defined putative elements and a downstream enhancer element in gene expression. These experiments were carried out in vitro using a line of pre-pubertal mouse Sertoli cells, transienly transfected with circular DNA constructs with variously mutated promoter elements. A downstream enhancer element, situated immediately 3’ of the polyadenylation (PA) signal for Amh, has been inserted in an equivalent position in the d2EGFP construct. When the Amh promoter is unmodified, the downstream enhancer (DE) is positively associated with a large increase in EGFP expression. This is at least partly the consequence of an increased rate of expression by individual cells. Experiments using variously truncated Amh promoters indicate that an upstream region (-214 to -336) may play a minor role in facilitating enhancement. However mutation of the Wilms tumour factor-1 element, situated between the tata box and the start of translation, results in an almost complete suppression of enhancement.
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    Mutated elements of a complex promoter (Amh) can help to demonstrate the role of certain elements in controlling differential gene expression
    (Springer Science+Business Media, 2012-10) Dresser, David W.
    Amh is a single copy gene which is expressed in different ways during mammalian development. Several potential promoter elements have been identified using physiological experimentation and on the basis of interspecific sequence comparison. The role of putative promoter elements in controlling gene expression has been investigated by many workers over the last two decades and here by individually mutating each element. Expression was measured in vitro in cells of Sertoli descent by flowcytometry using EGFP as a reporter gene. Three lines of murine cells were used; pre- and post-pubertal Sertoli and granulosa cells. Differences between the three lines of cells, support the view that differentiation in this in vitro model system is likely to be at the level of available transcription factors at given points in development.
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    Super-Enhancement and Control of Amh Expression
    (Scientific Research Publishing, 2016-07) Dresser, David W.
    In previous work it was shown that mutation of site 1 in the downstream enhancer sequence (DE) led to ablation of enhancement. Mutation of the Wilms tumour factor element (Wt), situated in the Amh promoter between the tata box and the start of translation (TSS), also led to ablation of enhancement. This suggested that these sites may be the anchor points for a specific duplex factor bridging remote DNA elements to the promoter. Mutation analysis of the DNA sequence between sections 1 and 2 of DE was carried out by site directed mutagenesis. It is reported here that site 4 lying between DE1 and DE2, plays a key role in controlling the level of enhancement.