Gene expression analysis. (A) Northern blot analysis. RNA was prepared from EB-PE cells grown with IGF-1, KL, and Epo (lanes 1) and with bFGF and Epo (lanes 2). After electrophoresis, RNA was transferred to a nylon membrane and hybridized with fgfr-1, flk-1, or EpoR probe. GAPDH is shown as a loading control. (B) RT-PCR analysis. RNA was prepared from EB-PE cells grown with IGF-1, KL, and Epo (lanes 1) or with bFGF and Epo (lanes 2), and subjected to RT-PCR. β-actin is shown as a control. The amplified DNA sizes are as follows: fgfr-1, 236 bp; EpoR, 452 bp; β-actin, 443 bp.