Figure 1.

DNA constructs. (A) GFAP tv-a (Gtv-a) transgene. A 2.2-kb fragment of the GFAP promoter drives expression of the tv-a cDNA. The fragment from the mouse protamine gene (MP-1) supplies an intron and signal for polyadenylylation. (B) RCAS vectors. These vectors carry an exogenous gene 3′ of env. RCAS-AP, RCAS-puro, and RCAS-bFGF carry the human placental AP cDNA, the bacterial gene for puromycin resistance, and the mouse bFGF cDNA, respectively. These exogenous genes are expressed in both avian and mammalian cells from a spliced message as illustrated, although viruses are produced only by avian cells.