Excretion of the anti-sigma factor through a flagellar substructure couples flagellar gene expression with flagellar assembly in Salmonella typhimurium

1994 ◽  
Vol 243 (6) ◽  
pp. 605-612 ◽  
Author(s):  
Kazuhiro Kutsukake
Keyword(s):  
Gene Expression ◽  
Salmonella Typhimurium ◽  
Sigma Factor ◽  
Flagellar Gene ◽  
Flagellar Assembly

scholarly journals FliZ Is a Posttranslational Activator of FlhD4C2-Dependent Flagellar Gene Expression

2008 ◽  
Vol 190 (14) ◽  
pp. 4979-4988 ◽  
Author(s):  
Supreet Saini ◽  
Jonathon D. Brown ◽  
Phillip D. Aldridge ◽  
Christopher V. Rao
Keyword(s):  
Gene Expression ◽  
Sigma Factor ◽  
Flagellar Gene ◽  
Critical Aspect ◽  
Swarming Motility ◽  
Flagellar Biosynthesis ◽  
Serovar Typhimurium ◽  
Flagellar Assembly

ABSTRACT Flagellar assembly proceeds in a sequential manner, beginning at the base and concluding with the filament. A critical aspect of assembly is that gene expression is coupled to assembly. When cells transition from a nonflagellated to a flagellated state, gene expression is sequential, reflecting the manner in which the flagellum is made. A key mechanism for establishing this temporal hierarchy is the σ28-FlgM checkpoint, which couples the expression of late flagellar (Pclass3) genes to the completion of the hook-basal body. In this work, we investigated the role of FliZ in coupling middle flagellar (Pclass2) gene expression to assembly in Salmonella enterica serovar Typhimurium. We demonstrate that FliZ is an FlhD4C2-dependent activator of Pclass2/middle gene expression. Our results suggest that FliZ regulates the concentration of FlhD4C2 posttranslationally. We also demonstrate that FliZ functions independently of the flagellum-specific sigma factor σ28 and the filament-cap chaperone/FlhD4C2 inhibitor FliT. Furthermore, we show that the previously described ability of σ28 to activate Pclass2/middle gene expression is, in fact, due to FliZ, as both are expressed from the same overlapping Pclass2 and Pclass3 promoters at the fliAZY locus. We conclude by discussing the role of FliZ regulation with respect to flagellar biosynthesis based on our characterization of gene expression and FliZ's role in swimming and swarming motility.

scholarly journals New class of transcription factors controls flagellar assembly by recruiting RNA polymerase II in Chlamydomonas

2018 ◽  
Vol 115 (17) ◽  
pp. 4435-4440 ◽  
Author(s):  
Lili Li ◽  
Guangmei Tian ◽  
Hai Peng ◽  
Dan Meng ◽  
Liang Wang ◽  
...  
Keyword(s):  
Gene Expression ◽  
Transcription Factor ◽  
Transcriptional Regulation ◽  
Transcription Factors ◽  
Rna Polymerase Ii ◽  
Flagellar Gene ◽  
Pol Ii ◽  
Biochemical Function ◽  
Flagellar Assembly ◽  
Flagellar Genes

Cells have developed regulatory mechanisms that underlie flagellar assembly and maintenance, including the transcriptional regulation of flagellar genes, an initial step for making flagella. Although transcriptional regulation of flagellar gene expression is required for flagellar assembly in Chlamydomonas, no transcription factor that regulates the transcription of flagellar genes has been identified. We report that X chromosome-associated protein 5 (XAP5) acts as a transcription factor to regulate flagellar assembly in Chlamydomonas. While XAP5 proteins are evolutionarily conserved across diverse organisms and play vital roles in diverse biological processes, nothing is known about the biochemical function of any member of this important protein family. Our data show that loss of XAP5 leads to defects in flagellar assembly. Posttranslational modifications of XAP5 track flagellar length during flagellar assembly, suggesting that cells possess a feedback system that modulates modifications to XAP5. Notably, XAP5 regulates flagellar gene expression via directly binding to a motif containing a CTGGGGTG-core. Furthermore, recruitment of RNA polymerase II (Pol II) machinery for transcriptional activation depends on the activities of XAP5. Our data demonstrate that, through recruitment of Pol II, XAP5 defines a class of transcription factors for transcriptional regulation of ciliary genes. This work provides insights into the biochemical function of the XAP5 family and the fundamental biology of the flagellar assembly, which enhance our understanding of the signaling and functions of flagella.

scholarly journals Small RNAs OmrA and OmrB promote class III flagellar gene expression by inhibiting the synthesis of anti-Sigma factor FlgM

