A HERPES-SIMPLEX VIRUS-1 VECTOR CONTAINING THE RAT TYROSINE-HYDROXYLASE PROMOTER DIRECTS CELL-TYPE-SPECIFIC EXPRESSION OF BETA-GALACTOSIDASE IN CULTURED RAT PERIPHERAL NEURONS

A defective herpes simplex virus-1 (HSV-1) vector system was used to s tudy cell type-specific expression of the tyrosine hydroxylase (TH) ge ne. HSV-1 particles containing 663 bp (pTHlac 663), 278 bp (pTHlac 278 ), or 181 bp (pTHlac 181) of the rat TH promoter driving E. coli LacZ were used to infect superior cervical ganglia (SCG: TH-expressing tiss ue) and dorsal root ganglia (DRG: non-TH-expressing tissue) cultures. One day after infection, expression of beta-galactosidase was visualiz ed by X-gal cytochemistry. Following viral transduction with pTHlac 66 3 at a multiplicity of infection of 0.2, 14.4% of the SCG neurons were X-gal positive whereas only about 0.9% of DRG neurons were X-gal posi tive. Infection with either pTHlac278 or 181 resulted in 3-fold more X -gal-positive DRG neurons. These results suggest that (i) the defectiv e HSV-1 vector system may be useful in defining regulatory promoter mo tifs; (ii) 663 bp of the rat TH promoter contains sufficient informati on for cell type-specific expression in peripheral nervous system neur ons; and (iii) sequences between -278 and -663 contain an element(s) t hat represses gene expression in non-catecholamingeric neurons.