Mouse Emi2 as a distinctive regulatory hub in second meiotic metaphase

Toru Suzuki, E Suzuki, N Yoshida, A Kubo, H Li, E Okuda, M Amanai, Anthony C F Perry

Research output: Contribution to journalArticle

46 Citations (Scopus)

Abstract

The oocytes of vertebrates are typically arrested at metaphase II (mII) by the cytostatic factor Emi2 until fertilization. Regulatory mechanisms in Xenopus Emi2 (xEmi2) are understood in detail but contrastingly little is known about the corresponding mechanisms in mammals. Here, we analyze Emi2 and its regulatory neighbours at the molecular level in intact mouse oocytes. Emi2, but not xEmi2, exhibited nuclear targeting. Unlike xEmi2, separable N- and C-terminal domains of mouse Emi2 modulated metaphase establishment and maintenance, respectively, through indirect and direct mechanisms. The C-terminal activity was mapped to the potential phosphorylation target Tx5SxS, a destruction box (D-box), a lattice of Zn2+-coordinating residues and an RL domain. The minimal region of Emi2 required for its cytostatic activity was mapped to a region containing these motifs, from residue 491 to the C terminus. The cytostatic factor Mos-MAPK promoted Emi2-dependent metaphase establishment, but Mos autonomously disappeared from meiotically competent mII oocytes. The N-terminal Plx1-interacting phosphodegron of xEmi2 was apparently shifted to within a minimal fragment (residues 51-300) of mouse Emi2 that also contained a calmodulin kinase II (CaMKII) phosphorylation motif and which was efficiently degraded during mII exit. Two equimolar CaMKII. isoform variants were present in mII oocytes, neither of which phosphorylated Emi2 in vitro, consistent with the involvement of additional factors. No evidence was found that calcineurin is required for mouse mII exit. These data support a model in which mammalian meiotic establishment, maintenance and exit converge upon a modular Emi2 hub via evolutionarily conserved and divergent mechanisms.
LanguageEnglish
Pages3281-3291
Number of pages11
JournalDevelopment
Volume137
Issue number19
Early online date18 Aug 2010
DOIs
StatusPublished - 1 Oct 2010

Fingerprint

Metaphase
Xenopus
Oocytes
Proto-Oncogene Proteins c-mos
Calcium-Calmodulin-Dependent Protein Kinases
Maintenance
Phosphorylation
Calcineurin
Cytostatic Agents
Fertilization
Vertebrates
Mammals
Protein Isoforms

Keywords

  • mammalian meiosis
  • emi2
  • xenopus
  • metaphase II

Cite this

Mouse Emi2 as a distinctive regulatory hub in second meiotic metaphase. / Suzuki, Toru; Suzuki, E; Yoshida, N; Kubo, A; Li, H ; Okuda, E; Amanai, M; Perry, Anthony C F.

In: Development, Vol. 137, No. 19, 01.10.2010, p. 3281-3291.

Research output: Contribution to journalArticle

Suzuki, T, Suzuki, E, Yoshida, N, Kubo, A, Li, H, Okuda, E, Amanai, M & Perry, ACF 2010, 'Mouse Emi2 as a distinctive regulatory hub in second meiotic metaphase', Development, vol. 137, no. 19, pp. 3281-3291. https://doi.org/10.1242/dev.052480
Suzuki T, Suzuki E, Yoshida N, Kubo A, Li H, Okuda E et al. Mouse Emi2 as a distinctive regulatory hub in second meiotic metaphase. Development. 2010 Oct 1;137(19):3281-3291. https://doi.org/10.1242/dev.052480
Suzuki, Toru ; Suzuki, E ; Yoshida, N ; Kubo, A ; Li, H ; Okuda, E ; Amanai, M ; Perry, Anthony C F. / Mouse Emi2 as a distinctive regulatory hub in second meiotic metaphase. In: Development. 2010 ; Vol. 137, No. 19. pp. 3281-3291.
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