scholarly journals Genetic and Transcriptional Organization of the clpC Locus in Bifidobacterium breve UCC 2003

2005 ◽  
Vol 71 (10) ◽  
pp. 6282-6291 ◽  
Author(s):  
Marco Ventura ◽  
Gerald F. Fitzgerald ◽  
Douwe van Sinderen
Keyword(s):  
Promoter Region ◽  
Specific Binding ◽  
Transcriptional Regulator ◽  
Biologically Active ◽  
Slot Blot ◽  
Bifidobacterium Breve ◽  
Homologous Genes ◽  
Species Analysis ◽  
Atpase Gene

ABSTRACT A homolog of the clpC ATPase gene was identified in the genome of Bifidobacterium breve UCC 2003. Since this gene is very well conserved among eubacteria, we employed a PCR-based approach using primers based on highly conserved regions of ClpC proteins in order to identify homologous genes in other bifidobacterial species. Analysis by slot blot, Northern blot, and primer extension experiments showed that transcription of clpC is induced in response to moderate heat shock regimes. Moreover, we identified in the genome sequence of B. breve UCC 2003 a gene, designated clgR, which is predicted to encode a transcriptional regulator involved in regulation of the bifidobacterial clpC gene. The role of this protein in the regulation of B. breve UCC 2003 clpC gene expression was investigated by performing gel retardation experiments. We show that a biologically active ClgR molecule requires one or more proteinaceous coactivators to assist in the specific binding of ClgR to the clpC promoter region.

The Role of Thyroxine Binding in the Establishment of Thyroid Status

1969 ◽  
Vol 14 (11) ◽  
pp. 375-380 ◽  
Author(s):  
W. A. Harland ◽  
J. S. Orr
Keyword(s):  
Specific Binding ◽  
Free Thyroxine ◽  
Biologically Active ◽  
Active Fraction ◽  
Distribution Space ◽  
Thyroid Status ◽  
Published Evidence ◽  
Plasma Hormone ◽  
Considerable Body

This paper reviews previously published evidence concerning the view of thyroxine metabolism which holds that thyroxine exchanges rapidly and freely throughout its distribution space. This view is essential for the well known concept of ‘free thyroxine’, that small fraction of the plasma hormone not bound to protein but in equilibrium with the specific binding proteins. ‘Free thyroxine’ is held to be the biologically active fraction of the plasma hormone. A considerable body of evidence inconsistent with the ‘free thyroxine’ hypothesis is examined and details of experiments indicating the essentially permanent nature of thyroxine binding are reviewed. It is concluded that the ‘free thyroxine’ concept as currently defined, is no longer acceptable. A new model of thyroxine metabolism is presented.

Fucose-Mediated Transcriptional Activation of the fcs Operon by FcsR in Streptococcus pneumoniae

2015 ◽  
Vol 25 (2-3) ◽  
pp. 120-128 ◽  
Author(s):  
Irfan Manzoor ◽  
Sulman Shafeeq ◽  
Muhammad Afzal ◽  
Oscar P. Kuipers
Keyword(s):  
Streptococcus Pneumoniae ◽  
Transcriptional Activation ◽  
Promoter Region ◽  
Transcriptional Regulator ◽  
Transcriptional Activator ◽  
Regulatory Site ◽  
Rt Pcr ◽  
The Impact

In this study, we explore the impact of fucose on the transcriptome of <i>S. pneumoniae</i> D39. The expression of various genes and operons, including the fucose uptake PTS and utilization operon (<i>fcs</i> operon) was altered in the presence of fucose. By means of quantitative RT-PCR and β-galactosidase analysis, we demonstrate the role of the transcriptional regulator FcsR, present upstream of the <i>fcs</i> operon, as a transcriptional activator of the <i>fcs</i> operon. We also predict a 19-bp putative FcsR regulatory site (5′-ATTTGAACATTATTCAAGT-3′) in the promoter region of the <i>fcs</i> operon. The functionality of this predicted FcsR regulatory site was further confirmed by promoter-truncation experiments, where deletion of half of the FscR regulatory site or full deletion led to the abolition of expression of the <i>fcs</i> operon.

scholarly journals The ClgR Protein Regulates Transcription of the clpP Operon in Bifidobacterium breve UCC 2003

2005 ◽  
Vol 187 (24) ◽  
pp. 8411-8426 ◽  
Author(s):  
Marco Ventura ◽  
Ziding Zhang ◽  
Michelle Cronin ◽  
Carlos Canchaya ◽  
John G. Kenny ◽  
...  
Keyword(s):  
Promoter Region ◽  
Specific Binding ◽  
Three Dimensional ◽  
Binding Mode ◽  
Dna Interaction ◽  
Dimensional Structure ◽  
Mobility Shift ◽  
Significant Similarity ◽  
Bifidobacterium Breve

