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

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 ref lect 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.

Under arrest: cytostatic factor (CSF)-mediated metaphase arrest in vertebrate eggs

“…This suggests that one of the functions of active MAPK on kinetochores during mitosis is to regulate the interaction of CENP-E with microtubules and monitor mitotic progression. Inasmuch as CENP-E is essential for the spindle assembly checkpoint (Abrieu et al 2000), CENP-E is a possible target for CSF arrest, because CSFarrested spindles in both Xenopus and mouse eggs have been reported to have certain CENP-E epitopes masked compared with spindles in meiosis I or mitosis (Duesbery et al 1997). In addition, these epitopes are unmasked in oocytes from mos −/− mice, suggesting that CENP-E is phosphorylated downstream of Mos activity during meiosis II.…”

“…In the maturing oocyte, these spindles are organized in the absence of centrioles, and ␥-tubulin-staining foci are not found at the spindle poles (McKim and Hawley 1995;Waters and Salmon 1995;Heald et al 1996;Matthies et al 1996). Rather, chromosomes themselves have been suggested to play a role in organizing microtubules and the meiotic spindle through regulation of microtubule-associated proteins and kinesin-like microtubule motors (Hatsumi and Endow 1992;Theurkauf and Hawley 1992;McKim and Hawley 1995;Waters and Salmon 1995;Matthies et al 1996;Duesbery et al 1997;Giunta et al 2002;Lefebvre et al 2002). It has been suggested that one of the targets of CSF activity during the establishment of CSF arrest is microtubule-associated proteins important for the establishment of the metaphase spindle (Duesbery et al 1997;Lefebvre et al 2002).…”

“…Rather, chromosomes themselves have been suggested to play a role in organizing microtubules and the meiotic spindle through regulation of microtubule-associated proteins and kinesin-like microtubule motors (Hatsumi and Endow 1992;Theurkauf and Hawley 1992;McKim and Hawley 1995;Waters and Salmon 1995;Matthies et al 1996;Duesbery et al 1997;Giunta et al 2002;Lefebvre et al 2002). It has been suggested that one of the targets of CSF activity during the establishment of CSF arrest is microtubule-associated proteins important for the establishment of the metaphase spindle (Duesbery et al 1997;Lefebvre et al 2002). Protein synthesis is essential for the establishment of the meiotic spindle in meiosis I or II, and treatment of GVBD oocytes with the protein synthesis inhibitor cycloheximide (CHX) causes them to enter interphase instead of proceeding into meiosis II (Wasserman and Masui 1975;Gerhart et al 1984;Kobayashi et al 1991;Roy et al 1991;Huchon et al 1993;Furuno et al 1994).…”

Starfish andXenopusoocyte maturation

“…One of the proteins responsible for the II metaphase arrest is the CENP-E, a kinetochore motor, which is probably masked during the arrest (Duesbery et al 1997). A comparison between starfish and Xenopus oocyte maturation is reported in Figure 3.…”

Molecular insights into mechanisms regulating faithful chromosome separation in female meiosis

“…109 For the latter role, Bub1 may function through controlling Shugoshin (see below) localization according to results obtained from mitosis. 61,62 CENP-E function is essential for meiosis I in pig, 110 mouse, rat and frog, 111,112 since it is a binding partner of BubR1. The localization of MAP kinase kinase (MEK) and MAP kinase is similar to some spindle checkpoint proteins [113][114][115][116][117][118] in oocytes.…”