BIOMAT Database Logo BIOMAT Database Logo

Regulation of flagellar, motility and chemotaxis genes in Rhizobium leguminosarum by the VisN/R-Rem cascade. 2010

Dinah D Tambalo, and Kate L Del Bel, and Denise E Bustard, and Paige R Greenwood, and Audrey E Steedman, and Michael F Hynes
University of Calgary, Department of Biological Sciences, 2500 University Drive NW, Calgary, AB T2N 1N4, Canada.

In this paper, we describe the regulatory roles of VisN, VisR and Rem in the expression of flagellar, motility and chemotaxis genes in Rhizobium leguminosarum biovar viciae strains VF39SM and 3841. Individual mutations in the genes encoding these proteins resulted in a loss of motility and an absence of flagella, indicating that these regulatory genes are essential for flagellar synthesis and function. Transcriptional experiments involving gusA-gene fusions in wild-type and mutant backgrounds were performed to identify the genes under VisN/R and Rem regulation. Results showed that the chemotaxis and motility genes of R. leguminosarum could be separated into two groups: one group under VisN/R-Rem regulation and another group that is independent of this regulation. VisN and VisR regulate the expression of rem, while Rem positively regulates the expression of flaA, flaB, flaC, flaD, motA, motB, che1 and mcpD. All of these genes except mcpD are located within the main motility and chemotaxis gene cluster of R. leguminosarum. Other chemotaxis and motility genes, which are found outside of the main motility gene cluster (che2 operon, flaH for VF39SM, and flaG) or are plasmid-borne (flaE and mcpC), are not part of the VisN/R-Rem regulatory cascade. In addition, all genes exhibited the same regulation pattern in 3841 and in VF39SM, except flaE and flaH. flaE is not regulated by VisN/R-Rem in 3841 but it is repressed by Rem in VF39SM. flaH is under VisN/R-Rem regulation in 3841, but not in VF39SM. A kinetics experiment demonstrated that a subset of the flagellar genes is continuously expressed in all growth phases, indicating the importance of continuous motility for R. leguminosarum under free-living conditions. On the other hand, motility is repressed under symbiotic conditions. Nodulation experiments showed that the transcriptional activators VisN and Rem are dramatically downregulated in the nodules, suggesting that the symbiotic downregulation of motility-related genes could be mediated by repressing the expression of VisN/R and Rem.

UI MeSH Term Description Entries
D009876 Operon In bacteria, a group of metabolically related genes, with a common promoter, whose transcription into a single polycistronic MESSENGER RNA is under the control of an OPERATOR REGION. Operons
D002633 Chemotaxis The movement of cells or organisms toward or away from a substance in response to its concentration gradient. Haptotaxis
D005407 Flagella A whiplike motility appendage present on the surface cells. Prokaryote flagella are composed of a protein called FLAGELLIN. Bacteria can have a single flagellum, a tuft at one pole, or multiple flagella covering the entire surface. In eukaryotes, flagella are threadlike protoplasmic extensions used to propel flagellates and sperm. Flagella have the same basic structure as CILIA but are longer in proportion to the cell bearing them and present in much smaller numbers. (From King & Stansfield, A Dictionary of Genetics, 4th ed) Flagellum
D005408 Flagellin A protein with a molecular weight of 40,000 isolated from bacterial flagella. At appropriate pH and salt concentration, three flagellin monomers can spontaneously reaggregate to form structures which appear identical to intact flagella.
D005809 Genes, Regulator Genes which regulate or circumscribe the activity of other genes; specifically, genes which code for PROTEINS or RNAs which have GENE EXPRESSION REGULATION functions. Gene, Regulator,Regulator Gene,Regulator Genes,Regulatory Genes,Gene, Regulatory,Genes, Regulatory,Regulatory Gene
D005810 Multigene Family A set of genes descended by duplication and variation from some ancestral gene. Such genes may be clustered together on the same chromosome or dispersed on different chromosomes. Examples of multigene families include those that encode the hemoglobins, immunoglobulins, histocompatibility antigens, actins, tubulins, keratins, collagens, heat shock proteins, salivary glue proteins, chorion proteins, cuticle proteins, yolk proteins, and phaseolins, as well as histones, ribosomal RNA, and transfer RNA genes. The latter three are examples of reiterated genes, where hundreds of identical genes are present in a tandem array. (King & Stanfield, A Dictionary of Genetics, 4th ed) Gene Clusters,Genes, Reiterated,Cluster, Gene,Clusters, Gene,Families, Multigene,Family, Multigene,Gene Cluster,Gene, Reiterated,Multigene Families,Reiterated Gene,Reiterated Genes
D001426 Bacterial Proteins Proteins found in any species of bacterium. Bacterial Gene Products,Bacterial Gene Proteins,Gene Products, Bacterial,Bacterial Gene Product,Bacterial Gene Protein,Bacterial Protein,Gene Product, Bacterial,Gene Protein, Bacterial,Gene Proteins, Bacterial,Protein, Bacterial,Proteins, Bacterial
D015536 Down-Regulation A negative regulatory effect on physiological processes at the molecular, cellular, or systemic level. At the molecular level, the major regulatory sites include membrane receptors, genes (GENE EXPRESSION REGULATION), mRNAs (RNA, MESSENGER), and proteins. Receptor Down-Regulation,Down-Regulation (Physiology),Downregulation,Down Regulation,Down-Regulation, Receptor
D015964 Gene Expression Regulation, Bacterial Any of the processes by which cytoplasmic or intercellular factors influence the differential control of gene action in bacteria. Bacterial Gene Expression Regulation,Regulation of Gene Expression, Bacterial,Regulation, Gene Expression, Bacterial
D016961 Rhizobium leguminosarum A species of gram-negative, aerobic bacteria that is found in soil and which causes formation of root nodules on some, but not all, types of field pea, lentil, kidney bean, and clover.