RNA Biology ◽  
2020 ◽  
Vol 17 (6) ◽  
pp. 872-880
Author(s):  
Cédric Romilly ◽  
Mirthe Hoekzema ◽  
Erik Holmqvist ◽  
E. Gerhart H. Wagner
Keyword(s):  
Gene Expression ◽  
Sigma Factor ◽  
Small Rnas ◽  
Flagellar Gene ◽  
Class Iii

scholarly journals FliZ Induces a Kinetic Switch in Flagellar Gene Expression

2010 ◽  
Vol 192 (24) ◽  
pp. 6477-6481 ◽  
Author(s):  
Supreet Saini ◽  
Santosh Koirala ◽  
Emily Floess ◽  
Patrick J. Mears ◽  
Yann R. Chemla ◽  
...  
Keyword(s):  
Gene Expression ◽  
Positive Feedback ◽  
Salmonella Enterica ◽  
Feedback Loop ◽  
Flagellar Gene ◽  
Positive Feedback Loop ◽  
Gene Expression Dynamics ◽  
Flagellar Assembly

ABSTRACT FliZ is an activator of class 2 flagellar gene expression in Salmonella enterica. To understand its role in flagellar assembly, we investigated how FliZ affects gene expression dynamics. We demonstrate that FliZ participates in a positive-feedback loop that induces a kinetic switch in class 2 gene expression.

scholarly journals Negative transcriptional regulation in the Caulobacter flagellar hierarchy

1989 ◽  
Vol 86 (17) ◽  
pp. 6656-6660 ◽  
Author(s):  
H Xu ◽  
A Dingwall ◽  
L Shapiro
Keyword(s):  
Gene Expression ◽  
Basal Body ◽  
Caulobacter Crescentus ◽  
Negative Control ◽  
Negative Regulation ◽  
Flagellar Gene ◽  
Structural Genes ◽  
Number Of Genes ◽  
Flagellar Assembly ◽  
Transcriptional Fusions

The Caulobacter crescentus flagellum is formed at a specific time in the cell cycle and its assembly requires the ordered expression of a large number of genes. These genes are controlled in a positive trans-acting hierarchy that reflects the order of assembly of the flagellum. Using plasmids carrying transcriptional fusions of either a neo or a lux reporter gene to the promoters of three flagellar genes representing different ranks in the hierarchy (the hook operon, a basal body gene flbN, and the flaO gene), we have measured the level of chimeric gene expression in 13 flagellar mutant backgrounds. Mutants in the hook operon or in basal body genes caused overproduction of both hook operon and basal body gene chimeric mRNAs, suggesting that negative regulation is superimposed on the positive trans-acting control for these early events in the flagellar hierarchy. Mutants in the structural genes and in genes involved in flagellar assembly had no effect on flaO expression, placing the flaO gene near the top of the hierarchy. However, flaO expression appears to be under negative control by two regulatory genes flaS and flaW. Negative control, as a response to the completion of specific steps in the assembly process, may be an important mechanism used by the cell to turn off flagellar gene expression once the gene product is no longer needed.

scholarly journals Negative Control of Flagellum Synthesis in Pseudomonas aeruginosa Is Modulated by the Alternative Sigma Factor AlgT (AlgU)

1999 ◽  
Vol 181 (23) ◽  
pp. 7401-7404 ◽  
Author(s):  
Edward S. Garrett ◽  
Demetra Perlegas ◽  
Daniel J. Wozniak
Keyword(s):  
Gene Expression ◽  
Cystic Fibrosis ◽  
Pseudomonas Aeruginosa ◽  
Sigma Factor ◽  
Negative Control ◽  
Alternative Sigma Factor ◽  
Flagellar Gene

ABSTRACT Many respiratory isolates of Pseudomonas aeruginosafrom cystic fibrosis patients are mucoid (alginate producing) yet lack flagella. It was hypothesized that an alginate regulator inhibits flagellar gene expression. Mutations in algB,algR, and algT resulted in nonmucoid derivatives, yet algT mutants expressed flagella. AlgT-dependent control of flagellum synthesis occurred through inhibition of fliC but not rpoN transcription.

scholarly journals Two Tandem Mechanisms Control Bimodal Expression of the Flagellar Genes in Salmonella enterica

2020 ◽  
Vol 202 (13) ◽  
Author(s):  
Xiaoyi Wang ◽  
Santosh Koirala ◽  
Phillip D. Aldridge ◽  
Christopher V. Rao
Keyword(s):  
Gene Expression ◽  
Salmonella Enterica ◽  
Feedback Loop ◽  
Growth Conditions ◽  
Double Negative ◽  
Flagellar Gene ◽  
Content Type ◽  
Motile Cells ◽  
Flagellar Assembly ◽  
Flagellar Genes

