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Fig. 4 Loss of ubiad1 function results in decreased cranial vasculature and endothelial cells due to increased endothelial karyorrhexis. (A-D) Confocal projections of 48 and 72 hpf Tg(fli1a:nEGFP);Tg(kdrl:cherry-ras) (A,C) control morpholino (MO) and (B,D) ubiad1 MO-injected zebrafish reveal that there are not only fewer reh endothelial cells but there is also an increase in nuclear fragmentation (karyorrhexis) in ubiad1 morpholino-injected zebrafish when compared with control-injected animals. Arrowheads indicate missing cranial vessels. (E) The number of endothelial nuclei is reduced in ubiad1 morpholino-injected zebrafish when compared with control morpholino-injected zebrafish. The number of endothelial nuclei observed per high-power field at 72 hpf. (F) An increase in the number of endothelial cells undergoing nuclear fragmentation was observed in ubiad1 morpholino-injected zebrafish when compared with control morpholino-injected zebrafish. The number of endothelial nuclei undergoing karyorrhexis per high-power field from 48 to 72 hpf. Mean+s.e.m. Student’s t-test, *P<0.05 (n=5). (G-H′′) Time-lapse imaging of boxed areas in C (G-G33) and D (H-H33) shows that endothelial nuclei from (H-H′′ ′′) ubiad1 morpholino-injected but not (G-G′′ ′′) control morpholino-injected zebrafish exhibit increased nuclear fragmentation, resulting in subsequent endothelial cell death. Yellow arrows indicate endothelial nuclei undergoing fragmentation.