Northern blot analysis of megakaryocyte or erythroid maturation-associated genes. UT-7/GM cells were cultured in tissue culture flasks with GM-CSF (10 ng/mL), EPO (10 U/mL), TPO (100 ng/mL), or their combinations. One month later, the cells were obtained and prepared for isolation of total cellular RNA. The expression of EPOR, γ-globin, PF-4, and GPIIb mRNAs was examined by Northern blotting. The membrane was rehybridized with ³²P-labeled human ribosomal DNA probe to show the amount of RNA loaded.