Application of the BC1 RNA gene promoter for short hairpin RNA expression in cultured neuronal cells

BC1 RNA is a neuronal cell-specific non-messenger RNA transcribed by RNA polymerase III (Pol III). We previously reported that the transcription of BC1 RNA is controlled both by intragenic promoters for Pol III and by a 5′-flanking region containing several unique cis-elements that are possible members of the Pol II transcription system. In this study, we chose β-secretase (BACE1) as a target and applied the promoter to produce a short hairpin RNA (shRNA) for RNA interference (RNAi) in cultured neuronal cells. A plasmid vector in which the promoter was linked to a target sequence functioned in rodent NG108-15 cells and suppressed BACE1 protein expression, but did not function in non-neuronal NIH3T3 cells. It was also effective in rat primary hippocampal neurons. We further showed that the promoter can be active in human neuroblastoma SH-SY5Y cells and reduced expression of targeted protein, although the BC1 RNA gene is a rodent-specific gene. The use of this vector-based system for shRNA expression may be an important component of future development of neuronal cell-selective RNAi in both transgenic and therapeutic applications.