Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

---

Query: UNIPROT:P51532 (transcriptional activator)
6,546 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The highly metastatic B16a melanoma has been shown to express higher levels of cathepsin B (CB) mRNA when compared to the less metastatic variants, B16-F1 and B16-F10, and with normal mouse tissues. This increased expression is now shown to be due to increased gene transcription by nuclear run-off assays and measurements of mRNA stability. Transient expression assays, using promoter fragments from the mouse and human CB genes, demonstrated that both promoters were more active in B16a than in the less metastatic melanomas, B16-F1 and B16-F10. The differential gene expression did not depend on the presence of multiple Sp1 sites in both promoters. A Gel shift assay revealed a specific CB promoter binding protein whose levels are correlated with CB expression and the metastatic potential of the three B16 melanoma variants. These results indicate that the increased expression of CB in the B16a melanoma is due to a specific increase in the amount or activity of a transcriptional activator of the CB gene. The ability of the human CB promoter to activate gene expression in B16a melanoma cells suggests similarities in the regulation of CB expression in tumors from humans and mice.
...
PMID:Transcriptional regulation of cathepsin B expression in B16 melanomas of varying metastatic potential. 803 44

Many strains of Escherichia coli express type 1 pili which undergo phase variation during growth in broth, but become uniformly nonpiliated when passaged on agar media. In a previous analysis of these agar phase locked strains, we demonstrated that fimB and fimE, which mediate the site-specific DNA rearrangement involved in phase variation, are differentially transcribed under the two growth conditions. In this study the fimB promoter region was sequenced and characterized in agar phase locked strain J96. Primer extension analysis of the fimB gene identified three putative transcription initiation sites. Transcription starting from two of the sites (P1 and P2) would produce an mRNA that approximates the transcript size of fimB previously detected by Northern blot hybridizations. Gel mobility shift studies revealed the presence of promoter binding activity in broth-grown cell extracts, but not in extracts from agar-grown cells, that reacted specifically with DNA fragments upstream of the P1 and P2 promoter regions. This putative binding protein may be involved in the regulation of fimB, perhaps by acting as a transcriptional activator.
...
PMID:Analysis of the fimB promoter region involved in type 1 pilus phase variation in Escherichia coli. 812 17

A novel DNA-binding activity, designated CBF, has been identified in nuclear extracts from tobacco leaf, stem and root tissue. CBF interacts specifically with a 30 bp promoter fragment, referred to as cyt-1, of the Agrobacterium tumefaciens T-DNA cytokinin (T-cyt) gene. The T-cyt promoter, although of bacterial origin is active in planta and the 30 bp cyt-1 element is located within a region that is essential for T-cyt promotor activity in leaf, stem and root cells of tobacco plants. Gel retardation assays using different synthetic oligonucleotides and methylation interference experiments pinpointed the binding site of CBF to a GC-rich sequence ATGCCCCACA within the cyt-1 element. Site-directed mutagenesis of the CBF binding site within the T-cyt promoter by using PCR resulted in an almost complete loss of T-cyt promoter activity in transgenic tobacco plants. In a gain-of-function experiment a hexamer of cyt-1 was shown to be able to confer leaf, stem and root expression when fused upstream of a TATA box containing -55 derivative of the T-cyt promoter. A mutant cyt-1 hexamer, defective in CBF binding, did not show activity above background levels. These results indicate that binding of CBF to the cyt-1 element is required for cyt-1 directed gene expression, suggesting that CBF might act as a transcriptional activator. Apart from the ASF-1 binding site of the CaMV 35S promoter, which is also present in the T-DNA nopaline and octopine synthase genes, the cyt-1 element is the only other identified element reported until now that in combination with a TATA box is sufficient to drive gene expression in multiple tobacco tissue types.
...
PMID:Interaction between the tobacco DNA-binding activity CBF and the cyt-1 promoter element of the Agrobacterium tumefaciens T-DNA gene T-CYT correlates with cyt-1 directed gene expression in multiple tobacco tissue types. 822 Apr 94

