| abstract |
There are disclosed mammary gland tissue-specific expression systems using the promoter site for the β-casein gene of Korean native goats, by use of which physiological activating substances can be produced. In each of the expression systems, that is, novel plasmids pGbc, pGbc_L and pGbc_S (deposition Nos. KCTC 0515BP, 0514BP and 0513BP, respectively), a β-casein gene expression-regulating region, a physiological activating substance gene and a termination-regulating region are linked. Human granulocyte colony stimulating factor (hG-CSF) or human granulocyte macrophage colony stimulating factor (hGM-CSF) can be produced in HC11 cells, a mouse mammary gland tissue-derived cell line, and in the milk secreted from the transgenic mice by use of a hG-CSF or hGM-CSF gene-carrying pGbc, pGbc_L or pGbc_S in transfection into cell and microinjection to mouse. The proteins are those which experience the posttranslational modification and maintain their normal activity in the human body. The expression systems make it possible to easily produce the proteins at a great amount, to scale up protein production to the extent of industrialization, and to isolate and purify the desired protein with ease and safety. |