The present proposal describes a novel approach for delivering recombinant DNA to hepatocytes. This approach takes advantage of the parasite invasion that takes place minutes after a mosquito bite. Malaria parasites (sporozoites) enter hepatocytes, where they multiply. This invasion is very specific and highly efficient. The objective of the present research is to investigate the possibility of developing a gene targeting system using the malaria sporozoite protein as a carrier. The circumsporozoite protein (CS) (ligand) after being complexed with recombinant DNA, will be directly injected into the circulation. The complex should home-in to the hepatic receptor. Through receptor-mediated endocytosis, the DNA will be internalized. We also propose to use viral fusogenic peptides and liposomes to enhance the levels of targeted gene expression by releasing the internalized DNA from endosomal entrapment. This delivery system should be speedy, therefore, minimizing the possible nuclease and/or protease effects on the DNA complex. Furthermore, the immunoreactive domain in the ligand will be removed. This should reduce the possible immunogenic complication to the host cells. The development of CS conjugate as DNA carrier, in complement to the existing asialoglycoprotein carrier system, should allow one to test the synergism in the targeting specificity and enhancement of expression of the duo delivery systems. Most importantly, the proposed studies utilize synthetic molecular conjugates and impose minimal risk to patients and the general population. We believe that the proposed studies described in this application possess a potential application to gene therapy of metabolic disorders resulting from liver gene malfunction. Furthermore, the potential application of using CS protein as a DNA carrier for gene therapy of other genetic diseases can be explored.