Video Experimental Relacionado
Updated: Feb 9, 2026
02:31
Phase Transitions and Effect of Intermolecular Forces
23.3K
La oscilación estructural acoplada al ciclo celular de los nucleosomas centroméricos en levaduras
Manjunatha Shivaraju1, Jay R Unruh, Brian D Slaughter
1Stowers Institute for Medical Research, Kansas City, MO 64110, USA.
Cell
|July 24, 2012
Resumen
Los centrómeros de levadura en ciernes contienen una copia de la variante de histona Cse4 (nucleosoma centromérico) durante la mayor parte del ciclo celular. Esta estructura se duplica a dos copias durante la anafase, lo que indica cambios acoplados al ciclo celular en la estructura centromérica del nucleosoma.
Área de la Ciencia:
- Biología celular Biología celular.
- Biología Molecular Biología Molecular
- Genética La genética.
Sus antecedentes:
- El centrómero es crucial para una segregación cromosómica precisa durante la división celular.
- Los centrómeros se caracterizan por nucleosomas especializados que contienen variantes de la histona H3.
- En la levadura en ciernes, Cse4 es la variante canónica de la histona H3 que se encuentra en los centrómeros.
Objetivo del estudio:
- Para investigar el número de copias y la dinámica estructural de la variante centromérica de la histona H3, Cse4, en células de levadura vivas.
- Para explorar las alteraciones dependientes del ciclo celular en la composición centromérica de los nucleosomas.
Principales métodos:
- Desarrolló un nuevo método que combina la espectroscopia de correlación de fluorescencia (FCS) y la imagen calibrada para el análisis cuantitativo en levaduras vivas.
- Se utilizaron ensayos de reconstitución de nucleosomas y ChIP (inmunoprecipitación de cromatina) para analizar la composición de los nucleosomas.
- Interacciones investigadas Cse4-Cse4 y el papel de Scm3 durante el ciclo celular.
Principales resultados:
- Número de copias de Cse4 cuantificado en los nucleosomas centroméricos, revelando una copia durante la interfase y dos copias durante la anafase.
- Se observaron cambios estructurales acoplados al ciclo celular en los nucleosomas centroméricos, con mayor incorporación y deposición de Cse4 en la anafase.
- Confirmó la presencia de H2A/H2B en ambas estructuras Cse4 y observó cambios similares específicos de la anafase en Candida albicans.
Conclusiones:
- Los nucleosomas centroméricos exhiben una oscilación acoplada al ciclo celular en su estructura, específicamente con respecto al número de copias Cse4.
- Los hallazgos apoyan un modelo dinámico para la estructura centromérica del nucleosoma que cambia durante la división celular.
- El fenómeno observado se conserva en diferentes especies de levaduras, lo que sugiere una importancia fundamental.
Videos de Conceptos Relacionados
02:31Phase Transitions
23.3K
Whether solid, liquid, or gas, a substance's state depends on the order and arrangement of its particles (atoms, molecules, or ions). Particles in the solid pack closely together, generally in a pattern. The particles vibrate about their fixed positions but do not move or squeeze past their neighbors. In liquids, although the particles are closely spaced, they are randomly arranged. The position of the particles are not fixed—that is, they are free to move past their neighbors to...
23.3K
02:58Properties of Transition Metals
30.0K
Transition metals are defined as those elements that have partially filled d orbitals. As shown in Figure 1, the d-block elements in groups 3–12 are transition elements. The f-block elements, also called inner transition metals (the lanthanides and actinides), also meet this criterion because the d orbital is partially occupied before the f orbitals.
30.0K
01:58Cooperative Allosteric Transitions
8.8K
Cooperative allosteric transitions can occur in multimeric proteins, where each subunit of the protein has its own ligand-binding site. When a ligand binds to any of these subunits, it triggers a conformational change that affects the binding sites in the other subunits; this can change the affinity of the other sites for their respective ligands. The ability of the protein to change the shape of its binding site is attributed to the presence of a mix of flexible and stable segments in the...
8.8K
02:39Phase Transitions: Vaporization and Condensation
21.5K
The physical form of a substance changes on changing its temperature. For example, raising the temperature of a liquid causes the liquid to vaporize (convert into vapor). The process is called vaporization—a surface phenomenon. Vaporization occurs when the thermal motion of the molecules overcome the intermolecular forces, and the molecules (at the surface) escape into the gaseous state. When a liquid vaporizes in a closed container, gas molecules cannot escape. As these gas phase molecules...
21.5K
02:33Phase Transitions: Sublimation and Deposition
20.3K
Some solids can transition directly into the gaseous state, bypassing the liquid state, via a process known as sublimation. At room temperature and standard pressure, a piece of dry ice (solid CO2) sublimes, appearing to gradually disappear without ever forming any liquid. Snow and ice sublimate at temperatures below the melting point of water, a slow process that may be accelerated by winds and the reduced atmospheric pressures at high altitudes. When solid iodine is warmed, the solid sublimes...
20.3K
02:39Phase Transitions: Melting and Freezing
15.2K
Heating a crystalline solid increases the average energy of its atoms, molecules, or ions, and the solid gets hotter. At some point, the added energy becomes large enough to partially overcome the forces holding the molecules or ions of the solid in their fixed positions, and the solid begins the process of transitioning to the liquid state or melting. At this point, the temperature of the solid stops rising, despite the continual input of heat, and it remains constant until all of the solid is...
15.2K