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/jcs.095448

Cited by 35 publications

(68 citation statements)

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“…As such, tracking chromosomes/spindle motion at high spatiotemporal resolution should be informative. We note that a pulling and a pushing force are not mutually exclusive [Bezanilla and Wadsworth, 2009;Azoury et al, 2011;Field and Lenart, 2011]. The chromosomes/spindle could be pushed by formin-2 nucleated actin dynamics when it is deep in the center of the cytoplasm and then pulled by another actin population as it approaches the cortex.…”

Section: Spindle Migration: Where and How The Force Is Generatedmentioning

confidence: 90%

“…Immunofluorescence analysis suggested that the endogenous formin-2 localizes to the cortex at prophase, disappears at GVBD, and re-emerges later in the cortex opposite the spindle [Azoury et al, 2011]. Ectopically expressed formin-2-EGFP localizes at the cortex and then translocates to the cytoplasm before spindle migration [Schuh and Ellenberg, 2008].…”

Section: Spindle Migration: Where and How The Force Is Generatedmentioning

confidence: 99%

“…This probe is based on the N-terminal 261 aa of utrophin that contains two tandem calponin homology (CH) domains, which bind specifically to F-actin but not G-actin (globular actin) [Burkel et al, 2007]. The actin meshwork detected by UtrCH is absent in formin-2 null oocytes, suggesting these actin filaments are derived from formin-2 nucleation [Azoury et al, 2008;Schuh and Ellenberg, 2008;Azoury et al, 2011]. Interestingly, in the same work Schuh and Ellenberg (2008) also microinjected fluorescently labeled phalloidin and observed a dense actin network connecting MI spindle and the adjacent oocyte cortex, which appeared forming an inward curvature.…”

Section: Spindle Migration: Where and How The Force Is Generatedmentioning

confidence: 99%

“…A recent study found that formin-2 overexpression induced nuclear deformations (invaginations) before GVBD, indicating that the formin-2 nucleated actin filaments may indeed exert pushing forces in nuclear vicinity [Azoury et al, 2011]. Quantitative and unbiased analysis of actin dynamics in concert with spindle movement will be essential for detailing the origin and nature of the actin-based force.…”

Section: Spindle Migration: Where and How The Force Is Generatedmentioning

confidence: 99%

“…The chromosomes/spindle could be pushed by formin-2 nucleated actin dynamics when it is deep in the center of the cytoplasm and then pulled by another actin population as it approaches the cortex. Azoury et al [2011] speculated that this second actin population may depend on a cortically associated actin nucleator possibly activated by the approaching chromosomes [Azoury et al, 2011].…”

Section: Spindle Migration: Where and How The Force Is Generatedmentioning

confidence: 99%

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Actin cytoskeleton in cell polarity and asymmetric division during mouse oocyte maturation

2012

Cytoskeleton

104

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Mammalian oocyte maturation involves two successive rounds of extremely asymmetric cell divisions (known as polar body extrusion) to generate a functional haploid egg. Successful polar body extrusion relies on establishment of an asymmetric spindle position and cortical polarity. Decades of studies using mouse oocytes as a model have revealed critical roles for a dynamic actin cytoskeleton in this process. Here, we review the contribution of actin to the critical events during oocyte meiotic cell divisions with an emphasis on recent advances in understanding the underlying molecular and physical mechanisms. V C 2012 Wiley Periodicals, Inc

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Section: Spindle Migration: Where and How The Force Is Generatedmentioning

confidence: 90%

Section: Spindle Migration: Where and How The Force Is Generatedmentioning

confidence: 99%

Section: Spindle Migration: Where and How The Force Is Generatedmentioning

confidence: 99%

Section: Spindle Migration: Where and How The Force Is Generatedmentioning

confidence: 99%

Section: Spindle Migration: Where and How The Force Is Generatedmentioning

confidence: 99%

See 3 more Smart Citations

Actin cytoskeleton in cell polarity and asymmetric division during mouse oocyte maturation

2012

Cytoskeleton

104

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Polar body cytokinesis

2012

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Polar body cytokinesis is the physical separation of a small polar body from a larger oocyte or ovum. This maternal meiotic division shares many similarities with mitotic and spermatogenic cytokinesis, but there are several distinctions, which will be discussed in this review. We synthesize results from many different model species, including those popular for their genetics and several that are more obscure in modern cell biology. The site of polar body division is determined before anaphase, by the eccentric, cortically associated meiotic spindle. Depending on the species, either the actin or microtubule cytoskeleton is required for spindle anchoring. Chromatin is necessary and sufficient to elicit differentiation of the associated cortex, via Ran-based signaling. The midzone of the anaphase spindle serves as a hub for regulatory complexes that elicit Rho activation, and ultimately actomyosin contractile ring assembly and contraction. Polar body cytokinesis uniquely requires another Rho family GTPase, Cdc42, for dynamic reorganization of the polar cortex. This is perhaps due to the considerable asymmetry of this division, wherein the polar body and the oocyte/ovum have distinct fates and very different sizes. Thus, maternal meiotic cytokinesis appears to occur via simultaneous polar relaxation and equatorial contraction, since the polar body is extruded from the spherical oocyte through the nascent contractile ring. As such, polar body cytokinesis is an interesting and important variation on the theme of cell division. V C 2012 Wiley Periodicals, Inc

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Actin assembly mediated by a nucleation promoting factor WASH is involved in MTOC–TMA formation during Xenopus oocyte maturation

Yamagishi

Abe

2018

Cytoskeleton

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During Xenopus oocyte maturation, the microtubule organizing center and transient microtubule array (MTOC-TMA) forms at the vegetal side of the nucleus and we have previously demonstrated that this formation requires actin reorganization. However, the molecular mechanism that coordinates actin filaments with microtubules (MTs) during oocyte maturation is unknown. Here we show that the actin nucleation promoting factor WASH is involved in MTOC-TMA assembly. WASH depletion disrupted the alignment of actin filaments and MT at the base of MTOC-TMA. In vitro cosedimentation assays revealed that the Xenopus WASH VCA domain, which comprises the actin and Arp2/3 complex binding region, directly bound to MT but that the WHD2 domain, which had been previously reported to be an MT-binding domain of mammalian WASH, did not. Injection of the WHD2-deleted mutant into oocytes caused a drastic accumulation of actin filaments in the cytoplasm and malformation of MTOC-TMA, suggesting that the WHD2 domain negatively regulates the VCA domain activity during oocyte maturation. Our results suggest that WASH complex-dependent actin nucleation is involved in the assembly of MTOC-TMA.

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

Cited by 35 publications

References 1 publication

Actin cytoskeleton in cell polarity and asymmetric division during mouse oocyte maturation

Actin cytoskeleton in cell polarity and asymmetric division during mouse oocyte maturation

Polar body cytokinesis

Actin assembly mediated by a nucleation promoting factor WASH is involved in MTOC–TMA formation during Xenopus oocyte maturation

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