Expression of C9ORF72 in nuclear and cytoplasmic protein fractions over development. a Representative western blot of C9ORF72 in nuclear and cytoplasmic fractions from E18, P1, P7, and P56 mouse brain. HDAC2 and GAPDH were used to demonstrate nuclear and cytoplasmic fractions respectively. C9ORF72 isoforms were present at differing levels and in specific fractions throughout the time course. b Relative quantitation of C9ORF72 isoform expression in nuclear and cytoplasmic fractions over the time course. Overall, the 55 kDa protein was significantly (p < 0.05) increased within nuclear fractions compared to cytoplasmic fractions and specifically at E18 and P1 compared to P56 (p < 0.05). Within nuclear fractions, the 55 kDa protein was significantly (p < 0.05) increased at P1 compared to P56. There were no significant differences in nuclear and cytoplasmic expression for the 50 kDa band. Overall, the 35 kDa band was significantly (p < 0.05) increased within cytoplasmic fractions compared to nuclear fractions and specifically at E18 compared to P56 (p< 0.05). Within cytoplasmic fractions, the 35 kDa protein was significantly increased (p < 0.05) at E18, P1 and P7 compared to P56. Values represent mean ± standard error. *p < 0.05 nuclear vs. cytoplasmic at E18 and P1. + p < 0.05 E18 vs. P56 (nuclear for 55 kDa bad, cytoplasmic for 35 kDa band). # p < 0.05 P1 vs. P56 (nuclear for 55 kDa band, cytoplasmic for 35 kDa band)