Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Promotion”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 379 records · Page 21Linked to original sources
PubMed1999

Identification of promoter elements in mycobacteria: mutational analysis of a highly symmetric dual promoter directing the expression of replication genes of the Mycobacterium plasmid pAL5000.

The 120 bp origin of replication (ori) for the Mycobacterium plasmid pAL5000 has been shown to comprise the binding sites for the replication protein RepB as well as the start site of transcription for the repA and repB genes, encoding the replication proteins RepA and RepB. In this work it is demonstrated that a third gene product, Rap, is involved in replication in addition to the previously described proteins. Mycobacterium smegmatis cells transformed with replicons carrying the rap gene recover markedly faster upon electroporation than those transformed with the minimal replicon, which lacks rap. The rap gene, oppositely orientated to repA/B, was shown to be transcribed from a promoter orientated back-to-back to and overlapping the repA/B promoter. As a consequence of the extensive dyad symmetry in this region the two promoters share several elements, most of which are situated inside the high-affinity RepB-binding motif in the ori. Transcription of rap runs through the low-affinity RepB-binding site, which is part of the ori and necessary for replication. Both promoters were shown to be repressed by RepB. These divergent promoters were studied through site-specific mutagenesis in a xylE reporter gene assay. The analysis furnished evidence supporting the existence of a distal as well as a proximal element in mycobacterial promoters.

Bacterial Proteins↗
PubMed2003

Stability of the Sp3-DNA complex is promoter-specific: Sp3 efficiently competes with Sp1 for binding to promoters containing multiple Sp-sites.

The transcription regulatory protein Sp3 shares more than 90% sequence homology with Sp1 in the DNA-binding domain and they bind to the same cognate DNA-element. However, the transcriptional activities of these two Sp-family factors are not equivalent. While Sp1 functions strictly as a transcriptional activator, Sp3 has been shown to be transcriptionally inactive for promoters containing multiple Sp-binding sites. In the present study, we show that the DNA-binding property of Sp3 is promoter dependent and is different from Sp1. The 116 kDa Sp3 polypeptide binds as a monomer to a single Sp-binding site but readily forms slower migrating complexes with adjacent Sp-binding sites. The slower migrating Sp3-DNA complexes are significantly more stable than monomeric Sp3-DNA complexes or multimeric Sp1-DNA complexes. As a consequence, Sp3 can efficiently compete with Sp1 for binding to regions containing multiple Sp sites. The transcription regulatory function of Sp3 is also significantly different from Sp1. Unlike Sp1, Sp3 does not synergistically activate transcription of promoters containing multiple Sp-binding sites. Therefore, although Sp3 is a transcription activator, Sp3 reduces Sp1-dependent transcription of promoters containing adjacent Sp-binding sites by competing with Sp1 for promoter occupancy and thereby blocking the synergistic transactivation function of Sp1. Taken together, this study provides a possible mechanism of the promoter-specific transcription repression function of Sp3.

Animals↗
PubMed2004

The maize O2 and PBF proteins act additively to promote transcription from storage protein gene promoters in rice endosperm cells.

A transient expression assay system was employed to investigate the possible use of the maize Opaque 2 (O2) and prolamin box binding factor (PBF) proteins as transcriptional activators of rice and wheat storage protein gene promoters. When assayed in developing rice endosperm cells, either O2 or PBF alone could increase transcription from the promoter of the rice glutelin gene, Gt1. However, mutant forms of O2 and PBF that are defective in DNA binding could not. Co-transfection with both transcriptional activators resulted in an additive increase in transactivation of the Gt1 promoter. Co-bombardment of a Gt1::GUS construct with plasmids expressing the DNA binding domains of O2 and PBF in antisense orientation resulted in a decrease of GUS expression below background levels. Similar stimulatory and additive effects of O2 and PBF could be observed on the promoters from other storage protein genes including rice globulin (Glb), prolamins (RP6 and PG5a) and a wheat glutenin (Bx7). However, responsiveness of the promoters from non-storage protein genes like rice actin and CaMV 35S to O2 and PBF was insignificant. Our results indicate that the maize O2 and PBF proteins can act singly or additively as effective stimulators of heterologous storage protein promoters in developing rice endosperm cells. These data support the use of well-characterized transcription factors from maize as an effective means of increasing the expression level of recombinant proteins in developing rice seeds.

