Fertilization and InsP3-induced Ca2+ release stimulate a persistent increase in the rate of degradation of cyclin B1 specifically in mature mouse oocytes
| dc.contributor.author | Marangos, Petros | en |
| dc.contributor.author | Carroll, John | en |
| dc.date.accessioned | 2015-11-24T16:33:24Z | |
| dc.date.available | 2015-11-24T16:33:24Z | |
| dc.identifier.issn | 0012-1606 | - |
| dc.identifier.uri | https://olympias.lib.uoi.gr/jspui/handle/123456789/7655 | |
| dc.rights | Default Licence | - |
| dc.subject | Fertilization | en |
| dc.subject | InsP3 | en |
| dc.subject | Mouse oocytes | en |
| dc.title | Fertilization and InsP3-induced Ca2+ release stimulate a persistent increase in the rate of degradation of cyclin B1 specifically in mature mouse oocytes | en |
| heal.abstract | Vertebrate oocytes proceed through meiosis I before undergoing a cytostatic factor (CSF)-mediated arrest at metaphase of meiosis II. Exit from MII arrest is stimulated by a sperm-induced increase in intracellular Ca2+. This increase in Ca2+ results in the destruction of cyclin B1, the regulatory subunit of cdk1 that leads to inactivation of maturation promoting factor (MPF) and egg activation. Progression through meiosis I also involves cyclin B1 destruction, but it is not known whether Ca2+ can activate the destruction machinery during MI. We have investigated Ca2+-induced cyclin destruction in MI and MII by using a cyclin B1-GFP fusion protein and measurement of intracellular Ca2+. We find no evidence for a role for Ca2+ in MI since oocytes progress through MI in the absence of detectable Ca2+ transients. Furthermore, Ca2+ increases induced by photorelease of InsP3 stimulate a persistent destruction of cyclin B1-GFP in MII but not MI stage oocytes. In addition to a steady decrease in cyclin B1-GFP fluorescence, the increase in Ca2+ stimulated a transient decrease in fluorescence in both MI and MII stage oocytes. Similar transient decreases in fluorescence imposed on a more persistent fluorescence decrease were detected in cyclin-GFP-injected eggs undergoing fertilization-induced Ca2+ oscillations. The transient decreases in fluorescence were not a result of cyclin B1 destruction since transients persisted in the presence of a proteasome inhibitor and were detected in controls injected with eGFP and in untreated oocytes. We conclude that increases in cytosolic Ca2+ induce transient changes in autofluorescence and that the pattern of cyclin B1 degradation at fertilization is not stepwise but exponential. Furthermore, this Ca2+-induced increase in degradation of cyclin B1 requires factors specific to mature oocytes, and that to overcome arrest at MII, Ca2+ acts to release the CSF-mediated brake on cyclin B1 destruction. | en |
| heal.access | campus | - |
| heal.fullTextAvailability | TRUE | - |
| heal.identifier.primary | http://dx.doi.org/10.1016/j.ydbio.2004.04.012 | - |
| heal.identifier.secondary | http://www.sciencedirect.com/science/article/pii/S0012160604002817 | - |
| heal.journalName | Dev Biol | en |
| heal.journalType | peer reviewed | - |
| heal.publicationDate | 2004 | - |
| heal.recordProvider | Πανεπιστήμιο Ιωαννίνων. Σχολή Επιστημών και Τεχνολογιών. Τμήμα Βιολογικών Εφαρμογών και Τεχνολογιών | el |
| heal.type | journalArticle | - |
| heal.type.el | Άρθρο Περιοδικού | el |
| heal.type.en | Journal article | en |
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