Golyshev S A, Poliakov V Iu
Tsitologiia. 2008;50(1):29-39.
Conformational changes in chromatin structure are nowadays the object of intensive research due to its importance for proper regulation of intranuclear processes. The fine structure of chromatin within the DNA replication sites was studied in in situ fixed cells and cells permebilized by low ionic strength solutions in the presence of divalent cations. The latter method provides visualization of higher level chromatin structures such as globular chromomeres and chromonema fibres. Nascent DNA was detected immunochemically using anti-BrdU antibodies on the surface of ultrathin sections prepared from Epon-embedded material. It was shown that newly replicated DNA preferentially localized within the zones filled with globular and fibrillar elements with characteristic diameter of 30 nm, and not in chromonema fibres, while after replication had been completed DNA became embedded into as thick as 60-80 nm chromonema elements. The results obtained are discussed in the context of conception of hierarchical folding of chromatin fibers.
由于染色质结构的构象变化对核内过程的正常调控至关重要，如今它已成为深入研究的对象。在原位固定细胞以及在二价阳离子存在下用低离子强度溶液通透处理的细胞中，研究了DNA复制位点内染色质的精细结构。后一种方法能够观察到更高层次的染色质结构，如球状染色粒和染色线纤维。使用抗BrdU抗体，通过免疫化学方法在由Epon包埋材料制备的超薄切片表面检测新生DNA。结果表明，新复制的DNA优先定位在充满直径为30 nm的球状和纤维状元件的区域内，而不是在染色线纤维中，而在复制完成后，DNA则嵌入到厚度达60 - 80 nm的染色线元件中。在染色质纤维分级折叠概念的背景下，对所得结果进行了讨论。