Antisense Elements (Genetics)↗
PubMed2003

Induction of the Hahsp17.7G4 promoter by root-knot nematodes: involvement of heat-shock elements in promoter activity in giant cells.

Root-knot nematodes feed from specialized giant cells induced in the plants that they parasitize. We found that the promoter of the Hahsp17.7G4 gene, which encodes a small heat-shock protein involved in embryogenesis and stress responses, directed GUS expression in tobacco galls induced by the root-knot nematode Meloidogyne incognita. In roots containing a GUS reporter fusion to the Hahsp17.7G4 promoter, 10% of the galls stained for GUS expression 1 to 3 days after infection and the fraction stained increased to 60 to 80% 17 to 20 days after infection. A DNA fragment from -83 to +163, which contains heat-shock element (HSE) core sequences, is sufficient to support a promoter activity largely restricted to giant cells within the galls. Two-point mutations in HSE cores, previously reported to abolish the heat-shock response and to strongly reduce the embryogenesis response of the same promoter, did not reduce expression in giant cells. This suggests a distinct regulation of the promoter by nematodes. However, additional point mutations located at positions crucial for binding of heat-shock transcription factors (HSFs) caused a severe decrease in the nematode response. These results demonstrate that HSEs are involved in the promoter activation in giant cells and suggest that HSFs may mediate this response.

Animals↗
PubMed2002

The Epstein-Barr virus ZEBRA protein activates transcription from the early lytic F promoter by binding to a promoter-proximal AP-1-like site.

The ZEBRA protein encoded by the Epstein-Barr virus (EBV) genome activates a switch from the latent to the lytic gene expression programme of the virus. ZEBRA, a member of the basic leucine zipper family of DNA-binding proteins, is a transcriptional activator capable of inducing expression from several virus lytic cycle promoters by binding to activator protein 1 (AP-1)-like sites. The Epstein-Barr virus BamHI F promoter, Fp, was for some time believed to initiate EBNA1-specific transcription in EBV-transformed latent cells. More recent data, however, show that Fp is an early lytic promoter and that the dominant EBNA1 gene promoter in latent cells is Qp, located about 200 bp downstream of Fp. In the present investigation we confirm that Fp displays the characteristics of a lytic promoter. Fp is downregulated in latently EBV-infected cells, both in the endogenous virus genome and in reporter plasmids that carry Fp regulatory sequences upstream of position -136 and down to +10 relative to the Fp transcription start site (+1), and is activated on induction of the virus lytic cycle. We show that the repression of Fp in latent stages of infection can be abolished by ZEBRA, and demonstrate that ZEBRA activates Fp through a direct interaction with an AP-1-like site at position -52/-46 in the promoter-proximal Fp region.

B-Lymphocytes↗
PubMed1998

Comparison of PhoP binding to the tuaA promoter with PhoP binding to other Pho-regulon promoters establishes a Bacillus subtilis Pho core binding site.

The phosphate-deficiency response in Bacillus subtilis is regulated by PhoP and PhoR, a pair of two-component regulatory proteins. PhoR is a histidine kinase and PhoP is a response regulator. Genetic evidence indicates that the Pho-regulon genes, which are induced or repressed under phosphate starvation conditions, are regulated by PhoP and PhoR at the transcriptional level. It has previously been shown that PhoP binds to four Pho-regulon promoters in both unphosphorylated and phosphorylated forms. This study demonstrates that another Pho-regulon gene promoter, the tuaA promoter preceding the operon which is responsible for cell wall teichuronic acid synthesis, is also transcriptionally regulated and is bound by PhoP. The binding affinity for phosphorylated PhoP was about 10-fold higher than that for unphosphorylated PhoP. Both unphosphorylated and phosphorylated PhoP bound upstream of the -20 region in the tuaA promoter. By aligning the PhoP-binding sites within the Pho-regulon promoters, a consensus core PhoP-binding region composed of four TT(A/T)ACA direct repeats, each separated by 5 +/- 2 non-conserved nucleotides was identified. PhoP, phosphorylated or unphosphorylated, binds to such a sequence in all Pho-regulon promoters studied. Phosphorylated PhoP binds to the core binding region with high affinity and to additional regions surrounding this region with similar or lower affinity.

