scholarly journals Identification of σE-Dependent Promoter Upstream of clpB from the Pathogenic Spirochaete Leptospira interrogans by Applying an E. coli Two-Plasmid System

2019 ◽  
Vol 20 (24) ◽  
pp. 6325
Author(s):  
Sabina Kędzierska-Mieszkowska ◽  
Katarzyna Potrykus ◽  
Zbigniew Arent ◽  
Joanna Krajewska

There is limited information on gene expression in the pathogenic spirochaete Leptospira interrogans and genetic mechanisms controlling its virulence. Transcription is the first step in gene expression that is often determined by environmental effects, including infection-induced stresses. Alterations in the environment result in significant changes in the transcription of many genes, allowing effective adaptation of Leptospira to mammalian hosts. Thus, promoter and transcriptional start site identification are crucial for determining gene expression regulation and for the understanding of genetic regulatory mechanisms existing in Leptospira. Here, we characterized the promoter region of the L. interrogans clpB gene (clpBLi) encoding an AAA+ molecular chaperone ClpB essential for the survival of this spirochaete under thermal and oxidative stresses, and also during infection of the host. Primer extension analysis demonstrated that transcription of clpB in L. interrogans initiates at a cytidine located 41 bp upstream of the ATG initiation codon, and, to a lesser extent, at an adenine located 2 bp downstream of the identified site. Transcription of both transcripts was heat-inducible. Determination of clpBLi transcription start site, combined with promoter transcriptional activity assays using a modified two-plasmid system in E. coli, revealed that clpBLi transcription is controlled by the ECF σE factor. Of the ten L. interrogans ECF σ factors, the factor encoded by LIC_12757 (LA0876) is most likely to be the key regulator of clpB gene expression in Leptospira cells, especially under thermal stress. Furthermore, clpB expression may be mediated by ppGpp in Leptospira.

2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Fumiko Taniuchi ◽  
Koji Higai ◽  
Tomomi Tanaka ◽  
Yutaro Azuma ◽  
Kojiro Matsumoto

Theα1,2-fucosyltransferase I (FUT1) enzyme is important for the biosynthesis of H antigens, Lewis B, and Lewis Y. In this study, we clarified the transcriptional regulation of FUT1 in the DLD-1 colon cancer cell line, which has high expression of Lewis B and Lewis Y antigens, expresses theFUT1gene, and showsα1,2-fucosyltransferase (FUT) activity. 5′-rapid amplification of cDNA ends revealed a FUT1 transcriptional start site −10 nucleotides upstream of the site registered at NM_000148 in the DataBase of Human Transcription Start Sites (DBTSS). Using the dual luciferase assay,FUT1gene expression was shown to be regulated at the region −91 to −81 nt to the transcriptional start site, which contains the Elk-1 binding site. Site-directed mutagenesis of this region revealed the Elk-1 binding site to be essential for FUT1 transcription. Furthermore, transfection of the dominant negative Elk-1 gene, and the chromatin immunoprecipitation (CHIp) assay, supported Elk-1-dependent transcriptional regulation ofFUT1gene expression in DLD-1 cells. These results suggest that a defined region in the 5′-flanking region of FUT1 is critical for FUT1 transcription and that constitutive gene expression ofFUT1is regulated by Elk-1 in DLD-1 cells.


2005 ◽  
Vol 187 (20) ◽  
pp. 7027-7037 ◽  
Author(s):  
Jennifer L. Robbins-Manke ◽  
Zoran Z. Zdraveski ◽  
Martin Marinus ◽  
John M. Essigmann

ABSTRACT DNA adenine methylation by DNA adenine methyltransferase (Dam) in Escherichia coli plays an important role in processes such as DNA replication initiation, gene expression regulation, and mismatch repair. In addition, E. coli strains deficient in Dam are hypersensitive to DNA-damaging agents. We used genome microarrays to compare the transcriptional profiles of E. coli strains deficient in Dam and mismatch repair (dam, dam mutS, and mutS mutants). Our results show that >200 genes are expressed at a higher level in the dam strain, while an additional mutation in mutS suppresses the induction of many of the same genes. We also show by microarray and semiquantitative real-time reverse transcription-PCR that both dam and dam mutS strains show derepression of LexA-regulated SOS genes as well as the up-regulation of other non-SOS genes involved in DNA repair. To correlate the level of SOS induction and the up-regulation of genes involved in recombinational repair with the level of DNA damage, we used neutral single-cell electrophoresis to determine the number of double-strand breaks per cell in each of the strains. We find that dam mutant E. coli strains have a significantly higher level of double-strand breaks than the other strains. We also observe a broad range in the number of double-strand breaks in dam mutant cells, with a minority of cells showing as many as 10 or more double-strand breaks. We propose that the up-regulation of recombinational repair in dam mutants allows for the efficient repair of double-strand breaks whose formation is dependent on functional mismatch repair.


2011 ◽  
Vol 2011 ◽  
pp. 1-7
Author(s):  
Mika Ohta ◽  
Aki Sugano ◽  
Shuji Goto ◽  
Surini Yusoff ◽  
Yushi Hirota ◽  
...  

We have been investigating the molecular efficacy of electroacupuncture (EA), which is one type of acupuncture therapy. In our previous molecular biological study of acupuncture, we found an EA-induced gene, named acupuncture-induced 1-L (Aig1l), in mouse skeletal muscle. The aims of this study consisted of identification of the full-length cDNA sequence ofAig1lincluding the transcriptional start site, determination of the tissue distribution ofAig1land analysis of the effect of EA onAig1lgene expression. We determined the complete cDNA sequence including the transcriptional start site via cDNA cloning with the cap site hunting method. We then analyzed the tissue distribution ofAig1lby means of northern blot analysis and real-time quantitative polymerase chain reaction. We used the semiquantitative reverse transcriptase-polymerase chain reaction to examine the effect of EA onAig1lgene expression. Our results showed that the complete cDNA sequence ofAig1lwas 6073 bp long, and the putative protein consisted of 962 amino acids. All seven tissues that we analyzed expressed theAig1lgene. In skeletal muscle, EA induced expression of theAig1lgene, with high expression observed after 3 hours of EA. Our findings thus suggest that theAig1lgene may play a key role in the molecular mechanisms of EA efficacy.


