Shao H, Li R, Ma C, Chen E, Liu XJ.

MOP89973 Canadian Institutes of Health Research

	Figure 1. Karyotyping Xenopus oocytes during meiosis. (A) Schematic illustration of karyotyping Xenopus oocytes: two mini-cells are shown, one without a polar body (left, with overhead light) and the other with a first polar body (pb) still attached (right, photographed with transmission light). (B) Representative images of oocytes at metaphase I, anaphase I, cytokinesis, and metaphase II. The graph summarizes karyotypes of 94 oocytes (>10 experiments) analyzed between 115 and 145 min after GVBD. Numbers are used to facilitate chromosome counting, not to imply chromosome identities. The inset shows two dyads. (C) A representative karyotype image of oocytes injected with xSecurin-DM mRNA at 3 h after GVBD. The inset depicts a single bivalent. (D) Metaphase I (left) and metaphase II (right) chromosome spreads double-stained with Sytox orange and anti–Aur-B. In metaphase I spread, each bivalent (inset) has two pairs of Aur-B foci representing two maternal and two paternal sister centromeres, respectively. In metaphase II spread, each dyad (inset) has two closely associated Aur-B foci representing the two sister centromeres. (E) Metaphase II oocytes before (left) and 15 min after (right) prick activation (n = 7). Note that metaphase II chromosome dyads in these oocytes have more elongated arms than those shortly after polar body emission (see B). Anaphase II spread consists of two sets of sister chromatids (arrow). Bars: (insets) 10 µm.
	Figure 2. Bivalent-to-dyad transition in the absence of spindle microtubules. (A) An oocyte injected with mChe-H2B and EMTB-3GFP was imaged 1 h after GVBD (left). Nocodazole was added to the imaging well (3.3 µM in OR2), followed by time-lapse imaging for >2 h. Shown on the right are images 4 min after the addition of nocodazole. The schematic depicts the position of spindle/chromosomes in live oocyte before (left) and after (right) nocodazole treatment. See Video 1 for the entire series. The images are representative of three movies. (B) 1 h after GVBD, the oocytes were placed in OR2 plus 3.3 µM nocodazole. Oocytes were karyotyped in the presence of 3.3 µM nocodazole such that the mini-cells burst onto glass slides either <100 min after GVBD (metaphase I) or 3 h after GVBD (metaphase II, inset showing one dyad). The slides were stained with Sytox orange and anti–Aur-B. (C) Oocytes were treated as described in B, except that all oocytes were karyotyped between 110 and 130 min after GVBD. The graph summarizes three experiments (n = 25). (D) Control oocytes, or oocytes treated with nocodazole, were lysed individually at germinal vesicles (no progesterone) 2 h after the addition of progesterone but before GVBD (GV′), at GVBD (BD), or at the indicated time after GVBD. Extracts were immunoblotted with anti–cyclin B2. Each lane represents half the extract from one oocyte. The red box indicates time of metaphase I–to–anaphase I transition in frog oocytes. Data are representative of three experiments. (E) Control oocytes, nocodazole-treated oocytes (from GVDB, 1 h), and oocytes injected with xSecurin-DM mRNA were selected individually at 3 h after GVBD. The oocytes were either lysed immediately (metaphase II) or 10 min after being pricked. The resulting extracts were subjected to immunoblotting with anti–cyclin B2, followed by anti–α-tubulin of the same membrane. Note the residual cyclin B2 signal on the α-tubulin blot. Data shown are representative of five experiments.
	Figure 3. Colcemid-treated oocytes are arrested in metaphase II. (A) A representative colcemid-treated (50 µM) oocyte karyotyped 3 h after GVBD, stained with Sytox orange and anti–Aur-B (n = 9). The inset depicts a single dyad. (B) A colcemid-treated (50 µM) oocyte was imaged live, beginning at 3 h after GVBD (00:00). The oocyte was then exposed to UV excitation until the end of the imaging experiment. The oocyte was pricked immediately after the scan at 00:16. The schematic depicts position of the spindle/chromosomes in a live oocyte. Note that the egg chromosomes at 00:53 would be forming the female pronucleus and be beyond the depth of the confocal imaging system. See Video 2 for the entire series.
