Soft viscoelastic properties of nuclear actin age oocytes due to gravitational creep.

TitleSoft viscoelastic properties of nuclear actin age oocytes due to gravitational creep.
Publication TypeJournal Article
Year of Publication2015
AuthorsFeric, M, Broedersz, CP, Brangwynne, CP
JournalSci Rep
Date Published2015 Nov 18
KeywordsActins, Animals, Cell Nucleus, Cellular Senescence, Elasticity, Gravitation, Models, Biological, Oocytes, Organelles, Rheology, Viscosity, Xenopus laevis

<p>The actin cytoskeleton helps maintain structural organization within living cells. In large X. laevis oocytes, gravity becomes a dominant force and is countered by a nuclear actin network that prevents liquid-like nuclear bodies from immediate sedimentation and coalescence. However, nuclear actin's mechanical properties, and how they facilitate the stabilization of nuclear bodies, remain unknown. Using active microrheology, we find that nuclear actin forms a weak viscoelastic network, with a modulus of roughly 0.1 Pa. Embedded probe particles subjected to a constant force exhibit continuous displacement, due to viscoelastic creep. Gravitational forces also cause creep displacement of nuclear bodies, resulting in their asymmetric nuclear distribution. Thus, nuclear actin does not indefinitely support the emulsion of nuclear bodies, but only kinetically stabilizes them by slowing down gravitational creep to ~2 months. This is similar to the viability time of large oocytes, suggesting gravitational creep ages oocytes, with fatal consequences on long timescales.</p>

Alternate JournalSci Rep
PubMed ID26577186
PubMed Central IDPMC4649616
Grant ListDP2 GM105437 / GM / NIGMS NIH HHS / United States
1DP2GM105437-01 / DP / NCCDPHP CDC HHS / United States