Researchers Reconstitute Regulatory Cascade, and It Works!

2010 ◽  
Vol 5 (4) ◽  
pp. 173-173
Keyword(s):  
Regulatory Cascade

Involvement of a novel regulatory cascade consisting of SET-H3K18ac/H3K27ac-53BP1 in Cr(VI)-induced malignant transformation of 16HBE cells

2021 ◽  
Vol 339 ◽  
pp. 70-77
Author(s):  
Zhihong Chen ◽  
Jiacheng Zhong ◽  
Xiaohu Ren ◽  
Wei Liu ◽  
Desheng Wu ◽  
...  
Keyword(s):  
Malignant Transformation ◽  
Regulatory Cascade

scholarly journals FarRRegulates the farAB-Encoded Efflux Pump of Neisseriagonorrhoeae via an MtrR RegulatoryMechanism

2003 ◽  
Vol 185 (24) ◽  
pp. 7145-7152 ◽  
Author(s):  
E.-H. Lee ◽  
C. Rouquette-Loughlin ◽  
J. P. Folster ◽  
W. M. Shafer
Keyword(s):  
Regulatory Mechanism ◽  
Efflux Pump ◽  
Regulatory Protein ◽  
Transcriptional Repressors ◽  
Sequence Database ◽  
Mobility Shift ◽  
Pump System ◽  
Regulatory Cascade ◽  
Genome Sequence Database ◽  
Gel Mobility Shift

ABSTRACT The farAB operon of Neisseria gonorrhoeae encodes an efflux pump which mediates gonococcal resistance to antibacterial fatty acids. It was previously observed that expression of the farAB operon was positively regulated by MtrR, which is a repressor of the mtrCDE-encoded efflux pump system (E.-H. Lee and W. M. Shafer, Mol. Microbiol. 33:839-845, 1999). This regulation was believed to be indirect since MtrR did not bind to the farAB promoter. In this study, computer analysis of the gonococcal genome sequence database, lacZ reporter fusions, and gel mobility shift assays were used to elucidate the regulatory mechanism by which expression of the farAB operon is modulated by MtrR in gonococci. We identified a regulatory protein belonging to the MarR family of transcriptional repressors and found that it negatively controls expression of farAB by directly binding to the farAB promoter. We designated this regulator FarR to signify its role in regulating the farAB operon. We found that MtrR binds to the farR promoter, thereby repressing farR expression. Hence, MtrR regulates farAB in a positive fashion by modulating farR expression. This MtrR regulatory cascade seems to play an important role in adjusting levels of the FarAB and MtrCDE efflux pumps to prevent their excess expression in gonococci.

scholarly journals Analysis of a Gene Regulatory Cascade Mediating Circadian Rhythm in Zebrafish

2013 ◽  
Vol 9 (2) ◽  
pp. e1002940 ◽  
Author(s):  
Ying Li ◽  
Guang Li ◽  
Haifang Wang ◽  
Jiulin Du ◽  
Jun Yan
Keyword(s):  
Circadian Rhythm ◽  
Regulatory Cascade ◽  
Gene Regulatory

The complete denitrification pathway of the symbiotic, nitrogen-fixing bacterium Bradyrhizobium japonicum

2005 ◽  
Vol 33 (1) ◽  
pp. 141-144 ◽  
Author(s):  
E.J. Bedmar ◽  
E.F. Robles ◽  
M.J. Delgado
Keyword(s):  
Nitric Oxide ◽  
Nitrous Oxide ◽  
Bradyrhizobium Japonicum ◽  
Mutational Analysis ◽  
Control Level ◽  
Gene Clusters ◽  
Alternative Form ◽  
Nitrate Respiration ◽  
Regulatory Cascade ◽  
Denitrification Genes

