Active diffusion positions the nucleus in mouse oocytes

  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},
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… 
Control of nucleus positioning in mouse oocytes.
Centering based on active diffusion in mouse oocytes is non-specific
The mechanism for nucleus centering in mouse oocytes results from a gradient of actin-positive vesicles, which induces a general centering force, akin to an effective pressure gradient, leading to centering of oil droplets with velocities comparable to nuclear ones.
Active fluctuations modulate gene expression in mouse oocytes
A mechano-transduction model is proposed whereby nucleus positioning via microfilaments modulates oocyte transcriptome, essential for further embryo development, through F-actin-mediated activity promotes nuclear envelope shape fluctuations and chromatin motion.
Active diffusion and advection in Drosophila oocytes result from the interplay of actin and microtubules
Differential dynamic microscopy with different contrast mechanisms is used to provide a thorough characterization of the dynamics of the Drosophila oocyte and finds distinct contributions of cytoskeletal components to advection and active diffusion.
F-actin mechanics control spindle centring in the mouse zygote
Using interdisciplinary approaches, it is shown that F-actin-dependent mechanics operate the switch between asymmetric to symmetric division required at the oocyte to embryo transition.
Active diffusion and microtubule-based transport oppose myosin forces to position organelles in cells
Modelling reveals that microtubule-based directed transport and active diffusion support distribution, mobility and mixing of POs, and in mammalian COS-7 cells, microtubules and F-actin also counteract each other to distribute POs.


Centrosome positioning in interphase cells
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
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
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.
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.