Transcription-coupled nucleoid architecture in bacteria
Transcription-coupled nucleoid architecture in bacteria
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DOI：
10.1111/j.1365-2443.2007.01125.x
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发表时间：
2007-10-01
期刊：
影响因子：
2.1
通讯作者：
Takeyasu, Kunio
中科院分区：
文献类型：
--
作者：
Ohniwa, Ryosuke L.;Morikawa, Kazuya;Takeyasu, Kunio
环状细菌基因组DNA以类核形式存在于细胞中。在本研究中，利用遗传、分子和结构生物学技术，我们发现新生单链rna参与了类核纤维的阶梯折叠。在大肠杆菌中，RNase A将较厚的纤维（30和80 nm宽）降解为较薄的纤维（10 nm宽），而RNase III和RNase H将80 nm的纤维降解为30 nm（但不是10 nm）的纤维。同样，在金黄色葡萄球菌中，RNase A处理产生了10nm的纤维。在没有RNase A的情况下，转录抑制剂利福平将大多数类核纤维改变为10纳米纤维。类核暴露DNA的蛋白酶- k处理。因此，最小的结构单元是由DNA和蛋白质组成的抗RNase a的10纳米纤维，细菌染色体的层次结构由转录本身控制。此外，由30纳米纤维形成80纳米纤维需要双链RNA和RNA- dna异双工。RNA在对数相非凝聚和固定相凝聚类核的结构中是明显的。
The circular bacterial genome DNA exists in cells in the form of nucleoids. In the present study, using genetic, molecular and structural biology techniques, we show that nascent single-stranded RNAs are involved in the step-wise folding of nucleoid fibers. In Escherichia coli, RNase A degraded thicker fibers (30 and 80 nm wide) into thinner fibers (10 nm wide), while RNase III and RNase H degraded 80-nm fibers into 30-nm (but not 10-nm) fibers. Similarly in Staphylococcus aureus, RNase A treatment resulted in 10-nm fibers. Treatment with the transcription inhibitor, rifampicin, in the absence of RNase A changed most nucleoid fibers to 10-nm fibers. Proteinase-K treatment of nucleoids exposed DNA. Thus, the smallest structural unit is an RNase A-resistant 10-nm fiber composed of DNA and proteins, and the hierarchical structure of the bacterial chromosome is controlled by transcription itself. In addition, the formation of 80-nm fibers from 30-nm fibers requires double-stranded RNA and RNA-DNA hetero duplex. RNA is evident in the architecture of log-phase uncondensed and stationary-phase condensed nucleoids.