Fatty acid desaturase expression in an HC11 in vitro model

Because of increasing health awareness in today’s society, there is an interest in consuming products with lower levels of saturated fatty acids. Dairy products have a high level of saturated fatty acids in part due to the hydrogenation of fatty acids in the rumen and the absence of Δ12 and Δ15 desaturase enzymes in the mammary gland. If the fatty acid composition could be altered to consist of higher percentages of polyunsaturated fatty acids (PUFAs), a new market could be opened for these new and improved dairy products. It is proposed that the expression of the Δ12 and Δ15 desaturase transgenes from Caenorhabditis elegans could increase the proportions of PUFAs when expressed in mammary epithelial cells. Production of milk with increased PUFAs would have beneficial human health implications and could provide new markets for the American dairy industry

In addition to an in vivo mouse model, it would be beneficial to develop an in vitro system in which transgene expression levels are comparable to those in the in vivo model. This could be used to analyze transgene expression and its effects on fatty acid composition in a more efficient manner. HC11 cells, an immortal murine mammary epithelial cell line, have been chosen for its simple maintenance requirements. The cell line will be stably transfected with a plasmid construct containing the Δ12 and/or Δ15 desaturase transgenes under the control of the goat beta-casein promoter. Transgene expression and its effect on fatty acid composition will be analyzed and compared to results from the expression in the transgenic mouse.