The fli1EGFP-positive hematopoietic cells in the ventral wall of DA co-express c-myb and contribute to T cells. (A) Antibody staining of EGFP in the 30-hpf Tg(fli1:eGFP) transgenic embryo. (B) Fluorescence in situ staining of c-myb mRNA in the same embryo in panel A. (C, D) Confocal images of the boxed region 1 in panels A and B show EGFP and c-myb signals in the anterior part of ventral wall of DA. (C, D) Merged image of panels C and D. (C, D) Superimposed view of panels C, D and differential interference contrast (DIC) image. (E, F) Confocal images of the boxed region 2 in panels A and B show EGFP and c-myb signals in the posterior part of ventral wall of DA. (E, F) Merged image of panels E and F. (E, F) Superimposed view of panels E, F and DIC image. (G) Live image of the 30 hpf Tg(fli1:eGFP) transgenic embryo indicates the uncaging positions in the anterior (boxed region 3) and posterior (boxed region 4) part of ventral wall of DA. (H-K) Confocal images of the boxed area 3 and 4 in G show the elevation of green fluorescence upon uncaging: H-K, images taken before uncaging; H'-K', images taken immediately after uncaging; H, H', J, and J', green fluorescence; I, I', K, and K', superimposed view of H, H', J, and J' with DIC images respectively. Arrows (H-K') indicate the successfully uncaged cells. (L, M) Confocal images of the flu and rag1 signals in the 5-dpf thymus. The embryos were uncaged in boxed region 3 in G, fixed at 5 dpf, and co-stained with flu and rag1 RNA. (L/M) Merged image of L and M. (L'/M') Superimposed view of L/M and 4′6-diamidino-2-phenylindole 2HCl (DAPI) staining (blue). (N, O) Confocal images of the flu and rag1 signals in the 5 dpf thymus. The embryos were uncaged in boxed region 4 in G, fixed at 5 dpf, and co-stained with flu and rag1 RNA. (N/O) Merged image of N and O. (N'/O') Superimposed view of N/O and DAPI staining (blue). Arrows (L-N'/O') indicate the overlapping of flu and rag1 staining.