皮层张力中的异位变异揭示了极化皮层流动的物理基础
Mirjam Mayer1, Martin Depken, Justin S Bois
1Max Planck Institute of Molecular Cell Biology and Genetics, 01307 Dresden, Germany.
Nature
|September 21, 2010
概括
在Caenorhabditis elegans zygotes中,大规模的皮层流对于细胞两极分化至关重要. 这项研究表明,皮质张力中的异质,而不是张力梯度,驱动了这种流动,需要actomyosin收缩度梯度和足够的皮质粘度.
科学领域:
- 细胞生物学 细胞生物学
- 发育生物学 发展生物学
- 生物物理学的生物物理.
背景情况:
- 不对称的细胞分裂对于多细胞生物的发展至关重要.
- 对称细胞的两极分化,就像Caenorhabditis elegans zygote一样,在不对称分裂之前发生.
- 阿克托米奥辛皮层的大规模流动是C. elegans zygote的前后两极分化的关键,但其物理驱动因素尚不清楚.
研究的目的:
- 为了研究在极化C. elegans zygotes中皮层张力的亚细胞分布.
- 阐明控制大规模actomyosin皮质流动的物理原理和力量.
- 了解在产生细胞不对称性时,actomyosin收缩性和皮质张力之间的相互作用.
主要方法:
- 利用位置和方向敏感的激光切除来测量亚细胞皮质张力.
- 结合实验数据与主动皮层力学理论建模.
- 分析了皮层张力分布和皮层流动力学之间的关系.
主要成果:
- 皮质流是由皮质张力中的异构 (不同方向的属性差异) 驱动的,而不是梯度 (跨空间的属性差异).
- 证明,为了启动皮层流动,需要对actomyosin收缩性的梯度.
- 确定了足够的皮质粘度作为长距离皮质流动的先决条件.
结论:
- 大规模的皮质流需要收缩梯度来驱动运动和高粘度来实现远程传播.
- 这些发现挑战了先前的假设,认为张力梯度是皮层流动的主要驱动因素.
- 这项研究澄清了细胞内皮层流的物理要求,这对于C. elegans的胚胎偏向至关重要.
相关概念视频
01:18Polarity of the Cytoskeleton
The intrinsic polarity of cells can be primarily attributed to two factors- i) the asymmetric accumulation of mobile components such are regulatory molecules and subcellular components across the cell and ii) the orientation of polar cytoskeletal filaments that make up the cytoskeletal networks, specifically microfilaments, and microtubules arranged along the axis of polarity. Interactions between the cytoskeletal filaments are crucial for the establishment and maintenance of the polar nature...
01:29Potential Due to a Polarized Object
A neutral atom consists of a positively charged nucleus surrounded by a negatively charged electron cloud. When placed in an external electric field, the external electric force pulls the electrons and nucleus apart, opposite to the intrinsic attraction between the nucleus and the electrons. The opposing forces balance each other with a slight shift between the center of masses of the nucleus and the electron cloud, resulting in a polarized atom. On the other hand, a few molecules, like water,...
01:15Stress: General Loading Conditions
To grasp the intricacy of real-world conditions where multiple loads are applied simultaneously to a structure, one might visualize a section passing through a specific point within a body, aligned parallel to the xy plane. This section is subjected to various forces, including original loads, normal forces, and shearing forces.
The shearing force, possessing potential directionality within the plane of the section, is simplified into two component forces running parallel to the x and y axes.
The shearing force, possessing potential directionality within the plane of the section, is simplified into two component forces running parallel to the x and y axes.
01:18Transformation of Plane Stress
Studying stress transformation is essential in understanding how stress components within a material, like a cube under plane stress, change with rotation. This change is analyzed by considering a prismatic element within the cube. As the element rotates, the stress components acting on it—both normal and shearing stresses—change in magnitude and orientation. This change is quantified using trigonometric functions of the rotation angle, relating the forces acting on the rotated element's faces...
01:24Principal Stresses
The graphical depiction of normal and shearing stress equations is represented by a circle, demonstrating the interplay between these stresses under different angular conditions. The center of this circle C, located on the vertical axis, represents the average normal stress, while its radius shows the range of stress variations. At points A and B, where the circle intersects the horizontal axis, the maximum and minimum normal stresses are observed, occurring without shearing stress. These...
01:16Stress on an Oblique Plane
Understanding stress on an oblique plane under axial loading is pivotal in material mechanics. This analysis offers insight into a material's durability and strength, which is crucial for civil engineering and structural design. Axial loading refers to force application along the material's central axis, causing compression or elongation and leading to normal stress. Normal stress occurs when a force acts perpendicularly to the material's area, resulting in compressive or tensile stress. When...