Co-expression of two gene products in the CNS using double-cassette defective herpes simplex virus vectors.

Defective herpes simplex virus (HSV) vectors are an efficient means to deliver genes to cells of the central nervous system (CNS). Such vectors containing two independent transcription units would be extremely valuable for many studies, including the comparative analysis of promoter function and expression of multiple gene products in the CNS. We have constructed a 'double-cassette' vector expressing two easily detectable marker enzymes, beta-galactosidase (beta-gal) and human placental alkaline phosphatase (AP). Cells infected in vitro, including neurons and glia, and in vivo expressed both gene products.