Fig. 10. Nkx2.2 can drive the expression of GFP under the control of the PLP promoter. NIH 3T3 cells were transiently transfected with Nkx2.2 alone (A), PLP-GFP alone (B'), GFAP-GFP alone (C'), Nkx2.2 and PLP-GFP (B) and Nkx2.2 and GFAP-GFP (C). Few, if any, cells are GFP positive in cells transfected with Nkx2.2 alone, PLP-GFP alone or GFAP-GFP alone. In the presence of Nkx2.2 (stained in red), the number of GFP-positive cells (stained in green, indicated by arrows) is dramatically increased by co-transfection with PLP-GFP, but with not GFAP-GAP. (D) The sum of GFP-positive cells in various experiments. In the Nkx2.2/PLP-GFP co-transfection experiment, the vast majority of cells that were GFP positive were also Nkx2.2 positive (n=244, blue bar), although a small number of cells were Nkx2.2/GFP positive (n=8, red bar). For each transfection experiment, 50 random fields of cells were counted for GFP-positive cells.