(a,b) Representative whole mount in-situ hybridizations to scl (a) and pu.1 (b) on 28?hours post fertilization (hpf) embryos. Increased number of cells expressing the two genes in the PBI of wnt10b-injected embryos (arrowheads; scl, n?=?62; pu.1, n?=?114) in comparison to controls (asterisks; scl, n?=?34; pu.1, n?=?66). Scale bar, 100??m. Magnification scale bar, 50??m. (c) Forced wnt10b upregulation in 28 hpf gata1:DsRed transgenic embryos, expressing the red fluorescent protein DsRed in erythroid progenitors, caused the increase in the number of gata1-positive cells in the PBI in 30% of the injected embryos (wnt10b-injected embryos n?=?58 and controls n?=?41). Scale bar, 125??m. (d) Representative wnt10b-injected and control 48 hpf mpx:GFP transgenic embryos characterized by GFP expression in differentiated neutrophils. Scale bar, 300??m. (e) wnt10b overexpression in 48 hpf mpx:GFP transgenic embryos caused a marked reduction in the number of GFP-positive circulating cells in 52% of the injected embryos (wnt10b-injected embryos, n?=?18; control embryos, n?=?10, mean?±?s.d.). **<0.01 with Student?s t-test.

wnt10b overexpression promotes the accumulation of the hematopoietic precursors in the PBI.

a, b, Magnification of representative whole mount in-situ hybridizations to scl and pu.1 on hours post fertilization (hpf) c, d, wnt10b-injected and control embryos. Wnt10b overexpressing embryos display a higher number of scl- and pu.1-expressing cells in the PBI (see also Figure 1). Some of the images are composed of different pictures corresponding to several focal planes, since a single focal plane cannot comprise all the labeled areas. Scale bar, 50 ?m.