Biol Reprod. April 1, 2008; 78 (4):
Ca2+ homeostasis regulates Xenopus oocyte maturation.
Sun L , Hodeify R , Haun S , Charlesworth A , MacNicol AM , Ponnappan S , Ponnappan U , Prigent C , Machaca K .
AbstractIn contrast to the well-defined role of Ca2+ signals during mitosis, the contribution of Ca2+ signaling to meiosis progression is controversial, despite several decades of investigating the role of Ca2+ and its effectors in vertebrate oocyte maturation. We have previously shown that during Xenopus oocyte maturation, Ca2+ signals are dispensable for entry into meiosis and for germinal vesicle breakdown. However, normal Ca2+ homeostasis is essential for completion of meiosis I and extrusion of the first polar body. In this study, we test the contribution of several downstream effectors in mediating the Ca2+ effects during oocyte maturation. We show that calmodulin and calcium-calmodulin-dependent protein kinase II (CAMK2) are not critical downstream Ca2+ effectors during meiotic maturation. In contrast, accumulation of Aurora kinase A (AURKA) protein is disrupted in cells deprived of Ca2+ signals. Since AURKA is required for bipolar spindle formation, failure to accumulate AURKA may contribute to the defective spindle phenotype following Ca2+ deprivation. These findings argue that Ca2+ homeostasis is important in establishing the oocyte''s competence to undergo maturation in preparation for fertilization and embryonic development.
Pubmed Id: 18094360Article link: Biol Reprod.
AG13081 NIA NIH HHS, GM-61829 NIGMS NIH HHS , HD35688 NICHD NIH HHS , R01 GM061829-07 NIGMS NIH HHS , R01 GM061829-08 NIGMS NIH HHS , R01 HD035688-08A2 NICHD NIH HHS , RR20146 NCRR NIH HHS