Fig. 6

Pu.1 suppresses emergency monopoiesis after intravenous infection of E. coli (5–10 × 10³ cfu).

(A), Time-lapse imaging of an infected 2 dpf pu.1^G242D/G242D/Tg(lyz:eGFP) CHT from 6 hpi to 19 hpi. The white stars indicate that lyz-GFP⁺ neutrophils phagocytosed bacteria to form small foci. The white arrowheads represent free bacteria. The white cross star denotes the large E. coli foci. Scale bars, 20 μm (see also Video S7). (B,C), SB staining (B) and calculation of SB⁺ neutrophils (C) in the CHT of treated WT (172.90 ± 26.23 vs 77.10 ± 16.47 in E. coli vs PBS group. N = 8 in each group) or pu.1^G242D/G242D larvae (198.00 ± 21.13 vs 140.80 ± 23.92 in E. coli vs PBS group. N = 8 in each group). (D,E), WISH (D) and calculation (E) of the pu.1⁺ myeloid progenitors in the CHT of stressed WT (214.50 ± 13.98 vs 78.10 ± 6.89 in E. coli vs PBS group. N = 8 in each group) or pu.1^G242D/G242D larvae (230.30 ± 24.54 vs 187.00 ± 17.78 in E. coli vs PBS group. N = 8 in each group). (F,G), WISH (F) and calculation (G) of mfap4⁺ macrophages in the CHT of challenged WT (128.80 ± 7.32 vs 75.60 ± 5.09 in E. coli vs the group. N = 8 in each group) or pu.1^G242D/G242D larvae (174.50 ± 14.03 vs 49.30 ± 3.12 in E. coli vs PBS group. N = 8 in each group). (H), The fold expansion of various cell types in both the infected WT (SB⁺: 2.24; pu.1⁺: 2.75; mfap4⁺: 1.70) or pu.1^G242D/G242D (SB⁺: 1.41; pu.1⁺: 1.22; mfap4⁺: 3.54) at 2 dpi. (I), Kaplan–Meier survival analysis of PBS- and E. coli-treated WT and pu.1^G242D/G242D embryos. The total numbers of animals used in each experiment are 100 (log-rank/Mantel–Cox statistic). Red arrows indicate WISH signals.