Browse
Submit Data
Databases
API
Help

Dataset Information

0 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

The orphan response regulator DigR is required for synthesis of extracellular matrix fibrils in Myxococcus xanthus

ABSTRACT: In Myxococcus xanthus, two component systems have crucial roles in regulating motility behavior and development. Here, we describe an orphan response regulator consisting of an N-terminal receiver domain and a C-terminal DNA binding domain, which is required for A- and type IV pili dependent gliding motility. Genetic evidence suggests that phosphorylation of the conserved, phosphorylatable aspartate residue in the receiver domain is required for DigR activity. Consistent with the defect in type IV pili dependent motility, a digR mutant is slightly reduced in type IV pili biosynthesis and the composition of the extracellular matrix fibrils is abnormal with an increased content of polysaccharides and decreased accumulation of the FibA metalloprotease. Using genome-wide transcriptional profiling, 118 genes were identified that are directly or indirectly regulated by DigR. These genes only include two genes, agmQ and cheY4, previously implicated in A- and type IV pili dependent motility, respectively. In silico analyses showed that 36% of the differentially expressed genes are likely to encode exported proteins. Moreover, four genes encoding homologs of ECF sigma factors, which typically control aspects of cell envelope homeostasis, are differentially expressed in a digR mutant. We suggest that the DigR response regulator has an important function in cell envelope homeostasis and that the motility defects in a digR mutant are instigated by the abnormal cell envelope and abnormal expression of agmQ and cheY4. Keywords: vegetative analysis (delta)DigR / DK1622 (wt)

ORGANISM(S): Myxococcus xanthus

PROVIDER: GSE9501 | GEO | 2007/11/02

SECONDARY ACCESSION(S): PRJNA103293

REPOSITORIES: GEO

ACCESS DATA

Json Xml

Similar Datasets

Role of σ54 in the regulation of genes involved in biogenesis of type I and type IV pili in Xylella fastidiosa

Project description:The phytopathogen Xylella fastidiosa produces two classes of pili, long type IV pili and short type I pili, which are involved in motility and adhesion. In this work, we have investigated the role of σ54 factor and its involvement in the regulation of fimbrial biogenesis in X. fastidiosa. An rpoN null mutant was constructed from citrus strain J1a12, and analyses of global gene expression profile by microarrays comparing the wild type and rpoN mutant strains showed that few genes exhibited differential expression. At least one gene, pilA1 (XF2542), which encodes the structural pilin protein of type IV fimbriae, showed decreased expression in the rpoN mutant whereas an operon encoding proteins of type I fimbriae were twofold more expressed in the mutant. Quantitative real time RT-PCR (qRT-PCR) analysis confirmed that pilA1 transcript was significantly reduced in the rpoN mutant. The transcriptional start site of pilA1 was determined by primer extension, and a canonical σ54-dependent promoter was found upstream of the start site. Genome sequence analysis of X. fastidiosa revealed five paralogues of pilA, but microarray and qRT-PCR data demonstrated that only the pilA1 transcript was significantly affected in the rpoN mutant. The rpoN mutant made more biofilm than the wild type strain and presented a cell-cell aggregative phenotype. These results indicate that σ54 regulates biofilm formation, probably via differential regulation of genes involved in type IV and type I fimbrial biogenesis. Keywords: rpoN mutant strain, pili

2007-10-22 | GSE8097 | GEO

Flagellar mutants have reduced pilus synthesis in Caulobacter crescentus

Project description:Surface appendages such as flagella and type IV pili mediate a broad range of bacterial behaviors including motility, attachment, and surface sensing. While many species harbor both flagella and type IV pili, little is known about how or if their synthesis is coupled. Here, we show that deletions of genes encoding different flagellum machinery components result in a reduction of pilus synthesis in Caulobacter crescentus. First, we show that different flagellar mutants exhibit different levels of sensitivity to a pilus-dependent phage and that less cells within populations of flagellar mutants make pili. Furthermore, we find that single cells within flagellar mutant populations produce less pili per cell. We demonstrate that these gene deletions result in reduced transcription of pilus-associated genes and have a broad effect on global transcription profiles. Finally, we show that the decrease in pilus production is due to a reduction in the pool of pilin subunits that are polymerized into pilus fibers. These data demonstrate that mutations in flagella gene components affect not only motility but can also have considerable and unexpected consequences on other aspects of cell biology.

