Lara-Tejero M, Galán J E
Section of Microbial Pathogenesis, Boyer Center for Molecular Medicine, Yale School of Medicine, New Haven, CT 06536, USA.
Science. 2000 Oct 13;290(5490):354-7. doi: 10.1126/science.290.5490.354.
Many bacterial pathogens encode a multisubunit toxin, termed cytolethal distending toxin (CDT), that induces cell cycle arrest, cytoplasm distention, and, eventually, chromatin fragmentation and cell death. In one such pathogen, Campylobacter jejuni, one of the subunits of this toxin, CdtB, was shown to exhibit features of type I deoxyribonucleases. Transient expression of this subunit in cultured cells caused marked chromatin disruption. Microinjection of low amounts of CdtB induced cytoplasmic distention and cell cycle arrest. CdtB mutants with substitutions in residues equivalent to those required for catalysis or magnesium binding in type I deoxyribonucleases did not cause chromatin disruption. CDT holotoxin containing these mutant forms of CdtB did not induce morphological changes or cell cycle arrest.
许多细菌病原体编码一种多亚基毒素，称为细胞致死性膨胀毒素（CDT），它可诱导细胞周期停滞、细胞质膨胀，并最终导致染色质碎片化和细胞死亡。在一种这样的病原体空肠弯曲菌中，这种毒素的一个亚基CdtB被证明具有I型脱氧核糖核酸酶的特征。该亚基在培养细胞中的瞬时表达导致明显的染色质破坏。微量注射CdtB会诱导细胞质膨胀和细胞周期停滞。在与I型脱氧核糖核酸酶催化或镁结合所需残基等效的位置进行替换的CdtB突变体不会导致染色质破坏。含有这些CdtB突变形式的CDT全毒素不会诱导形态变化或细胞周期停滞。