The Epstein-Barr virus protein EBNA2 acts as a transcriptional activator of cellular and viral genes and plays a crucial role in the immortalization of human primary B-cells by EBV. We have shown previously that EBNA2 transactivates the promoters of the latent membrane antigens LMP, TP1 and TP2. The promoter of the TP1 gene was chosen as a model system to study the molecular mechanism of EBNA2 mediated transactivation. To identify an EBNA2 dependent cis-acting element, various TP1 promoter-reporter gene constructs were transfected in the absence and presence of an EBNA2 expression vector into the established B-cell line BL41-P3HR1. We were able to delineate an 81 bp EBNA2 responsive region between -258 and -177 relative to the TP1 RNA start site. The element worked in either orientation and could mediate EBNA2 dependent transactivation on a heterologous promoter. Electrophoretic mobility shift assays revealed three specific protein-DNA complexes formed with sequences of the EBNA2 responsive element. Two of these were not cell type specific, but the third was detected only in EBNA2 positive cell extracts. Gel-shift analysis in the presence of EBNA2 specific monoclonal antibodies revealed that EBNA2 is a component of the third complex. Thus, these experiments demonstrate that EBNA2 interacts with an EBNA2 responsive cis-element of the TP1 promoter.
...
PMID:The Epstein-Barr virus nuclear antigen 2 interacts with an EBNA2 responsive cis-element of the terminal protein 1 gene promoter. 838 49

Rhabdomyosarcoma cells express the myogenic helix-loop-helix proteins of the MyoD family but do not differentiate into skeletal muscle cells. Gel shift and transient transfection assays revealed that MyoD in the rhabdomyosarcoma cells was capable of binding DNA but was relatively nonfunctional as a transcriptional activator. Heterokaryon formation with fibroblasts resulted in the restoration of transcriptional activation by MyoD and the differentiation of the rhabdomyosarcoma cells into skeletal muscle cells. These results suggest that rhabdomyosarcomas are deficient in a factor required for MyoD activity.
...
PMID:Deficiency in rhabdomyosarcomas of a factor required for MyoD activity and myogenesis. 838 79

Heat shock proteins of the 82-90 kDa class (hsp82 and hsp90) are abundant, conserved, and ubiquitous from prokaryotes to eukaryotes. Although proposed to be chaperones, they had not been reported to possess enzymatic activity until our recent observation that pure trypanosomatid hsp83 had potent ATPase activity (Nadeau, K., Sullivan, M., Engman, D., and Walsh, C. T. (1992) Protein Sci. 1, 970-979). We have now purified the hsp90 homolog from Escherichia coli (HtpG) and from Saccharomyces cerevisiae (hsp82) to homogeneity and observe ATPase activity with kcat values of 3 min-1 and 140 min-1. In addition, examinations of purified rat hsp90 and human hsp90 detect ATPase activity with a kcat of 0.6 min-1 and 10 min-1. Each of these hsp90s undergoes autophosphorylation on serine or threonine residues. In prokaryotes and eukaryotes, the induction of hsps during heat shock is controlled, respectively, by the binding of an alternate sigma 32 or a transcriptional activator (heat shock factor or HSF) at heat shock promoter elements. Here we show that E. coli HtpG immobilized to Affi-Gel beads selectively retains sigma 32 while the yeast hsp90 and rat hsp90 retain HSF. The peptidyl prolyl isomerase hsp59 of the FK506 binding class is known to bind to hsp90. We also detect binding of the other family of PPIases, the cyclophilins, to immobilized hsp90, consistent with a functional convergence of protein foldases.
...
PMID:Hsp90 chaperonins possess ATPase activity and bind heat shock transcription factors and peptidyl prolyl isomerases. 841 47

The transcriptional activator AppY is required for anaerobic and stationary-phase induction of the cyx-appA and hya operons of Escherichia coli, and expression of the appY gene itself is induced by these environmental conditions. The sequence of the appY gene and its promoter region is unusually AT rich. The nucleoid-associated protein H-NS has a DNA-binding specificity for intrinsically curved AT-rich DNA. Using a single-copy transcriptional appY-lacZ fusion, we have shown that appY gene expression is derepressed in hns mutants during aerobic exponential growth. In the hns mutant, growth phase and growth rate regulation under aerobic conditions was maintained, while ArcA-dependent anaerobic induction was greatly diminished. Judged by two-dimensional gel electrophoresis, the appY promoter fragment exhibits the features characteristic of curved DNA. Gel retardation assays showed that purified H-NS protein bound with high affinity to two different segments of the appY promoter region. The role of H-NS in the AppY regulatory cascade is discussed and compared with its function in the regulatory cascades of the AppY homologs CfaD and VirF.
...
PMID:The histone-like protein H-NS acts as a transcriptional repressor for expression of the anaerobic and growth phase activator AppY of Escherichia coli. 865 36

