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Query: UNIPROT:P00750 (PLA)
 16,800 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The Escherichia coli-derived tet regulatory elements from Tn10 have been used to construct vectors allowing the regulated, inducible, high-level expression of foreign genes in Bacillus subtilis. While the wild-type tet promoters are inactive in B. subtilis, a synthetic mutant tet sequence with improved promoter consensus sequences and upstream poly A blocks shows activity in B. subtilis. The expression of an indicator cat gene is inducible by sublethal amounts of tetracycline, indicating that the Tet repressor protein and the tet operator sequences are functional. However, the inducibility and maximal expression are not sufficient in this construct. To improve these properties a tet operator sequence was placed between the -35 and -10 boxes of the B. subtilis-derived very strong xyl promoter. In the presence of a tetR gene this construct is about 100-fold inducible and has high promoter strength, but some basal expression. This is avoided by placing a second tet operator downstream resulting in no detectable basal expression at the expense of reduced inducibility. Using the system with a single tet operator inducible expression of glucose dehydrogenase from B. megaterium was obtained at a very high level, and inducible expression of human single-chain urokinase-like plasminogen activator was achieved at the same level as in E. coli. Unlike in E. coli, the product was not degraded up to 4 h after induction in B. subtilis. These results demonstrate that the regulated expression vector described here should be very useful for production of foreign gene products from B. subtilis cultures.
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PMID:Regulated expression of heterologous genes in Bacillus subtilis using the Tn10 encoded tet regulatory elements. 136 98

Transcription of the human urokinase type plasminogen activator (uPA) gene in HeLa cells is induced by phorbol myristate acetate (PMA), interleukin-1 (IL-1) and tumor necrosis factor alpha (TNF alpha). The response to these factors is rapid, independent of new protein synthesis and amplified in the presence of an inhibitor of protein synthesis, indicating the presence of a labile repressor. A DNA element, similar to the binding site for the transcription factor NFkB, is located around--1865 with respect to the start site of transcription in the uPA promoter and confers superinducibility by these agents in the presence of cycloheximide (CHX). A synthetic copy of this element confers superinducibility on a minimal uPA gene promoter and on the thymidine kinase (TK) gene promoter linked to the chloramphenicol acetyl transferase (CAT) gene. CHX alone does not increase transcription from these constructs in HeLa cells, although it superinduces the effects of PMA, IL-1 and TNF alpha. A second NFkB-like binding site located at around--1835 is not capable of conferring transcriptional activation under the same conditions. Our results suggest that maximal transcriptional activation of the uPA gene by PMA, IL-1 and TNF alpha requires the induction of NFkB activity and the decay of a short lived repressor protein, possibly IkB.
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PMID:A labile repressor acts through the NFkB-like binding sites of the human urokinase gene. 190 4

Bacterial pathogenesis depends on changes in metabolic and virulence gene expression in response to changes within a pathogen's environment. The plague-causing pathogen, Yersinia pestis, requires expression of the gene encoding the Pla protease for progression of pneumonic plague. The catabolite repressor protein Crp, a global transcriptional regulator, may serve as the activator of pla in response to changes within the lungs as disease progresses. By using gene reporter fusions, the spatial and temporal activation of the crp and pla promoters was measured in a mouse model of pneumonic plague. In the lungs, crp was highly expressed in bacteria found within large aggregates resembling biofilms, while pla expression increased over time independent of the aggregated state. Increased expression of crp and pla correlated with a reduction in lung glucose levels. Deletion of the glucose-specific phosphotransferase system EIIBC (PtsG) of Y. pestis rescued glucose levels in the lungs, resulting in reduced expression of both crp and pla We propose that activation of pla expression during pneumonic plague is driven by an increase of both Crp and cAMP levels following consumption of available glucose in the lungs by Y. pestis Thus, Crp operates as a sensor linking the nutritional environment of the host to regulation of virulence gene expression.IMPORTANCE Using Yersinia pestis as a model for pneumonia, we discovered that glucose is rapidly consumed, leading to a catabolite-repressive environment in the lungs. As a result, expression of the gene encoding the plasminogen activator protease, a target of the catabolite repressor protein required for Y. pestis pathogenesis, is activated. Interestingly, expression of the catabolite repressor protein itself was also increased in the absence of glucose but only in biofilms. The data presented here demonstrate how a bacterial pathogen senses changes within its environment to coordinate metabolism and virulence gene expression.
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PMID:Depletion of Glucose Activates Catabolite Repression during Pneumonic Plague. 2955