Reinitiation of meiosis in starfish oocytes requires an increase in nuclear Ca2+.
Here we report that an increase in nuclear Ca2+ is hormonally regulated and is required for reinitiation of meiosis in starfish oocytes. We have shown in Asterina pectinifera that a Ca2+ transient and a baseline increase of Ca2+ occur both in the cytoplasm and in the nucleus. These increases are in response to 1-methyladenine (1-MA), the hormone responsible for the induction of meiotic maturation. The Ca2+ transients are not necessary for the reinitiation of meiosis. However, blocking the baseline increase in nuclear Ca2+ blocks both the nuclear envelope breakdown (NEBD) and the continuation of meiosis.
Santella
L
L
Laboratory of Cell Biology, Stazione Zoologica, Napoli, Italy.
Kyozuka
K
K
D000225:Adenine / Q000031:analogs & derivatives / Q000494:pharmacology; D000818:Animals; D002118:Calcium / Q000378:metabolism*; D002467:Cell Nucleus / Q000187:drug effects / Q000378:metabolism* / Q000648:ultrastructure; D003593:Cytoplasm / Q000187:drug effects / Q000378:metabolism; D004533:Egtazic Acid / Q000031:analogs & derivatives / Q000494:pharmacology; D005260:Female; D066298:In Vitro Techniques; D007700:Kinetics; D008540:Meiosis / Q000187:drug effects; D008854:Microscopy, Electron; D008856:Microscopy, Fluorescence; D009865:Oocytes / Q000166:cytology* / Q000378:metabolism* / Q000648:ultrastructure; D013215:Starfish; D013997:Time Factors
C008407:1-methyladenine; D004533:Egtazic Acid; D000225:Adenine; C025603:1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid; D002118:Calcium