The Experts below are selected from a list of 309 Experts worldwide ranked by ideXlab platform
Tom Lewis - One of the best experts on this subject based on the ideXlab platform.
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Transcriptional regulation of the pdt gene cluster of pseudomonas stutzeri kc involves an arac xyls family Transcriptional Activator pdtc and the cognate siderophore pyridine 2 6 bis thiocarboxylic acid
Applied and Environmental Microbiology, 2006Co-Authors: Sergio E Morales, Tom LewisAbstract:In order to gain an understanding of the molecular mechanisms dictating production of the siderophore and dechlorination agent pyridine-2,6-bis(thiocarboxylic acid) (PDTC), we have begun characterization of a gene found in the pdt gene cluster of Pseudomonas stutzeri KC predicted to have a regulatory role. That gene product is an AraC family Transcriptional Activator, PdtC. Quantitative reverse transcription-PCR and expression of Transcriptional reporter fusions were used to assess a role for pdtC in the transcription of pdt genes. PdtC and an upstream, promoter-proximal DNA segment were required for wild-type levels of expression from the promoter of a predicted biosynthesis operon (PpdtF). At least two other Transcriptional units within the pdt cluster were also dependent upon pdtC for expression at wild-type levels. The use of a heterologous, Pseudomonas putida host demonstrated that pdtC and an exogenously added siderophore were necessary and sufficient for expression from the pdtF promoter, i.e., none of the PDTC utilization genes within the pdt cluster were required for Transcriptional signaling. Tests using the promoter of the pdtC gene in Transcriptional reporter fusions indicated siderophore-dependent negative autoregulation similar to that seen with other AraC-type regulators of siderophore biosynthesis and utilization genes. The data increase the repertoire of siderophore systems known to be regulated by this type of Transcriptional Activator and have implications for PDTC signaling.
Steven J Triezenberg - One of the best experts on this subject based on the ideXlab platform.
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phosphorylation of the vp16 Transcriptional Activator protein during herpes simplex virus infection and mutational analysis of putative phosphorylation sites
Virology, 2006Co-Authors: Soren Ottosen, Francisco J Herrera, James R Doroghazi, Angela Hull, Sheenu Mittal, William S Lane, Steven J TriezenbergAbstract:VP16 is a virion phosphoprotein of herpes simplex virus and a Transcriptional Activator of the viral immediate-early (IE) genes. We identified four novel VP16 phosphorylation sites (Ser18, Ser353, Ser411, and Ser452) at late times in infection but found no evidence of phosphorylation of Ser375, a residue reportedly phosphorylated when VP16 is expressed from a transfected plasmid. A virus carrying a Ser375Ala mutation of VP16 was viable in cell culture but with a slow growth rate. The association of the mutant VP16 protein with IE gene promoters and subsequent IE gene expression was markedly reduced during infection, consistent with prior transfection and in vitro results. Surprisingly, the association of Oct-1 with IE promoters was also diminished during infection by the mutant strain. We propose that Ser375 is important for the interaction of VP16 with Oct-1, and that the interaction is required to enable both proteins to bind to IE promoters.
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Transcriptional adaptor and histone acetyltransferase proteins in arabidopsis and their interactions with cbf1 a Transcriptional Activator involved in cold regulated gene expression
Nucleic Acids Research, 2001Co-Authors: Eric J Stockinger, Yaopan Mao, Martha K Regier, Steven J Triezenberg, Michael F ThomashowAbstract:The Arabidopsis CBF Transcriptional Activators bind to the CRT/DRE regulatory element present in the promoters of many cold-regulated genes and stimulate their transcription. Expression of the CBF1 proteins in yeast activates reporter genes carrying a minimal promoter with the CRT/DRE as an upstream regulatory element. Here we report that this ability of CBF1 is dependent upon the activities of three key components of the yeast Ada and SAGA complexes, namely the histone acetyltransferase (HAT) Gcn5 and the Transcriptional adaptor proteins Ada2 and Ada3. This result suggested that CBF1 might function through the action of similar complexes in Arabidopsis. In support of this hypothesis we found that Arabidopsis has a homolog of the GCN5 gene and two homologs of ADA2, the first report of multiple ADA2 genes in an organism. The Arabidopsis GCN5 protein has intrinsic HAT activity and can physically interact in vitro with both the Arabidopsis ADA2a and ADA2b proteins. In addition, the CBF1 Transcriptional Activator can interact with the Arabidopsis GCN5 and ADA2 proteins. We conclude that Arabidopsis encodes HAT-containing adaptor complexes that are related to the Ada and SAGA complexes of yeast and propose that the CBF1 Transcriptional Activator functions through the action of one or more of these complexes.
Hiroshi Nakajima - One of the best experts on this subject based on the ideXlab platform.
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Recognition of target DNA and transcription activation by the CO-sensing Transcriptional Activator CooA.
