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Specific regulation of CENP‐E and kinetochores during meiosis I/meiosis II transition in pig oocytes
Author(s) -
Lee Jibak,
Miyano Takashi,
Dai Yanfeng,
Wooding Peter,
Yen Tim J.,
Moor Robert M.
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(200005)56:1<51::aid-mrd7>3.0.co;2-n
Subject(s) - kinetochore , biology , meiosis ii , microbiology and biotechnology , meiosis , anaphase , sister chromatids , cohesin , spindle checkpoint , spindle apparatus , oocyte , genetics , cell division , cell cycle , chromosome , cell , embryo , gene
To understand the mechanisms which regulate meiosis‐specific cell cycle and chromosome distribution in mammalian oocytes, the level and the localization of CENP‐E and the kinetochore number and direction on a half bivalent were examined during pig oocyte maturation. CENP‐E is a kinetochore motor protein whose intracellular level and localization are strictly regulated in the somatic cell cycle. The localizations of CENP‐E on meiotic chromosomes from diakinesis stage to anaphase I and at the spindle midzone at telophase I were shown by immunofluorescent confocal microscopy to be similar to those in somatic cells of pig and other species. Further, ultrastructural analysis revealed the presence of CENP‐E on fibrous corona and outer plate of kinetochores of the meiotic chromosomes. However, unlike mitosis, CENP‐E staining was continuously detected either at the spindle midzone or on the kinetochores of segregated chromosomes during the first polar body emission. Consistent with this, immunoblot analysis revealed that CENP‐E level remained high during meiosis I/meiosis II (MI/MII) transition and that some of CENP‐E survived through the transition even in cycloheximide‐treated oocytes in which cyclin B1 was completely degraded. Furthermore, examinations of CENP‐E signals in confocal microscopy and kinetochores in electron microscopy in MI and MII oocytes provide the cytological evidence in mammalian oocytes which suggests that each sister chromatid in a pair has its own kinetochore which localizes side‐by‐side so that two sister chromatids on a half bivalent are oriented toward and connected to the same pole in MI. Mol. Reprod. Dev. 56:51–62, 2000. © 2000 Wiley‐Liss, Inc.