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Human hypoblast formation is not dependent on FGF signalling.

Roode M, Blair K, Snell P, Elder K, Marchant S, Smith A, Nichols J - Dev. Biol. (2011)

Bottom Line: These differentiation processes are associated with restricted expression of key transcription factors (Cdx2, Oct4, Nanog and Gata6).However, the formation of hypoblast in the human is apparently not dependent upon FGF signalling, in contrast to rodent embryos.Nonetheless, the persistence of Nanog-positive cells in embryos following treatment with FGF inhibitors is suggestive of a transient naïve pluripotent population in the human blastocyst, which may be similar to rodent epiblast and ES cells but is not sustained during conventional human ES cell derivation protocols.

View Article: PubMed Central - PubMed

Affiliation: Wellcome Trust Centre for Stem Cell Research, University of Cambridge, Cambridge CB2 1QR, UK.

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Human embryos segregate putative hypoblast by day 7 of development. Human embryos were thawed and cultured in standard IVF medium until they formed cavitated blastocysts, upon which they were moved to N2B27 medium. Embryos were fixed and immunostained for Oct4 (white), Nanog (green) and Gata6 (red). At day 6 of in vitro development (A) Nanog is restricted to a few cells within the embryo, whilst Gata6 and Oct4 are broadly expressed. Confocal images of two representative embryos with a maximum projection of the 3D reconstruction of the blastocyst are shown. (B) A single slice in a z stack of each of the two embryos shown in (A), indicating that Nanog and Gata6 can both be expressed highly in the same cell (arrowheads) or that Gata6 can be low as Nanog is high (arrows). (C and D) Embryos were developed to day 7 in vitro and immunostained for Nanog (green), Oct4 (white) and Gata4 (red) (C) or Sox17 (red) (D). In contrast to the stainings observed at day 6, Oct4 is restricted to the cells of the ICM. Gata4 and Sox17 are restricted to a subset of cells within the embryo, distinct from the Nanog positive cells: the putative hypoblast. In all embryos nuclei were counterstained with DAPI (blue). The total number of cells in each embryo is written in the top right hand corner of the panel.
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f0005: Human embryos segregate putative hypoblast by day 7 of development. Human embryos were thawed and cultured in standard IVF medium until they formed cavitated blastocysts, upon which they were moved to N2B27 medium. Embryos were fixed and immunostained for Oct4 (white), Nanog (green) and Gata6 (red). At day 6 of in vitro development (A) Nanog is restricted to a few cells within the embryo, whilst Gata6 and Oct4 are broadly expressed. Confocal images of two representative embryos with a maximum projection of the 3D reconstruction of the blastocyst are shown. (B) A single slice in a z stack of each of the two embryos shown in (A), indicating that Nanog and Gata6 can both be expressed highly in the same cell (arrowheads) or that Gata6 can be low as Nanog is high (arrows). (C and D) Embryos were developed to day 7 in vitro and immunostained for Nanog (green), Oct4 (white) and Gata4 (red) (C) or Sox17 (red) (D). In contrast to the stainings observed at day 6, Oct4 is restricted to the cells of the ICM. Gata4 and Sox17 are restricted to a subset of cells within the embryo, distinct from the Nanog positive cells: the putative hypoblast. In all embryos nuclei were counterstained with DAPI (blue). The total number of cells in each embryo is written in the top right hand corner of the panel.

Mentions: We first examined human embryos at 6 days post-fertilisation. Nanog is confined to a few inner cells within the embryo (Fig. 1A). Gata6 and Oct4 are widely expressed throughout the embryo, with levels varying between individual cells, consistent with previous data (Cauffman et al., 2005; Cauffman et al., 2006; Chen et al., 2009; Kimber et al., 2008). Some inner cells exhibit high levels of Nanog and low levels of Gata6 (Fig. 1B, arrows), whilst in other cells both markers are expressed at about the same level (Fig. 1B, arrowheads). This pattern is similar to that observed in the early mouse blastocyst (Plusa et al., 2008).


