The eukaryotic genome is organized into different domains by cis‐acting elements, such as boundaries/insulators and matrix attachment regions, and is packaged with different degrees of condensation. In the M phase, the chromatin becomes further highly condensed into chromosomes. The first step for transcriptional activation of a given gene, at a particular time during development, in any locus, is the opening of its chromatin domain. This locus needs to be kept in this state in each early G1 phase during every cell (...) cycle. Certain distal enhance elements, including locus control regions (LCRs) and enhancers, are believed to perform this target chromatin domain opening process and several models have been proposed to explain distal enhance action. But they did not explain precisely how a given chromatin domain is opened. Based on various studies, we propose a hypothesis for the mechanism of opening chromatin on a large scale. One important mechanism may involved breaking one or two DNA strands and reducing the linking numbers within chromatin domain. The topological changes can overpass some complexes formed on DNA strands and can be transmitted from specific localized points over a broad region, until boundary elements or insulators are reached. These may initiate downstream events such as propagation of histone acetylation and the binding of transcription factors to proximal promoters and may further augment the action mediated by distal enhancer elements. BioEssays 25:507–514, 2003. © 2003 Wiley Periodicals, Inc. (shrink)

Political philosophy begins with systematic reflection on existing political practices; and yet it requires something more than this. Since any persisting political practice both originated from a specific culture of the past and will shape a stable but alterable culture in the future, through its own character in interaction with other cultures, political philosophers should open a wider horizon than the political ideas of a certain culture, and seek a deeper insight than questionable belief in the incompatibility of different political (...) cultures. (shrink)

Of all the persisting civilizations in the world, Chinese civilization has endured the vicissitudes of history the longest without abrupt collapse. In the formation and development of Chinese civilization, China at some times experienced unity, strength, prosperity, and glory, and at other times experienced disunion, weakness, depression, and even humiliation. In its long continuous history, China has had a peculiar characteristic of recurrence in which an era of political strength and social prosperity would be superseded by an era of political (...) weakness and social chaos, and finally a lively new era would appear to continue the historical cycle. (shrink)