EphB/EphrinB signaling controls HPD lumen morphogenesis independently of other morphogenetic roles. a Conditional ephrinb1EC expression is induced by heat-shock prior to or during CBD remodeling, at 50 hpf or 54 hpf, respectively. Embryos were analysed at 60 hpf (heat-shock at 50 hpf: n = 7, heat-shock at 54 hpf: n = 7, both N = 1). b–d Hnf4α (green), Prox1 (magenta) and aPKC (gray) labeling show that unlike in controls (b), conditional ephrinb1EC expression at 50 hpf (c) and 54 hpf (d) leads to HPD, liver and pancreas morphology defects, ectopic Prox1-positive cells throughout the HPD (blue arrowheads), with a subset associated with ectopic lumina bifurcating from the main duct (outlined with blue dashed line) disrupted and disorganized HPD lumen (red arrowheads, c, d). Yellow dotted lines: liver, yellow dashed line: pancreas; blue arrow: HPD system, orange arrow: CBD, green arrowhead: HPA
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