High-level and erythroid-specific expression of human glucose-6-phosphate dehydrogenase in transgenic mice.

Human Glc-6-P dehydrogenase (Glc-6-P) cDNA spanning the entire coding region was subcloned into a pSG5 vector that contains an early SV40 promoter, intron II of the rabbit beta-globin gene, and a polyadenylation signal. This expression cassette was then placed downstream of the human beta-globin locus control region and injected into fertilized mouse eggs. Among five transgenic founders that contained intact copies of the construct, one founder expressed human Glc-6-P dehydrogenase enzyme in a high-level and erythroid-specific fashion (5 x higher than endogenous Glc-6-P dehydrogenase activity). When this male founder mated with a normal individual, all the offspring that carried the transgene showed high-level expression of Glc-6-P dehydrogenase activity in erythroid cells. The endogenous mouse Glc-6-P dehydrogenase in all high-expression mice could be competed out by forming a hybrid with human Glc-6-P dehydrogenase. Our results indicate that the locus control region can drive the human Glc-6-P dehydrogenase gene to be specifically expressed in the erythroid cells of transgenic mice. The results described here provide a basis for experiments designed to express human Glc-6-P dehydrogenase in transgenic mice and suggest a suitable approach to producing a mouse model for studying human Glc-6-P dehydrogenase deficiency.