Serial sections of bone marrow from transgenic progeny of F0 no. 16 show megakaryocyte-specific β-gal expression. (A) In the bone marrow of transgenic mice, positive megakaryocyte staining by IGSS (brown color) is shown. Hematoxylin counterstaining provides the nuclear blue staining. (B) 4A5-labeled (red stained) bone marrow shows the location of immature and mature megakaryocytes. Comparison of (A) and (B) documents transgene expression in all identifiable immature (small arrows) and mature (large arrows) megakaryocytes. (C) IGSS negative control; IGSS staining of transgenic mouse without primary antibody shows absence of brown color. (D) 4A5 negative control; 4A5 staining of transgenic mouse without primary antibody shows absence of red color. (Original magnification × 400). (E, F) Nontransgenic negative control; IGSS (E, wider field under lower magnification) and 4A5 (F) staining of the bone marrow of a wild-type mouse under identical conditions as (A) and (B), respectively. IGSS is negative, whereas 4A5 is positive as expected.
