Analysis of the transcriptional regulatory elements that control silk gene expression

Spider silk has outstanding material properties. It has high tensile strength, extensibility, and toughness, which are ideal features for its use for medical, military, and automotive applications. The pursuit of large-scale industrial production of synthetic spider silk is a highly sought endeavor for material scientists. One current challenge that exists for the silk community involves the production of vast quantities of recombinant silk protein for the spinning process. Our studies are aimed at understanding the transcriptional regulation of spider silk genes with a long-term goal of being able to generate specialized immortalized spider silk cell lines that overexpress key transcriptional regulators that induce the expression and secretion of spider silk protein, a process that would accelerate materials development. In our studies, we have identified a conserved DNA-binding site within the promoter regions of the MaSp genes (Major Ampullate Spidroin), which encode the major constituents of dragline silk. Using computational approaches and transcriptome analyses we have identified a potential transcriptional regulatory factor that controls spider gene transcription. In order to further test this hypothesis, we have amplified the cDNA coding for this transcription factor, an ortholog to Drosophila Daughterless, and tested its ability to drive activation of the MaSp1 promoter using transient transfection assays and reporter gene constructs