Bacillus subtilis↗
PubMed2004

The human L1 promoter: variable transcription initiation sites and a major impact of upstream flanking sequence on promoter activity.

Human L1 elements are non-LTR retrotransposons that comprise approximately 17% of the human genome. Their 5'-untranslated region (5'-UTR) serves as a promoter for L1 transcription. Now we find that transcription initiation sites are not restricted to nucleotide +1 but vary considerably in both downstream and upstream directions. Transcription initiating upstream explains additional nucleotides often seen between the 5'-target site duplication and the L1 start site. A higher frequency of G nucleotides observed upstream from the L1 can be explained by reverse transcription of the L1 RNA 5'-CAP, which is further supported by extra Gs seen for full-length HERV-W pseudogenes. We assayed 5'-UTR promoter activities for several full-length human L1 elements, and found that upstream flanking cellular sequences strongly influence the L1 5'-UTR promoter. These sequences either repress or enhance the L1 promoter activity. Therefore, the evolutionary success of a human L1 in producing progeny depends not only on the L1 itself, but also on its genomic integration site. The promoter mechanism of L1 is reminiscent of initiator (Inr) elements that are TATA-less promoters expressing several cellular genes. We suggest that the L1 5'-UTR is able to form an Inr element that reaches into upstream flanking sequence.

5' Untranslated Regions↗
PubMed2002

High-level and ubiquitous expression of the rice cytochrome c gene OsCc1 and its promoter activity in transgenic plants provides a useful promoter for transgenesis of monocots.

Expression patterns of a rice (Oryza sativa) cytochrome c gene OsCc1 and its promoter activity were characterized in transgenic rice plants. OsCc1 transcripts accumulate in most cell types, but to varying levels. Large amounts of OsCc1 transcripts are found in the roots, calli, and suspension cells, but relatively lower in mature leaves, demonstrating its higher levels of expression in non-photosynthetic tissues. Unlike the human cytochrome c gene, which is responsive to cAMP, OsCc1 expression is not enhanced in various rice tissues after dibutyryl cAMP treatments. OsCc1 promoter was linked to the sgfp gene and its activities in different tissues and cell types of transgenic rice plants were analyzed in comparison with the Act1 and RbcS promoters. OsCc1 promoter directs expression in virtually all organs of transgenic plants including roots, leaves, calli, embryos, and suspension cells, showing a particularly high activity in calli and roots. Activity of the OsCc1 promoter was 3-fold higher than Act1 in calli and roots and comparable with RbcS in leaves, representing a useful alternative to the maize (Zea mays) Ubi1 and the rice Act1 promoters for transgene expression in monocots.

Actins↗
PubMed2005

Trait-associated sequence variation in the bovine growth hormone receptor 1A promoter does not affect promoter activity in vitro.

Growth hormone (GH) plays a central role in growth and metabolism in cattle by binding to growth hormone receptor (GHR) and stimulating production of insulin-like growth factor 1 (IGF1). Two sequence variations in the promoter transcribing a major GHR mRNA variant, GHR 1A mRNA, have been reported to be associated with quantitative differences in growth rate or blood concentration of IGF1 in cattle. One such variation is in the length of a TG-repeat, being 11 or 16-20; the other variation is in the nucleotide 155 bp upstream from the transcription start site, being G or A. In this study, we determined whether these sequence variations would affect the activity of GHR 1A promoter. We cloned GHR 1A promoters bearing different sequence variations and linked each of them to a reporter gene. Transient transfection analyses revealed that these promoter-reporter constructs did not differ in reporter gene expression. Cotransfection analyses demonstrated that they also did not differ in activation by hepatocyte nuclear factor 4alpha, hepatocyte nuclear factor 4gamma and nuclear receptor subfamily 2 group F member 2, known transcription factors for bovine GHR 1A promoter. These in vitro results, together with a previous observation that neither the nucleotide 155 bp upstream from the transcription start site nor the TG-repeat was part of the GHR 1A promoter region interacting with nuclear proteins from bovine liver, do not support a cause-effect relationship between the reported sequence variations and the associated changes in growth rate or blood IGF1 concentration in cattle.

