(A) Model depicting stage-specific requirement for Gata2 −77 and +9.5 enhancers during developmental hematopoiesis. As the +9.5 enhancer deletion abrogates HSC genesis in the AGM of +9.5−/− embryos, whether it exerts essential activities in fetal liver hematopoietic cells was unclear.
(B) Genotypes of WT, +9.5+/−, −77+/− and CH embryos at timed developmental stages and at time of weaning. The numbers of dead embryos at each developmental stage are shown in parentheses. Significance was analyzed using the Chi-squared test.
(C) Representative E13.5 CH embryos exhibiting reduced liver size and hemorrhage (arrows). (D) Representative whole-mount staining of E10.5 WT and CH embryos showing CD31+ cells (magenta) and c-Kit+ cells (green) within the dorsal aorta (DA). Scale bar, 100 µm. Quantitation of c-Kit+ cells within the DA (WT [n = 5], +9.5+/− [n = 4] and CH [n = 4]). Graphs depict mean ± SEM; **p < 0.01, ***p < 0.001. Significance was analyzed using the 2-tailed unpaired Student’s t test.