Universal expression of C9orf72 mRNA in human neural cells. Expression of the chromosome 9 open reading frame 72 (C9orf72) transcript encoding isoform a or isoform b was studied by RT-PCR in human tissues and cultured cells. (a) Isoform a. (b) Isoform b. (c) G3PDH, a housekeeping gene for a positive control. Lane 1, frontal cortex of the human cerebrum (CBR) without inclusion of the reverse transcription step; lane 2, CBR with inclusion of the reverse transcription step; lane 3, astrocytes (AS); lane 4, neuronal progenitor (NP) cells; lane 5, NTera2 teratocarcinoma-derived neurons; lane 6, SK-N-SH neuroblastoma; lane 7, IMR-32 neuroblastoma; lane 8, U-373MG glioblastoma; lane 9, HMO6 microglia; lane 10, peripheral blood mononuclear cells (PBMC).