	Figure 4. Monopolar Aur-B122R oocytes underwent anaphase I and anaphase II. (A, top) Time series (side view) of a representative oocyte injected with wild-type Aur-B (as control), depicting metaphase I (00:04), anaphase I (00:08 and 00:12), and cytokinesis (00:14 and 00:18). See Video 3 for the entire series. The far right image (metaphase II) was from a different oocyte in the same experiment. (A, bottom) Time series (side view) of a representative Aur-B122R mRNA-injected oocyte exhibiting a monopolar spindle (00:14), monopolar anaphase (00:17 and 00:26), and metaphase II with another monopolar spindle (01:06). Cross-sectional views of selective time points are also shown to depict the transient membrane protrusion (00:26, arrows). The schematic depicts the position of the monopolar spindle/chromosomes in live oocyte. See Video 4 for the entire series (n = 9). (B, top) Time series (side view) of a control oocyte undergoing meiosis I, via imaging chromosomes (H2B) and the spindle poles (Alexa Fluor 488 anti–Aur-A). See Video 5 for the entire series (n = 9). (B, bottom) Time series (side view) of a representative monopolar Aur-B122R oocyte, depicting chromosome poleward movement (00:15 and 00:27) followed by the formation of another monopolar (meiosis II) spindle (00:48). See Video 6 for the entire series (n = 13). (C) Karyotype analyses of monopolar Aur-B122R oocytes at metaphase I (top), metaphase II (middle), and 15 min after prick activation (bottom). (D) Monopolar Aur-B122R oocytes were karyotyped between 110 and 145 min after GVBD. The graph summarizes >10 experiments (n = 72).
	Figure 5. Monopolar anaphase in STLC-treated oocytes. (A) Oocytes injected with mChe-H2B and EMTB-3GFP were incubated overnight with progesterone (control) or progesterone plus 2 µM STLC. Oocytes were imaged live. Shown are representative images (side view) of a control oocyte (left) and an STLC-treated oocyte (right). (B) Time series of an STLC (2 µM)-treated oocyte during metaphase I–to–anaphase I transition (00:00–00:17), and arrested at metaphase II (02:18; n = 5). See Video 8 for the entire series. (C) Typical karyotype image of STLC-treated oocytes 3 h after GVBD. The inset depicts a dyad.

Batiha, Evidence that the spindle assembly checkpoint does not regulate APC(Fzy) activity in Drosophila female meiosis. 2012, Pubmed

Batiha, Evidence that the spindle assembly checkpoint does not regulate APC(Fzy) activity in Drosophila female meiosis. 2012, Pubmed
Bayaa, The classical progesterone receptor mediates Xenopus oocyte maturation through a nongenomic mechanism. 2000, Pubmed , Xenbase
Belloc, A deadenylation negative feedback mechanism governs meiotic metaphase arrest. 2008, Pubmed , Xenbase
Benink, Concentric zones of active RhoA and Cdc42 around single cell wounds. 2005, Pubmed , Xenbase
Brunet, Kinetochore fibers are not involved in the formation of the first meiotic spindle in mouse oocytes, but control the exit from the first meiotic M phase. 1999, Pubmed
Clark-Maguire, Localization of the mei-1 gene product of Caenorhaditis elegans, a meiotic-specific spindle component. 1994, Pubmed
Clute, Regulation of the appearance of division asynchrony and microtubule-dependent chromosome cycles in Xenopus laevis embryos. 1995, Pubmed , Xenbase
Eichenlaub-Ritter, Nocodazole sensitivity, age-related aneuploidy, and alterations in the cell cycle during maturation of mouse oocytes. 1989, Pubmed
Ferrell, The biochemical basis of an all-or-none cell fate switch in Xenopus oocytes. 1998, Pubmed , Xenbase
Furuno, Suppression of DNA replication via Mos function during meiotic divisions in Xenopus oocytes. 1994, Pubmed , Xenbase
Gall, Examining the contents of isolated Xenopus germinal vesicles. 2010, Pubmed , Xenbase
Gerhart, Cell cycle dynamics of an M-phase-specific cytoplasmic factor in Xenopus laevis oocytes and eggs. 1984, Pubmed , Xenbase
Graf, Genetics of Xenopus laevis. 1991, Pubmed , Xenbase
