TRANSGENIC MAMMALS THAT PRODUCE EXOGENOUS PROTEINS IN MILK

摘要

The invention relates to a non-human transgenic mammal that is useful for the production of a protein of interest that may be toxic to the mammal. The mammal is characterized by the fact that it is transgenic for the production in its milk of an inactive form of the protein of interest, preferably recombinant human insulin. It is not possible to produce recombinant human insulin in transgenic mammals since this molecule has a certain degree of biological activity in the mammals and could be toxic to the mammal. Thus, the invention involves cloning a genetic construct comprising a sequence encoding a modified human insulin precursor under the control of a beta casein promoter in an expression vector. It also involves transfecting the expression plasmid into fetal bovine somatic cells, such as fibroblasts, and enucleating bovine oocytes by nuclear transfer to generate transgenic embryos. The invention gives rise to transgenic bovine that will be able to produce a modified human insulin precursor in their mammary glands. Afterwards, the milk of these transgenic mammals can be collected, the modified human insulin precursor can be converted in vitro into recombinant human insulin, and the recombinant human insulin can be purified to homogeneity as a pure biopharmaceutical product.