FOG-1 acts independently of GATA-1 during thymic development. Lateral views of uninjected/Tg(lck:eGFP)/control embryos (A,D,G,J) compared with embryos injected with GATA-1MO (B,E,H,K) or FOG-1MO (C,F,I,L). The pericardial effusion is noted in the FOG-1 morphant (C black arrow). Knocking down of either GATA-1 or FOG-1 shows drastic anemia when stained with o-dianisidine for hemoglobinized cells (D-F). The transgenic zebrafish [Tg(lck:eGFP)] injected with FOG-1 MO shows complete absence of eGFP⁺-T lymphocytes in the thymi (comparing G,J with I,L). In contrast, GATA-1 morphant shows normal levels of eGFP expression in the thymi (H,K).