Year: 2011
Type: article
Abstract: BACKGROUND: An oocyte undergoes two rounds of asymmetric division to generate a haploid gamete and two small polar bodies designed for apoptosis. Chromosomes play important roles in specifying the asymmetric meiotic divisions in the oocytes but the underlying mechanism is poorly understood. RESULTS: Chromosomes independently induce spindle formation and cortical actomyosin assembly into special cap and ring structures in the cortex of the oocyte. The spindle and the cortical cap/ring interact to generate mechanical forces, leading to polar body extrusion. Two distinct force-driven membrane changes were observed during 2nd polar body extrusion: a protrusion of the cortical cap and a membrane invagination induced by an anaphase spindle midzone. The cortical cap protrusion and invagination help rotate the spindle perpendicularly so that the spindle midzone can induce bilateral furrows at the shoulder of the protruding cap, leading to an abscission of the polar body. It is interesting to note that while the mitotic spindle midzone induces bilateral furrowing, leading to efficient symmetric division in the zygote, the meiotic spindle midzone induced cytokinetic furrowing only locally. CONCLUSIONS: Distinct forces driving cortical cap protrusion and membrane invagination are involved in spindle rotation and polar body extrusion during meiosis II in mouse oocytes.
Source: Cell Division
Authors: Qiong Wang, Catherine Racowsky, Manqi Deng
Language: English
Subfield: Cell Biology
Domain: Life Sciences
Open Access status: gold
Estimated APC paid: $3,190
Funder: Brigham and Women's Hospital
OpenAlex ID: W1967144051