Antigen marker analysis of a GM-dependent PU.1−/− myeloid cell line. PU.1−/− fetal liver cultures were set up with GM-CSF. GM-dependent myeloid cells that grew from these cultures were cloned. One of the clones, GM-pu4, was analyzed by flow cytometry for the expression of various markers. Cells were incubated with either unconjugated (ER-MP12, ER-MP20, and ER-MP58), FITC-conjugated (Moma-2, Gr-1, CD11b, F4/80, c-Kit, and Sca-1), or PE-conjugated (CD18 and CD16/32) antibodies. FITC- or PE-conjugated secondary antibody was used to detect ER-MP12, ER-MP20, or ER-MP58. The light tracings on the histogram plots show background staining using isotype control antibodies.