2ND CYTO-TOXIC PATHWAY OF DIPHTHERIA-TOXIN SUGGESTED BY NUCLEASE ACTIVITY
2ND CYTO-TOXIC PATHWAY OF DIPHTHERIA-TOXIN SUGGESTED BY NUCLEASE ACTIVITY
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DOI：
10.1126/science.2531465
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发表时间：
1989-12-01
期刊：
影响因子：
56.9
通讯作者：
WISNIESKI, BJ
中科院分区：
文献类型：
--
作者：
CHANG, MP;BALDWIN, RL;WISNIESKI, BJ
白喉毒素（DTx）在细胞裂解前引起广泛的核小体间DNA降解。DNA分裂源于细胞内毒素分子对染色体的直接攻击的可能性通过dtx相关核酸酶活性的体外测定进行了测试。DTx与DNA在溶液中孵育或在DNA凝胶试验中显示Ca2+和Mg2+刺激的核酸酶活性。该活性易受特异性抗毒素的抑制，并随毒素片段A迁移。使用超螺旋双链DNA的分析显示了快速的核内溶解攻击。dtx相关核酸酶活性的发现支持了dtx诱导的细胞裂解不是蛋白质合成抑制的简单结果的模型。
Diphtheria toxin (DTx) provokes extensive internucleosomal degradation of DNA before cell lysis. The possibility that DNA cleavage stems from direct chromosomal attack by intracellular toxin molecules was tested by in vitro assays for a DTx-associated nuclease activity. DTx incubated with DNA in solution or in a DNA-gel assay showed Ca2+- and Mg2+-stimulated nuclease activity. This activity proved susceptible to inhibition by specific antitoxin and migrated with fragment A of the toxin. Assays in which supercoiled double-stranded DNA was used revealed rapid endonucleolytic attack. Discovery of a DTx-associated nuclease activity lends support to the model that DTx-induced cell lysis is not a simple consequence of protein synthesis inhibition.