BRE-gal reporter activity in mouse embryos at pre-primitive streak and early primitive streak stages (E5.5–6.5).

<p>Wholemount X-gal staining of BRE-gal mouse embryos showed BRE-dependent Bmp signaling in extra-embryonic structures. A pre-primitive streak embryo (E5.5) is shown in (A), with a corresponding sagittal section (B). The plane of this section is slightly oblique. An early primitive streak embryo (E6.5) is shown in (C), with corresponding transverse sections through the (D1) extraembryonic and (D2) embryonic regions. The dashed lines in (C) indicate the plane of the sections shown in (D1, D2). All sections are slightly enlarged with respect to the corresponding image of the whole embryo. Sections are 10 µm thickness. Abbreviations: de, decidua; e, embryonic region; ec, ectoplacental cone; eec, embryonic ectoderm; pc, proamniotic cavity; x, extraembryonic region; xec, extraembryonic ectoderm; xen, extraembryonic visceral endoderm. Scalebar 200 µm.