Hara, A cytoplasmic clock with the same period as the division cycle in Xenopus eggs. 1980, Pubmed , Xenbase
Hodges, Simultaneous analysis of chromosomes and chromosome-associated proteins in mammalian oocytes and embryos. 2002, Pubmed
Homer, Mad2 is required for inhibiting securin and cyclin B degradation following spindle depolymerisation in meiosis I mouse oocytes. 2005, Pubmed
Hu, Cell polarization during monopolar cytokinesis. 2008, Pubmed
Kolano, Error-prone mammalian female meiosis from silencing the spindle assembly checkpoint without normal interkinetochore tension. 2012, Pubmed
Leblanc, The small GTPase Cdc42 promotes membrane protrusion during polar body emission via ARP2-nucleated actin polymerization. 2011, Pubmed , Xenbase
LeMaire-Adkins, Lack of checkpoint control at the metaphase/anaphase transition: a mechanism of meiotic nondisjunction in mammalian females. 1997, Pubmed
Liu, Oocyte isolation and enucleation. 2006, Pubmed , Xenbase
Ma, Biphasic activation of Aurora-A kinase during the meiosis I- meiosis II transition in Xenopus oocytes. 2003, Pubmed , Xenbase
Ma, Cdc42 activation couples spindle positioning to first polar body formation in oocyte maturation. 2006, Pubmed , Xenbase
Matthews, ZYG-9, a Caenorhabditis elegans protein required for microtubule organization and function, is a component of meiotic and mitotic spindle poles. 1998, Pubmed
Murray, Dominoes and clocks: the union of two views of the cell cycle. 1989, Pubmed
Musacchio, The spindle-assembly checkpoint in space and time. 2007, Pubmed
Nagaoka, Oocyte-specific differences in cell-cycle control create an innate susceptibility to meiotic errors. 2011, Pubmed
Ohan, RHO-associated protein kinase alpha potentiates insulin-induced MAP kinase activation in Xenopus oocytes. 1999, Pubmed , Xenbase
Ohsumi, Meiosis-specific cell cycle regulation in maturing Xenopus oocytes. 1994, Pubmed , Xenbase
Peter, The APC is dispensable for first meiotic anaphase in Xenopus oocytes. 2001, Pubmed , Xenbase
Pines, Mitosis: a matter of getting rid of the right protein at the right time. 2006, Pubmed
Rieder, Anaphase onset in vertebrate somatic cells is controlled by a checkpoint that monitors sister kinetochore attachment to the spindle. 1994, Pubmed
Rieder, The checkpoint delaying anaphase in response to chromosome monoorientation is mediated by an inhibitory signal produced by unattached kinetochores. 1995, Pubmed
Schultz, Biochemical studies of mammalian oogenesis: Protein synthesis during oocyte growth and meiotic maturation in the mouse. 1977, Pubmed
Shao, Aurora B regulates spindle bipolarity in meiosis in vertebrate oocytes. 2012, Pubmed , Xenbase
Skoufias, S-trityl-L-cysteine is a reversible, tight binding inhibitor of the human kinesin Eg5 that specifically blocks mitotic progression. 2006, Pubmed
Sluder, Role of spindle microtubules in the control of cell cycle timing. 1979, Pubmed
Soewarto, Consequences of non-extrusion of the first polar body and control of the sequential segregation of homologues and chromatids in mammalian oocytes. 1995, Pubmed
Taieb, Activation of the anaphase-promoting complex and degradation of cyclin B is not required for progression from Meiosis I to II in Xenopus oocytes. 2001, Pubmed , Xenbase
Tian, Identification of XPR-1, a progesterone receptor required for Xenopus oocyte activation. 2000, Pubmed , Xenbase
Verlhac, Asymmetric division in mouse oocytes: with or without Mos. 2000, Pubmed
von Dassow, Action at a distance during cytokinesis. 2009, Pubmed , Xenbase
Wassarman, Meiotic maturation of mouse oocytes in vitro: inhibition of maturation at specific stages of nuclear progression. 1976, Pubmed
Zhang, Polar body emission requires a RhoA contractile ring and Cdc42-mediated membrane protrusion. 2008, Pubmed , Xenbase
Zou, Identification of a vertebrate sister-chromatid separation inhibitor involved in transformation and tumorigenesis. 1999, Pubmed , Xenbase