Human polymorphonuclear leukocytes (PMN) have been reported to completely lack of DNA-dependent protein kinase (DNA-PK) which is composed of Ku protein and the catalytic subunit DNA-PKcs, needed for nonhomologous end-...Human polymorphonuclear leukocytes (PMN) have been reported to completely lack of DNA-dependent protein kinase (DNA-PK) which is composed of Ku protein and the catalytic subunit DNA-PKcs, needed for nonhomologous end-joining (NHEJ) of DNA double-strand breaks. Promyelocytic HL-60 cells express a variant form of Ku resulting in enhanced radiation sensitivity. This raises the question if low efficiency of NHEJ, instrumental for the cellular repair of oxidative damage, is a normal characteristic of myeloid differentiation. Here we confirmed the complete lack of DNAPK in P MN protein extracts, and the expression of the truncated Ku86 variant form in HL-60. However, this degradation of DNA-PK was shown to be due to a DNA-PK-degrading protease in PMN and HL-60. In addition, by using a protease-resistant whole cell assay, both Ku86 and DNA-PKcs could be demonstrated in PMN, suggesting the previously reported absence in PMN of DNA-PK to be an artefact. The levels of Ku86 and DNA-PKcs were much reduced in PMN, as compared with that of the lymphocytes, whereas HL-60 displayed a markedly elevated DNA-PK concentration.In conclusion, our findings provide evidence of reduced, not depleted expression of DNA-PK during the mature stages of myeloid differentiation.展开更多
为全面优化Web前端界面综合性能,保障各个功能模块间良好通信,提升前端界面运行流畅性,本研究将超文本标记语言第5版本(Hyper Text Markup Language,HTML5)应用于Web前端开发中。对HTML5在Web前端开发中的应用现状进行分析,并深度探究We...为全面优化Web前端界面综合性能,保障各个功能模块间良好通信,提升前端界面运行流畅性,本研究将超文本标记语言第5版本(Hyper Text Markup Language,HTML5)应用于Web前端开发中。对HTML5在Web前端开发中的应用现状进行分析,并深度探究Web前端系统和HTML5关键技术之后,进一步融合模型、视图、控制(Model-View-Controller,MVC)开发模式,构建基于基础视图层、核心逻辑层、数据模型层的数据可视化(Data Visualization Layout,DVL)框架。以此实现在服务器端、前后端之间的有效通信;完善Web前端界面与响应指令的直接连接;促进前端场景有效集成与渲染;建立Web前端表单,保障前端展示信息的完善性。展开更多
文摘Human polymorphonuclear leukocytes (PMN) have been reported to completely lack of DNA-dependent protein kinase (DNA-PK) which is composed of Ku protein and the catalytic subunit DNA-PKcs, needed for nonhomologous end-joining (NHEJ) of DNA double-strand breaks. Promyelocytic HL-60 cells express a variant form of Ku resulting in enhanced radiation sensitivity. This raises the question if low efficiency of NHEJ, instrumental for the cellular repair of oxidative damage, is a normal characteristic of myeloid differentiation. Here we confirmed the complete lack of DNAPK in P MN protein extracts, and the expression of the truncated Ku86 variant form in HL-60. However, this degradation of DNA-PK was shown to be due to a DNA-PK-degrading protease in PMN and HL-60. In addition, by using a protease-resistant whole cell assay, both Ku86 and DNA-PKcs could be demonstrated in PMN, suggesting the previously reported absence in PMN of DNA-PK to be an artefact. The levels of Ku86 and DNA-PKcs were much reduced in PMN, as compared with that of the lymphocytes, whereas HL-60 displayed a markedly elevated DNA-PK concentration.In conclusion, our findings provide evidence of reduced, not depleted expression of DNA-PK during the mature stages of myeloid differentiation.
