染色质折叠后组蛋白H1和H5球状结构域对抗体的可及性。

Accessibility of the globular domain of histones H1 and H5 to antibodies upon folding of chromatin.

作者信息

Russanova V R, Dimitrov S I, Makarov V L, Pashev I G

出版信息

Eur J Biochem. 1987 Sep 1;167(2):321-6. doi: 10.1111/j.1432-1033.1987.tb13339.x.

DOI:10.1111/j.1432-1033.1987.tb13339.x

Abstract

Antibodies to the globular domain of histones H1 and H5 were purified by affinity chromatography and used to study the accessibility of this region of H1 and H5 in folded and unfolded rat liver and hen erythrocyte chromatin respectively. The different conformations of the chromatin filament were induced by varying the ionic strength from 1 mM to 80 mM NaCl and maintained by fixation with glutaraldehyde. Treatment with glutaraldehyde at a given salt concentration affected neither the orientation of nucleosomes relative to the fiber axis nor the compactness of chromatin. Solid-phase immunoassay and inhibition experiments showed no binding of the antibody against the globular domain of H1 to chromatin at the entire range of salt concentrations, while the antibody to the whole H1 molecule reacted with chromatin at low salt. On the other hand, the antibody to the globular region of H5 reacted with hen erythrocyte chromatin independently of the extent of chromatin condensation. These results indicate that the antigenic determinants of the globular domain of H5 are accessible to the antibody both in folded and unfolded chromatin, while those of the same region of H1 are masked, probably by interaction with DNA or proteins.

摘要

通过亲和层析纯化了针对组蛋白H1和H5球状结构域的抗体，并分别用于研究H1和H5该区域在折叠和未折叠的大鼠肝脏及鸡红细胞染色质中的可及性。通过将离子强度从1 mM NaCl变化到80 mM NaCl来诱导染色质丝的不同构象，并用戊二醛固定来维持。在给定盐浓度下用戊二醛处理既不影响核小体相对于纤维轴的取向，也不影响染色质的紧密程度。固相免疫测定和抑制实验表明，在整个盐浓度范围内，针对H1球状结构域的抗体均不与染色质结合，而针对整个H1分子的抗体在低盐条件下与染色质反应。另一方面，针对H5球状区域的抗体与鸡红细胞染色质反应，而与染色质凝聚程度无关。这些结果表明，H5球状结构域的抗原决定簇在折叠和未折叠的染色质中均可被抗体识别，而H1同一区域的抗原决定簇可能因与DNA或蛋白质相互作用而被掩盖。