... and extension; no umbilical artery or vein formation; chorio–allantoic attachment defect; ECs present but fail to form plexus; chorio–allantoic attachment defect; lethal by E10.5 Naiche et al., 2011 ; Naiche and Papaioannou, 2003 Vcam1 (allantois mesothelium, cortex) ∼52-80% allantoises were abnormal...

...). When aspirated via a mouth-held microcapillary pipette, the entire allantois can be removed from these insertion sites. We aspirated allantoises from early headfold to 1-2 s conceptuses with a glass pipette(Fig. 2A). Following aspiration, we carefully trimmed several cell layers from the base...

... of the allantois and for amnion closure, as demonstrated by loss of Bmp signalling. By contrast, the appearance of ectopic PGC-like cells and regionalized ectopic vasculogenesis and haematopoiesis in thickened Smad5 m1/m1 amnion are amnion defects that have not been associated with loss of Bmp signalling...

... the posterior streak and proximal allantois (n =1, 7 and 4 for +/+, T C / + and T C /T C ,respectively), the latter similar to previous fate mapping this region(Smith et al., 1994). Allantoises were explanted, cultured and processed as previously described(Downs, 2006). For halved allantoises, whole...

... P for the total embryonic vessel number per placental labyrinth and for the average embryonic vessel width. E7.5 and E8.25 allantoises were dissected from 0- to 3- and 5- to 7-somite embryos, respectively. The isolated allantois was fixed in immunohistochemistry-zinc-fixative (BD Biosciences...

... mesoderm to the allantois throughout the latter's early development, microsurgery was used to remove allantoises at ten developmental stages. Subsequent whole embryo culture of operated conceptuses resulted in the formation of regenerated allantoises at all time points. Aside from being generally shorter...

... chorioallantoic fusion and die by 10.5 days post coitus. The allantoises of Tbx4 -mutant embryos are stunted, apoptotic and display abnormal differentiation. Endothelial cells within mutant allantoises do not undergo vascular remodeling. Heterozygous embryos show a mild, transient growth defect in the allantois...

... in yolk sac or allantois; chorioallantoic fusion fails; the amnion does not expand with the growth of the embryo, but misexpresses vascular and hematopoietic markers. Separation of the bulk of yolk sac mesoderm from the endodermal layer and adherence between mesoderm of yolk sac and amnion, indicate...

... cells to the allantois. Finally, when removed from conceptuses and cultured in isolation, neural plate and headfold-stage allantoises formed a conspicuous vascular network that was positive for Flk-1. Hence, the vasculature of the allantois is formed intrinsically by vasculogenesis rather than...

... Bars (A,C) 200 μm. (B) 100 μ Allantoises of lacZ /+ hemizygous genotype were removed through two vitelline sites (Fig. 2): (1) through non-blood island tissue slightly distal to the level of the site of insertion of the allantois with the amnion, or (2) directly through visible yolk sac...

... is the expression of Wnt2 in the early heart field of 7.5–8.5 dpc (days post-coitum) mouse embryos, making Wnt2 a potentially useful gene marker for the early stages of heart development. Expression was also detected in the allantois from 8.0 dpc and at later stages in the placenta and umbilicus. Mice deficient...

... experiments, transplanted allantoises typically attached to the chorion despite loss of their connection with the hindgut region of the fetus. Hence selective attachment of the allantois to the chorion clearly cannot depend simply on its directed growth. While the transplanted allantoic tissue attached...

... dpc T/T +/+ chimeras exhibit many morpho-logical features of intact T/T mutants. In addition, a dramatic bias of T/T cells towards caudal regions (such as tail and allantois) was observed in all chimeras tested. This is likely to result from accumulation of nascent T/T mesoderm cells with time near...

... that these cells in the fetus and allantois have a similar role, the establishment of fetal-allantoic-placental communication. It will be interesting to examine whether irp in non-mammalian vertebrates is also involved in the formation of equivalent tissues in these species, tissues that are not formed during...