Engineering viral promoters for gene transfer to human neuroblasts

The strength and activity of several viral promoters in human neuroblasts w ere evaluated in vitro. Several luciferase reporter gene contructs under the control of different v iral promoters (HIV-1 LTR, HTLV-I LTR, MMTV LTR, RSV LTR, CMV, SV40), in th e presence or in the absence of the viral SV40 enhancer, were transfected i nto two well-established human neural cell lines, including one derived fro m human embryonic olfactory cells (B4) and one derived from an adrenal neur oblastoma (SH-SY-5Y). The epithelial cell line HeLa was used as a control. The enzymatic activity of luciferase was evaluated after normalization with an internal control. The results indicated that in the context of the repo rter gene constructs, the CMV promoter alone was, overall, the most active in any tested cell line. However, addition of the SV40 enhancer to the CMV promoter abolished luciferase activity in SHSY-SY cells while significantly increasing luciferase expression in the CNS derived B4 fetal neuroblasts. The results suggest that gene therapeutic vectors aimed to promote enzymati c activity through gene transfer into undifferentiated human neural cells a re feasible. However, since differences in promoter activity in neuroectode rmal-derived cells are very relevant, gene construct variants should be con sidered to optimize the system.