Actually, there was a cross-inhibitory mechanism between the expression of gata1 and pu.1 in zebrafish [20], which indicated that the level of pu.1 expression was determined by the ability of RUNX1-Evi-1 to regulate both pu.1 and gata1, thus increased the repopulation of immature myeloid cells and anemia. This evidence concerns the gene SPI1 and anemia (phenotype).