The torI gene has been identified by using a genetic multicopy approach as a negative regulator of the torCAD operon that encodes the trimethylamine N-oxide reductase respiratory system in Escherichia coli. The negative effect was due to a previously unidentified small ORF (66 aa) of phage origin that we called torI for Tor inhibition. Overexpression of torI led to an 8-fold decrease of the torCAD operon transcription. This operon is positively regulated, in the presence of trimethylamine N-oxide, by a four-step phosphorelay involving the TorS sensor and the TorR response regulator. Epistatic experiments showed that TorI acts downstream of TorS and needs the presence of TorR. In vitro experiments showed that it is neither a TorR phosphatase nor a histidine kinase inhibitor and that it binds to the effector domain of TorR. Unexpectedly, TorI did not impede TorR DNA binding, and we propose that it may prevent RNA polymerase recruitment to the torC promoter. This study thus reveals a previously uncharacterized class of response regulator inhibitors.
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http://dx.doi.org/10.1073/pnas.0401927101 | DOI Listing |
Appl Biochem Biotechnol
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Department of Internal Medicine-Cardiovascular, Guangzhou Twelfth People's Hospital, No.1, Tianqiang Road, Tianhe District, Guangzhou City, Guangdong Province, 510620, China.
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View Article and Find Full Text PDFCurr Osteoporos Rep
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Department of Immunology, Tufts University, Boston, MA, 02111, USA.
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Psychopharmacology (Berl)
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Department of Molecular Biology, Ariel University, Ariel, Israel.
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Naunyn Schmiedebergs Arch Pharmacol
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Oral Biology Department, Faculty of Dentistry, Galala Plateau, Galala University, 15888), Attaka, Suez Governorate, Egypt.
Leukemia covers a broad category of cancer malignancies that specifically affect bone marrow and blood cells. While different kinds of leukemia have been identified, effective treatments are still lacking for most forms, and even those treatments considered effective can lead to relapses. MicroRNAs, or miRNAs, are short endogenous non-coding single-stranded RNAs that help control the epigenetics of gene expression.
View Article and Find Full Text PDFCurr Obes Rep
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