Transient transfection assays using primary rat neocortical neurons. The human β1 promoter (475 bp) fused to a luciferase reporter was co-transfected with an expression construct for either full-length PHF1b or an empty vector. The CMV promoter was used for PHF1b over-expression. (*) indicates significance of (p < .05), Student’s T test. Results are presented as mean values ± SEM (n=7). Luciferase counts were normalized to mg protein/dish.