2019-07-05 | GSE126478 | GEO

Role of Ï54 in the regulation of genes involved in biogenesis of type I and type IV pili in Xylella fastidiosa

Project description:The phytopathogen Xylella fastidiosa produces two classes of pili, long type IV pili and short type I pili, which are involved in motility and adhesion. In this work, we have investigated the role of Ï54 factor and its involvement in the regulation of fimbrial biogenesis in X. fastidiosa. An rpoN null mutant was constructed from citrus strain J1a12, and analyses of global gene expression profile by microarrays comparing the wild type and rpoN mutant strains showed that few genes exhibited differential expression. At least one gene, pilA1 (XF2542), which encodes the structural pilin protein of type IV fimbriae, showed decreased expression in the rpoN mutant whereas an operon encoding proteins of type I fimbriae were twofold more expressed in the mutant. Quantitative real time RT-PCR (qRT-PCR) analysis confirmed that pilA1 transcript was significantly reduced in the rpoN mutant. The transcriptional start site of pilA1 was determined by primer extension, and a canonical Ï54-dependent promoter was found upstream of the start site. Genome sequence analysis of X. fastidiosa revealed five paralogues of pilA, but microarray and qRT-PCR data demonstrated that only the pilA1 transcript was significantly affected in the rpoN mutant. The rpoN mutant made more biofilm than the wild type strain and presented a cell-cell aggregative phenotype. These results indicate that Ï54 regulates biofilm formation, probably via differential regulation of genes involved in type IV and type I fimbrial biogenesis. Direct comparison between wild type strain J1a12 and mutant strain rpoN-.

2010-06-25 | E-GEOD-8097 | biostudies-arrayexpress

A new twist on bacterial motility – two distinct type IV pili revealed by cryoEM

Project description:Many bacteria express filaments called type IV pili on their surface, which are involved in motility (twitching), surface adhesion, biofilm formation and DNA uptake (natural transformation). Type IV pili are comprised of a helical assembly of repeating pilin subunits that allow both flexibility and strength. They are therefore powerful structures that enable bacterial proliferation and genetic adaptation, potentially leading to the development of pathogenicity and antibiotic resistance. They are also targets for drug development. By electron cryo-microscopy and mass spectrometry, we show that the bacterium Thermus thermophilus produces two forms of type IV pilus, differing in structure and protein composition. We have determined the structures of both and built atomic models, which reveal a new pilin, how the subunits assemble and their glycosylation patterns. We also delineate the roles of the two filaments in promoting twitching and natural transformation.

2020-03-09 | PXD017353 | Pride

The orthologue of the RNA chaperone Hfq is essential for cell motility of the cyanobacterium Synechocystis PCC 6803

Project description:The gene ssr3341 was previously suggested to encode an orthologue of the RNA chaperone Hfq in Synechocystis sp. strain PCC 6803. When a phototactic strain of this cyanobacterium was insertionally inactivated at ssr3341, the mutants were not transformable, and were rendered non-phototactic compared to the wild type. The loss of motility was complemented by re-introduction of the wild-type gene, correlated with the re-establishment of type IV pili on the cell surface. Microarray analyses revealed a small set of genes with drastically reduced transcript levels in the knock-out mutant over wild-type cells. Among the most strongly affected genes are with slr1667, slr1668, slr2015, slr2016 and slr2018 five genes which belong to two operons that previously were shown to be involved in motility and controlled by the SYCRP1-cAMP receptor protein. This fact constitutes a link between cAMP signalling, motility, and the involvement of RNA-based regulation. This is the first report demonstrating a functional role of Hfq in cyanobacteria. Keywords: comparative expression profiling

2008-03-15 | GSE10708 | GEO

The pilus retraction protein PilT has a global influence on the transcriptome of Neisseria gonorrhoeae

Project description:The ATPase protein PilT mediates retraction of type IV pili. We performed microarrays comparing the transcription profile of the Neisseria gonorrhoeae wild-type strain MS11 and its isogenic pilT mutant. 63 open reading frames were found to be differentially regulated in the pilT mutant. Most interestingly, a loss of function mutation in pilT leads to an upregulation of pilE, which encodes the pilus subunit protein.

