Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P51532 (transcriptional activator)
 6,546 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

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.
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PMID:A novel heme protein that acts as a carbon monoxide-dependent transcriptional activator in Rhodospirillum rubrum. 894 49

In-frame deletion mutagenesis was used to study the roles of two Bradyrhizobium japonicum proteins, HoxX and HoxA, in hydrogenase biosynthesis; based on their sequences, these proteins were previously proposed to be sensor and regulator proteins, respectively, of a two-component regulatory system necessary for hydrogenase transcription. Deletion of the hoxX gene resulted in a strain that expressed only 30 to 40% of wild-type hydrogenase activity. The inactive unprocessed form of the hydrogenase large subunit accumulated in this strain, indicating a role for HoxX in posttranslational processing of the hydrogenase enzyme but not in transcriptional regulation. Strains containing a deletion of the hoxA gene or a double mutation (hoxX and hoxA) did not exhibit any hydrogenase activity under free-living conditions, and extracts from these strains were inactive in gel retardation assays with a 158-bp fragment of the DNA region upstream of the hupSL operon. However, bacteroids from root nodules formed by all three mutant types (hoxX, hoxA, and hoxX hoxA) exhibited hydrogenase activity comparable to that of wild-type bacteroids. Bacteroid extracts from all of these strains, including the wild type, failed to cause a shift of the hydrogenase upstream region used in our assay. It was shown that HoxA is a DNA-binding transcriptional activator of hydrogenase structural gene expression under free-living conditions but not under symbiotic conditions. Although symbiotic hydrogenase expression is still sigma54 dependent, a transcriptional activator other than HoxA functions presumably upstream of the HoxA binding site.
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PMID:Roles of HoxX and HoxA in biosynthesis of hydrogenase in Bradyrhizobium japonicum. 917 16

To gain insights on the transcriptional switches that modulate proper copper homeostasis in yeast, we have examined in detail functional interactions of the relevant transcriptional activator Mac1. We identified Hir1 transcriptional repressor and histone chaperone as a Mac1-interacting protein. This association directly recruits Hir1 on a Mac1 target, CTR1 promoter, quantitatively under induction conditions. We also found Hir1 interacting directly with a previously unknown partner, the Ssn6 (Cyc8) co-regulator. On the non-induced CTR1 promoter, a Hir1 transcriptional activation function was revealed, in the absence of Ssn6, which was dependent on the presence of Snf2 (Swi2) nucleosome remodeler. Moreover, Ssn6 was identified as a Mac1-dependent prominent repressor of CTR1 transcription, antagonizing Snf2 occupancy. Transcriptional induction by copper depletion was effected by the quantitative recruitment of Snf2 directed mainly by Mac1 and redundantly by the quantitatively accumulated Hir1 and Ssn6 pair. Our analysis showed that the activation-effecting chromatin remodeling of CTR1 was due to Snf2 and not to the Hir1 histone chaperone activity or ability to regulate histone levels and stoichiometry. Following initiation, Hir1 and Snf2, but not Ssn6, were found to associate also with the actively transcribing CTR1 coding region, where Hir1 followed the pattern of the elongating RNA polymerase II. Therefore, we have shown that, at the CTR1 gene, in association with Mac1 DNA-binding transcriptional activator, the distinct and alternate genetic and physical collaboration of three global regulators modulates the transcriptional state of a switch involved in copper homeostasis.
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PMID:Synergy of Hir1, Ssn6, and Snf2 global regulators is the functional determinant of a Mac1 transcriptional switch in S. cerevisiae copper homeostasis. 3068 22

While it is known that ScRad9 DNA damage checkpoint protein is recruited to damaged DNA by recognizing specific histone modifications, here we report a different way of Rad9 recruitment on chromatin under non DNA damaging conditions. We found Rad9 to bind directly with the copper-modulated transcriptional activator Mac1, suppressing both its DNA binding and transactivation functions. Rad9 was recruited to active Mac1-target promoters (CTR1, FRE1) and along CTR1 coding region following the association pattern of RNA polymerase (Pol) II. Hir1 histone chaperone also interacted directly with Rad9 and was partly required for its localization throughout CTR1 gene. Moreover, Mac1-dependent transcriptional initiation was necessary and sufficient for Rad9 recruitment to the heterologous ACT1 coding region. In addition to Rad9, Rad53 kinase also localized to CTR1 coding region in a Rad9-dependent manner. Our data provide an example of a yeast DNA-binding transcriptional activator that interacts directly with a DNA damage checkpoint protein in vivo and is functionally restrained by this protein, suggesting a new role for Rad9 in connecting factors of the transcription machinery with the DNA repair pathway under unchallenged conditions.
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PMID:Distinct associations of the Saccharomyces cerevisiae Rad9 protein link Mac1-regulated transcription to DNA repair. 3178 68