Figure 2: Expression of uPAR by PC12 cells. (a) Binding isotherm of 125I-scu-PA to PC12 cells. Cells in suspension were incubated with 125I-scu-PA, and bound ligand was separated from free by centrifugation over sucrose. Nonspecific binding was determined in the presence of unlabeled scu-PA. (b) Scatchard analysis of the binding isotherm in Panel A. (c) Northern blot analysis showing expression of uPAR in PC12 cells. Poly(A)-enriched RNA was isolated from PC12 cells and Northern blotted with a 458 bp SMaI + BamHI (nuc. 41–493) human uPAR cDNA probe. Northern blotting of U937 cell poly(A) RNA is shown for comparison. (d) cDNA sequence of PC12 uPAR. The rat uPAR sequence was obtained by screening a PC12 cDNA library using a 609 bp EcoRI + NcoI (nuc. 110–718) human uPAR cDNA probe labeled with [α-32P] dCTP.