FACILITATED DNA TRANSFER TO RAT SUBMANDIBULAR-GLAND IN-VIVO AND GRP-CA GENE-REGULATION

The internalization of DNA can be facilitated by adenovirus infection. Using the replication-deficient adenovirus, Ad-dl312, and a plasmid-b ased firefly luciferase gene as a reporter, we have optimized the upta ke and expression of DNA in rat submandibular glands in vivo. Lucifera se expression is transient and peaked at similar to 18 h after infecti on. Luciferase activity increased with plasmid concentration and was g reatest at 10(9) to 10(10) plaque-forming units of Ad-dl312 per gland. We next examined the expression in vivo of plasmids containing deleti ons of the glutamine/glutamic acid-rich protein (GRP-Ca isoform) gene upstream region linked to a chloramphenicol acetyltransferase (CAT) re porter. Constructs with 9.4, 6.3, and 2.7 kb and 17 base pairs of upst ream sequence gave relative CAT activities of 100, 30, 7.6, and 38.5, respectively. With the 9.4-kb GRP-Ca construct, CAT was preferentially expressed in acinar cells, which is characteristic of GRP. This gene transfer approach should prove useful in the further study of gene exp ression in salivary glands and other organs.