Expression of cytokine genes by feeder cells. RT-PCR analysis was performed on cDNA (+RT) or mRNA (−RT) from positive control cells (+), untransduced CV-1 cells (CV1), CV-1 cells transduced with Wnt-5A, Wnt-2B, or Wnt-10B(CV1/5A, CV1/2B, or CV1/10B, respectively), and a no-template control (−). The positive control cells were human fetal brain (EPO), human FBM (flt3, IL-6, SCF), human fetal kidney (G-CSF), or KG-1 cells (GM-CSF, IL-3). DNA size ladder (M) consists of a 1-kb ladder (Life Technologies). Expected size products for the PCR amplification reactions are 410 bp (EPO), 390 bp (flt3), 547 bp (G-CSF), 396 bp (GM-CSF), 401 bp (IL-3), 495 bp (IL-6), and 590 bp (SCF).