Localization of ER β in human megakaryocytes using dual color immunofluorescence microscopy.

CD34⁺ bone marrow cells, grown in serum-free and phenol-red–free medium, were treated for 7 days with PEG-rhMGDF and harvested for microscopy. (A) Negative control using mouse and rabbit IgGs as irrelevant primary antibodies. The same field is shown in panels B through E. (B) Dapi staining of nucleic acid. The polyploid nucleus is easily appreciated. (C) GPIIb detected by monoclonal antibody SZ22 (green). (D) ER β detected by specific rabbit polyclonal antisera (red). (E) The co-localization of GPIIb and ER β shown by summing the channels used in panels C and D. Although both GPIIb and ER β localize predominantly to the cytoplasm, the intensity of the GPIIb stain dominates in panel E to the extent that less yellow color is appreciated. Original magnification of panels B through E: ×1300.