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Neurulation in the chick, after the node regresses. Typical vertebrate organization of the chick embryo (and >200 selector gene domains). “ Somatic mesoderm ”. “ Visceral mesoderm ”. Notochord. **Or wait until the embryo lifts off the yolk sac. Extra-embryonic membranes of the chick.
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Typical vertebrate organization of the chick embryo(and >200 selector gene domains) “Somatic mesoderm” “Visceral mesoderm” Notochord **Or wait until the embryo lifts off the yolk sac
Amnion and chorion: contain ectoderm and somatic mesodermYolk sac and allantois: contain enododerm and visceral mesoderm
Human or mouse embryo: pre-implantation stages gene expressionstarts 2 2. Blastocyst cavity formation 3. Cell sorting (hypo vs. epi) 1. compaction 4. hatching 128 cell Day 7-human Day 5.5-mouse
Mouse pre-implantation stages: compaction, apical-basal polarization, cleavage, blastocyst cavity formation 128-cell blastocyst compaction 128-cell blastocyst Compaction at the late 8-cell stage, With apical-basal polarization of cells
Oct4 gene expression in epiblast Human 128cell blastocyst before/during hatching “zona” Holding pipet Injection pipet Injection of ES cells into the blastocyst cavity Mouse embryonic stem cells (ES cells) from the inner cell mass, growing in a culture dish
Mouse transgenesis (insertion of a foreign gene into the mouse genome) Dr. Mario Capecchi-1984 Univ. of Utah (random) (e.g., GFP with promoter) FOSTERMOTHER non-homologous integration (2x) Green ES cells Gene for red fluorescent protein (RFP) Gene for green fluorescent protein (GFP) from jellyfish
Implantation of the human blastocyst in the uterine wall. Mouse implantation is also invasive, like human Syncytio- trophoblast Maternal tissue Uterine fluid
Role of the AVE (anterior visceral endoderm) in establishing the anterior-posterior axis of the mouse embryo Day 5.25 Day 5.5 Day 6.25 Cylindrical Symmetry Bilateral Symmetry Otx2 Anterior neural ectoderm A P Nodal, Vg1, Cripto (co-receptor For Nodal and Vg1) Endo-mesoderm induction or hypoblast Epiblast ectoderm Cerberus (anti-Nodal) Dkk (anti-Wnt) Lefty (anti-Nodal) Endo-mesoderm induction, Primitive streak Nodal, wnt, brachyury, fgf expressed