scholarly journals Studies on the function of the riboregulator 6S RNA from E. coli: RNA polymerase binding, inhibition of in vitro transcription and synthesis of RNA-directed de novo transcripts

2007 ◽  
Vol 35 (6) ◽  
pp. 1885-1896 ◽  
Author(s):  
Nina Gildehaus ◽  
Thomas Neußer ◽  
Reinhild Wurm ◽  
Rolf Wagner
Keyword(s):  
Rna Polymerase ◽  
De Novo ◽  
In Vitro Transcription ◽  
E Coli ◽  
6S Rna ◽  
Binding Inhibition ◽  
Polymerase Binding

Vibrio harveyi RNA polymerase: purification and resolution from gyrase A

1992 ◽  
Vol 70 (8) ◽  
pp. 698-702 ◽  
Author(s):  
Elana Swartzman ◽  
Edward A. Meighen
Keyword(s):  
Rna Polymerase ◽  
Topoisomerase Ii ◽  
Vibrio Harveyi ◽  
In Vitro Transcription ◽  
E Coli ◽  
Gyrase A ◽  
A Subunit ◽  
Terminal Amino ◽  
Promoter Specificity

RNA polymerase was purified from Vibrio harveyi and found to contain polypeptides (β,β′, α, and σ) closely corresponding to those of the Escherichia coli enzyme. In vitro transcription studies using V. harveyi and E. coli RNA polymerase demonstrated that the purified V. harveyi RNA polymerase is functional and that the two enzymes have the same promoter specificity. Chromatography through a monoQ column was required to remove a 100-kilodalton protein that was present in large amounts and copurified with the RNA polymerase. N-terminal amino acid sequencing showed that the first 18 amino acids of the 100-kilodalton protein shares 78% sequence identity with the A subunit of gyrase or topoisomerase II. The abundance of the gyrase A protein is unprecedented and may be linked to bioluminescence.Key words: Vibrio harveyi, RNA polymerase, gyrase, bioluminescence.

scholarly journals Substitutions in Bacteriophage T4 AsiA andEscherichia coli ς70 That Suppress T4motA Activation Mutations

2001 ◽  
Vol 183 (7) ◽  
pp. 2289-2297 ◽  
Author(s):  
Marco P. Cicero ◽  
Meghan M. Sharp ◽  
Carol A. Gross ◽  
Kenneth N. Kreuzer
Keyword(s):  
Rna Polymerase ◽  
Burst Size ◽  
Bacteriophage T4 ◽  
In Vitro Transcription ◽  
Positive Control ◽  
Plaque Morphology ◽  
Mutant Proteins ◽  
E Coli

ABSTRACT Bacteriophage T4 middle-mode transcription requires two phage-encoded proteins, the MotA transcription factor and AsiA coactivator, along with Escherichia coli RNA polymerase holoenzyme containing the ς70 subunit. AmotA positive control (pc) mutant, motA-pc1, was used to select for suppressor mutations that alter other proteins in the transcription complex. Separate genetic selections isolated two AsiA mutants (S22F and Q51E) and five ς70 mutants (Y571C, Y571H, D570N, L595P, and S604P). All seven suppressor mutants gave partial suppressor phenotypes in vivo as judged by plaque morphology and burst size measurements. The S22F mutant AsiA protein and glutathione S-transferase fusions of the five mutant ς70 proteins were purified. All of these mutant proteins allowed normal levels of in vitro transcription when tested with wild-type MotA protein, but they failed to suppress the mutant MotA-pc1 protein in the same assay. The ς70 substitutions affected the 4.2 region, which binds the −35 sequence of E. coli promoters. In the presence of E. coli RNA polymerase without T4 proteins, the L595P and S604P substitutions greatly decreased transcription from standard E. colipromoters. This defect could not be explained solely by a disruption in −35 recognition since similar results were obtained with extended −10 promoters. The generalized transcriptional defect of these two mutants correlated with a defect in binding to core RNA polymerase, as judged by immunoprecipitation analysis. The L595P mutant, which was the most defective for in vitro transcription, failed to support E. coli growth.

scholarly journals A Positive cis-Acting DNA Element Is Required for High-Level Transcription in Chlamydia

2000 ◽  
Vol 182 (18) ◽  
pp. 5167-5171 ◽  
Author(s):  
Chris S. Schaumburg ◽  
Ming Tan
Keyword(s):  
Escherichia Coli ◽  
Chlamydia Trachomatis ◽  
Rna Polymerase ◽  
Promoter Region ◽  
In Vitro Transcription ◽  
Transcription Assay ◽  
Cis Acting ◽  
E Coli ◽  
High Level

