Bukharina T A, Furman D P
Ontogenez. 2011 Mar-Apr;42(2):83-93.
Asymmetric cell division (ACD) is the basic process which creates diversity in the cells of multicellular organisms. As a result of asymmetric cell division, daughter cells acquire the ability to differentiate and specialize in a given direction, which is different from that of their parent cells and from each other. This type of division is observed in a wide range of living organisms from bacteria to vertebrates. It has been shown that the molecular-genetic control mechanism of ACD is evolutionally conservative. The proteins involved in the process of ACD in different kinds of animals have a high degree of homology. Sensory organs--setae (macrochaetae)--of Drosophila are widely used as a model system for studying the genetic control mechanisms of asymmetric division. Setae located in an orderly manner on the head and body of the fly play the role of mechanoreceptors. Each of them consists of four specialized cells--offspring of the only sensory organ precursor cell (SOPC), which differentiates from the imaginal wing disc at the larval stage of the late third age. The basic differentiation and further specialization of the daughter cells of SOPC is an asymmetric division process. In this summary, experimental data on genes and their products controlling asymmetric division of SOPC and daughter cells, and also the specialization of the latter, have been systemized. The basic mechanisms which determine the time cells enter into asymmetric mitosis and which provides the structural characteristics of the asymmetric division process--the polar distribution of protein determinants Numb and Neuralized--the orientation of the mitotic spindle in relation to these determinants, and the uneven segregation of the determinants into the daughter cells that determines the direction of their development have been discussed.
不对称细胞分裂（ACD）是在多细胞生物体细胞中产生多样性的基本过程。由于不对称细胞分裂，子细胞获得了在特定方向上分化和特化的能力，这与它们的母细胞不同，并且彼此之间也不同。这种分裂类型在从细菌到脊椎动物的广泛生物体中都能观察到。已经表明，ACD的分子遗传控制机制在进化上是保守的。不同种类动物中参与ACD过程的蛋白质具有高度同源性。果蝇的感觉器官——刚毛（大刚毛）——被广泛用作研究不对称分裂遗传控制机制的模型系统。有序排列在果蝇头部和身体上的刚毛起着机械感受器的作用。每根刚毛由四个特化细胞组成——它们是唯一的感觉器官前体细胞（SOPC）的后代，该前体细胞在第三龄后期幼虫阶段从成虫翅芽分化而来。SOPC子细胞的基本分化和进一步特化是一个不对称分裂过程。在本综述中，关于控制SOPC及其子细胞不对称分裂的基因及其产物，以及后者特化的实验数据已经系统化。讨论了决定细胞进入不对称有丝分裂时间的基本机制，以及提供不对称分裂过程结构特征的机制——蛋白质决定因子Numb和Neuralized的极性分布、有丝分裂纺锤体相对于这些决定因子的方向，以及决定因子向子细胞的不均匀分离，后者决定了它们的发育方向。