Biochemical and biophysical research communications, 1999Co-Authors: Shigetoshi Aono, T Kamiya, Hidenori Takasaki, Hideaki Unno, Hiroshi NakajimaAbstract:Abstract CooA from Rhodospirillum rubrum is a heme-based CO-sensing Transcriptional Activator, in which CO acts as a physiological effector. In this study, we examined the mechanism of site-specific recognition and Transcriptional activation by CooA by elucidating the Transcriptional Activator activity of the mutant CooA proteins and the chimeric proteins derived from CRP and CooA and the promoter activity of the mutant promoters. Site-directed mutagenesis has revealed that Arg 177 , Gln 178 , and Ser 181 on the recognition helix of the helix-turn-helix motif in CooA are responsible for the site-specific recognition. The side chains of these amino acid residues at positions 177, 178, and 181 are believed to be hydrogen bonding to the G:A, T:A, and C:G pairs at positions 2/15, 3/14, and 4/13 in the CooA-dependent promoters to recognize the DNA site for CooA. The properties of the CRP/CooA chimeric proteins constructed in this work suggest that CooA activates transcription by a similar mechanism to that of CRP at Class II CRP-dependent promoters.
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a novel heme protein that acts as a carbon monoxide dependent Transcriptional Activator in rhodospirillum rubrum
Biochemical and Biophysical Research Communications, 1996Co-Authors: Shigetoshi Aono, Hiroshi Nakajima, Kimio Saito, Motoshi OkadaAbstract:The gene coding for a carbon monoxide-dependent Transcriptional Activator (cooA) in Rhodospirillum rubrum has been expressed in E. coli, and the recombinant CooA has been purified. CooA contains b-type heme which may act as a CO sensor in vivo. CO-bound CooA was formed when reduced CooA was reacted with CO, but not in the case of oxidized CooA. CooA is the first example of the heme protein acting as a DNA-binding Transcriptional Activator.
Shigetoshi Aono - One of the best experts on this subject based on the ideXlab platform.
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Recognition of target DNA and transcription activation by the CO-sensing Transcriptional Activator CooA.
Biochemical and biophysical research communications, 1999Co-Authors: Shigetoshi Aono, T Kamiya, Hidenori Takasaki, Hideaki Unno, Hiroshi NakajimaAbstract:Abstract CooA from Rhodospirillum rubrum is a heme-based CO-sensing Transcriptional Activator, in which CO acts as a physiological effector. In this study, we examined the mechanism of site-specific recognition and Transcriptional activation by CooA by elucidating the Transcriptional Activator activity of the mutant CooA proteins and the chimeric proteins derived from CRP and CooA and the promoter activity of the mutant promoters. Site-directed mutagenesis has revealed that Arg 177 , Gln 178 , and Ser 181 on the recognition helix of the helix-turn-helix motif in CooA are responsible for the site-specific recognition. The side chains of these amino acid residues at positions 177, 178, and 181 are believed to be hydrogen bonding to the G:A, T:A, and C:G pairs at positions 2/15, 3/14, and 4/13 in the CooA-dependent promoters to recognize the DNA site for CooA. The properties of the CRP/CooA chimeric proteins constructed in this work suggest that CooA activates transcription by a similar mechanism to that of CRP at Class II CRP-dependent promoters.
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a novel heme protein that acts as a carbon monoxide dependent Transcriptional Activator in rhodospirillum rubrum
Biochemical and Biophysical Research Communications, 1996Co-Authors: Shigetoshi Aono, Hiroshi Nakajima, Kimio Saito, Motoshi OkadaAbstract:The gene coding for a carbon monoxide-dependent Transcriptional Activator (cooA) in Rhodospirillum rubrum has been expressed in E. coli, and the recombinant CooA has been purified. CooA contains b-type heme which may act as a CO sensor in vivo. CO-bound CooA was formed when reduced CooA was reacted with CO, but not in the case of oxidized CooA. CooA is the first example of the heme protein acting as a DNA-binding Transcriptional Activator.
Sergio E Morales - One of the best experts on this subject based on the ideXlab platform.
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Transcriptional regulation of the pdt gene cluster of pseudomonas stutzeri kc involves an arac xyls family Transcriptional Activator pdtc and the cognate siderophore pyridine 2 6 bis thiocarboxylic acid
Applied and Environmental Microbiology, 2006Co-Authors: Sergio E Morales, Tom LewisAbstract:In order to gain an understanding of the molecular mechanisms dictating production of the siderophore and dechlorination agent pyridine-2,6-bis(thiocarboxylic acid) (PDTC), we have begun characterization of a gene found in the pdt gene cluster of Pseudomonas stutzeri KC predicted to have a regulatory role. That gene product is an AraC family Transcriptional Activator, PdtC. Quantitative reverse transcription-PCR and expression of Transcriptional reporter fusions were used to assess a role for pdtC in the transcription of pdt genes. PdtC and an upstream, promoter-proximal DNA segment were required for wild-type levels of expression from the promoter of a predicted biosynthesis operon (PpdtF). At least two other Transcriptional units within the pdt cluster were also dependent upon pdtC for expression at wild-type levels. The use of a heterologous, Pseudomonas putida host demonstrated that pdtC and an exogenously added siderophore were necessary and sufficient for expression from the pdtF promoter, i.e., none of the PDTC utilization genes within the pdt cluster were required for Transcriptional signaling. Tests using the promoter of the pdtC gene in Transcriptional reporter fusions indicated siderophore-dependent negative autoregulation similar to that seen with other AraC-type regulators of siderophore biosynthesis and utilization genes. The data increase the repertoire of siderophore systems known to be regulated by this type of Transcriptional Activator and have implications for PDTC signaling.