ABSTRACT The spacer A/T region is a positive cis-acting DNA element that was identified in the Chlamydia trachomatisrRNA promoter region. We have now demonstrated that similar sequences in other chlamydial promoters are important for transcription. Substitution of candidate spacer A/T regions in four chlamydial promoters decreased transcription by partially purified C. trachomatis RNA polymerase in an in vitro transcription assay. Addition of a spacer A/T region to the dnaK promoter, which does not contain an identifiable spacer A/T region, increased transcription 16-fold. Transcription of Escherichia colipromoters by C. trachomatis RNA polymerase also appeared to be dependent on the spacer A/T region. However, the effect of the spacer A/T region on transcription by E. coli RNA polymerase was small. In summary, the spacer A/T region is a novel DNA element that is required for high-level transcription of many promoters by chlamydial RNA polymerase.

scholarly journals Mutational Analysis of the Chlamydia trachomatis rRNA P1 Promoter Defines Four Regions Important for Transcription In Vitro

1998 ◽  
Vol 180 (9) ◽  
pp. 2359-2366 ◽  
Author(s):  
Ming Tan ◽  
Tamas Gaal ◽  
Richard L. Gourse ◽  
Joanne N. Engel
Keyword(s):  
Escherichia Coli ◽  
Chlamydia Trachomatis ◽  
Rna Polymerase ◽  
Mutational Analysis ◽  
In Vitro Transcription ◽  
Rna Polymerases ◽  
Rich Region ◽  
E Coli ◽  
Transcription In Vitro

ABSTRACT We have characterized the Chlamydia trachomatisribosomal promoter, rRNA P1, by measuring the effect of substitutions and deletions on in vitro transcription with partially purifiedC. trachomatis RNA polymerase. Our analyses indicate that rRNA P1 contains potential −10 and −35 elements, analogous toEscherichia coli promoters recognized by E-ς70. We identified a novel AT-rich region immediately downstream of the −35 region. The effect of this region was specific for C. trachomatis RNA polymerase and strongly attenuated by single G or C substitutions. Upstream of the −35 region was an AT-rich sequence that enhanced transcription by C. trachomatis and E. coli RNA polymerases. We propose that this region functions as an UP element.

scholarly journals In vitro transcription of herpes simplex virus ANG DNA by E. coli RNA polymerase

1977 ◽  
Vol 4 (6) ◽  
pp. 1793-1802 ◽  
Author(s):  
Giinter P. Strauss ◽  
Inge B. Maichle ◽  
Rita Schatten ◽  
Hans Christian Kaerner
Keyword(s):  
Herpes Simplex Virus ◽  
Herpes Simplex ◽  
Rna Polymerase ◽  
In Vitro Transcription ◽  
E Coli ◽  
Simplex Virus

Electron-microscopic mapping of AT-rich regions and of E. coli RNA polymerase-binding sites on the circular kinetoplast DNA of Trypanosoma cruzi

1975 ◽  
Vol 17 (3) ◽  
pp. 287-306
Author(s):  
C. Brack ◽  
E. Delain
Keyword(s):  
Dna Replication ◽  
Trypanosoma Cruzi ◽  
Rna Polymerase ◽  
Binding Sites ◽  
Specific Binding ◽  
Kinetoplast Dna ◽  
Electron Microscopic ◽  
E Coli ◽  
Polymerase Binding

Partial alkaline denaturation of the circular kinetoplast DNA (kDNA) of Trypanosoma cruzi has shown the existence of 4 small, well-defined AT-rich regions with an average size of about 200 base pairs. They are almost equally distributed, separated by approximately 90 degrees on the circular molecule. All minicircles, whether free or linked in networks, have the same denaturation pattern and, therefore, seem to contain the same information. The long linear molecules present in low amounts in the kDNA samples do not show the same denaturation pattern. Partial denaturation of molecules in larger associations indicates that the circular units may be linked to each other by one strand only. kDNA can be transcribed in vitro by the RNA polymerase of E. coli. RNA polymerase-kDNA complexes have been studied in the electron microscope. By spreading the DNA-protein complexes by adhesion to positively charged carbon films and dark-field observation, it was possible to show the existence of 4 specific binding sites of the E. coli RNA polymerase on the kDNA circles. Comparing the position of the polymerase-binding sites and the AT-rich melted zones, it is suggested that a correlation exists between the two. As had been shown in earlier work, the replication of circular kDNA can be blocked by treating the trypanosomes with the trypanocidal drug Berenil. The comparison of the relative position of the Berenil-blocked replication forks with the position of the 4 denaturation loops shows that the DNA replication is stopped at these AT-rich regions. Since there is evidence that Berenil binds preferentially to AT-rich DNA and seems to be involved in inhibition of DNA replication, the following hypothetical model can be proposed. The replication of the circular kDNA molecules is discontinuous and involves the synthesis of RNA primers; when Berenil is bound to the AT-rich regions, synthesis of new RNA primers is inhibited and replication is blocked at these points, leading to the accumulation of replicating intermediates with defined branch lengths.

