Effect of mta3 knockdown on hematopoietic marker expression. (A-C) The expression of the erythroblast marker gata1 (A,C, in blue), the erythrocyte marker hbbe3 (B), and the paraxial mesoderm marker myod (C, in red) in cMO-, tMO-, or sMO-injected embryos at the 10-somite (10 s, dorsal view) stage and 24 hpf (24 hours, lateral view). The numbers indicated in the lower lefthand corner of each picture are the number (left) of affected embryos with phenotype similar to what is shown in the picture and the total number (right) of observed embryos. For gata1 expression in tMO-injected embryos at 24 hpf, the numbers from left to right were the number of embryos without expression and of embryos with reduced expression and the total number of observed embryos. The same number labeling was used thereafter. (D) Detection of hemoglobin in red blood cells staining with O-dianisidine at 48 hpf. Embryos in the top panel are shown in lateral view at lower magnification. Their anterior regions are shown in ventral view at higher magnification in the bottom panel, with indicating the red blood cells. (E-G) The expression of the myeloid marker pu.1 (E) and the pronephric duct markers pax2.1 (F) and cdh17 (G) in cMO- or tMO-injected embryos. Note that knockdown of mta3 resulted in reduction of pu.1 expression in anterior lateral mesoderm but in its loss in posterior lateral mesoderm at the 10-somite stage (dorsal views), and that mta3 knockdown had little effect on pu.1 expression at 24 hpf (dorsoanterior views). The expression of pax2.1 and cdh17 appeared normal in mta3 morphants.