Related Publications

Dinah D Tambalo, and Kate L Del Bel, and Denise E Bustard, and Paige R Greenwood, and Audrey E Steedman, and Michael F Hynes
VisN and VisR are global regulators of chemotaxis, flagellar, and motility genes in Sinorhizobium (Rhizobium) meliloti.
February 2000, Journal of bacteriology,
Dinah D Tambalo, and Kate L Del Bel, and Denise E Bustard, and Paige R Greenwood, and Audrey E Steedman, and Michael F Hynes
Cascade regulation of Caulobacter flagellar and chemotaxis genes.
March 1987, Journal of molecular biology,
Dinah D Tambalo, and Kate L Del Bel, and Denise E Bustard, and Paige R Greenwood, and Audrey E Steedman, and Michael F Hynes
Regulation of tryptophan genes in Rhizobium leguminosarum.
March 1982, Journal of bacteriology,
Dinah D Tambalo, and Kate L Del Bel, and Denise E Bustard, and Paige R Greenwood, and Audrey E Steedman, and Michael F Hynes
R factor transfer in Rhizobium leguminosarum.
September 1974, Journal of general microbiology,
Dinah D Tambalo, and Kate L Del Bel, and Denise E Bustard, and Paige R Greenwood, and Audrey E Steedman, and Michael F Hynes
Rhizobium leguminosarum methyl-accepting chemotaxis protein genes are down-regulated in the pea nodule.
December 2004, Archives of microbiology,
Dinah D Tambalo, and Kate L Del Bel, and Denise E Bustard, and Paige R Greenwood, and Audrey E Steedman, and Michael F Hynes
Expression of Rhizobium leguminosarum CFN42 genes for lipopolysaccharide in strains derived from different R. leguminosarum soil isolates.
February 1990, Journal of bacteriology,
Dinah D Tambalo, and Kate L Del Bel, and Denise E Bustard, and Paige R Greenwood, and Audrey E Steedman, and Michael F Hynes
[Chemotaxis of Rhizobium leguminosarum bv. viciae to organic substances].
January 2009, Mikrobiolohichnyi zhurnal (Kiev, Ukraine : 1993),
Dinah D Tambalo, and Kate L Del Bel, and Denise E Bustard, and Paige R Greenwood, and Audrey E Steedman, and Michael F Hynes
Characterization of swarming motility in Rhizobium leguminosarum bv. viciae.
June 2010, FEMS microbiology letters,
Dinah D Tambalo, and Kate L Del Bel, and Denise E Bustard, and Paige R Greenwood, and Audrey E Steedman, and Michael F Hynes
Motility and Chemotaxis of Rhizobium meliloti in Soil.
November 1983, Applied and environmental microbiology,
Dinah D Tambalo, and Kate L Del Bel, and Denise E Bustard, and Paige R Greenwood, and Audrey E Steedman, and Michael F Hynes
The motility and chemosensory systems of Rhizobium leguminosarum, their role in symbiosis, and link to PTSNtr regulation.
January 2024, Environmental microbiology,
Copied contents to your clipboard!