Denitrification is an alternative form of respiration in which bacteria sequentially reduce nitrate or nitrite to nitrogen gas by the intermediates nitric oxide and nitrous oxide when oxygen concentrations are limiting. In Bradyrhizobium japonicum, the N2-fixing microsymbiont of soya beans, denitrification depends on the napEDABC, nirK, norCBQD, and nosRZDFYLX gene clusters encoding nitrate-, nitrite-, nitric oxide- and nitrous oxide-reductase respectively. Mutational analysis of the B. japonicum nap genes has demonstrated that the periplasmic nitrate reductase is the only enzyme responsible for nitrate respiration in this bacterium. Regulatory studies using transcriptional lacZ fusions to the nirK, norCBQD and nosRZDFYLX promoter region indicated that microaerobic induction of these promoters is dependent on the fixLJ and fixK2 genes whose products form the FixLJ–FixK2 regulatory cascade. Besides FixK2, another protein, nitrite and nitric oxide respiratory regulator, has been shown to be required for N-oxide regulation of the B. japonicum nirK and norCBQD genes. Thus nitrite and nitric oxide respiratory regulator adds to the FixLJ–FixK2 cascade an additional control level which integrates the N-oxide signal that is critical for maximal induction of the B. japonicum denitrification genes. However, the identity of the signalling molecule and the sensing mechanism remains unknown.

scholarly journals DNA microarray analysis of global gene regulation by A-factor in Streptomyces griseus

Microbiology ◽  
2009 ◽  
Vol 155 (7) ◽  
pp. 2197-2210 ◽  
Author(s):  
Hirofumi Hara ◽  
Yasuo Ohnishi ◽  
Sueharu Horinouchi
Keyword(s):  
Gene Expression ◽  
Microarray Analysis ◽  
Dna Microarray ◽  
Streptomyces Griseus ◽  
Exponential Growth Phase ◽  
Mobility Shift ◽  
Dna Microarray Analysis ◽  
Regulatory Cascade ◽  
Transcriptional Units ◽  
Inducible Genes

A-factor (2-isocapryloyl-3R-hydroxymethyl-γ-butyrolactone) is a microbial hormone that triggers morphological differentiation and secondary metabolism in Streptomyces griseus. The effects of A-factor on global gene expression were determined by DNA microarray analysis of transcriptomes obtained with the A-factor-deficient mutant ΔafsA. A-factor was added at a concentration of 25 ng ml−1 to mutant ΔafsA at the middle of the exponential growth phase, and RNA samples were prepared from the cells grown after A-factor addition for a further 5, 15 and 30 min, and 1, 2, 4, 8 and 12 h. The effects of A-factor on transcription of all protein-coding genes of S. griseus were evaluated by comparison of the transcriptomes with those obtained from cells grown in the absence of A-factor. Analysis of variance among the transcriptomes revealed that 477 genes, which were dispersed throughout the chromosome, were differentially expressed during the 12 h after addition of A-factor, when evaluated by specific criteria. Quality threshold clustering analysis with regard to putative polycistronic transcriptional units and levels of upregulation predicted that 152 genes belonging to 74 transcriptional units were probable A-factor-inducible genes. Competitive electrophoretic mobility shift assays using DNA fragments including putative promoter regions of these 74 transcriptional units suggested that AdpA bound 37 regions to activate 72 genes in total. Many of these A-factor-inducible genes encoded proteins of unknown function, suggesting that the A-factor regulatory cascade of S. griseus affects gene expression at a specific time point more profoundly than expected.

scholarly journals Bradyrhizobium japonicum NnrR, a Denitrification Regulator, Expands the FixLJ-FixK2 Regulatory Cascade

2003 ◽  
Vol 185 (13) ◽  
pp. 3978-3982 ◽  
Author(s):  
Socorro Mesa ◽  
Eulogio J. Bedmar ◽  
Astrid Chanfon ◽  
Hauke Hennecke ◽  
Hans-Martin Fischer
Keyword(s):  
Bradyrhizobium Japonicum ◽  
Control Level ◽  
Nitric Oxide Reductase ◽  
Regulatory Cascade ◽  
Additional Control ◽  
Mutant Strains ◽  
Genes Encoding ◽  
Maximal Induction ◽  
Nitrate And Nitrite ◽  
Denitrification Genes

