SIMULATION TESTING OF MECHANISMS FOR INDUCING THE FORMATION OF THE CONTRACTILE RING IN CYTOKINESIS
SIMULATION TESTING OF MECHANISMS FOR INDUCING THE FORMATION OF THE CONTRACTILE RING IN CYTOKINESIS
复制标题
DOI：
10.1083/jcb.109.5.2215
复制
发表时间：
1989-11-01
影响因子：
7.8
通讯作者：
GEWALT, SL
中科院分区：
文献类型：
--
作者：
HARRIS, AK;GEWALT, SL
有说服力的证据表明，有丝分裂装置(MA)在细胞质分裂中的作用是控制分裂沟的位置。MA和皮质之间的这种相互作用的几何方面是复杂的，因此，计算机模拟可以成为检验关于诱导过程的假说的有用手段。怀特和鲍西(1983)。J·西奥。比奥尔。101：289-316)使用计算机模拟表明，来自星座的长程信号与距离的不同幂成反比，产生的总和效应在球状单元的赤道处最小。他们的研究结果似乎支持“极地松弛”假说，在这种假说中，ASTs的作用是削弱大脑皮层的收缩能力，使其在赤道的收缩达到最大，因为赤道的收缩受到的抑制最小。然而，RapPaport和RapPaport(1988)的实验研究。J.Exp.祖尔。247：92-98)表明紫苏实际上增强了皮质的收缩能力。在这篇文章中，我们使用计算机模拟来确定来自MA的信号将如何随着距离的函数而变化，以使得在要诱导皱纹的地方皮质收缩能力变得最大。虽然我们证实相反的功率抑制信号可以在球形细胞中诱导赤道皱纹，但我们也发现这种能力通过将细胞扁平、收缩或扭曲成圆柱形而被破坏，拉帕波特的S实验显示这种几何形状形成了皱纹(1986年)。内部赛托尔牧师。105：245-281)。然后，我们展示了正确类型的刺激信号将在观察到的位置上引发皱纹，在球形细胞中以及被实验操作扭曲的细胞中。这些信号必须在阈值距离外保持恒定，但在超过该距离后会突然减弱。我们还表明，这种能力依赖于“下降”阈值发生在恰到好处的距离相对于细胞的尺寸和星座的分离。
There is persuasive evidence that the role of the mitotic apparatus (MA) in cytokinesis is to control the location of the cleavage furrow. The geometric aspects of this interaction between the MA and the cortex are complex and, thus, computer simulation can be a useful means for testing hypotheses about the induction process. White and Borisy (1983. J. Theor. Biol. 101:289-316) used computer simulations to show that long-range signals from the asters, varying inversely as various powers of distance, produce summed effects that are minima at the equator of spherical cells. Their results have seemd to support the "polar relaxation" class of hyptheses, in which the effect of the asters is to weaken cortical contractility so that contraction becomes maximized at the equator because it is least inhibited there. However, the experimental studies of Rappaport and Rappaport (1988. J. Exp. Zool. 247:92-98) indicate that the asters actually strengthen cortical contractility. In this paper, we use computer simulation to determine how signals from the MA will need to vary in effect as functions of distance to cause cortical contractility to become maximized where the furrows are to be induced. Although we confirm that inverse power inhibitory signals could induce equatorial furrows in spherical cells, we also found that this ability is destroyed by flattening, constricting, or distorting cells into cylinders, geometries for which Rappaport''s experiments show furrows form (1986. Int. Rev. Cytol. 105:245-281). We then show that stimulatory signals of the right kind would induce furrows at the locations observed, in spherical cells as well as cells distorted by experimental manipulation. These signals must be constant out to a threshold distance but decrease abruptly beyond that distance. We also show that this ability depends on having the "drop-off" threshold occur at just the right distance relative to the dimensions of the cell and separation of the asters.