Excessive formation of linear actin bundles weakens endothelial cell resistance to blood flow.a Endothelial-specific ectopic expression of Fascin1a (Fscn1a)-T2A-mKate2CAAX (magenta) at 30 hpf. Box, region of DLAV undergoing lumenisation. Arrow, expanding apical membrane (00:08). Arrowheads, basal blebs (from 02:16). Blebbing was observed in 7 out of 8 ECs with overexpression of Fscn1a (n = 6 embryos from two independent experiments). b Treatment of a 2 dpf Tg(kdr-l:ras-mCherry)s916 embryo with 400 µM CK666 for 1 hour induces basal blebs (i and ii, arrowheads) and apical blebs (iii, arrow; 4 out of 4 embryos from one experiment). Boxes are observed regions. c Increase in linear actin bundle formation modifies EC membrane behavior and response to haemodynamic forces. 00:00, hours:minutes. Scale bars, 10 µm (a) and 5 µm (b).
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