Utilization of Lactating Mammary Glands to Identify Eukaryotic Gene Expression Vectors

Zhou Xueyan~(2)Zhang Shoufeng~(1)Yao Wei~(1)Ren Wenzhi~(1)Fan Zhiqiang~(1)Hu Rongliang~(1)(~(1)Veterinary Institute, Academy of Military Medical Science, Changchun130062; ~(2)China-Japan Union Hospital of Jilin University,Changchun130031)

Three eukaryotic vectors, pICLK,pLLKSN and pIbLK, were constructed, by using CMV immediate early promoter, SV40 early promoter and beta-casein promoter as regulatory element, respectively, and utilizing the lumbrokinase cDNA as gene of interest. The recombinant expression plasmids were large-scale made and 400μg of each were injected into lactating goat mammary glands. Milk were collected at different periods and assayed for fibrinolytic activity. Results showed that the lumbrokinase was immediately expressed from the three different recombinant plasmids. The expression reaches summit at 6~9h after injection and persists for up to 72h. Although variation in expression level exists between different vectors, the difference is not significant. It was demonstrated that expression of eukaryotic protein in lactating mammary glands would be a rapid and effective approach to identify eukaryotic gene and its expression vector.