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Event: 721

Key Event Title

A descriptive phrase which defines a discrete biological change that can be measured. More help

Disorganization, Meiotic Spindle

Short name
The KE short name should be a reasonable abbreviation of the KE title and is used in labelling this object throughout the AOP-Wiki. More help
Disorganization, Meiotic Spindle
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Biological Context

Structured terms, selected from a drop-down menu, are used to identify the level of biological organization for each KE. More help
Level of Biological Organization

Cell term

The location/biological environment in which the event takes place.The biological context describes the location/biological environment in which the event takes place.  For molecular/cellular events this would include the cellular context (if known), organ context, and species/life stage/sex for which the event is relevant. For tissue/organ events cellular context is not applicable.  For individual/population events, the organ context is not applicable.  Further information on Event Components and Biological Context may be viewed on the attached pdf. More help
Cell term
eukaryotic cell

Organ term

The location/biological environment in which the event takes place.The biological context describes the location/biological environment in which the event takes place.  For molecular/cellular events this would include the cellular context (if known), organ context, and species/life stage/sex for which the event is relevant. For tissue/organ events cellular context is not applicable.  For individual/population events, the organ context is not applicable.  Further information on Event Components and Biological Context may be viewed on the attached pdf. More help

Key Event Components

The KE, as defined by a set structured ontology terms consisting of a biological process, object, and action with each term originating from one of 14 biological ontologies (Ives, et al., 2017; Biological process describes dynamics of the underlying biological system (e.g., receptor signalling).Biological process describes dynamics of the underlying biological system (e.g., receptor signaling).  The biological object is the subject of the perturbation (e.g., a specific biological receptor that is activated or inhibited). Action represents the direction of perturbation of this system (generally increased or decreased; e.g., ‘decreased’ in the case of a receptor that is inhibited to indicate a decrease in the signaling by that receptor).  Note that when editing Event Components, clicking an existing Event Component from the Suggestions menu will autopopulate these fields, along with their source ID and description.  To clear any fields before submitting the event component, use the 'Clear process,' 'Clear object,' or 'Clear action' buttons.  If a desired term does not exist, a new term request may be made via Term Requests.  Event components may not be edited; to edit an event component, remove the existing event component and create a new one using the terms that you wish to add.  Further information on Event Components and Biological Context may be viewed on the attached pdf. More help
Process Object Action
spindle organization spindle decreased

Key Event Overview

AOPs Including This Key Event

All of the AOPs that are linked to this KE will automatically be listed in this subsection. This table can be particularly useful for derivation of AOP networks including the KE.Clicking on the name of the AOP will bring you to the individual page for that AOP. More help
AOP Name Role of event in AOP Point of Contact Author Status OECD Status
Tubulin binding and aneuploidy KeyEvent Francesco Marchetti (send email) Open for citation & comment Under Review

Taxonomic Applicability

Latin or common names of a species or broader taxonomic grouping (e.g., class, order, family) that help to define the biological applicability domain of the KE.In many cases, individual species identified in these structured fields will be those for which the strongest evidence used in constructing the AOP was available in relation to this KE. More help
Term Scientific Term Evidence Link
mouse Mus musculus High NCBI
human Homo sapiens High NCBI

Life Stages

An indication of the the relevant life stage(s) for this KE. More help
Life stage Evidence
All life stages High

Sex Applicability

An indication of the the relevant sex for this KE. More help
Term Evidence
Mixed High

Key Event Description

A description of the biological state being observed or measured, the biological compartment in which it is measured, and its general role in the biology should be provided. More help

The spindle is a cytoskeletal structure present in every eukaryotic cell that must form before cell division in order to properly separate chromosomes between daughter cells [Prosser and Pelletier, 2017]. The spindle organizes itself in a bipolar configuration within the cell prior to cell division. Several hundred proteins are required to assemble a functioning spindle, and microtubules are the most abundant components of the machinery. Although the function of the spindle is similar between mitotic and meiotic cells, spindle formation occurs via distinct mechanisms in female germ cells with respect to other cell types (including male germ cells) [Dumont and Desai, 2012]. This is because spindle formation is generally driven by centrioles, which are lacking in eggs [Szollosi et al., 1972; Manandhar et al., 2005]. The processes in somatic cells and male germ cells versus those operating in oocytes are briefly described below. In this key event, a bipolar spindle configuration is not achieved. Alternatively, there may be some spindle fibers that are not of the appropriate length, shape or structure to ensure that chromosomes can be properly aligned at metaphase and equally distributed between daughter cells.

