(A) The EPOR fails to induce the c-fos orbcl-2 proto-oncogene mRNA in HT-2 cells. HT-2, HT-2.EPOR.3, and HT-2EPOβγ cells were incubated in media without growth factors for 15 hours and stimulated with no cytokine (U, lanes 1, 5, and 14) 50 U/mL EPO (lanes 2 through 4, 9 through 13, 15 through 17) or 10 nmol/L IL-2 (lanes 6 through 8) for the indicated time periods. Total cellular RNA was prepared, separated on a denaturing agarose/formaldehyde gel, and probed with ³²P-labeled c-fos, bcl-2, orGAPD cDNA probes. (B) The EPOR fails to induce bcl-xproto-oncogene mRNA in HT-2 cells. HT-2.EPOR.3 and 371.2.EPOR cells were starved as described in (A) and stimulated with no cytokine (lane 1), EPO (lanes 2 through 4), or IL-2 (lanes 5 through 7) for the indicated time periods. RNA from 371.2.EPOR cells serves as a positive control (lane 8). RNA was prepared and blotted as in (A) and probed with a ³²P-labeled bcl-x cDNA probe derived from the 5′ end of the gene.