This is perhaps due to the considerable asymmetry of this division, wherein the polar body and the oocyte/ovum have distinct fates and very different sizes. Polar body cytokinesis uniquely requires another Rho family GTPase, Cdc42, for dynamic reorganization of the polar cortex. The midzone of the anaphase spindle serves as a hub for regulatory complexes that elicit Rho activation, and ultimately actomyosin contractile ring assembly and contraction. Chromatin is necessary and sufficient to elicit differentiation of the associated cortex, via Ran-based signaling. Depending on the species, either the actin or microtubule cytoskeleton is required for spindle anchoring. The site of polar body division is determined before anaphase, by the eccentric, cortically associated meiotic spindle. We synthesize results from many different model species, including those popular for their genetics and several that are more obscure in modern cell biology. This maternal meiotic division shares many similarities with mitotic and spermatogenic cytokinesis, but there are several distinctions, which will be discussed in this review. Polar body cytokinesis is the physical separation of a small polar body from a larger oocyte or ovum.

Zen bound 2 protrusion iv