Somatic cells and male germ cells:

The spindle of mitotic cells and that of male germ cells is organized by the centrosome which is composed by a pair of centrioles surrounded by an amorphous pericentriolar material containing more than 100 proteins [Andersen et al., 2003]. Many proteins that are involved in regulating microtubule dynamics and spindle assembly checkpoint (SAC) are contained in the centrosome. The centrosome is the principal microtubule-organizing center (MTOC) in mammalian cells and plays a major role in controlling microtubule dynamics, nucleation, and kinetochore–microtubule attachments [Conduit et al., 2015]. Errors in these processes lead to structural and functional abnormalities in the mitotic spindle [Rivera-Rivera and Saavedra, 2016].

Centriole and centrosome duplication are tightly coordinated with DNA replication, mitosis, and cytokinesis and play key roles in regulating transitions through the cell cycle [Chan, 2011]. The centrioles, cylindrical particles composed by nine triplet microtubules [Gogendeau et al., 2015], duplicate by forming daughter centrioles oriented at right angles with respect to the parent centrioles and then become surrounded by separate pericentriolar material during S-phase [Bettencourt-Dias and Glover, 2007]. Before mitosis, the newly formed centrosomes move to the opposite site of the nucleus and originate the two poles of the mitotic spindle [Kellog, 1989; Paintrand et a.l, 1992; Chavali et al., 2012]. Microtubules begin to radiate away from the centrosome and move toward the metaphase plate forming the mitotic spindle. During the assembly of the mitotic spindle, some microtubule fibers attach to the kinetochores on chromosomes, some radiate from the spindle poles toward the cell cortex and others extend past the metaphase plate forming a region of overlap with spindle fibers originating from the opposite centrosome [Cassimeris and Skibbens, 2003; Prosser and Pelletier, 2017]. Although a bipolar spindle can be formed in the absence of centrosomes, having too many centrosomes can result in a morphologically abnormal spindle and increase the chance of chromosome missegration [Hinchcliffe, 2014; Nigg and Holland, 2018].

Oocytes: In mammalian oocytes, centrioles and centrosomes are absent [Manandhar et al.. 2005] and the meiotic spindle starts its growth from several MTOCs that substitute for the conventional centrosome pair. A mouse oocyte can have up to 80 of these MTOCs [Dumont and Desai, 2012]. These MTOCs gradually coalesce and surround the chromosomes [Schuh and Ellenberg, 2007]. Then, microtubules elongate forming a barrel-shape bipolar spindle. Recent data suggest that MTOCs undergo a three-step decondensation and fragmentation process that facilitate their equal distribution to the spindle poles [Clift and Schuh, 2015]. In addition, recent evidence has shown the presence of actin fibers in the mammalian oocyte spindle that are important for ensuring proper chromosome segregation [Mogessie and Schuh, 2017]. Evidence is also emerging about differences in spindle assembly between rodent and human oocytes. Specifically, human oocytes may lack MTOCs and spindle assembly is mediated by chromosomes and the small guanosine triphosphate Ran [Holubcová et al., 2015].

How It Is Measured or Detected

A description of the type(s) of measurements that can be employed to evaluate the KE and the relative level of scientific confidence in those measurements.These can range from citation of specific validated test guidelines, citation of specific methods published in the peer reviewed literature, or outlines of a general protocol or approach (e.g., a protein may be measured by ELISA). Do not provide detailed protocols. More help

Spindle abnormalities in its structure and shape that can be recorded are: reduction of microtubule density, loss of barrel shape, monopolar or multipolar spindle, reduced distance between the poles [Ibanez et al., 2003; Shen et al., 2005; Eichenlaub-Ritter et al., 2007; Xu et al., 2012]. In addition, the use of enhanced polarizing microscope (Polscope/SpindleViewTM) allows the detection of reduction in the birefringency and reduced light retardance of the spindle, which are indicators of loss of organization, at doses below which spindle abnormalities are detected with more conventional immunofluorescence methods [Shen et al., 2005].

