Emergency derepression: stringency allows RNA polymerase to override negative control by an active repressor

2000 ◽  
Vol 35 (2) ◽  
pp. 435-443 ◽  
Author(s):  
Kristian Kvint ◽  
Carsten Hosbond ◽  
Anne Farewell ◽  
Ole Nybroe ◽  
Thomas Nystrom
Keyword(s):  
Rna Polymerase ◽  
Negative Control ◽  
Active Repressor

GalR Represses galP1 by Inhibiting the Rate-determining Open Complex Formation Through RNA Polymerase Contact: A GalR Negative Control Mutant

2004 ◽  
Vol 344 (3) ◽  
pp. 609-618 ◽  
Author(s):  
Siddhartha Roy ◽  
Szabolcs Semsey ◽  
Mofang Liu ◽  
Gary N. Gussin ◽  
Sankar Adhya
Keyword(s):  
Complex Formation ◽  
Rna Polymerase ◽  
Negative Control ◽  
Open Complex Formation

scholarly journals Mutational Analysis of the Bacillus subtilis RNA Polymerase α C-Terminal Domain Supports the Interference Model of Spx-Dependent Repression

2006 ◽  
Vol 188 (12) ◽  
pp. 4300-4311 ◽  
Author(s):  
Ying Zhang ◽  
Shunji Nakano ◽  
Soon-Yong Choi ◽  
Peter Zuber
Keyword(s):  
Bacillus Subtilis ◽  
Rna Polymerase ◽  
Transcriptional Activation ◽  
Transcriptional Control ◽  
Mutational Analysis ◽  
Solid Phase ◽  
Response Regulator ◽  
Negative Control ◽  
Alanine Scanning Mutagenesis ◽  
Terminal Domain

ABSTRACT The Spx protein of Bacillus subtilis exerts both positive and negative transcriptional control in response to oxidative stress by interacting with the C-terminal domain of the RNA polymerase (RNAP) alpha subunit (αCTD). Thus, transcription of the srf operon at the onset of competence development, which requires the ComA response regulator of the ComPA signal transduction system, is repressed by Spx-αCTD interaction. Previous genetic and structural analyses have determined that an Spx-binding surface resides in and around the α1 region of αCTD. Alanine-scanning mutagenesis of B. subtilis αCTD uncovered residue positions required for Spx function and ComA-dependent srf transcriptional activation. Analysis of srf-lacZ fusion expression, DNase I footprinting, and solid-phase promoter retention experiments indicate that Spx interferes with ComA-αCTD interaction and that residues Y263, C265, and K267 of the α1 region lie within overlapping ComA- and Spx-binding sites for αCTD interaction. Evidence is also presented that oxidized Spx, while enhancing interference of activator-RNAP interaction, is not essential for negative control.

scholarly journals Quantitative conservation of chromatin-bound RNA polymerases I and II in mitosis. Implications for chromosome structure.

1979 ◽  
Vol 80 (2) ◽  
pp. 451-464 ◽  
Author(s):  
S I Matsui ◽  
H Weinfeld ◽  
A A Sandberg
Keyword(s):  
Cell Cycle ◽  
Rna Polymerase ◽  
Rna Synthesis ◽  
Negative Control ◽  
Rna Polymerases ◽  
Chromatin Interaction ◽  
Condensed State ◽  
Metaphase Chromosomes ◽  
A Genome ◽  
Per Se

RNA synthesis almost ceases in mitosis. It is ambiguous whether this temporal, negative control of RNA synthesis is solely because of the nature of chromosomes per se, (i.e., their condensed state), or to a physical loss of RNA polymerases along with other nuclear proteins which have been shown to pass into the cytoplasm in mitosis, or to their combined feature. Aside from such regulatory considerations, a question has also been raised as to whether RNA polymerases are constituents of metaphase chromosomes. To clarify these aspects of RNA polymerase-chromatin interaction in mitosis, the enzymes in chromosomes were quantitated and their levels compared to those in interphase nuclei and cells at various phases of the cell cycle. The results show that the amounts of form I, form II, and probably form III enzymes bound to a genome-equivalent of chromatin stay constant during the cell cycle. Thus, the mechanism for the negative control of RNA synthesis in mitosis appears to exist in the chromosomes per se, but not to be directly related to the RNA polymerase levels. This quantitative conservation of chromatin-bound RNA polymerases implies that they may persist as structural components of the chromosomes in mitosis.

RNA polymerase: Preparation and structural analysis of helical polymers

1984 ◽  
Vol 42 ◽  
pp. 152-153
Author(s):  
E. Loren Buhle ◽  
Pamela Rew ◽  
Ueli Aebi
Keyword(s):  
Structural Analysis ◽  
Rna Polymerase ◽  
Molecular Level ◽  
X Ray Diffraction ◽  
Helical Polymers ◽  
X Ray ◽  
E Coli ◽  
The Past ◽  
Ordered Arrays ◽  
Low Ionic Strength

While DNA-dependent RNA polymerase represents one of the key enzymes involved in transcription and ultimately in gene expression in procaryotic and eucaryotic cells, little progress has been made towards elucidation of its 3-D structure at the molecular level over the past few years. This is mainly because to date no 3-D crystals suitable for X-ray diffraction analysis have been obtained with this rather large (MW ~500 kd) multi-subunit (α2ββ'ζ). As an alternative, we have been trying to form ordered arrays of RNA polymerase from E. coli suitable for structural analysis in the electron microscope combined with image processing. Here we report about helical polymers induced from holoenzyme (α2ββ'ζ) at low ionic strength with 5-7 mM MnCl2 (see Fig. 1a). The presence of the ζ-subunit (MW 86 kd) is required to form these polymers, since the core enzyme (α2ββ') does fail to assemble into such structures under these conditions.

