Fig. 6

brd3a is required for differentiation and not maintenance of thrombocytes.

(A) Exposure of zebrafish embryos to 1 μg/ml (+)-JQ1 from 24 hpf resulted in a severe reduction in the number of thrombocytes compared to DMSO or (-)-JQ1 treated embryos. (B) A graph to illustrate the average number of thrombocytes at 3 dpf. Embryos were exposed to DMSO, (-)-JQ1 or (+)-JQ1 starting from 24 hpf. Each dot represents thrombocyte count for a single embryo. Horizontal line denotes average thrombocyte number. Student t test, ** p = 1.6×10^-8, n = 17. (C) To assess whether brd3a is essential for differentiation of thrombocytes or for their maintenance and survival we incubated Tg(cd41:EGFP) embryos in DMSO or with (+)-JQ1 inhibitor starting from 3 dpf and checked thrombocyte number 24 hours later, at 4 dpf. We found that in untreated (DMSO) embryos the number of thrombocytes markedly increased between 3- and 4 dpf; however, in (+)-JQ1 treated embryos there was no change in the number of thrombocytes. In contrast, the inhibitor had no adverse effect on the number of HSCs during this 24 h period of treatment (D). Representative confocal images of CHT region are shown. All embryos are oriented with anterior to the left and dorsal to the top.