In Vitro Transcription of Adenovirus 2 DNA by E. coli RNA Polymerase

1974 ◽  
Vol 39 (0) ◽  
pp. 501-504 ◽  
Author(s):  
S. Surzycki ◽  
J. A. Surzycki ◽  
W. DeLorbe ◽  
G. N. Gussin
Keyword(s):  
Rna Polymerase ◽  
In Vitro Transcription ◽  
E Coli

A conformational switch is responsible for the reversal of the 6S RNA-dependent RNA polymerase inhibition in Escherichia coli

2012 ◽  
Vol 393 (12) ◽  
pp. 1513-1522 ◽  
Author(s):  
Benedikt Steuten ◽  
Rolf Wagner
Keyword(s):  
Rna Polymerase ◽  
Stationary Phase ◽  
De Novo ◽  
Release Reaction ◽  
Conserved Sequence ◽  
6S Rna ◽  
Stable Association ◽  
The Individual ◽  
Rna Complex

Abstract 6S RNA is a bacterial transcriptional regulator, which accumulates during stationary phase and inhibits transcription from many promoters due to stable association with σ70-containing RNA polymerase. This inhibitory RNA polymerase~6S RNA complex dissociates during nutritional upshift, when cells undergo outgrowth from stationary phase, releasing active RNA polymerase ready for transcription. The release reaction depends on a characteristic property of 6S RNAs, namely to act as template for the de novo synthesis of small RNAs, termed pRNAs. Here, we used limited hydrolysis with structure-specific RNases and in-line probing of isolated 6S RNA and 6S RNA~pRNA complexes to investigate the molecular details leading to the release reaction. Our results indicate that pRNA transcription induces the refolding of the 6S RNA secondary structure by disrupting part of the closing stem (conserved sequence regions CRI and CRIV) and formation of a new hairpin (conserved sequence regions CRIII and CRIV). Comparison of the dimethylsulfate modification pattern of 6S RNA in living cells at stationary growth and during outgrowth confirmed the conformational change observed in vitro. Based on our results, a model describing the individual steps of the release reaction is presented.

scholarly journals Conversion of the Vibrio fischeriTranscriptional Activator, LuxR, to a Repressor

2000 ◽  
Vol 182 (3) ◽  
pp. 805-811 ◽  
Author(s):  
Kristi A. Egland ◽  
E. P. Greenberg
Keyword(s):  
Rna Polymerase ◽  
Transcriptional Activation ◽  
Vibrio Fischeri ◽  
Homoserine Lactone ◽  
Acyl Homoserine Lactone ◽  
Mutant Proteins ◽  
E Coli ◽  
Polymerase Binding ◽  
Regulatory Dna

ABSTRACT The Vibrio fischeri luminescence (lux) operon is regulated by a quorum-sensing system that involves the transcriptional activator (LuxR) and an acyl-homoserine lactone signal. Transcriptional activation requires the presence of a 20-base inverted repeat termed the lux box at a position centered 42.5 bases upstream of the transcriptional start of the lux operon. LuxR has proven difficult to study in vitro. A truncated form of LuxR has been purified, and together with ς70 RNA polymerase it can activate transcription of the lux operon. Both the truncated LuxR and RNA polymerase are required for binding tolux regulatory DNA in vitro. We have constructed an artificial lacZ promoter with the lux box positioned between and partially overlapping the consensus −35 and −10 hexamers of an RNA polymerase binding site. LuxR functioned as an acyl-homoserine lactone-dependent repressor at this promoter in recombinant Escherichia coli. Furthermore, multiplelux boxes on an independent replicon reduced the repressor activity of LuxR. Thus, it appears that LuxR can bind tolux boxes independently of RNA polymerase binding to the promoter region. A variety of LuxR mutant proteins were studied, and with one exception there was a correlation between function as a repressor of the artificial promoter and activation of a nativelux operon. The exception was the truncated protein that had been purified and studied in vitro. This protein functioned as an activator but not as a repressor in E. coli. The data indicate that the mutual dependence of purified, truncated LuxR and RNA polymerase on each other for binding to the lux promoter is a feature specific to the truncated LuxR and that full-length LuxR by itself can bind to lux box-containing DNA.

Sign in / Sign up

Export Citation Format

Share Document