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30 Cards in this Set
- Front
- Back
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β-catenin (Micromeres) |
β-catenin activates Wnt8 expression in micromeres |
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Veg2 induction |
Delta on micromeres activates Notch in adjacent Veg2 cells (juxtacrine) to induce them to be secondarymesenchyme. |
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Gastrulation |
Mesoderm and Endoderm cells migrate to the center of the embryo. |
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Cell and Tissue Movements During Gastrulati |
InvaginationInvolutionIngressionDelaminationEpiboly |
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blastocoel |
At the 4-cell stage and thereafter, a cavity forms in the centerof the embryo. |
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Primary mesenchyme cells, derived from skel. micromeres |
ingress into blastocoel cavity.-epithelial to mesenchymal transition. |
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archenteron |
Vegetal plate cells (meso. and endo.) invaginate -forms the blastopore. |
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C. elegans Early Development |
Founder Cells: AB: skin, neurons (ectoderm) MS: muscle (mesoderm) E: gut (endoderm) C, D: muscle (mesoderm) Stem cell: P4 lineage (germline). |
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Cytoplasmic polarity |
Sperm pronucleus cause posterior localization of PAR-2 PAR-3 localizes away from sperm pronucleus PAR-2 and PAR-3 ensure that PAR-1 is localized posteriorly. MEX-5 reorganized to the anterior. |
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Dorsal-ventral axis |
When AB divides, the ABp daughter displaces the P1 cell to theFuture ventral. ABp defines the dorsal, whereas the P1 cell daughter EMSDefines the ventral. |
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skn-1 mutant |
EMS forms skin instead of muscle and gut.-SKN-1 required for EMS fate. |
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pal-1 mutant |
C and D-derived cell types not formed. -PAL-1 required for P2, C, D fate. -regulated by MEX-3, which inhibits pal-1 translation innon-P2, C, D cells. |
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pie-1 mutant |
germline does not form.-PIE-1 required for germline (P stem cell) fate |
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P2 Induces ABp |
ABa forms neurons, skin and pharynx.ABp forms neurons, skin. P2-ABp signaling requires aNotch signaling pathway.APX-1: Delta (on P2)GLP-1: Notch (on ABp and ABa) |
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P2 also induces the E cell fate. |
Separate P2 and EMS. -EMS divides to form two MS cells instead ofan E and an MS cell. -A signal from P2 polarizes EMS and results inthe generation of E and MS. MOM-2, Wnt, expressed by P2. MOM-5, Frizzled, expressed by EMS. |
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bicoid Mutant
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Two-tailed. Head and thorax replaced by a tail structure
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nanos Mutant
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No abdominal (posterior) structures
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Maternal-Effect genes
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bicoid controls anterior specification
Dynein (a - -end motor). hunchback specifies anterior structures nanos controls posterior specification Kinesin(a + -end motor) caudal specifies posterior structures |
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Segment Polarity |
Wnt-hedghog boundary defines segment boundary |
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AXIS FORMATION |
The organizer:frogs: dorsal blastopore lip organizer. birds: primitive streak. fish: embryonic shield |
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VegT |
a Txn factor, autonomously specifies vegetal (endo.)fates. Vg1/TGFbeta induces marginal zone cells to form mesoderm. |
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Nieuwkoop center |
gray crescent marks the site of the future organizer initiate gastrulation (invaginatingEndoderm, bottle cells) Nieuwkoop induces DBL |
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Block cortical rotation with UV |
-“belly piece”, no dorsal. |
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Manually induce secondary cortical rotation after first and in theOpposite direction |
“Twinning” |
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knockdown of b-catenin |
no dorsalinduction. |
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overactivation of GSK-3 |
blocks dorsal induction |
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Dishevelled |
vegetal cortex, inhibits GSK-3 and b-cateninis active |
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Xenopus Paracrine systems |
TGFβ (BMP) - A vegetally-derived signal that induces ventralAnd mesodermal fates.
Wnt - signal coming from the ventral surface that inducesventral cell fates. no Wnt signal, neural tissue forms. |
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Noggin, Chordin, Nodal-related 3 |
perturb BMP4signaling in the dorsal regions Follistatin binds to receptor |
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GASTRULATION birds |
Epiblast cells delaminate into subgerminal cavity to formpolyinvagination islands or the primary hypoblast. |