ABSTRACT Five clp genes (clpC, clpB, clpP1, clpP2, and clpX), representing chaperone- and protease-encoding genes, were previously identified in Bifidobacterium breve UCC 2003. In the present study, we characterize the B. breve UCC 2003 clpP locus, which consists of two paralogous genes, designated clpP1 and clpP2, whose deduced protein products display significant similarity to characterized ClpP peptidases. Transcriptional analyses showed that the clpP1 and clpP2 genes are transcribed in response to moderate heat shock as a bicistronic unit with a single promoter. The role of a clgR homologue, known to control the regulation of clpP gene expression in Streptomyces lividans and Corynebacterium glutamicum, was investigated by gel mobility shift assays and DNase I footprint experiments. We show that ClgR, which in its purified form appears to exist as a dimer, requires a proteinaceous cofactor to assist in specific binding to a 30-bp region of the clpP promoter region. In pull-down experiments, a 56-kDa protein copurified with ClgR, providing evidence that the two proteins also interact in vivo and that the copurified protein represents the cofactor required for ClgR activity. The prediction of the ClgR three-dimensional structure provides further insights into the binding mode of this protein to the clpP1 promoter region and highlights the key amino acid residues believed to be involved in the protein-DNA interaction.

scholarly journals GalR Acts as a Transcriptional Activator of galKT in the Presence of Galactose in Streptococcus pneumoniae

2015 ◽  
Vol 25 (6) ◽  
pp. 363-371 ◽  
Author(s):  
Muhammad Afzal ◽  
Sulman Shafeeq ◽  
Irfan Manzoor ◽  
Oscar P. Kuipers
Keyword(s):  
Streptococcus Pneumoniae ◽  
Promoter Region ◽  
Regulatory Mechanism ◽  
Transcriptional Regulator ◽  
Transcriptional Activator ◽  
Regulatory Site ◽  
Wild Type ◽  
Rt Pcr ◽  
Leloir Pathway

We explored the regulatory mechanism of Leloir pathway genes in <i>Streptococcus pneumoniae</i> D39. Here, we demonstrate that the expression of <i>galKT</i> is galactose dependent. By microarray analysis and quantitative RT-PCR, we further show the role of the transcriptional regulator GalR, present upstream of <i>galKT</i>, as a transcriptional activator of <i>galKT</i> in the presence of galactose. Moreover, we predict a 19-bp regulatory site (5′-GATAGTTTAGTAAAATTTT-3′) for the transcriptional regulator GalR in the promoter region of <i>galK</i>, which is also highly conserved in other streptococci. Growth comparison of D39 &#x0394;<i>galK</i> with the D39 wild type grown in the presence of galactose shows that <i>galK</i> is required for the proper growth of <i>S. pneumoniae</i> on galactose.

Study of the role of histidyl, tyrosyl, α- or ε-amino residues in the specific binding of 3,5,3'-triiodothyronine to rat liver nuclear receptors

1988 ◽  
Vol 117 (2) ◽  
pp. 159-165 ◽  
Author(s):  
Julius Brtko ◽  
Ján Knopp
Keyword(s):  
Nuclear Receptors ◽  
Nuclear Receptor ◽  
Rat Liver ◽  
Binding Capacity ◽  
Specific Binding ◽  
Biologically Active ◽  
Amino Groups ◽  
Trinitrobenzenesulfonic Acid ◽  
Receptor Molecule

Abstract. The role of histidyl, tyrosyl, α-or ε-amino residues of rat liver nuclear receptors for the specific binding of T3 was studied by chemically modifying the receptor molecule. The kinetics of the formation of N-carbethoxyhistidyl derivative from histidyl groups of nuclear receptors by diethylpyrocarbonate was examined. The modified nuclear receptor fraction was separated from diethylpyrocarbonate by gel filtration and the T3 binding parameters (Ka and MBC) at pH 8.0 were tested by Scatchard plot analysis. At 0.1 mmol/l diethylpyrocarbonate, the value of Ka was significantly (P < 0.01) decreased without any change in maximal binding capacity (MBC). The modification of α- or ε-amino groups of nuclear receptors by excess of trinitrobenzenesulfonic acid, 6.3 mmol/l at pH 8.5, resulted in a 4-fold increase in MBC of T3 specific binding without any change in Ka. In addition, acetylation of tyrosyl residues of nuclear receptors at pH 7.5 with an excess of 24 mmol/l N-acetylimidazole was performed. No changes in nuclear receptor Ka or MBC were observed after N-acetylimidazole treatment. Histidine and/or amino groups of the receptor molecule seem to hold a key position in the generation of the biologically active T3-nuclear receptor complex in the rat liver.