Spindle organization is generally assessed by fluorescent immunodetection of its components and confocal microscopy [Ibanez et al., 2003; Shen et al., 2005; Eichenlaub-Ritter et al., 2007; Xu et al., 2012]. Localization of proteins with a known role in spindle function is also assessed [Tong et al., 2002; Yao et al., 2004; Cao et al., 2005]. 3D live imaging of cells expressing fluorescent-tagged proteins provides the possibility to follow spindle function at high resolution, and to describe and measure abnormal parameters (e.g., spindle morphology, altered distance between the two poles, mono- or multipolarity) [Schuh and Ellenberg, 2007]. Enhanced polarizing microscope has also been used to assess spindle integrity in human oocytes during in vitro fertilization techniques [Wang et al., 2001a,b; Keefe et al., 2003; Staessen et al., 1997].

Domain of Applicability

A description of the scientific basis for the indicated domains of applicability and the WoE calls (if provided).  More help

All eukaryotic cells possess a spindle that must be properly organized for normal cellular division. Thus, this key event, although typically measured in mouse and human cells, is theoretically relevant to any eukaryotic cell type.


List of the literature that was cited for this KE description. More help

Andersen JS, Wilkinson CJ, Mayor T, Mortensen P, Nigg EA, Mann M. 2003. Proteomic characterization of the human centrosome by protein correlation profiling. Nature 426:570-574.

Bettencourt-Dias M, Glover DM. 2007. Centrosome biogenesis and function: centrosomics brings new understanding. Nat Rev Mol Cell Biol 8:451-463.

Cao Y-K, Zhong Z-S, Chen D-Y, Zhang G-X, Schatten H, Sun Q-Y. 2005. Cell cycle-dependent localization and possible roles of the small GTPase Ran in mouse oocyte maturation, fertilization and early cleavage. Reproduction 130:431-440.

Cassimeris L, Skibbens RV. 2003. Regulated assembly of the mitotic spindle: a perspective from two ends. Curr Issues Mol Biol 5:99-112.

Chan JY. 2011. A clinical overview of centrosome amplification in human cancers. Int J Biol Sci 7:1122-1144.

Chavali PL, Peset I, Gergely F. 2012. Centrosomes and mitotic poles: a recent liason?  Biochem Soc Trans 43:13-18.

Conduit PT, Wainman A, Raff JW. 2015. Centrosome function and assembly in animal cells. Nat Rev Mol Cell Biol 16:611-624.

Clift D, Schuh M. 2015. A three-step MTOC fragmentation mechanism facilitate bipolar spindle assembly in mouse oocytes. Nat Commun 6:7217, 10.1038/ncomm8217.

Dumont J, Desai A. 2012. Acentrosomal spindle assembly and chromosome segregation during oocyte meiosis. Trends Cell Biol 22: 241-249.

Eichenlaub-Ritter U, Winterscheidt U, Vogt E, Shen Y, Tinneberg HR, Sorensen R. 2007. 2-methoxyestradiol induces spindle aberrations, chromosome congression failure, and nondisjunction in mouse oocytes. Biol Reprod 76:784-793.

Gogendeau D, Guichard P, Tassin AM. 2015. Purification of centrosomes from mammalian cell lines. Methods Cell Biol. 129:171-189.

Hinchcliffe EH. 2014. Centrosomes and the art of mitotic spindle maintenance. Int Rev Cell Mol Biol 313:179-217.

Holubcová Z, Blayney M, Elder K, Schuh M. 2015. Error-prone chromosome-mediated spindle assembly favors chromosome segregation defects in human oocytes. Science 348:1143-1147.

Ibanez E, Albertini DF, Overstrom EW. 2003. Demecolcine-induced oocyte enucleation for somatic cell cloning: coordination between cell-cycle egress, kinetics of cortical cytoskeletal interactions, and second polar body extrusion. Biol Reprod 68:1249-1258.

