共查询到20条相似文献,搜索用时 0 毫秒
1.
2.
3.
4.
5.
In prokaryotes, DNA supercoiling regulates the expression of many genes; for example, the expression of Klebsiella pneumoniae nifLA operon depends on DNA negative supercoiling in anaerobically grown ceils, which indicates that DNA supercoiling might play a role in gene regulation of the anaerobic response. Since the expression of the nifH promoter in Sinorhizobium meliloti is not repressed by oxygen, it is proposed that the status of DNA supercoiling may not affect the expression of the nifH promoter. We tested this hypothesis by analyzing nifH promoter activity in wild-type and gyr- Escherichia coli in the presence and absence of DNA gyrase inhibitors. Our results show that gene expression driven by the S.meliloti nifH promoter requires the presence of active DNA gyrase. Because DNA gyrase increases the number of negative superhelical turns in DNA in the presence of ATP, our data indicate that negative supercoiling is also important for nifH promoter activity. Our study also shows that the DNA supercoiling-dependent S. meliloti nifH promoter activity is related to the trans-acting factors NtrC and NifA that activate it. DNA supercoiling appeared to have a stronger effect on NtrC-activated nifH promoter activity than on NifA-activated promoter activity. Collectively, these results from the S. meliloti nifH promoter model system seem to indicate that, in addition to regulating gene expression during anaerobic signaling, DNA supercoiling may also provide a favorable topology for trans-acting factor binding and promoter activation regardless of oxygen status. 相似文献
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
Cherstvy AG 《Journal of biological physics》2011,37(2):227-238
We study the deformations of charged elastic rods under applied end forces and torques. For neutral filaments, we analyze
the energetics of initial helical deformations and loop formation. We supplement this elastic approach with electrostatic
energies of bent filaments and find critical conditions for buckling depending on the ionic strength of the solution. We also
study force-induced loop opening, for parameters relevant for DNA. Finally, some applications of this nano-mechanical DNA
model to salt-dependent onset of the DNA supercoiling are discussed. 相似文献
16.
17.
Regulation of gene expression via the core promoter and the basal transcriptional machinery 总被引:1,自引:0,他引:1
Tamar Juven-Gershon 《Developmental biology》2010,339(2):225-229
18.
19.
20.
The transcriptional regulator network of human inflammatory macrophages is defined by open chromatin
Susanne V Schmidt Wolfgang Krebs Thomas Ulas Jia Xue Kevin Ba?ler Patrick Günther Anna-Lena Hardt Hartmut Schultze Jil Sander Kathrin Klee Heidi Theis Michael Kraut Marc Beyer Joachim L Schultze 《Cell research》2016,26(2):151-170