Regulation of human clotting factor IX cDNA expression in transgenic mice

To study the expression of human clotting factor IX cDNA in transgenic mice, which is an essential work on gene therapy for hemophilia B, 3 recombinant constructions containing different lengths of human clotting factor IX cDNA have been introduced into the cultured cells. All of the recombinant constructions were found to be expressed well in vitro. They were then microinjected into the male pronuclei of the fertilized mouse eggs respectively for generating transgenic mice. Unfortunately, none of them was expressed in any transgenic mice. These results show that the expression of the human clotting factor IX cDNA in the transgenic mice can be determined by cis regulatory element(s). As compared with the results from other related works, it is suggested that the cis regulatory element(s) is resided in the 5'-end non-coding region.