Targeting genes: delivery and persistent expression of a foreign gene driven by mammalian regulatory elements in vivo.
We present evidence that a foreign gene driven by natural mammalian regulatory elements can be targeted to hepatocytes and the resultant gene expression made to persist. This was accomplished using a soluble DNA carrier system consisting of two covalently linked components: 1) a polycation, poly-L-lysine, that can bind DNA in a strong but non-damaging interaction, and 2) an asialoglycoprotein which can be targeted specifically to hepatocytes by cell surface asialoglycoprotein receptors unique to this cell type. A plasmid, palb-CAT, containing the gene for chloramphenicol acetyltransferase (CAT) driven by mouse albumin regulatory sequences was complexed to the carrier system. Intravenous injection of palb-CAT DNA in the form of a complex resulted in the presence of CAT enzyme activity in liver homogenates 24 h after injection. The targeted gene expression, however, was transient, reaching a maximum of 10 units/g liver at 24 h but was not detectable by 96 h. However, partial hepatectomy 30 min after injection resulted in persistent high levels of hepatic CAT activity (11.3 units/g) through 11 weeks post-injection. Southern analysis of livers 11 weeks after partial hepatectomy demonstrated that some of the targeted DNA had been integrated into the host genome. We conclude that a foreign gene driven by natural mammalian regulatory elements can be delivered to hepatocytes by intravenous injection in vivo using a soluble DNA carrier system. Foreign gene expression targeted in this manner can be made to persist by stimulation of hepatocyte replication.
Wu
C H
CH
Department of Medicine, University of Connecticut School of Medicine, Farmington 06032.
Wilson
J M
JM
Wu
G Y
GY
D000418:Albumins / Q000235:genetics; D000818:Animals; D001212:Asialoglycoproteins; D015500:Chloramphenicol O-Acetyltransferase / Q000235:genetics*; D003001:Cloning, Molecular; D004247:DNA / Q000235:genetics* / Q000378:metabolism; D005260:Female; D015870:Gene Expression / Q000235:genetics*; D005809:Genes, Regulator / Q000235:genetics*; D006498:Hepatectomy; D008099:Liver / Q000201:enzymology*; D051379:Mice; D009693:Nucleic Acid Hybridization; D009961:Orosomucoid / Q000378:metabolism / Q000031:analogs & derivatives; D010957:Plasmids; D011107:Polylysine / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains; D014162:Transfection
D000418:Albumins; D001212:Asialoglycoproteins; D009961:Orosomucoid; C017030:asialoorosomucoid; D011107:Polylysine; D004247:DNA; D015500:Chloramphenicol O-Acetyltransferase