PRPH and retinal degeneration: NPs carrying pcDNA-MOP-NMP (NMP-normal mouse peripherin/retinal degeneration slow) drove photoreceptor gene expression for up to 10 months (longest timepoint examined) [15], and our ongoing work has shown photoreceptor and RPE expression for up to 15 months and 2 years, respectively (unpublished data) with a variety of vectors.