Functional analysis of amylase gene promoters in Drosophila melanogaster.
|Title:||Functional analysis of amylase gene promoters in Drosophila melanogaster.|
|Abstract:||We were able to demonstrate that amylase genes carrying short promoter sequences are still fully functional and show their characteristic pattern of glucose repression in transformed larvae. Amy (amylase) promoter sequences linked to the coding sequences of unrelated genes, the luciferase gene of the firefly, or the Adh (alcohol dehydrogenase) gene of D. melanogaster, mediate a pattern of tissue-specificity and glucose repression typical of amylase. A reciprocal gene construct, in which Amy coding sequences are controlled by upstream sequences of the Adh gene (Adh-Amy hybrid construct) confirmed that Amy coding sequences do not contribute to glucose repression or tissue-specificity. Amylase promoter sequences were further analyzed in order to localize promoter elements mediating expression and glucose repression. A deletion analysis and site-directed mutagenesis of the Amy-1 proximal gene showed that 109 bp of upstream sequences are sufficient for full expression, and that a sequence element essential for gene expression is present between $-$109 and $-$82; no single region was found to be responsible for glucose repression in these tests indicating the possibility that multiple elements mediate the glucose response. The study of the distal amylase gene indicated that a short promoter sequence is also sufficient to control expression of this gene. A deletion analysis combined with DNA sequence comparisons revealed similarities between the proximal and distal promoters, although with some variation in the position of sequence elements important for gene expression. The DNA sequence comparison of the coding regions of proximal and distal amylase genes from the same chromosome allowed us to uncover unexpectedly high levels of nucleotide similarity, suggesting the occurrence of concerted evolution. (Abstract shortened by UMI.)|
|Collection||Thèses, 1910 - 2010 // Theses, 1910 - 2010|