On the Role of Transferrin in 67Ga Uptake by Tumor Cells

1988 ◽  
Vol 27 (04) ◽  
pp. 151-153
Author(s):  
P. Thouvenot ◽  
F. Brunotte ◽  
J. Robert ◽  
L. J. Anghileri
Keyword(s):  
Specific Binding ◽  
Subcellular Fractionation ◽  
Animal Blood ◽  
Tumor Bearing ◽  
Cell Structures ◽  
The Difference ◽  
Sarcoma Cells ◽  
In Vitro Uptake

In vitro uptake of 67Ga-citrate and 59Fe-citrate by DS sarcoma cells in the presence of tumor-bearing animal blood plasma showed a dramatic inhibition of both 67Ga and 59Fe uptakes: about ii/io of 67Ga and 1/5o of the 59Fe are taken up by the cells. Subcellular fractionation appears to indicate no specific binding to cell structures, and the difference of binding seems to be related to the transferrin chelation and transmembrane transport differences

Anti-Hypertensive Potential and Epigenetics of Angiotensin II type 2 Receptor (AT2R)

2020 ◽  
Vol 16 ◽  
Author(s):  
Mayank Chaudhary
Keyword(s):  
Blood Pressure ◽  
Angiotensin Ii ◽  
Renin Angiotensin System ◽  
Blood Pressure Regulation ◽  
Biologically Active ◽  
Pressure Regulation ◽  
Tissue Remodelling ◽  
Critical Pathway

Background:: Renin angiotensin system (RAS) is a critical pathway involved in blood pressure regulation. Octapeptide, angiotensin II (Ang aII), is biologically active compound of RAS pathway which mediates its action by binding to either angiotensin II type 1 receptor (AT1R) or angiotensin II type 2 receptor (AT2R). Binding of Ang II to AT1R facilitates blood pressure regulation whereas AT2R is primarily involved in wound healing and tissue remodelling. Objective:: Recent studies have highlighted additional role of AT2R to counter balance detrimental effects of AT1R. Activation of angiotensin II type 2 receptor using AT2R agonist has shown effect on natriuresis and release of nitric oxide. Additionally, AT2R activation has been found to inhibit angiotensin converting enzyme (ACE) and enhance angiotensin receptor blocker (ARB) activity. These findings highlight the potential of AT2R as novel therapeutic target against hypertension. Conclusion:: The potential role of AT2R highlights the importance of exploring additional mechanisms that might be crucial for AT2R expression. Epigenetic mechanisms including DNA methylation and histone modification have been explored vastly with relation to cancer but role of such mechanisms on expression of AT2R has recently gained interest.

scholarly journals Reconstitution in Proteoliposomes of the Recombinant Human Riboflavin Transporter 2 (SLC52A2) Overexpressed in E. coli

2019 ◽  
Vol 20 (18) ◽  
pp. 4416 ◽  
Author(s):  
Lara Console ◽  
Maria Tolomeo ◽  
Matilde Colella ◽  
Maria Barile ◽  
Cesare Indiveri
Keyword(s):  
Cardiovascular Disease ◽  
Amino Acids ◽  
Risk Factor ◽  
Biologically Active ◽  
Suitable Model ◽  
Native Protein ◽  
E Coli ◽  
Few Data ◽  
Riboflavin Transport

Background: the SLC52A2 gene encodes for the riboflavin transporter 2 (RFVT2). This transporter is ubiquitously expressed. It mediates the transport of Riboflavin across cell membranes. Riboflavin plays a crucial role in cells since its biologically active forms, FMN and FAD, are essential for the metabolism of carbohydrates, amino acids, and lipids. Mutation of the Riboflavin transporters is a risk factor for anemia, cancer, cardiovascular disease, neurodegeneration. Inborn mutations of SLC52A2 are associated with Brown-Vialetto-van Laere syndrome, a rare neurological disorder characterized by infancy onset. In spite of the important metabolic and physio/pathological role of this transporter few data are available on its function and regulation. Methods: the human recombinant RFVT2 has been overexpressed in E. coli, purified and reconstituted into proteoliposomes in order to characterize its activity following the [3H]Riboflavin transport. Results: the recombinant hRFVT2 showed a Km of 0.26 ± 0.07 µM and was inhibited by lumiflavin, FMN and Mg2+. The Riboflavin uptake was also regulated by Ca2+. The native protein extracted from fibroblast and reconstituted in proteoliposomes also showed inhibition by FMN and lumiflavin. Conclusions: proteoliposomes represent a suitable model to assay the RFVT2 function. It will be useful for screening the mutation of RFVT2.

Sign in / Sign up

Export Citation Format

Share Document