Fig. 2

gfi1aa and gfi1b expression pattern during primitive and definitive hematopoiesis. The expression pattern of gfi1aa and gfi1b was detected by WISH of developing zebrafish embryos. (A) For the primitive wave of hematopoiesis, FOG-1 was included as a reference control. Dark-blue staining indicates pre-zygotic maternal expression of gfi1aa and gfi1b transcripts, along with FOG-1, at the 2-cell and 1000-cell stages (a–f). At the 5 and 10 ss, zygotic gfi1aa and FOG-1 expression is localized to the LPM (black arrowheads) (g–h, j–k), while gfi1b is expressed in the ectoderm (i, l). As the LPM converges to the ICM at the 15 ss, gfi1aa and FOG-1 expression remains localized to the LPM (j–k, m, n), while gfi1b transitions from ectoderm to LPM expression (l, o). (The vertical arrow indicates the anterior–posterior axis and the horizontal arrow indicates the rostral–caudal axis.) gfi1aa and gfi1b are strongly expressed in the ICM at the 20 ss along with FOG-1 (s–u). At 24 hpf, gfi1b and FOG-1 remain strongly expressed in the ICM, while expression of gfi1aa shows a relative decrease in ICM expression (v–x, insert). (B) AGM expression of gfi1aa and gfi1b during definitive hematopoiesis was analyzed by whole-mount and sectioned in situs using runx-1 and c-myb as reference controls (a–f). The white arrowhead indicates AGM expression of runx-1 and c-myb in the ventral wall of the dorsal aorta (d).