Fig. 2

Hemogen expression in zebrafish embryos. (A-H) Wild-type embryos, WISH. (A) Epiboly at 9 hpf. Hemogen expression was not detected. (B) Ten-somite stage. Hemogen transcripts along the lateral plate mesoderm (LPM). (C) 20 hpf. Hemogen staining in the intermediate cells mass (ICM) and posterior blood island (PBI). The inset shows a sense probe control. (D) 33 hpf. Hemogen-positive primitive erythrocytes of the peripheral blood (PB) exited the Ducts of Cuvier (DC) onto the yolk. Staining at the midbrain-hindbrain boundary (MHB) was observed. (E) 144 hpf. Hemogen expression in the caudal hematopoietic tissue (CHT) and pronephric kidney (PK) and in erythrocytes in the heart (H). The asterisk indicates the plane of the cross-section in panel F. (F) 144 hpf. Cross-section of embryo in panel E showing heavily stained pronephric ducts. (G) 48 hpf. Lateral aspect of tail. Hemogen transcripts in the CHT and pronephric tubule duct (PD). (H) Kidney touch print from adult fish. Hemogen expression was observed in proerythroblasts (ProE) and normoblasts (N) but not in erythrocytes (E). (I) 48 hpf. View of circulating EGFP+ erythrocytes in the dorsal aorta (DA) of Tg(Lcr:EGFP)^cz3325Tg zebrafish after staining for Hemogen protein by indirect immunofluorescence. Hemogen (red signal) accumulated in nuclei (Nu) of erythrocytes whereas the cytoplasm (C) was marked by EGFP. Other abbreviations: AGM, aorta gonad mesonephros; PT, pronephric tubule; CV, caudal vein; DA, dorsal aorta; G, gut; M, myotomes; NC, notochord; SB, swim bladder; SC, spinal cord. Scale bars: (A-F) 250 µm; (G) 1 mm; (H) 100 µm; (I) 50 µm.