Fig. 3. Downstream consequences on vascular remodeling of the OUA connection as a result of earlier misplacement of the VOC.
(A, C, E) 3D models reconstructed from PECAM-1-immunostained arterial vessels and associated hindgut at the posterior embryonic-extraembryonic interface in TC littermates during vascular remodeling of the OUA connection (11s stage). Color key as described in Fig. 2, with the addition of green for the hindgut. mur, medial umbilical roots, missing in panel E (red arrow); white arrowhead (E), partial arterial union. Side views, posterior to the right. See text for further details. (B, D, F) Transverse PECAM-1-immunostained histological sections taken at the same level in each of the three T genotypes to illustrate the fully extended mur in the wildtype (B), reduced mur in the heterozygotes (D), and the absence of the mur (red arrows) in the homozygotes (F). (G) Volume of hindgut (7–10s) in TC littermates, depicted as mean ± SEM (error bars) with sample sizes indicated at the base of each bar; asterisk, significant P-values (Student t-Tests; T+/T+ vs TC/TC, P=0.0078; TC/T+ vs TC/TC, P=0.0005). (H) Average length of umbilical artery (upper data points) and lateral umbilical roots (lur; lower data points) as a function of nominal days postcoitum (“embryonic day, E”). Data plotted as mean ± SEM (error bars) with sample sizes for each stage and genotype (T+/T+, TC/T+) displayed below each data point; asterisk, significant P-values (Student t-Tests; E12.5 T+/T+ lur vs TC/T+ lur, P=0.0122; E13.5 T+/T+ lur vs TC/T+ lur, P=0.0002; E14.5 T+/T+ lur vs TC/T+ lur, P=0.0062). (I, J) Fetalplacental unit, ~E13.5, proximal portion of umbilical cord, i.e. closest to the fetus, is boxed and enlarged in insets. Arrowheads indicate the posterior extent of lateral umbilical roots in the umbilical cord. Scale bar (J): 22 μm (B, D, F); 1 mm (I, J). uv, umbilical vein.