Histologic examination of transgenic mouse bone marrow, spleen, and liver. The right column (A,C,E,G,I) and the left column (B,D,F,H,J) represent histologic examination of wild-type littermates and BACH1 transgenic mice, respectively. The photomicrographs in panels A-D show HE staining of bone marrow specimens. Yellow arrowhead in panel D indicates emperipolesis of granulocytes that was specifically observed in megakaryocytes from transgenic mice. (E-F) Silver impregnation staining of bone marrow. (G-H) Silver impregnation staining of spleen. Aggressive fibrosis was recognized in both tissues derived from transgenic mice. (I-J) HE staining of liver sections. Erythroid islets (white arrowhead in panel J) and megakaryocytes (white arrow in panel J) were observed in the sinusoids of the livers derived from transgenic mice. Representative staining sections were prepared using 4-month-old transgenic mice of line 705 and their corresponding wild-type littermates. Original magnifications × 200 (A-B,E-J) and × 400 (C-D).