Diploid and trisomic astrocytic progenitors derived by directed in vitro differentiation of hESCs exhibit transcript and alternative splicing patterns characteristic of astrocytic cells. A. Diploid H9 and trisomic BG01V hESCs colonies (unstained, left panels), express stem cell markers OCT-4 (red) and TRA-1-60 (green). Karyotypes of diploid H9 (46; XX) and trisomic BG01V (49; XXY, +12, +17) hESCs. Diploid and trisomic APCs express astrocytic marker, GFAP (red). B. Semiquantitative RT-PCR analysis demonstrating that stem cell transcripts Noggin (top panel) and Lin28 (second panel) are over expressed in both diploid H9 and trisomic BG01V hESC lines relative to all astrocytic-like cells including H9 APCs, BG01V APCs and CCF-STTG1 astrocytoma cells. GFAP transcripts are up regulated in astrocytic cells relative to hESCs (middle panel). Alternative splicing pattern of FGFR1 in diploid H9 hESCs is preserved in trisomic BG01V hESCs relative to all astrocytic cells. 18S RNA was used as control in all RT-PCR experiments (bottom panel). MW marker is included in the far left lane in each gel. C. DNA sequence analysis demonstrating that the FGFR1 transcript expressed in diploid H9 and trisomic BG01V hESCs includes exon 3, while astrocytic cells express a FGFR1 splice variant in which exon 3 has been excluded (from FGFR1 RT-PCR analysis in Figure 1B).