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

Jang, Woo-In; Jo, Yu-Jin; Kim, Hak-Cheol; Jia, Jialin; Namgoong, Suk; Kim, Nam‐Hyung

doi:10.4161/cc.29333

Cited by 18 publications

(40 citation statements)

References 57 publications

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“…82 Inhibition of ROCK by chemical inhibitors or siRNA decreases the phosphorylation of cofilin in oocytes, thereby increasing the activated portion of cofilin and impairing mouse oocyte maturation, 83 indicating that the maintenance of proper levels of activated cofilin is important for oocyte maturation control. Inhibition of ROCK or expression of the dominant-active form of cofilin decreases cortical actin levels and impairs oocyte maturation, 83,84 indicating that levels of activated cofilin should be regulated properly during oocyte maturation. Phosphorylated cofilin can be reactivated by slingshot phosphatases 85 through dephosphorylation of phosphoSer 3 in cofilin, and functional studies in Xenopus oocytes show the importance of slingshot phosphatases in meiotic spindle assembly.…”

Section: Actin Depolymerization Factor/cofilinmentioning

confidence: 99%

“…166 In oocytes, knockdown of tropomyosin decreases cortical actin levels and impairs cortical integrity during cytokinesis. 84 (C) The 2 ends of actin filaments have different affinities for the addition of actin monomer. 167 The fast-growing ends of actin filaments are capped by heterodimeric CP (shown as light blue and blue), which blocks the additional polymerization of actin filaments, 168 whereas the slow-growing ends of actin filaments are protected from depolymerization by tropomodulin (shown as green), which also binds with tropomyosin.…”

Section: Actin Depolymerization Factor/cofilinmentioning

confidence: 99%

“…88 In mouse oocytes, knockdown of the non-muscle isoform of tropomyosin (TPM3.1) decreases cortical actin levels and promotes formation of the membrane bleb structure, which is caused by the collapse of cortical actin during cytokinesis, 84 indicating that the maintenance of cortical integrity via the protection of actin filaments is crucial for proper asymmetric division. These phenotypes are similar to those induced by ROCK inhibition (i.e., increased amounts of active cofilin) 83 or overexpression of dominant-active cofilin.…”

Section: Tropomyosinmentioning

confidence: 99%

“…84 p-ERM is localized near the cortex but is excluded from the region near the spindle. 77,123 The RAN GTP signal is associated with exclusion of p-ERM near the spindle.…”

Section: Introductionmentioning

confidence: 99%

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Roles of actin binding proteins in mammalian oocyte maturation and beyond

Namgoong

Kim

2016

Cell Cycle

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Actin nucleation factors, which promote the formation of new actin filaments, have emerged in the last decade as key regulatory factors controlling asymmetric division in mammalian oocytes. Actin nucleators such as formin-2, spire, and the ARP2/3 complex have been found to be important regulators of actin remodeling during oocyte maturation. Another class of actin-binding proteins including cofilin, tropomyosin, myosin motors, capping proteins, tropomodulin, and Ezrin-Radixin-Moesin proteins are thought to control actin cytoskeleton dynamics at various steps of oocyte maturation. In addition, actin dynamics controlling asymmetric-symmetric transitions after fertilization is a new area of investigation. Taken together, defining the mechanisms by which actin-binding proteins regulate actin cytoskeletons is crucial for understanding the basic biology of mammalian gamete formation and pre-implantation development.

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Section: Actin Depolymerization Factor/cofilinmentioning

confidence: 99%

Section: Actin Depolymerization Factor/cofilinmentioning

confidence: 99%

Section: Tropomyosinmentioning

confidence: 99%

“…84 p-ERM is localized near the cortex but is excluded from the region near the spindle. 77,123 The RAN GTP signal is associated with exclusion of p-ERM near the spindle.…”

Section: Introductionmentioning

confidence: 99%

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Roles of actin binding proteins in mammalian oocyte maturation and beyond

Namgoong

Kim

2016

Cell Cycle

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“…Microinjection dsRNAs and cRNAs were microinjected into GV-stage mouse oocytes as described previously (Jang et al, 2014). To knock down capping protein, Capza1 dsRNA and Capzb2 dsRNA, which were diluted to 1 mg/ml, were microinjected into the cytoplasm of a fully grown GV-stage oocyte using an Eppendorf Femto Jet (Eppendorf AG, Hamburg, Germany) and a Nikon Diaphot ECLIPSE TE300 inverted microscope (Nikon UK Ltd, Kingston upon Thames, Surrey, UK) equipped with a Narishige MM0-202N hydraulic three-dimensional micromanipulator (Narishige Inc., Sea Cliff, NY).…”

Section: Real-time Quantitative Pcr Analysismentioning

confidence: 99%

Actin-capping proteins play essential roles in asymmetric division of maturing mouse oocytes

Jang

Namgoong

et al. 2014

Journal of Cell Science

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Actin polymerization is essential for various stages of mammalian oocyte maturation, including spindle migration, actin cap formation, polar body extrusion and cytokinesis. The heterodimeric actincapping protein is an essential element of the actin cytoskeleton. It binds to the fast-growing (barbed) ends of actin filaments and plays essential roles in various actin-mediated cellular processes. However, the roles of capping protein in mammalian oocyte maturation are poorly understood. We investigated the roles of capping protein in mouse oocytes and found that it is essential for correct asymmetric spindle migration and polar body extrusion. Capping protein mainly localized in the cytoplasm during maturation. By knocking down or ectopically overexpressing this protein, we revealed that it is crucial for efficient spindle migration and maintenance of the cytoplasmic actin mesh density. Expression of the capping-protein-binding region of CARMIL (also known as LRRC16A) impaired spindle migration and polar body extrusion during oocyte maturation and decreased the density of the cytoplasmic actin mesh. Taken together, these findings show that capping protein is an essential component of the actin cytoskeleton machinery that plays crucial roles in oocyte maturation, presumably by controlling the cytoplasmic actin mesh density.

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RNF20 Regulates Oocyte Meiotic Spindle Assembly by Recruiting TPM3 to Centromeres and Spindle Poles

Wang,

Liu,

et al. 2024

Advanced Science

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Previously a ring finger protein 20 (RNF20) is found to be essential for meiotic recombination and mediates H2B ubiquitination during spermatogenesis. However, its role in meiotic division is still unknown. Here, it is shown that RNF20 is localized at both centromeres and spindle poles, and it is required for oocyte acentrosomal spindle organization and female fertility. RNF20‐depleted oocytes exhibit severely abnormal spindle and chromosome misalignment caused by defective bipolar organization. Notably, it is found that the function of RNF20 in spindle assembly is not dependent on its E3 ligase activity. Instead, RNF20 regulates spindle assembly by recruiting tropomyosin3 (TPM3) to both centromeres and spindle poles with its coiled‐coil motif. The RNF20‐TPM3 interaction is essential for acentrosomal meiotic spindle assembly. Together, the studies uncover a novel function for RNF20 in mediating TPM3 recruitment to both centromeres and spindle poles during oocyte spindle assembly.

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

Cited by 18 publications

References 57 publications

Roles of actin binding proteins in mammalian oocyte maturation and beyond

Roles of actin binding proteins in mammalian oocyte maturation and beyond

Actin-capping proteins play essential roles in asymmetric division of maturing mouse oocytes

RNF20 Regulates Oocyte Meiotic Spindle Assembly by Recruiting TPM3 to Centromeres and Spindle Poles

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