2008-09-01 | GSE12258 | GEO

Cryo-EM structures of type IV pili complexed with nanobodies reveal immune escape mechanisms

Project description:Type IV pili (T4P) are prevalent, polymeric surface structures in pathogenic bacteria, making them ideal targets for effective vaccines. However, bacteria have evolved efficient strategies to evade type IV pili-directed antibody responses. Neisseria meningitidis are prototypical type IV pili-expressing Gram-negative bacteria responsible for life threatening sepsis and meningitis. This species has evolved several genetic strategies to modify the surface of its type IV pili based on recombination, phase variation and the presence of different alleles of genes involved in posttranslational modifications. This results in changes in pilin subunit amino acid sequence, nature of glycosylation and phosphoform modification, but how these different processes affect antibody binding at the structural level is still unknown. To explore this question, we provide cryo-electron microscopy structures of pili of different sequence types with sufficiently high resolution to visualize posttranslational modifications. We then generated nanobodies directed against type IV pili which alter pilus function in vitro and vivo; and determined their structures complexed with their pilus target. We also determined how the different types of pili surface modifications alter nanobody binding. These different structures shed light on the impressive complementarity between the different strategies used by bacteria to avoid antibody binding. Importantly, we also show that structural information can be used to make informed modifications in nanobodies as countermeasures to these immune evasion mechanisms.

2024-02-29 | PXD046119 | Pride

PilY1 and minor pilins form a complex priming the type IVa pilus in Myxococcus xanthus

Project description:Type IVa pili are ubiquitous and versatile bacterial cell surface filaments that undergo cycles of extension, adhesion and retraction powered by the cell-envelope spanning type IVa pilus machine (T4aPM). The overall architecture of the T4aPM and the location of 10 conserved core proteins within this architecture have been elucidated. Here, using genetics, cell biology, proteomics and cryo-electron tomography, we demonstrate that the PilY1 protein and four minor pilins, which are widely conserved in T4aP systems, are essential for pilus extension in Myxococcus xanthus and form a complex that is an integral part of the T4aPM. Moreover, these proteins are part of the extended pilus. Our data support a model whereby the PilY1/minor pilin complex functions as a priming complex in T4aPM for pilus extension, a tip complex in the extended pilus for adhesion, and a cork for terminating retraction to maintain a priming complex for the next round of extension.

2020-09-02 | PXD021163 | Pride

Impact of a conjugative plasmid on plant growth-promoting Bacillus velezensis

Project description:Bacillus velezensis strain GH1-13 with a native conjugative plasmid (pBV71) is thought to be beneficial to the bacterium, although no information on its effects exists. Here we show that strain GH1-13 frequently lost the plasmid during normal growth conditions in a rich medium and changed the morphology and sensitivity to selenite and tellurite. Compared to the plasmid-cured cells, the wild-type and complemented cells exhibited multicellular behavior with the expression of conjugative type IV pili and regulatory Rap homologous genes that regulate the interconnection between conjugation and biofilm formation. Further omics-based analyses of morphogenesis, biofilm formation, and antibiotic synthesis suggest that the conjugative plasmid activates envelope stress responses in association with increased biosynthesis of extracellular polysaccharide and antibiotics for protective functions of the host during exponential phase.

2021-05-17 | PXD017305 | Pride

Myxococcus xanthus

Project description:Myxococcus xanthus cells: wild-type vs. EBP mutant gene expression during development

| PRJNA110133 | ENA