Constitutive expression of human coagulating factor IX in HeLa cells by homologous recombination of the promoter

Constitutive expression of hFIX protein in nonhepatocytes was studied. The gene targeting vector was constructed and transferred into HeLa cells. With the detection system of PCR, we demonstrated that the endogenoushFIX promoter was replaced with anhCMV promoter when targeted insertion of the constructor was directed by the sequence homology. The expression ofhFIX in the modified HeLa cells, 11.2 ng/10⁶ cell/24 h, strongly suggested thathFIX gene could be activated by a powerful promoter in nonhepatocytes. The results would make it possible to examine the feasibility of re-regulate gene expression by promoter replacement.