Figure 1

Schematic diagrams of (A) the gC – BDNF construct, or (B) helper virus-free packaging for targeted gene transfer. A. gC – BDNF contains the gC promoter, a BDNF cDNA (preproBDNF, aa 1–247), a spacer of 5 aa, and a deletion of gC containing aa 153 to the C-terminus (aa 511) [21]. Expression of gC – BDNF will be regulated similar to the wt gC gene, as this construct retained the gC promoter and polyadenylation site. BDNF, a secreted protein, contains a signal sequence [46] to support proper posttranslational processing, and the gC deletion retains the transmembrane domain to support insertion into the envelope of HSV-1 particles. B. Helper virus-free packaging [7, 50] was performed using either pTHlac or pINS-TH-NFHlac and either gC – BDNF or gC – GDNF. A HSV-1 vector and a HSV-1 cosmid set that contained a modified gC construct and lacks an a sequence (contains the packaging site) were cotransfected into 2-2 cells [51]. The resulting HSV-1 vector particles should contain the vector, modified gC, and all the other HSV-1 envelope glycoproteins. Thus, these vector particles are designed to enable initial binding to either BDNF or GDNF receptors on the surface of cells, followed by entry using the same mechanism as used by wt HSV-1 particles [11].