Study on lactating mammary gland as an efficient eukaryotic gene expression system

  Objective   To demonstrate the possibility of lactating mammary gland as a rapid and effective expression system for eukaryotic genes.

  Methods   Three eukaryotic vectors, pICLK, pLLKSN and pIbLK, were construeted, by using ctytomegalovirus (CMV)immediate early promoter, SV40 early promoter and beta-casein promoter as regulatory element, respectively, and utilizing the lumbrokinase(LK)cDNA as gene of interest.The recombinant expression plasmids were large-scale made and different amounts of each were injected into lactating goat mammary glands.Milk were collected at different periods and assayed for fibrinolytic activity.

  Results   The lubrokinase was immediately expressed from the three different recombinant plasmids.The expression reaches summit at 6~9 h after injection and persists for up to 72 h.Although variation in expression level exityed between different vectors, the difference was not significant.

  Conclusion   The lactating mammary gland is a rapid and effective expression system for eukaryotic genes.