Formation of 50 kbp chromatin fragments in isolated liver nuclei is mediated by protease and endonuclease activation

来自 Wiley

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作者：

B Zhivotovsky，D Wade，A Gahm，S Orrenius，P Nicotera

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摘要：

Isolated rat liver nuclei were incubated in the presence of divalent cations, and the mechanisms underlying the subsequent chromatin fragmentation were investigated. Either of the two cations, Ca 2+ or Mg 2+ was sufficient to produce chromatin fragments with sizes between 700 and 300 kbp. The formation of chromatin fragments of 50 kbp as well as the following internucleosomal DNA cleavage - which are characteristic of apoptosis - were markedly stimulated in the presence of Ca 2+ . Chromatin degradation to 50 kbp and smaller (oligonucleosome-size) fragments was prevented by inhibitors of endonucleases and serine proteases. We suggest a mechanism whereby the concerted activity of both proteases and endonucleases results in the widespread chromatin cleavage observed in cellls undergoing apoptosis.

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关键词：

Apoptosis Chromatin Endonuclease Protease Liver nuclei ATA, aurintricarboxylic acid DTT, dithiothreitol EDTA, ethylenediamine tetraacetic acid EGTA, ethylene glycol- O, O′ -bis(2-aminoethyl- N, N, N′ N′ -tetraacetic acid HMW DNA, high molecular weight DNA