Human hypoblast formation is not dependent on FGF signalling.

Roode M, Blair K, Snell P, Elder K, Marchant S, Smith A, Nichols J - Dev. Biol. (2011)

Human embryos segregate putative hypoblast by day 7 of development. Human embryos were thawed and cultured in standard IVF medium until they formed cavitated blastocysts, upon which they were moved to N2B27 medium. Embryos were fixed and immunostained for Oct4 (white), Nanog (green) and Gata6 (red). At day 6 of in vitro development (A) Nanog is restricted to a few cells within the embryo, whilst Gata6 and Oct4 are broadly expressed. Confocal images of two representative embryos with a maximum projection of the 3D reconstruction of the blastocyst are shown. (B) A single slice in a z stack of each of the two embryos shown in (A), indicating that Nanog and Gata6 can both be expressed highly in the same cell (arrowheads) or that Gata6 can be low as Nanog is high (arrows). (C and D) Embryos were developed to day 7 in vitro and immunostained for Nanog (green), Oct4 (white) and Gata4 (red) (C) or Sox17 (red) (D). In contrast to the stainings observed at day 6, Oct4 is restricted to the cells of the ICM. Gata4 and Sox17 are restricted to a subset of cells within the embryo, distinct from the Nanog positive cells: the putative hypoblast. In all embryos nuclei were counterstained with DAPI (blue). The total number of cells in each embryo is written in the top right hand corner of the panel.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3368271&req=5

f0005: Human embryos segregate putative hypoblast by day 7 of development. Human embryos were thawed and cultured in standard IVF medium until they formed cavitated blastocysts, upon which they were moved to N2B27 medium. Embryos were fixed and immunostained for Oct4 (white), Nanog (green) and Gata6 (red). At day 6 of in vitro development (A) Nanog is restricted to a few cells within the embryo, whilst Gata6 and Oct4 are broadly expressed. Confocal images of two representative embryos with a maximum projection of the 3D reconstruction of the blastocyst are shown. (B) A single slice in a z stack of each of the two embryos shown in (A), indicating that Nanog and Gata6 can both be expressed highly in the same cell (arrowheads) or that Gata6 can be low as Nanog is high (arrows). (C and D) Embryos were developed to day 7 in vitro and immunostained for Nanog (green), Oct4 (white) and Gata4 (red) (C) or Sox17 (red) (D). In contrast to the stainings observed at day 6, Oct4 is restricted to the cells of the ICM. Gata4 and Sox17 are restricted to a subset of cells within the embryo, distinct from the Nanog positive cells: the putative hypoblast. In all embryos nuclei were counterstained with DAPI (blue). The total number of cells in each embryo is written in the top right hand corner of the panel.
Mentions: We first examined human embryos at 6 days post-fertilisation. Nanog is confined to a few inner cells within the embryo (Fig. 1A). Gata6 and Oct4 are widely expressed throughout the embryo, with levels varying between individual cells, consistent with previous data (Cauffman et al., 2005; Cauffman et al., 2006; Chen et al., 2009; Kimber et al., 2008). Some inner cells exhibit high levels of Nanog and low levels of Gata6 (Fig. 1B, arrows), whilst in other cells both markers are expressed at about the same level (Fig. 1B, arrowheads). This pattern is similar to that observed in the early mouse blastocyst (Plusa et al., 2008).

Bottom Line: These differentiation processes are associated with restricted expression of key transcription factors (Cdx2, Oct4, Nanog and Gata6).However, the formation of hypoblast in the human is apparently not dependent upon FGF signalling, in contrast to rodent embryos.Nonetheless, the persistence of Nanog-positive cells in embryos following treatment with FGF inhibitors is suggestive of a transient naïve pluripotent population in the human blastocyst, which may be similar to rodent epiblast and ES cells but is not sustained during conventional human ES cell derivation protocols.

View Article: PubMed Central - PubMed

Affiliation: Wellcome Trust Centre for Stem Cell Research, University of Cambridge, Cambridge CB2 1QR, UK.

Show MeSH