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Interaction of cell cycle kinases, microtubules, and chromatin in ascidian oocytes during meiosis
Author(s) -
Marino Marcella,
Wilding Martin,
Dale Brian
Publication year - 2000
Publication title -
molecular reproduction and development
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.745
H-Index - 105
eISSN - 1098-2795
pISSN - 1040-452X
DOI - 10.1002/(sici)1098-2795(200006)56:2<155::aid-mrd6>3.0.co;2-1
Subject(s) - maturation promoting factor , biology , microbiology and biotechnology , meiosis , meiosis ii , mapk/erk pathway , metaphase , kinase , oocyte , prophase , cell cycle , cyclin dependent kinase 1 , cell , genetics , embryo , chromosome , gene
We used kinase assays and confocal microscopy to study the interaction of cell cycle proteins with microtubule organising centres (MTOC) and chromatin in ascidian oocytes during meiosis. The activity of maturation promoting factor (MPF) and mitogen activated protein kinase (MAPK) appear not to be correlated in control oocytes. MPF activity peaks during metaphase I and II of the meiotic cell cycle whereas the activity of MAPK peaks at telophase I and is subsequently degraded to remain at low levels for the remainder of meiosis. The protein synthesis inhibitor emetine induces the degradation in MPF activity in unfertilized metaphase‐I (M‐I) oocytes, while MAPK is unaffected. Emetine does not alter the activities of these cell cycle kinases in fertilized oocytes during meiosis I but MPF activity remains low while MAPK activity is high for an elongated time period and oocytes do not complete meiosis I. Emetine induces maternal MTOC duplication in unfertilized M‐I oocytes and prevents sperm aster growth in fertilized oocytes, but it does not alter the M‐I meiotic apparatus in unfertilized oocytes. These experiments suggest that neither MPF alone nor emetine‐sensitive proteins are responsible for M‐I arrest in ascidian oocytes, MAPK may ensure this stability. In addition, we showed that the maternal MTOC is present at M‐I but suppressed from duplicating in an emetine‐sensitive manner. Mol. Reprod. Dev. 56:155–162, 2000. © 2000 Wiley‐Liss, Inc.