在后生动物细胞分裂的“教科书”模型中（该模型建立在对较大海洋动物细胞和Candida elegans细胞所做的一个世纪的研究基础之上），有丝分裂纺锤体被假设引导卵裂沟的位置。
现在，以检验这一模型是否足以解释一个较小细胞（果蝇成神经细胞）的非对称分裂过程中的卵裂沟位置为目的的实验表明，它是不能的。相反，一个新的路径在发挥作用，在这个路径中，Pins (partner of Inscuteable)极性复合物将形成卵裂沟的蛋白极化到基底皮层，在这里它们诱导收缩环形成。这种独立于纺锤体的细胞动力学卵裂沟机制可能与其他高度极化的细胞类型也相关。
推荐英文摘要：
Nature doi:10.1038/nature09334
A spindle-independent cleavage furrow positioning pathway
Clemens Cabernard，Kenneth E. Prehoda Chris Q. Doe
The mitotic spindle determines the cleavage furrow site during metazoan cell division1, 2, but whether other mechanisms exist remains unknown. Here we identify a spindle-independent mechanism for cleavage furrow positioning in Drosophila neuroblasts. We show that early and late furrow proteins (Pavarotti, Anillin, and Myosin) are localized to the neuroblast basal cortex at anaphase onset by a Pins cortical polarity pathway, and can induce a basally displaced furrow even in the complete absence of a mitotic spindle. Rotation or displacement of the spindle results in two furrows: an early polarity-induced basal furrow and a later spindle-induced furrow. This spindle-independent cleavage furrow mechanism may be relevant to other highly polarized mitotic cells, such as mammalian neural progenitors.