Animals↗
PubMed1995

Mode of promoter recognition by the Escherichia coli RNA polymerase holoenzyme containing the sigma S subunit: identification of the recognition sequence of the fic promoter.

Transcription of a number of genes during stationary phase in Escherichia coli requires the alternative sigma factor sigma S, encoded by the rpoS gene. No consensus sequence for the promoters recognized by the RNA polymerase holoenzyme containing the sigma S subunit (E sigma S) is known. To identify the E sigma S recognition sequence, we analysed the promoter region of the fic gene, whose expression depends on E sigma S both in vivo and in vitro. By random mutagenesis, we isolated a large number of the fic promoter mutants that had defective promoter activities in an rpoS+ strain. All such mutants contained alterations within the -10 region, TATACT, whereas no mutant was isolated with alterations in the -35 region. Based on further analyses including scanning mutagenesis and DNase I footprinting assays of the fic promoter region, and in vitro transcription assays, we conclude that the -10 hexamer is essential to transcription initiation from the fic promoter by E sigma S.

Bacterial Proteins↗
PubMed1995

Promoter selectivity control of Escherichia coli RNA polymerase by ionic strength: differential recognition of osmoregulated promoters by E sigma D and E sigma S holoenzymes.

Transcription in vitro of two osmoregulated promoters, for the Escherichia coli osmB and osmY genes, was analysed using two species of RNA polymerase holoenzyme reconstituted from purified core enzyme and either sigma D (sigma 70, the major sigma in exponentially growing cells) or sigma S (sigma 38, the principal sigma at stationary growth phase). Under conditions of low ionic strength, the osmB and osmY promoters were transcribed by both E sigma D and E sigma S. Addition of up to 400 mM potassium glutamate (K glutamate), mimicking the intracellular ionic conditions under hyperosmotic stress, specifically enhanced transcription at these promoters by E sigma S but inhibited that by E sigma D. At similar high concentrations of potassium chloride (KCl), however, initiation at both these promoters was virtually undetectable. These data suggest that the RNA polymerase, E sigma S, itself can sense osmotic stress by responding to changes in intracellular K glutamate concentrations and altering its promoter selectivity in order to recognize certain osmoregulated promoters.

DNA-Directed RNA Polymerases↗
PubMed1995

Characterization of the human alpha 1(VI) collagen promoter and its comparison with human alpha 2(VI) promoters.

From a human cosmid library, we isolated a clone (5B) with an insert of 32 kb, encoding the amino-terminal and the 5'-end flanking region of the alpha 1(VI) collagen gene. Exon 1 was found to be 194 bp and contain the 5' untranslated region plus 97 bp coding sequence. Exon 2 consists of 130 bp, a size that is conserved across the chicken and mouse species. S1-nuclease-protection assays and primer-extension analysis, using mRNA from human dermal fibroblasts, show the presence of multiple transcription start sites located in a region of approximately 20 nucleotides. Canonical TATA and CAAT boxes, as found in the chicken and mouse alpha 1 promoters, were absent in the human alpha 1(VI) promoter. The promoter region from positions -1 to -190, is a polypyrimidine/polypurine-rich region containing 12 CCCTCCCC (CT element consensus) sequences and has multiple potential binding sites for the Sp1, and AP2 transcription factors. These regulatory proteins bind to the alpha 2(VI) promoters [Saitta, B. & Chu, M.-L. (1994) Eur. J. Biochem. 223, 675-682]. To test the transcriptional activity of the alpha 1 promoter, transient transfection experiments of the DNA constructs were performed in human dermal fibroblasts and in human fibrosarcoma (HT1080) cell lines. The DNA constructs drive the expression of the chloramphenicol acetyl transferase (CAT) gene. The results show strong CAT activity for the constructs at positions -1700, -298 and -257, while low activity was found for the constructs at positions -4400, -142 and -5 when transfected in fibroblasts. The experiments also identified positive and negative regulatory regions in the alpha 1(VI) promoter CAT constructs when transfected in fibroblasts, but did not identify them in the fibrosarcoma cells.

