Deng G, Podack E R
Department of Microbiology and Immunology, University of Miami School of Medicine, Florida 33136, USA.
FASEB J. 1995 May;9(8):665-9. doi: 10.1096/fasebj.9.8.7768359.
IL-2-dependent CTLL2 cells, upon IL-2 deprivation, die by apoptosis, which is accompanied by the fragmentation of genomic DNA. Two major deoxyribonuclease activities were detected in the extract of IL-2-deprived CTLL2 cells in a zymographic assay. They were designated nuc-58 and nuc-40, based on their apparent molecular mass of 58 and 40 kDa. The activity of both DNases was greatly induced in CTLL2 cells deprived of IL-2 or treated with the kinase inhibitor staurosporine. Deregulated expression of bcl-2 cDNA suppressed the induction of both nuclease activities. Nuc-58 was dependent on both Ca2+ and Mg2+ ions alone. Nuc-40 showed a preferential nuclear localization over that of nuc-58, which was found primarily in the cytoplasm. Optimal activity of both DNases required neutral pH and was inhibited by zinc ions. The physicochemical characteristics of the nucleases indicate that they are novel DNases associated with apoptosis in CTLL2 cells.
依赖白细胞介素-2的CTLL2细胞，在白细胞介素-2缺失时，会因凋亡而死亡，这伴随着基因组DNA的片段化。在酶谱分析中，在白细胞介素-2缺失的CTLL2细胞提取物中检测到两种主要的脱氧核糖核酸酶活性。根据它们表观分子量58 kDa和40 kDa，分别命名为nuc-58和nuc-40。在缺乏白细胞介素-2或用激酶抑制剂星形孢菌素处理的CTLL2细胞中，两种脱氧核糖核酸酶的活性均被极大诱导。bcl-2 cDNA的失调表达抑制了两种核酸酶活性的诱导。Nuc-58仅依赖Ca2+和Mg2+离子。与主要存在于细胞质中的nuc-58相比，Nuc-40表现出优先的核定位。两种脱氧核糖核酸酶的最佳活性都需要中性pH，并且被锌离子抑制。这些核酸酶的物理化学特性表明它们是与CTLL2细胞凋亡相关的新型脱氧核糖核酸酶。
