Effects of jak2a knock-down on erythropoiesis, Stat signaling, and angiogenesis. (A) Flow cytometric analyses (x-axis, GFP; y-axis, side scatter) showing the effects of jak2a knock-down using jak2a^UTR and jak2a^SS morpholinos as well as a soluble jak2a inhibitor AG490 on GFP⁺ populations in Tg(gata1:GFP) embryos. Synergistic effect was seen when the embryos were coinjected with both MOs. Effects of jak2a^UTR-MOs could be rescued by wild-type jak2a mRNA. Each record was representative of 3 experiments using 20 embryos per experiment. (B) Western blotting showing reduced phospho-stat5 upon knock-down of jak2a functions. About 30 embryos were used in each experiment, and the result was representative of 3 experiments. (C,D) Fluorescent microscopy using Tg(fli1:GFP) showing knock-down of jak2a by jak2a^UTR-MOs had no effects on angiogenesis. AC indicates axial circulation; ISV, intersegmental vessels. Results were representative of at least 4 separate experiments using more than 5 embryos each time.