Immunofluorescence detection of Nox1 in MKs stimulated with TPO. (A) Immunofluorescence was performed on cytospins of cultured mouse femoral BM cells. Nox1 (red) expression was observed in MKs with dim cytosolic staining (top), with intense cytosolic staining (bottom), or no staining (as summarized in panel B). DAPI counterstain was used to stain nuclei and is shown with Nox1 staining in the center. Images are shown at ×900 magnification. (B) Summary of the percentage of MKs detected with Nox1 staining. For fresh BM, the percentages of intensely stained (i) and dimly stained (d) MKs are noted. (C) Nox1 staining in mitotic MKs is intense and non-nuclear. Nox1 was also present in all mitotic MKs examined (n = 13), as noted by condensed chromosomes.