Symmetry breaking in mouse oocytes requires transient F-actin meshwork destabilization

Azoury, Jessica; Lee, Karen Wingman; Georget, Virginie; Hikal, Pascale; Verlhac, Marie‐Hélène

doi:10.1242/dev.060269

Cited by 97 publications

(68 citation statements)

References 27 publications

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“…Actin transcript levels have been observed to decrease in this manner during meiotic maturation of human oocytes (Steuerwald et al, 2001). Tubulin protein levels fluctuate during meiosis I, increasing at GVB and MI stages, and then decreasing in MII (Figure 1C, D), as has been observed (Azoury et al, 2011). Thus, anillin transcript and protein are present during meiotic maturation of the mouse oocyte.…”

Section: Resultssupporting

confidence: 78%

Anillin localization suggests distinct mechanisms of division plane specification in mouse oogenic meiosis I and II

Sharif

Fadero

Maddox

2015

Gene Expression Patterns

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Anillin is a conserved cytokinetic ring protein implicated in actomyosin cytoskeletal organization and cytoskeletal-membrane linkage. Here we explored anillin localization in the highly asymmetric divisions of the mouse oocyte that lead to the extrusion of two polar bodies. The purposes of polar body extrusion are to reduce the chromosome complement within the egg to haploid, and to retain the majority of the egg cytoplasm for embryonic development. Anillin's proposed roles in cytokinetic ring organization suggest that it plays important roles in achieving this asymmetric division. We report that during meiotic maturation, anillin mRNA is expressed and protein levels steadily rise. In meiosis I, anillin localizes to a cortical cap overlying metaphase I spindles, and a broad ring over anaphase spindles that are perpendicular to the cortex. Anillin is excluded from the cortex of the prospective first polar body, and highly enriched in the cytokinetic ring that severs the polar body from the oocyte. In meiosis II, anillin is enriched in a cortical stripe precisely coincident with and overlying the meiotic spindle midzone. These results suggest a model in which this cortical structure contributes to spindle re-alignment in meiosis II. Thus, localization of anillin as a conserved cytokinetic ring marker illustrates that the geometry of the cytokinetic ring is distinct between the two oogenic meiotic cytokineses in mammals.

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Section: Resultssupporting

confidence: 78%

Anillin localization suggests distinct mechanisms of division plane specification in mouse oogenic meiosis I and II

Sharif

Fadero

Maddox

2015

Gene Expression Patterns

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“…who showed that the changes in density and dynamics of actin filaments were concomitant with the increase in nuclear permeability just before GVBD 45 . Luo et al .…”

Section: Discussionmentioning

confidence: 98%

Regulation of GVBD in mouse oocytes by miR-125a-3p and Fyn kinase through modulation of actin filaments

Grossman

Har-Paz

Gindi

et al. 2017

Sci Rep

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Meiotically arrested oocytes are characterized by the presence of the nuclear structure known as germinal-vesicle (GV), the breakdown of which (GVBD) is associated with resumption of meiosis. Fyn is a pivotal factor in resumption of the first meiotic division; its inhibition markedly decreases the fraction of oocytes undergoing GVBD. Here, we reveal that in mouse oocytes Fyn is post-transcriptionally regulated by miR-125a-3p. We demonstrate that in oocytes resuming meiosis miR-125a-3p and Fyn exhibit a reciprocal expression pattern; miR-125a-3p decreases alongside with an increase in Fyn expression. Microinjection of miR-125a-3p inhibits GVBD, an effect that is markedly reduced by Fyn over-expression, and impairs the organization of the actin rim surrounding the nucleus. Lower rate of GVBD is also observed in oocytes exposed to cytochalasin-D or blebbistatin, which interfere with actin polymerization and contractility of actin bundles, respectively. By down-regulating Fyn in HEK-293T cells, miR-125a-3p reduces the interaction between actin and A-type lamins, which constitute the nuclear-lamina. Our findings suggest a mechanism, by which a decrease in miR-125a-3p during oocyte maturation facilitates GVBD by allowing Fyn up-regulation and the resulting stabilization of the interaction between actin and A-type lamins.

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“…Compared with the cytoplasmic actin mesh in oocytes, which undergoes rapid polymerization and depolymerization, [22][23][24] cortical actin remains relatively stable during oocyte maturation, except for the formation of the cortical actin cap in the region toward which the spindle approaches.…”

Section: Overexpression Of Constitutively Active Cofilin (Ca-cofilin)mentioning

confidence: 99%

Non-muscle tropomyosin (Tpm3) is crucial for asymmetric cell division and maintenance of cortical integrity in mouse oocytes

Jang

Jo²,

Kim³

et al. 2014

Cell Cycle

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Symmetry breaking in mouse oocytes requires transient F-actin meshwork destabilization

Cited by 97 publications

References 27 publications

Anillin localization suggests distinct mechanisms of division plane specification in mouse oogenic meiosis I and II

Anillin localization suggests distinct mechanisms of division plane specification in mouse oogenic meiosis I and II

Regulation of GVBD in mouse oocytes by miR-125a-3p and Fyn kinase through modulation of actin filaments

Non-muscle tropomyosin (Tpm3) is crucial for asymmetric cell division and maintenance of cortical integrity in mouse oocytes

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