Active diffusion positions the nucleus in mouse oocytes

@article{Almonacid2015ActiveDP,
  title={Active diffusion positions the nucleus in mouse oocytes},
  author={Maria Almonacid and Wylie W. Ahmed and Matthias Bussonnier and Philippe Mailly and Timo Betz and Rapha{\"e}l Voituriez and Nir S. Gov and Marie-H{\'e}l{\`e}ne Verlhac},
  journal={Nature Cell Biology},
  year={2015},
  volume={17},
  pages={470-479}
}
In somatic cells, the position of the cell centroid is dictated by the centrosome. The centrosome is instrumental in nucleus positioning, the two structures being physically connected. Mouse oocytes have no centrosomes, yet harbour centrally located nuclei. We demonstrate how oocytes define their geometric centre in the absence of centrosomes. Using live imaging of oocytes, knockout for the formin 2 actin nucleator, with off-centred nuclei, together with optical trapping and modelling, we… 
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References

SHOWING 1-10 OF 44 REFERENCES
Centrosome positioning in interphase cells
TLDR
It is found that a MT-dependent dynein pulling force plays a key role in the positioning of the centrosome at the cell center, and that other forces applied to the Centrosomal MTs, including actomyosin contractility, can contribute to this process.
Centrosome positioning in vertebrate development
TLDR
Examples of centrosome and centriole positioning are reviewed with a particular emphasis on vertebrate developmental systems, and the roles ofCentrosome positioning, the cues that determine positioning and the mechanisms by which centrosomes respond to these cues are discussed.
A role for cytoplasmic dynein and LIS1 in directed cell movement
TLDR
It is found that dynein and its regulators dynactin and LIS1 localize to the leading cell cortex during this process of healing of wounded NIH3T3 cell monolayers, implicating a leading edge cortical pool of dyneIn in both early and persistent steps in directed cell movement.
Germinal vesicle position and meiotic maturation in mouse oocyte.
TLDR
It is shown that incompetent mouse oocytes possess a peripheral GV, while competent oocytes mainly exhibit a central position of the GV which could be used as a simple morphological marker of oocyte quality.
...
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