蚓激酶乳腺组织特异性表达载体构建及在山羊奶中的表达

以合成的蚓激酶cDNA突变体为目的基因，构建了其乳腺组织特异性表达载体pIbCP-LK-neo和含有两个目的基因拷贝的表达载体pIbCP-LK-LK。以山羊乳腺作为生物反应器，在稳定泌乳期于乳腺组织分别注射以上两种表达质粒，采集乳汁，通过纤维蛋白平板溶圈试验进行纤溶活性测定。结果显示，注射了蚓激酶表达质粒的山羊奶具有明显的纤溶活性；pIbCP-LK-LK蚓激酶在奶中的表达量高于pIbCP-LK-neo。经SDS-聚丙烯酰胺凝胶电泳(PAGE)分析表明，表达的蚓激酶分子量为26kDa。本试验系首次实现了蚓激酶的基因工程表达，为通过转基因途径生产蚓激酶奠定了基础。

Construction of Mammary Gland Specific Expression Vectors of Lumbrokinase and their Expression

Lumbrokinase cDNA mutant was used to construct expression vectors, pIbCP LK neo and pIbCP LK LK, in which the gene regulatory element was a caprine beta casein promoter. The two expression vectors were then injected into goat mammary glands for expression. The milk was collected and tested for fibrinolytic activity by the modified fibrin agarose plate assay. It was indicated that both plasmids were expressed in milk. The expression quantity of pIbCP LK LK was higher than that of pIbCP LK neo. SDS PAGE showed that the molecular weight of lumbrokinase is 26kDa. This is the first report on lumbrokinase expression by genetic engineering and it has provided solid foundation for lumbrokinase production.