1998 ◽  
Vol 180 (23) ◽  
pp. 6252-6259 ◽  
Author(s):  
Alejandro Peñaloza-Vázquez ◽  
Carol L. Bender

ABSTRACT Coronatine (COR) is a plasmid-encoded phytotoxin synthesized by several pathovars of phytopathogenic Pseudomonas syringae. The COR biosynthetic gene cluster in P. syringae pv. glycinea PG4180 is encoded by a 32-kb region which contains both the structural and regulatory genes needed for COR synthesis. The regulatory region contains three genes: corP,corS, and corR. corS is thought to function as a histidine protein kinase, whereas corP andcorR show relatedness to response regulators of the two-component regulatory paradigm. In the present study, we investigated whether CorR is a positive activator of COR gene expression. We also studied whether CorR specifically binds the DNA region located upstream of cfl, a gene located at the 5′ end of the gene cluster encoding coronafacic acid, the polyketide portion of COR. Complementation analysis with a corRmutant, PG4180.P2, and transcriptional fusions to a promoterless glucuronidase gene (uidA) indicated that CorR functions as a positive regulator of COR gene expression. Deletion analysis of the 5′ end of the cfl upstream region was used to define the minimal region required for COR gene expression. A 360-bp DNA fragment located over 500 bp upstream from the cfl transcriptional start site was used in DNase I protection assays to define the specific bases bound by CorR. An area extending from −704 to −650 with respect to the cfl transcriptional start site was protected by DNase I footprinting, indicating a rather large area of protection. This area was also conserved in the promoter region forcmaA, which encodes a transcript containing genes for coronamic acid synthesis, another intermediate in the COR biosynthetic pathway. The results obtained in the current study suggest that both the coronafacic acid and the coronamic acid structural genes are controlled by CorR, a positive activator of COR gene expression.


Author(s):  
Anna Zhukova ◽  
Luis Guilherme Fernandes ◽  
Perrine Hugon ◽  
Christopher J. Pappas ◽  
Odile Sismeiro ◽  
...  

2004 ◽  
Vol 32 (15) ◽  
pp. 4512-4523 ◽  
Author(s):  
Y. V. Sun ◽  
D. R. Boverhof ◽  
L. D. Burgoon ◽  
M. R. Fielden ◽  
T. R. Zacharewski

Abstract Comparative approaches were used to identify human, mouse and rat dioxin response elements (DREs) in genomic sequences unambiguously assigned to a nucleotide RefSeq accession number. A total of 13 bona fide DREs, all including the substitution intolerant core sequence (GCGTG) and adjacent variable sequences, were used to establish a position weight matrix and a matrix similarity (MS) score threshold to rank identified DREs. DREs with MS scores above the threshold were disproportionately distributed in close proximity to the transcription start site in all three species. Gene expression assays in hepatic mouse tissue confirmed the responsiveness of 192 genes possessing a putative DRE. Previously identified functional DREs in well-characterized AhR-regulated genes including Cyp1a1 and Cyp1b1 were corroborated. Putative DREs were identified in 48 out of 2437 human–mouse–rat orthologous genes between −1500 and the transcriptional start site, of which 19 of these genes possessed positionally conserved DREs as determined by multiple sequence alignment. Seven of these nineteen genes exhibited 2,3,7,8-tetrachlorodibenzo- p -dioxin-mediated regulation, although there were significant discrepancies between in vivo and in vitro results. Interestingly, of the mouse–rat orthologous genes with a DRE between −1500 and +1500, only 37% had an equivalent human ortholog. These results suggest that AhR-mediated gene expression may not be well conserved across species, which could have significant implications in human risk assessment.


2014 ◽  
Vol 197 (1) ◽  
pp. 18-28 ◽  
Author(s):  
Maureen K. Thomason ◽  
Thorsten Bischler ◽  
Sara K. Eisenbart ◽  
Konrad U. Förstner ◽  
Aixia Zhang ◽  
...  

While the model organismEscherichia colihas been the subject of intense study for decades, the full complement of its RNAs is only now being examined. Here we describe a survey of theE. colitranscriptome carried out using a differential RNA sequencing (dRNA-seq) approach, which can distinguish between primary and processed transcripts, and an automated prediction algorithm for transcriptional start sites (TSS). With the criterion of expression under at least one of three growth conditions examined, we predicted 14,868 TSS candidates, including 5,574 internal to annotated genes (iTSS) and 5,495 TSS corresponding to potential antisense RNAs (asRNAs). We examined expression of 14 candidate asRNAs by Northern analysis using RNA from wild-typeE. coliand from strains defective for RNases III and E, two RNases reported to be involved in asRNA processing. Interestingly, nine asRNAs detected as distinct bands by Northern analysis were differentially affected by therncandrnemutations. We also compared our asRNA candidates with previously published asRNA annotations from RNA-seq data and discuss the challenges associated with these cross-comparisons. Our global transcriptional start site map represents a valuable resource for identification of transcription start sites, promoters, and novel transcripts inE. coliand is easily accessible, together with the cDNA coverage plots, in an online genome browser.


Sign in / Sign up

Export Citation Format

Share Document