... that the avian allantois could contribute extensively to hematopoietic and endothelial cells in the adult bone marrow following engraftment into the coelom of host embryos, and thus has the potential to form definitive (adult) blood( Caprioli et al., 1998 ). In contrast, when headfold-stage murine allantoises...

... 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...

... /T C cells were capable of exiting the primitive streak and entering the allantois throughout the period of allantoic elongation. Fig. 2. Allantoic dysmorphogenesis and absence of endothelialization in T C /T C allantoises. ( A-F ) Hematoxylin and eosinstained sections of allantoises...

...-tailed t -test assuming equal variance was used to determine 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...

... 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...

... to the allantois. Scale 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...

... 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...

... the ventral lateral aspects of the body wall ( Fig. 6A,B,E,F ). Expression was localized to stellate, mesenchyme tissue surrounding the paired umbilical veins and ductus venosus . Expression continues into the allantois and allantoic stalk from its base of attachment to the body wall ( Fig. 6A,B,G,H...