皮質の緊張におけるアニゾトロピーは,皮質の流動を極化させる物理的な基礎を明らかにする
Mirjam Mayer1, Martin Depken, Justin S Bois
1Max Planck Institute of Molecular Cell Biology and Genetics, 01307 Dresden, Germany.
Nature
|September 21, 2010
まとめ
Caenorhabditis elegans zygotesにおける大規模な皮質フローは,細胞の極化に不可欠である. この研究は,緊張グラデーションではなく,皮質の緊張におけるアニゾトロピーが,この流れを駆動し,アクトミオシン収縮性グラデーションと十分な皮質粘度を必要とすることを示しています.
科学分野:
- 細胞生物学 細胞生物学
- 発達生物学 発達生物学とは
- バイオフィジックス 生物物理学
背景:
- 非対称な細胞分裂は,多細胞生物の発達に不可欠である.
- シンメトリックな細胞の二極化は,Caenorhabditis elegansのジゴートのように,非対称的な分裂に先行する.
- アクトミオシン皮質の大規模な流れは,C. elegans zygotesの前後極化の鍵ですが,その物理的なドライバーは不明です.
研究 の 目的:
- 極化C. elegans zygotesにおける皮質の緊張のサブセルラー分布を調査する.
- 大規模なアクトミオシン皮質の流れを制御する物理的原理と力を解明する.
- 細胞アシンメトリーの発生におけるアクトミオシン収縮性と皮質の緊張の相互作用を理解する.
主な方法:
- 位置と方向に敏感なレーザーアブレーションを使用して,細胞下皮質の緊張を測定しました.
- 実験データと,活発な皮質力学の理論的モデリングを組み合わせた.
- 皮質の張力分布と皮質フローのダイナミクスとの関係を分析した.
主要な成果:
- 皮質の流れは,皮質の張力におけるアニソトロピー (異なる方向の性質の違い) によって駆動されるが,グラデーション (空間全体の性質の違い) によってではない.
- アクトミオシン収縮性のグラデーションが皮質の流れを開始するために必要であることを実証しました.
- 十分な皮質粘度が,長距離の皮質フローの前提条件として特定されました.
結論:
- 大規模な皮質フローには,運動を駆動する収縮度グラデーションと,長距離の伝播を可能にする高粘度の両方が必要です.
- この発見は,前述の仮説に異議を唱え,緊張グラデーションが皮質の流れの主な原動力であることを示唆している.
- この研究は,C. elegansのジゴットの極化に不可欠な細胞内皮質フローの物理的要件を明確にします.
関連する概念動画
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...