2-15-13_gametes

Rms cervix ulmann et al1990 sci am 262642 48 ru486

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Unformatted text preview: .(1990). Sci. Am. 262(6):42-48 RU486 and Progesterone progesterone RU486 RU486/mifepristone binds the progesterone receptor but does not activate signaling, thereby competing with progesterone. Sea Urchin Egg Structure Egg jelly produces molecules that attract sperm. Sperm must digest it. Gilbert, 9e, Fig. 4.4 Sea Urchin Egg Structure: Vitelline Envelope The vitelline envelope will be remodelled after fertilization to form the fertilization envelope Gilbert, 9e, Fig. 4.6 Mammalian Oocyte Structure Sperm bind to and digest through the zona pellucida. Purves et al, 6e, Fig. 43.2 The cumulus complex contains proteoglycans. Sperm must digest it. Mammalian Oocyte Structure pronucleus cumulus cells Gilbert, 9e, Fig. 4.7 The Zona Pellucida Paul Wassarman Stages of Oocyte Meiotic Arrest Oocytes have not completed meiosis when they are fertilized. Eggs have completed meiosis. Gilbert, 9e, Fig. 4.5 Stages of Oocyte Meiotic Arrest Gilbert, 9e, Fig. 4.5 Most mammalian and amphibian oocytes are arrested in metaphase II MPF and CSF: Yoshio Masui Maturation promoting factor (MPF) causes oocyte maturation; cytostatic factor causes arrest at metaphase II by preventing destruction of MPF Meiotic Maturation: MPF Micropipette Cytoplasm is extracted from a mature egg cell Extracted cytoplasm is injected into an oocyte Hardin et al., World of the Cell 8e, Fig. 19.34 Meiotic Maturation: MPF Meiosis is triggered Mature egg cell results Conclusion: MPF promotes maturation, but results in arrest at metaphase II Hardin et al., World of the Cell 8e, Fig. 19.34 MPF Activation cyclin Cdk Cdk-cyclin complex (INACTIVE) MPF consists of a cyclin and a cyclindependent kinase (Cdk) Hardin et al., World of the Cell 8e, Fig. 19.36 MPF Activation Cdk- MPF is active when the Cdk is appropriately phosphorylated Hardin et al., World of the Cell 8e, Fig. 19.36 MPF Activation Cdk- MPF is...
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