Nutrient-regulated gene expression in eukaryotes

2006 ◽  
Vol 73 ◽  
pp. 85-96 ◽  
Author(s):  
Richard J. Reece ◽  
Laila Beynon ◽  
Stacey Holden ◽  
Amanda D. Hughes ◽  
Karine Rébora ◽  
...  
Keyword(s):  
Gene Expression ◽  
Rna Polymerase ◽  
Rna Polymerase Ii ◽  
Transcriptional Control ◽  
Direct Interaction ◽  
Signalling Pathways ◽  
A Cell ◽  
One Step ◽  
Higher Eukaryotes ◽  
Regulated Gene Expression

The recognition of changes in environmental conditions, and the ability to adapt to these changes, is essential for the viability of cells. There are numerous well characterized systems by which the presence or absence of an individual metabolite may be recognized by a cell. However, the recognition of a metabolite is just one step in a process that often results in changes in the expression of whole sets of genes required to respond to that metabolite. In higher eukaryotes, the signalling pathway between metabolite recognition and transcriptional control can be complex. Recent evidence from the relatively simple eukaryote yeast suggests that complex signalling pathways may be circumvented through the direct interaction between individual metabolites and regulators of RNA polymerase II-mediated transcription. Biochemical and structural analyses are beginning to unravel these elegant genetic control elements.

Oral Immune Activation by Disgust and Disease-Related Pictures

2015 ◽  
Vol 29 (3) ◽  
pp. 119-129 ◽  
Author(s):  
Richard J. Stevenson ◽  
Deborah Hodgson ◽  
Megan J. Oaten ◽  
Luba Sominsky ◽  
Mehmet Mahmut ◽  
...  
Keyword(s):  
Immune Response ◽  
Immune Responses ◽  
Innate Immune Response ◽  
Negative Control ◽  
Innate Immune ◽  
Innate Immune Responses ◽  
Immune Markers ◽  
Before And After ◽  
Secondary Analyses ◽  
Image Set

Abstract. Both disgust and disease-related images appear able to induce an innate immune response but it is unclear whether these effects are independent or rely upon a common shared factor (e.g., disgust or disease-related cognitions). In this study we directly compared these two inductions using specifically generated sets of images. One set was disease-related but evoked little disgust, while the other set was disgust evoking but with less disease-relatedness. These two image sets were then compared to a third set, a negative control condition. Using a wholly within-subject design, participants viewed one image set per week, and provided saliva samples, before and after each viewing occasion, which were later analyzed for innate immune markers. We found that both the disease related and disgust images, relative to the negative control images, were not able to generate an innate immune response. However, secondary analyses revealed innate immune responses in participants with greater propensity to feel disgust following exposure to disease-related and disgusting images. These findings suggest that disgust images relatively free of disease-related themes, and disease-related images relatively free of disgust may be suboptimal cues for generating an innate immune response. Not only may this explain why disgust propensity mediates these effects, it may also imply a common pathway.

PENGARUH EKSTRAK DAUN SIRIH MERAH (Piper crocatum Ruiz & Pav.) TERHADAP GLUKOSA DARAH MENCIT (Mus musculus L.) JANTAN YANG DIINDUKSI SUKROSA

BioScience ◽  
2018 ◽  
Vol 2 (1) ◽  
pp. 61
Author(s):  
Elsa Yuniarti
Keyword(s):  
Blood Glucose ◽  
Mus Musculus ◽  
Leaf Extract ◽  
Negative Control ◽  
State University ◽  
Betel Leaf ◽  
Randomized Design ◽  
The Subject ◽  
Effective Drugs ◽  
Zoology Department

Patients withdiabetes mellitus (DM) continues to grow because prosperity and people's lifestyles.Treatment of diabetes often usei njections of insulin and oral antidiabetic drugs. Thetreatment has no side effects. Therefore, it is necessary to find effective drugs using plants thatred betel leaf (Piper crocatum Ruiz & Pav.). Red betel leaf contains flavonoids which are antioxidants. This study aims to determine the effect and dose of extract of red betel leaf (Piper crocatum Ruiz & Pav.) The most effective agains blood glucose in mice(Mus musculusL.) male induced sucrose.This study was an experimental study. The research was conducted in October 2015 in the Division of Laboratory Animal and Zoology Department of Biology, State University of Padang. The subject of research in the form of mice (Mus musculus L.) males totaled 24 tails. The design used was completely randomized design (CRD) with 6 treatments and 4 repetitions. The treatment is given as follows: treatment I: the diabetes control without any treatment given, treatment II: as a negative control (sucrose 3 g/kg bw), treatment III: sucrose+suspension of red betel leaf extract (dosage 0,7 g/kg bw), treatment IV: sucrose+suspension of red betel leaf extract (dosage 1,4 g/kg bw), treatment V: sucrose+suspension of red betel leaf extract (dosage of 2,1 g/kg bw) and treatment VI: sucrose+suspension extracts red betel leaf (dosage 2,8 g/kg bw).The results showed that the extract of red betel leaf (Piper crocatum Ruiz & Pav.) at a dose of 0,8 g/kg bw 1,4 g/kg bw 2,1 g/kg bw and 2,8 g/kg bw can lowers blood glucose in mice. However, the most appropriate dose in lowering blood glucose in mice (Mus musculus L.) at 2,8 g/kg bw in mice.

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