Animals↗
PubMed1997

Characterisation of the rat tissue-type plasminogen activator gene promoter -- identification of a TAAT-containing promoter element.

Tissue-type plasminogen activator (tPA) activates plasminogen to the active protease plasmin and is implicated in many biological processes that require extracellular proteolysis. In rat ovarian cells, gonadotropins induce the tPA gene by a cAMP-dependent pathway and this induction correlates with the time of follicular rupture. We have previously identified several promoter elements within the first 621 bp of the rat tPA promoter that are important for constitutive and cAMP-induced expression of the gene, including a cAMP responsive element (CRE), a nuclear factor 1 (NF1) element, a SP1-binding site and a G+C-rich box. In this report we have extended our study by analysing promoter constructs, ranging in size from 7.7 kb to 135 bp fused to the luciferase reporter gene. Transient transfection analysis of rat granulosa cells and human 293 cells, reveal that the proximal 268 bp of the promoter is enough to confer high basal and cAMP-induced expression of the gene. At position -162 to -172, between the previously identified CRE and NF1 sites, a novel TAAT-containing promoter element was identified. Mutational inactivation of the TAAT motif indicates that this element is important for both constitutive and cAMP-induced expression of the gene, and for the binding of a presumably novel nuclear factor that we have termed tPA promoter factor-1 (tPF-1).

Animals↗
PubMed1985

Promoter region of the human Harvey ras proto-oncogene: similarity to the EGF receptor proto-oncogene promoter.

Regulation of transcription of members of the ras gene family undoubtably plays an important role in controlling cellular growth. Examination of this level of regulation requires identification of the promoter regions of the ras proto-oncogenes. Four major transcriptional start sites were detected in the human Harvey ras 1 proto-oncogene. The promoter region contains neither a TATA box nor a CAAT box in their characteristic upstream positions, has an extremely high G+C content (80 percent), and contains multiple GC boxes including seven CCGCCC repeats and three repeats of the inverted complement, GGGCGG. This region has strong promoter activity when placed upstream from the chloramphenicol acetyl transferase gene and transfected into monkey CV1 cells. In these ways the Harvey ras 1 proto-oncogene promoter resembles the promoter of the gene encoding the epidermal growth factor (EGF) receptor. The similarity between the two proto-oncogene promoters may be relevant to the mechanism by which the expression of such "growth control" genes is regulated.

DNA Restriction Enzymes↗
PubMed1985

Promoters recognized by Escherichia coli RNA polymerase selected by function: highly efficient promoters from bacteriophage T5.

Highly efficient promoters of coliphage T5 were identified by selecting for functional properties. Eleven such promoters belonging to all three expression classes of the phage were analyzed. Their average AT content was 75% and reached 83% in subregions of the sequences. Besides the well-known conserved sequences around -10 and -33, they exhibited homologies outside the region commonly considered to be essential for promoter function. Interestingly, the consensus hexamers around -10 (TAT AAT) and -35 (TTG ACA) were never found simultaneously within the sequence of highly efficient promoters. Several of these promoters compete extremely well for Escherichia coli RNA polymerase and can be used for the efficient in vitro synthesis of defined RNA species. In addition, some of these promoters accept 7-mGpppA as the starting dinucleotide, thus producing capped mRNA in vitro which can be utilized in various eucaryotic translation systems.

Base Sequence↗
PubMed1993

Two developmentally controlled promoters of Streptomyces coelicolor A3(2) that resemble the major class of motility-related promoters in other bacteria.

