CENP-E is an essential kinetochore motor in maturing oocytes and is masked during Mos-dependent, cell cycle arrest at metaphase II

CENP-E is an essential kinetochore motor in maturing oocytes and is masked during Mos-dependent, cell cycle arrest at metaphase II

^*ABL-Basic Research Program, National Cancer Institute–Frederick Cancer Research and Development Center, P.O. Box B, Frederick, MD 21702-1201; ^§Department of Biological Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD 21205; and ^‖Ludwig Institute for Cancer Research and University of California at San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0660

Contributed by George F. Vande Woude

Abstract

CENP-E, a kinesin-like protein that is known to associate with kinetochores during all phases of mitotic chromosome movement, is shown here to be a component of meiotic kinetochores as well. CENP-E is detected at kinetochores during metaphase I in both mice and frogs, and, as in mitosis, is relocalized to the midbody during telophase. CENP-E function is essential for meiosis I because injection of an antibody to CENP-E into mouse oocytes in prophase completely prevented progression of those oocytes past metaphase I. Beyond this, CENP-E is modified or masked during the natural, Mos-dependent, cell cycle arrest that occurs at metaphase II, although it is readily detectable at the kinetochores in metaphase II oocytes derived from mos-deficient (MOS^−/−) mice that fail to arrest at metaphase II. This must reflect a masking of some CENP-E epitopes, not the absence of CENP-E, in meiosis II because a different polyclonal antibody raised to the tail of CENP-E detects CENP-E at kinetochores of metaphase II-arrested eggs and because CENP-E reappears in telophase of mouse oocytes activated in the absence of protein synthesis.

Footnotes

↵ † N.S.D. and T.C. contributed equally to this paper.
↵ ‡ Present address: P.O. Box 61 Yu Song, Science Town, Taejon, 305–380 Korea.
↵ ¶ Present address: Laboratory of Gene Transfer, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD 20892.
↵ ** To whom reprint requests should be addressed.
ABBREVIATIONS:

GV,

germinal vesicle;

MII,

metaphase II;

MI,

metaphase I;

CSF,

cytostatic factor;

MAPK,

mitogen-activated protein kinase;

MPF,

maturation promoting factor;

MT,

microtubule;

DAPI,

4′,6-diamidino-2-phenylindole