Preobrazhenskaia O V, Starodubova E S, Karpov V L, Rouviere-Yaniv J
Mol Biol (Mosk). 2005 Jul-Aug;39(4):678-86.
HU, a nonspecific histone-like DNA binding protein is a major component of the bacterial nucleoid. HU is referred to as an accessory factor for complex protein-DNA assembly and as a protein involved in DNA compaction. In this study we investigated in vivo HU binding along the different regions of E. coli genome. For this purpose we used ChIP--in vivo formaldehyde crosslinking and immunoprecipitation of protein-DNA complexes with antiHU-antibodies. This technique allows to compare the local concentration of HU protein in the different regions of E. coli genomic DNA. In this study we analysed the HU-DNA crosslinking both in exponentially growing and stationary phase of bacteria in the following regions of E. coli genome: oriC region, promoter and structural regions of hupA and hupB genes coding two different subunits of HU, and structural parts of dps and glgS genes which are active only in stationary phase. Our results indicate that in exponentially growing E. coli cells the local concentration of HU protein is uniform for all analysed regions of genome and does not depend on their transcriptional status. The twofold increase of local concentration of HU protein was also shown for all analysed genome regions in the stationary phase cells.
HU是一种非特异性的组蛋白样DNA结合蛋白，是细菌类核的主要成分。HU被认为是复杂蛋白质-DNA组装的辅助因子，也是参与DNA压缩的蛋白质。在本研究中，我们研究了大肠杆菌基因组不同区域的体内HU结合情况。为此，我们使用了染色质免疫沉淀技术（ChIP）——即体内甲醛交联以及用抗HU抗体对蛋白质-DNA复合物进行免疫沉淀。该技术能够比较大肠杆菌基因组DNA不同区域中HU蛋白的局部浓度。在本研究中，我们分析了大肠杆菌基因组以下区域中，处于指数生长期和稳定期的细菌的HU-DNA交联情况：oriC区域、编码HU两个不同亚基的hupA和hupB基因的启动子及结构区域，以及仅在稳定期活跃的dps和glgS基因的结构部分。我们的结果表明，在指数生长的大肠杆菌细胞中，HU蛋白的局部浓度在基因组所有分析区域中是均匀的，且不依赖于它们的转录状态。在稳定期细胞的所有分析基因组区域中，HU蛋白的局部浓度也显示出两倍的增加。
