科研之友
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摘要
It is very important to develop an effective, specific, and robust expression cassette that ensures a high level of expression in the mammary glands. In this study, we designed and constructed a series of mammary gland-specific vectors containing a complex hybrid promoter/enhancer by utilizing promoter sequences from milk proteins (i.e., goat beta-casein, bovine as1-casein, or goat beta-lactoglobulin) and cytomegalovirus enhancer sequences; vectors containing a single milk protein promoter served as controls. Chicken beta-globin insulator sequences were also included in some of these vectors. The expression of constructs was analyzed through the generation of transgenic mice. Enzyme-linked immunosorbent assay (ELISA) analysis revealed that the hybrid promoter/enhancer could drive the expression of recombinant human lactoferrin (rhLF) cDNA at high levels (1.178.10?mg/ml) in the milk of transgenic mice, whereas control promoters achieved a very low rhLF expression (740?ng/ml). Moreover, the expression of rhLF was not detected in the serum or saliva of any transgenic animal. This result shows that all constructs, driven by the hybrid promoter/enhancer, had high mammary gland-specific expression pattern. Together, our results suggest that the use of a hybrid promoter/enhancer is a valuable alternative approach for increasing mammary-specific expression of recombinant hLF in a transgenic mouse model.Mol. Reprod. Dev. 79: 573-585, 2012.