Keefe D, Liu L, Wang W, Silva C. 2003. Imaging meiotic spindles by polarization light microscopy: principles and applications to IVF. Reprod Biomed Online 7:24–29.

Kellog DR. 1989. Centrosomes. Organizing cytoplasmic events. Nature 340:99-100.

Manandhar G, Schatten H, Sutovsky P. 2005. Centrosome reduction during gametogenesis and its significance. Biol Reprod 72:2-13.

Marchetti F, Massarotti A, Yauk CL, Pacchierotti F, Russo A. 2016. The adverse outcome pathway (AOP) for chemical binding to tubulin in oocytes leading to aneuploid offspring. Environ Mol Mutagen 57:87-113.

Mogessie B, Schuh M. 2017. Actin protects mammalian eggs against chromosome segregation errors. Science Aug 25;357(6353). pii: eaal1647.

Nigg EA, Holland AI. 2018. Once and only once: mechanisms of centriole duplication and their deregulation in disease. Nat Rev Mol Cell BIol 19:297-312.

Paintrand M, Moudjou M, Delacroix H, Bornens M. 1992. Centrosome organization and centriole architecture: their sensitivity to divalent cations. J Struct Biol 108:107–128.

Prosser SL, Pelletier L. 2017. Mitotic spindle assembly in animal cells: a fine balancing act. Nat Rev Mol Cell Biol 18:187-201.

Rivera-Rivera Y, Saavedra HI. Centrosome - a promising anti-cancer target. 2016. Biologics 10:167-176.

Schuh M, Ellenberg J. 2007. Self-organization of MTOCs replaces centrosome function during acentrosomal spindle assembly in live mouse oocytes. Cell 130:484-498.

Shen Y, Betzendahl I, Sun F, Tinneberg HR, Eichenlaub-Ritter U. 2005. Non-invasive method to assess genotoxicity of nocodazole interfering with spindle formation in mammalian oocytes. Reprod Toxicol 19:459-471.

Staessen C, Van Steirteghem AC. 1997. The chromosomal constitution of embryos developing from abnormally fertilized oocytes after intracytoplasmic sperm injection and and conventional in-vitro fertilization. Hum Reprod 12:321–327.

Szollosi D, Calarco P, Donahue RP. 1972. Absence of centrioles in the first and second meiotic spindles of mouse oocytes. J Cell Sci 11:521-541.

Tong C, Fan H-Y, Lian L, Li S-W, Chen D-Y, Schatten H, Sun Q-Y. 2002. Polo-like kinase-1 is a pivotal regulator of microtubule assembly during mouse oocyte meiotic maturation, fertilization, and early embryonic mitosis. Biol Reprod 67:546-554.

Wang WH, Meng L, Hackett RJ, Odenbourg R, Keefe DL. 2001a. The spindle observation and its relationship with fertilization after intracytoplasmic sperm injection in living human oocytes. Fertil Steril 75:348–353.

Wang WH, Meng L, Hackett RJ, Odenbourg R, Keefe DL. 2001b. Limited recovery of meiotic spindles in living human oocytes after cooling–rewarming observed using polarized light microscopy. Hum Reprod 16:2374–2378.

Xu XL, Ma W, Zhu YB, Wang C, Wang BY, An N, An L, Liu Y, Wu ZH, Tian JH. 2012. The microtubule-associated protein ASPM regulates spindle assembly and meiotic progression in mouse oocytes. PLoS One 7:e49303.

Yao LJ, Fan HY, Tong C, Chen DY, Schatten H, Sun QY. 2003. Polo-like kinase-1 in porcine oocyte meiotic maturation, fertilization and early embryonic mitosis. Cell Mol Biol 49:399-405.

Yao L-J, Zhong Z-S, Zhang L-S, Chen D-Y, Schatten H, Sun Q-Y. 2004. Aurora-A is a critical regulator of microtubule assembly and nuclear activity in mouse oocytes, fertilized eggs, and early embryos. Biol Reprod 70:1392-1399.