Active Fluctuations of the Nuclear Envelope Shape the Transcriptional Dynamics in Oocytes.

Active Fluctuations of the Nuclear Envelope Shape the Transcriptional Dynamics in Oocytes.
Dev Cell. 2019 Oct 09;:
Authors: Almonacid M, Al Jord A, El-Hayek S, Othmani A, Coulpier F, Lemoine S, Miyamoto K, Grosse R, Klein C, Piolot T, Mailly P, Voituriez R, Genovesio A, Verlhac MH
Abstract
Nucleus position in cells can act as a developmental cue. Mammalian oocytes position their nucleus centrally using an F-actin-mediated pressure gradient. The biological significance of nucleus centering in mammalian oocytes being unknown, we sought to assess the F-actin pressure gradient effect on the nucleus. We addressed this using a dedicated computational 3D imaging approach, biophysical analyses, and a nucleus repositioning assay in mouse oocytes mutant for cytoplasmic F-actin. We found that the cytoplasmic activity, in charge of nucleus centering, shaped the nucleus while promoting nuclear envelope fluctuations and chromatin motion. Off-centered nuclei in F-actin mutant oocytes were misshaped with immobile chromatin and modulated gene expression. Restoration of F-actin in mutant oocytes rescued nucleus architecture fully and gene expression partially. Thus, the F-actin-mediated pressure gradient also modulates nucleus dynamics in oocytes. Moreover, this study supports a mechano-transduction model whereby cytoplasmic microfilaments could modulate oocyte transcriptome, essential for subsequent embryo development.
PMID: 31607652 [PubMed...

Source: Developmental Cell - October 8, 2019 Category: Cytology Authors: Almonacid M, Al Jord A, El-Hayek S, Othmani A, Coulpier F, Lemoine S, Miyamoto K, Grosse R, Klein C, Piolot T, Mailly P, Voituriez R, Genovesio A, Verlhac MH Tags: Dev Cell Source Type: research