ABSTRACT Flagellar gene expression is bimodal in Salmonella enterica. Under certain growth conditions, some cells express the flagellar genes whereas others do not. This results in mixed populations of motile and nonmotile cells. In the present study, we found that two independent mechanisms control bimodal expression of the flagellar genes. One was previously found to result from a double negative-feedback loop involving the flagellar regulators RflP and FliZ. This feedback loop governs bimodal expression of class 2 genes. In this work, a second mechanism was found to govern bimodal expression of class 3 genes. In particular, class 3 gene expression is still bimodal, even when class 2 gene expression is not. Using a combination of experimental and modeling approaches, we found that class 3 bimodality results from the σ28-FlgM developmental checkpoint. IMPORTANCE Many bacterial use flagella to swim in liquids and swarm over surface. In Salmonella enterica, over 50 genes are required to assemble flagella. The expression of these genes is tightly regulated. Previous studies have found that flagellar gene expression is bimodal in S. enterica, which means that only a fraction of cells express flagellar genes and are motile. In the present study, we found that two separate mechanisms induce this bimodal response. One mechanism, which was previously identified, tunes the fraction of motile cells in response to nutrients. The other results from a developmental checkpoint that couples flagellar gene expression to flagellar assembly. Collectively, these results further our understanding of how flagellar gene expression is regulated in S. enterica.

scholarly journals Themes and Variations: Regulation of RpoN-Dependent Flagellar Genes across Diverse Bacterial Species

Scientifica ◽  
2014 ◽  
Vol 2014 ◽  
pp. 1-14 ◽  
Author(s):  
Jennifer Tsang ◽  
Timothy R. Hoover
Keyword(s):  
Gene Expression ◽  
Campylobacter Jejuni ◽  
Sigma Factor ◽  
Caulobacter Crescentus ◽  
Bacterial Species ◽  
Alternative Sigma Factor ◽  
Flagellar Gene ◽  
Complex Process ◽  
Flagellar Biogenesis ◽  
Flagellar Genes

Flagellar biogenesis in bacteria is a complex process in which the transcription of dozens of structural and regulatory genes is coordinated with the assembly of the flagellum. Although the overall process of flagellar biogenesis is conserved among bacteria, the mechanisms used to regulate flagellar gene expression vary greatly among different bacterial species. Many bacteria use the alternative sigma factorσ54(also known as RpoN) to transcribe specific sets of flagellar genes. These bacteria include members of the Epsilonproteobacteria (e.g.,Helicobacter pyloriandCampylobacter jejuni), Gammaproteobacteria (e.g.,VibrioandPseudomonasspecies), and Alphaproteobacteria (e.g.,Caulobacter crescentus). This review characterizes the flagellar transcriptional hierarchies in these bacteria and examines what is known about how flagellar gene regulation is linked with other processes including growth phase, quorum sensing, and host colonization.

scholarly journals Two tandem mechanisms control bimodal expression of the flagellar genes in Salmonella enterica

2019 ◽  
Author(s):  
Xiaoyi Wang ◽  
Santosh Koirala ◽  
Phillip D. Aldridge ◽  
Christopher V. Rao
Keyword(s):  
Gene Expression ◽  
Salmonella Enterica ◽  
Feedback Loop ◽  
Growth Conditions ◽  
Double Negative ◽  
Flagellar Gene ◽  
Motile Cells ◽  
Flagellar Assembly ◽  
Mixed Populations ◽  
Flagellar Genes

ABSTRACTFlagellar gene expression is bimodal in Salmonella enterica. Under certain growth conditions, some cells express the flagellar genes whereas others do not. This results in mixed populations of motile and non-motile cells. In the present study, we found that two independent mechanisms control bimodal expression of the flagellar genes. One was previously found to result from a double negative-feedback loop involving the flagellar regulators YdiV and FliZ. This feedback loop governs bimodal expression of class 2 genes. In this work, a second mechanism was found to govern bimodal expression of class 3 genes. In particular, class 3 gene expression is still bimodal even when class 2 gene expression is not. Using a combination of experimental and modeling approaches, we found that class 3 bimodalilty results from the σ28-FlgM developmental checkpoint.IMPORTANCEMany bacterial use flagella to swim in liquids and swarm over surface. In Salmonella enterica, over fifty genes are required to assemble flagella. The expression of these genes is tightly regulated. Previous studies have found that flagella gene expression is bimodal in S. enterica, which means that only a fraction of cells express flagellar genes and are motile. In the present study, we found that two separate mechanisms induce this bimodal response. One mechanism, which was previously identified, tunes the fraction of motile cells in response to nutrients. The other results from a developmental checkpoint that couples flagellar gene expression to flagellar assembly. Collectively, these results further our understanding of how flagellar gene expression is regulated in S. enterica.

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