In phototrophic and chemoautotrophic proteobacteria, genes encoding enzymes of the Calvin-Benson-Bassham pathway of CO2 fixation are often found in clusters that are transcribed from a single promoter under control of the LysR-type transcriptional activator, CbbR. Mutations affecting CbbR prevent induction of cbb genes. Gel-retardation assays have demonstrated CbbR binding to putative regulatory regions of cbb operons, and in two cases, footprinting experiments have delimited the nucleotide sequence protected by CbbR. Fusion of cbb control sequences to reporter genes has allowed the regions required for promoter activity to be defined, and recent experiments indicate that the cbb regulon in Rhodobacter is controlled by a global two-component signal transduction system that also regulates other metabolic processes in this organism. Different ways of regulating CBB cycle enzymes that also have roles in heterotrophic metabolism have recently been discovered. In cyanobacteria, the genes of the CBB pathway are organized and regulated differently, and these oxygen-evolving phototrophic bacteria have evolved different strategies to control the assimilation of CO2.
...
PMID:The molecular regulation of the reductive pentose phosphate pathway in Proteobacteria and Cyanobacteria. 870 90

The mechanisms involved in the regulation of the rainbow trout growth hormone (tGH) gene promoter by the pituitary-specific transcription factor GHF1 (growth hormone factor 1), also called Pit1 (pituitary transcriptional activator 1), and cAMP have been investigated in mammalian and fish cells. The -340 to +24 5'-flanking Fegion of the tGH gene focused to the luciferase gene was activated in rat pituitary GC cells and in HeLa cells cotransfected with an effector plasmid encoding rat GHFI. GC cell nuclear extracts produced four GHFI-specific footprints (sites Fl to F4) on the tGH promoter, each containing multiple W4NCAT (W, A or T) or closely related motifs. Mutational analysis performed in GC cells indicated that the proximal Fl site alone can direct transcription, but that the region encompassing the F2 and F3 sites is necessary for optimal activation and contains a TGACG motif (cAMP-response element, CRE) conferring cAMP responsiveness. The role of the TGACG motif in mediating cAMP regulation of the tGH promoter was confirmed in primary cultures of trout pituitary cells. Cotransfection studies in carp EPC cells using an effector plasmid encoding trout GHF1 demonstrated the GHF1 dependence of cAMP stimulation. Gel shift and southwestern experiments revealed nuclear proteins of 43 kDa and 30 kDa in GC and fish cells, respectively, that bind specifically to the tGH CRE, suggesting the involvement of CRE-binding-protein/activating-transcription-factor-l-related peptides in cAMP response. Incidentally, and in contrast with previous reports, we found the rat GH promoter, that lacks TGACG motifs, unresponsive to cAMP. Thus, the CAMP stimulation of the tGH gene is more similar to its human counterpart. that is also GHF1 dependent and mediated by TGACG motifs in the promoter. It is suggested that control of GH gene expression has evolved modularly, through various assortments of the same regulatory units, rather than molecularly, through innovative units.
...
PMID:A TGACG motif mediates growth-hormone factor-1/pituitary-transcriptional-activator-1-dependent cAMP regulation of the rainbow trout growth-hormone promoter. 870 56

The Proteus mirabilis and plasmid-encoded urease loci contain seven contiguous structural and accessory genes (ureDABCEFG) and the divergently transcribed ureR, which codes for an AraC-like transcriptional activator. Previously, it was shown that the plasmid-encoded ureR to ureD intergenic region contained divergent promoters (ureRp and ureDp). Transcription from these promoters required both the effector molecule urea and the activator protein UreR. In this report, we demonstrate that the P. mirabilis urease gene cluster contains similar divergent urea- and UreR-dependent promoters. The ureR gene products from either urease locus were able to activate transcription at both the plasmid-encoded and P. mirabilis promoters. The minimal concentration of urea required to activate transcription at ureRp or ureDp from either gene cluster was approximately 4 mM. The transcriptional start sites for the plasmid-encoded and P. mirabilis divergent promoters were similar in an Escherichia coli DH5 alpha background, as determined by primer-extension analysis. However, in P. mirabilis HI4320, transcription of ureR initiated predominately at an alternative site. Physical mapping and inhibition studies were used to localize the UreR-binding sites within the plasmid-encoded ureRp and ureDp intergenic sequences to regions of 68 bp and 86 bp, respectively. Gel shift analysis demonstrated that UreR bound to a 135 bp fragment in the approximate centre of the plasmid-encoded ureR to ureD intergenic region. The results presented here suggest that the P. mirabilis and plasmid-encoded urease gene clusters utilize similar mechanisms of transcriptional activation in response to urea.
...
PMID:Activation of transcription at divergent urea-dependent promoters by the urease gene regulator UreR. 886 86


<< Previous 1 2 3 4 5 6 Next >>

---