Movie demonstrates the uniquely human features of the human blastocyst stage embryo compared to to mouse.
Day6 : Blastocyst stage
Human blastocysts are used to study lineage specification and self-organization, which show species-specific features (Nature 2016, Deglincerti and Croft et al) relevant to understanding human embryonic stem cell biology and its therapeutic potential. Blastocysts were stained for markers of cell type: epiblast (OCT4, green), primitive endoderm (GATA6, red), all nuclei (DAPI/DNA, blue), Phalloidin, and trophectoderm (CDX2, aqua). Movie demonstrates the uniquely human features of the human blastocyst stage embryo compared to to mouse.
Day 8: Attachment and compaction of epiblast
The embryo attaches to the substrate, and the green (OCT4) cells of the inner cell mass sort away from the red (GATA6) primitive endoderm cells and compact to form the epiblast.
Day10 : Growth and epiblast cavitation (amniotic cavity) primitive endoderm yolk sac cavitation.
The epiblast (OCT4, green) cavitates, becomes a hollow sphere (enclosing the amniotic cavity); the primitive endoderm (GATA6, red) forms a layer on one side of the epiblast. On the other side of the primitive endoderm another typical cavity is formed, the yolk sac. Serial optical sections are used to travel through the embryo revealing cavities and cell populations one micrometer at a time.
Day12 : Inductive events and migratory epiblast cells and twinning
Unknown inductive events induce BRACHYURY (purple) expression in a few cells of the epiblast (OCT4, green). These cells migrate around the sides of the epiblast. This particular epiblast is the first ever observed twinning embryo at this stage of development: 2 amniotic cavities are seen formed instead of one.
Day14: Caldera formation by morphogenetic movement, the Day 6-14 time course of cell type (lineage) markers
We don’t understand what happens between day 12 and 14. But extensive morphogenetic movement creates a caldera or crater shape.
Soundtrack: The Man in Me, Bob Dylan