Experiments were designed to allow isolation of Streptomyces coelicolor promoters that depend on the whiG sporulation gene, which encodes a putative sigma factor important in the sporulation of aerial hyphae. The strategy, based on earlier evidence that sigma WhiG is limiting for sporulation (K. F. Chater, C. J. Burton, K. A. Plaskitt, M. J. Buttner, C. Méndez, and J. Helmann, Cell 59:133-143, 1989) was to seek DNA fragments that inhibit sporulation in aerial hyphae when present at a high copy number. In a suitable Sau3AI-generated library of DNA from S. coelicolor A3(2), two inserts were found to inhibit sporulation. Both inserts caused expression of the adjacent xylE reporter gene present in the vector in a developmentally normal strain of S. coelicolor, but there was no xylE expression in an otherwise isogenic whiG mutant. S1 nuclease protection experiments were done with RNAs isolated from these plasmid-bearing strains or from the wild-type strain lacking either recombinant plasmid. In each case, an apparent transcription start site was found upstream of an apparent open reading frame (ORF) and just downstream of sequences that resemble consensus features of promoters for motility-related genes in Bacillus subtilis and coliform bacteria. Such promoters depend on sigma factors (sigma D and sigma F, respectively) particularly similar to the deduced whiG gene product. Each of the putative whiG-dependent promoters is within an ORF that is upstream of, and potentially translationally coupled to, the putative whiG-dependent ORF (although use of one of the promoters would necessitate the use of a different start codon, further downstream). Thus, in unknown circumstances, the whiG-dependent ORFs may be expressed from a more remote promoter as part of a complex transcription unit.

Amino Acid Sequence↗
PubMed1999

The Escherichia coli Ada protein can interact with two distinct determinants in the sigma70 subunit of RNA polymerase according to promoter architecture: identification of the target of Ada activation at the alkA promoter.

The methylated form of the Ada protein (meAda) activates transcription from the Escherichia coli ada, aidB, and alkA promoters with different mechanisms. In this study we identify amino acid substitutions in region 4 of the RNA polymerase subunit sigma70 that affect Ada-activated transcription at alkA. Substitution to alanine of residues K593, K597, and R603 in sigma70 region 4 results in decreased Ada-dependent binding of RNA polymerase to the alkA promoter in vitro and impairs alkA transcription both in vivo and in vitro, suggesting that these residues define a determinant for meAda-sigma70 interaction. In a previous study (P. Landini, J. A. Bown, M. R. Volkert, and S. J. W. Busby, J. Biol. Chem. 273:13307-13312, 1998), we showed that a set of negatively charged amino acids in sigma70 region 4 is involved in meAda-sigma70 interaction at the ada and aidB promoters. However, the alanine substitutions of positively charged residues K593, K597, and R603 do not affect meAda-dependent transcription at ada and aidB. Unlike the sigma70 amino acids involved in the interaction with meAda at the ada and aidB promoters, K593, K597, and R603 are not conserved in sigmaS, an alternative sigma subunit of RNA polymerase mainly expressed during the stationary phase of growth. While meAda is able to promote transcription by the sigmaS form of RNA polymerase (EsigmaS) at ada and aidB, it fails to do so at alkA. We propose that meAda can activate transcription at different promoters by contacting distinct determinants in sigma70 region 4 in a manner dependent on the location of the Ada binding site.

Alanine↗
PubMed2005

Requirements for Vibrio cholerae HapR binding and transcriptional repression at the hapR promoter are distinct from those at the aphA promoter.

Virulence gene expression in certain strains of Vibrio cholerae is regulated in response to cell density by a quorum-sensing cascade that influences the levels of the LuxR homolog HapR through small regulatory RNAs that control the stability of its message. At high cell density, HapR represses the expression of the gene encoding the virulence gene activator AphA by binding to a site between -85 and -58 in the aphA promoter. We show here that a second binding site for HapR lies within the hapR promoter from which it functions to repress its own transcription. This site, as determined by gel mobility shift assay and DNaseI footprinting, is located between +8 and +36 from the transcriptional start and is not strongly conserved with the site at the aphA promoter. At low cell density, when the expression of a transcriptional hapR-lacZ fusion was low, no autorepression was observed. However, at high cell density, when the expression of the hapR-lacZ fusion was approximately 15-fold higher, the presence of HapR reduced its expression. Introduction of a single base pair change within the binding site at +18 prevented HapR binding in gel mobility shift assays. In the absence of HapR, this mutation did not significantly influence the expression of the hapR promoter, but in its presence, the expression of the promoter was increased at high cell density. These results indicate that HapR autorepresses from a single binding site in the hapR promoter and suggest a model for the temporal regulation of its expression as its intracellular levels increase.

Artificial Gene Fusion↗