Multi‐step DNA cleavage in rat liver nuclei is inhibited by thiol reactive agents

FEBS Letters

Inayat-Hussain, Salmaan H.¹  Cain, Kelvin¹  Cohen, Gerald M.¹  Kokileva, Ludmilla¹ 

[1] MRC Toxicology Unit, Hodgkin Building, University of Leicester, P.O. Box 138, Lancaster Rd, Leicester LE1 9HN, UK

关键词: Apoptosis;    Multi-step DNA cleavage;    Critical thiol;    anti-DIG;    antidigoxigenin-fluorescein FAB fragments;    DCI;    dichloroisocoumarin;    DMSO;    dimethyl sulphoxide;    Dig-11-dUTP;    digoxigenin-11-2′-deoxy-uridine-5′-triphosphate;    DTT;    dithiothreitol;    kbp;    kilobase pair;    FIGE;    field inversion gel electrophoresis;    PBS;    phosphate buffered saline;    TdT;    terminal deoxynucleotidyl transferase;    TLCK;    chloromethylketone;    TPCK;   

DOI  :  10.1016/0014-5793(94)01436-5

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

DNA fragmentation in isolated rat liver nuclei is a Mg²⁺-dependent, multi-step process which is potentiated by Ca²⁺ and cleaves the DNA into ≥700, 200–300 and 30–50 kilobase pair (kbp) fragments, prior to internucleosomal cleavage by Ca²⁺/Mg²⁺-dependent endonuclease(s). We now show that Cd²⁺, Hg²⁺, dichloroisocoumarin (DCI, a serine protease inhibitor) and N-ethylmaleimide (NEM) block both Mg²⁺ and Ca²⁺/Mg²⁺-dependent processes. Inhibition of DNA cleavage produced an increase in the size of the DNA fragments, from mono-/oligonucleosomes to 30–50, 200–300, ≥700 kbp and finally to intact DNA. NEM and DCI inhibition was blocked by dithiothreitol, and it is proposed that a critical thiol(s) is involved in the DNA cleavage reactions which are a feature of the apoptotic process.

【 授权许可】

Unknown