Activation of transcription initiation from a stable RNA promoter by a Fis protein-mediated DNA structural transmission mechanism
Activation of transcription initiation from a stable RNA promoter by a Fis protein-mediated DNA structural transmission mechanism
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DOI：
10.1111/j.1365-2958.2004.04147.x
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发表时间：
2004-07-01
影响因子：
3.6
通讯作者：
Hatfield, GW
中科院分区：
文献类型：
--
作者：
Opel, ML;Aeling, KA;Hatfield, GW
The leuV operon of Escherichia coli encodes three of the four genes for the tRNA(1)(Leu) isoacceptors. Transcription from this and other stable RNA promoters is known to be affected by a cis-acting UP element and by Fis protein interactions with the carboxyl-terminal domain of the alpha-subunits of RNA polymerase. In this report, we suggest that transcription from the leuV promoter also is activated by a Fis-mediated, DNA supercoiling-dependent mechanism similar to the IHF-mediated mechanism described previously for the ilvP(G) promoter (S. D. Sheridan et al., 1998, J Biol Chem 273: 21298-21308). We present evidence that Fis binding results in the translocation of superhelical energy from the promoter-distal portion of a supercoiling-induced DNA duplex destabilized (SIDD) region to the promoter-proximal portion of the leuV promoter that is unwound within the open complex. A mutant Fis protein, which is defective in contacting the carboxyl-terminal domain of the alpha-subunits of RNA polymerase, remains competent for stimulating open complex formation, suggesting that this DNA supercoiling-dependent component of Fis-mediated activation occurs in the absence of specific protein interactions between Fis and RNA polymerase. Fis-mediated translocation of superhelical energy from upstream binding sites to the promoter region may be a general feature of Fis-mediated activation of transcription at stable RNA promoters, which often contain A+T-rich upstream sequences.
