BIOL130 Lecture Notes - Blastocyst, Blastocoel, Trophoblast
28 Jan 2013
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Sperm receptor: species specificty antibody blockage no zp3 binding of fertilized eggs. B-1,4 galactosyltranferase: acrosome reaction / zp penetration. Outer acrosomal membrane fuses w/ sperm membrane. Requires intracellular ca rise, zp3 binding, and c 4. Acrosin release not requried but helps disperse other proteases. Zp2 binding keeps sperm in place: membrane fusion. Mediated by egg integrin + sperm fertilin (adam-family fusion protein: cortical reaction. Calcium waves release cortical granules triggered by plc (in sperm: block to polyspermy, egg activated, meisois 2 completes, pronuclei (male and female) form. Embryo size does not change: compaction - morula. E-cadherin makes tight junctions on outer surface and creates a polarity (outer vs. inner) Cadherin is essential for differentiation and zygote development (some maternal cadherin is present, but it quickly runs out: trophoectoderm/inner cell mass. Regulates fgf4 transcrption in icm --> stimulates ted prolif. Fgf4: blastocyst expansion formation of fluid-filled blastocoel requires ted-mediated fluid transport (atp driven) Ted secrete strypsin blastocoel convulsions allow hatching strypsin.