ABSTRACT In Bradyrhizobium japonicum, a gene named nnrR was identified which encodes a protein with high similarity to FNR/CRP-type transcriptional regulators. Mutant strains carrying an nnrR null mutation were unable to grow anaerobically in the presence of nitrate or nitrite, and they lacked both nitrate and nitrite reductase activities. Anaerobic activation of an nnrR′-′lacZ fusion required FixLJ and FixK2. In turn, N oxide-mediated induction of nir and nor genes encoding nitrite and nitric oxide reductase, respectively, depended on NnrR. Thus, NnrR expands the FixLJ-FixK2 regulatory cascade by an additional control level which integrates the N oxide signal required for maximal induction of the denitrification genes.

scholarly journals A meiotic gene regulatory cascade driven by alternative fates for newly synthesized transcripts

2011 ◽  
Vol 22 (1) ◽  
pp. 66-77 ◽  
Author(s):  
Nicole Cremona ◽  
Kristine Potter ◽  
Jo Ann Wise
Keyword(s):  
Fission Yeast ◽  
Rna Processing ◽  
Yeast Cells ◽  
Forkhead Transcription Factor ◽  
Rna Surveillance ◽  
Regulatory Cascade ◽  
Show Evidence ◽  
Gene Regulatory ◽  
Rna Accumulation ◽  
Temporal Profiles

To determine the relative importance of transcriptional regulation versus RNA processing and turnover during the transition from proliferation to meiotic differentiation in the fission yeast Schizosaccharomyces pombe, we analyzed temporal profiles and effects of RNA surveillance factor mutants on expression of 32 meiotic genes. A comparison of nascent transcription with steady-state RNA accumulation reveals that the vast majority of these genes show a lag between maximal RNA synthesis and peak RNA accumulation. During meiosis, total RNA levels parallel 3′ processing, which occurs in multiple, temporally distinct waves that peak from 3 to 6 h after meiotic induction. Most early genes and one middle gene, mei4, share a regulatory mechanism in which a specialized RNA surveillance factor targets newly synthesized transcripts for destruction. Mei4p, a member of the forkhead transcription factor family, in turn regulates a host of downstream genes. Remarkably, a spike in transcription is observed for less than one-third of the genes surveyed, and even these show evidence of RNA-level regulation. In aggregate, our findings lead us to propose that a regulatory cascade driven by changes in processing and stability of newly synthesized transcripts operates alongside the well-known transcriptional cascade as fission yeast cells enter meiosis.

scholarly journals Local and Global Regulators Linking Anaerobiosis to cupA Fimbrial Gene Expression in Pseudomonas aeruginosa

2007 ◽  
Vol 189 (23) ◽  
pp. 8667-8676 ◽  
Author(s):  
Isabelle Vallet-Gely ◽  
Josh S. Sharp ◽  
Simon L. Dove
Keyword(s):  
Gene Expression ◽  
Pseudomonas Aeruginosa ◽  
Opportunistic Pathogen ◽  
Phase Variable ◽  
Global Regulators ◽  
Variable Expression ◽  
Regulatory Cascade ◽  
Abiotic Surfaces ◽  
Positive Regulators ◽  
Anaerobic Environment

ABSTRACT The cupA gene cluster of Pseudomonas aeruginosa encodes components and assembly factors of a putative fimbrial structure that enable this opportunistic pathogen to form biofilms on abiotic surfaces. In P. aeruginosa the control of cupA gene expression is complex, with the H-NS-like MvaT protein functioning to repress phase-variable (on/off) expression of the operon. Here we identify four positive regulators of cupA gene expression, including three unusual regulators encoded by the cgrABC genes and Anr, a global regulator of anaerobic gene expression. We show that the cupA genes are expressed in a phase-variable manner under anaerobic conditions and that the cgr genes are essential for this expression. We show further that cgr gene expression is negatively controlled by MvaT and positively controlled by Anr and anaerobiosis. Expression of the cupA genes therefore appears to involve a regulatory cascade in which anaerobiosis, signaled through Anr, stimulates expression of the cgr genes, resulting in a concomitant increase in cupA gene expression. Our findings thus provide mechanistic insight into the regulation of cupA gene expression and identify anaerobiosis as an inducer of phase-variable cupA gene expression, raising the possibility that phase-variable expression of fimbrial genes important for biofilm formation may occur in P. aeruginosa persisting in the largely anaerobic environment of the cystic fibrosis host lung.

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