Leforestier A, Livolant F
Laboratoire de Physique des Solides, Université Paris-Sud, Orsay, France.
Biophys J. 1997 Oct;73(4):1771-6. doi: 10.1016/S0006-3495(97)78207-9.
Macromolecular crowding conditions occurring inside the cell nucleus were reproduced experimentally with solutions of mononucleosome core particles to study their supramolecular organization. We report here that under these conditions, and over a large range of monovalent salt concentrations, mononucleosome core particles self-assemble to form a discotic liquid crystalline phase characterized in polarizing and freeze-fracture electron microscopy. Mononucleosomes are stacked on each other to form columns, which are themselves closely packed into an hexagonal array. The nucleosome concentration, estimated from the network parameters, falls in the range of values measured in cell nuclei. We suggest that these concentrated solutions, although their organization cannot be immediately compared to the organization of chromatin in vivo, may be used to investigate the nucleosome-nucleosome interactions. Furthermore, this approach may be complexified to take into account the complexity of the eucaryotic chromatin.
利用单核小体核心颗粒溶液在实验中重现了细胞核内发生的大分子拥挤条件，以研究它们的超分子组织。我们在此报告，在这些条件下，以及在很大范围的单价盐浓度下，单核小体核心颗粒会自组装形成一种盘状液晶相，这在偏振和冷冻断裂电子显微镜下得到了表征。单核小体相互堆叠形成柱体，这些柱体本身又紧密堆积成六边形阵列。根据网络参数估算的核小体浓度落在细胞核中测得的值的范围内。我们认为，这些浓缩溶液虽然其组织结构不能直接与体内染色质的组织结构相比较，但可用于研究核小体与核小体之间的相互作用。此外，这种方法可以进一步复杂化，以考虑真核染色质的复杂性。
