Movatterモバイル変換

[0]ホーム
URL:

Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
Thehttps:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

NIH NLM Logo
Log inShow account info
Access keysNCBI HomepageMyNCBI HomepageMain ContentMain Navigation
pubmed logo
Advanced Clipboard
User Guide

Full text links

Public Library of Science full text link Public Library of Science Free PMC article
Full text links

Actions

Share

.2014 Mar 6;10(3):e1004164.
doi: 10.1371/journal.pgen.1004164. eCollection 2014 Mar.

Functional organization of a multimodular bacterial chemosensory apparatus

Affiliations

Functional organization of a multimodular bacterial chemosensory apparatus

Audrey Moine et al. PLoS Genet..

Abstract

Chemosensory systems (CSS) are complex regulatory pathways capable of perceiving external signals and translating them into different cellular behaviors such as motility and development. In the δ-proteobacterium Myxococcus xanthus, chemosensing allows groups of cells to orient themselves and aggregate into specialized multicellular biofilms termed fruiting bodies. M. xanthus contains eight predicted CSS and 21 chemoreceptors. In this work, we systematically deleted genes encoding components of each CSS and chemoreceptors and determined their effects on M. xanthus social behaviors. Then, to understand how the 21 chemoreceptors are distributed among the eight CSS, we examined their phylogenetic distribution, genomic organization and subcellular localization. We found that, in vivo, receptors belonging to the same phylogenetic group colocalize and interact with CSS components of the respective phylogenetic group. Finally, we identified a large chemosensory module formed by three interconnected CSS and multiple chemoreceptors and showed that complex behaviors such as cell group motility and biofilm formation require regulatory apparatus composed of multiple interconnected Che-like systems.

PubMed Disclaimer

Conflict of interest statement

The authors have declared that no competing interests exist.

Figures

Figure 1
Figure 1. Genetic clusters carryingche genes inM. xanthus.
Genetic organization of the genes composing the eightche clusters encoding the putative components of the chemosensory apparatus inMyxococcus xanthus. Predicted genes are indicated with their locus_tag, and their annotations and assigned names. The color code indicates homologous genes.
Figure 2
Figure 2. Motility and fruiting body formation defects ofΔmcp andΔcheA mutants.
(A) Motility was measured after 48 h. Colony spreading of each mutant was normalized with that of aΔpilA strain completely incapable of S motility, to exclude cell growth effects. Error bars indicate standard deviations. One star corresponds top<0.05; two stars correspond top<0.005. (B)ΔcheA fruiting body formation images at 48 h and 72 h are shown. We identified classes of mutants developing earlier or later than wild type. Pictures ofΔmcp fruiting bodies are shown in Figure S2. The blue color indicatesΔcheA mutants, greenΔmcp.
Figure 3
Figure 3.M. xanthus MCPs and CSS are organized in three taxonomic groups.
(A) Concatamers ofM. xanthus Che protein sequences were generated as described in Methods. Based on PP values, the eight concatamers can be divided into Group 1 (green background), Group 2 (blue background) and Group 3 (pink background). (B) The tree generated for the 21M. xanthus MCP homologs shows a similar partition in three groups. The MCPs in black belong toche operons, while the MCPs in color are the orphans. (C) A tree generated with the MCP conserved protein sequences involved in the MCP-CheW interaction (Vu et al., 2012) gives rise to the same distribution as in (B). The alignment of the protein sequences involved in the MCP-CheW interaction fromT. maritime andM. xanthus MCPs is shown. Colors indicate residues with the same properties. Numbers at nodes in (A) and (B) indicate posterior probabilities (PP) computed by MrBayes and bootstrap values (BV) computed by PhyML. Only PP and BV above 0.5 and 50% are shown. The scale bars represent the average number of substitutions per site.
Figure 4
Figure 4. MCP-GFP fusions localize in multiple dynamic clusters in cells.
(A) In the first row, fluorescence (left) and overlay between fluorescence and phase contrast images (right) are shown for each MCP-GFP. In the bottom row,n clusters (numbers indicated above the histograms) were analyzed for eachmcp-gfp strain and their relative position in cells in they-axis is shown (0.0 indicate the center of the cell along they-axis). Bars indicate the fraction of clusters localizing in the corresponding position in they-axis. (B) Average number of clusters for each MCP-GFP. (C) Box plots indicate the medians of the product of the relative cell length and the total distance covered by the MCP-GFP clusters *  = p<0.05; **  = p<0. 5E-04 (refer also to Methods, Table S2 and Figure S4).
Figure 5
Figure 5. MCPs colocalization analysis.
(A) Fluorescence micrographs ofmcp5-mCherry mcpM-gfp andfrzCD-gfp aglZ-mCherry cells are shown as examples. From (B) to (G) scatterplots of individual red and green pixel intensities of double-labeled cells are shown. (H) Average Pearson's correlation coefficients (PCCs) each calculated from ten scatterplots per strain.
Figure 6
Figure 6.In vivo MCP-CheW interactions.
Bacterial two-hydrid assays on plates. Interactions between MCPs and CheWs are shown. +++, ++ and + indicate bacterial colonies turning red within 24 h, 48 h and 72 h respectively. “NS” (not significant) means that the colony color was as the negative control. We only show interactions resulting positive for both the pUT18Cmcp/pKT25cheW and pKT25mcp/pUT18CcheW combinations and reproducible in two experiments performed in triplicate. Examples of colonies from negative control (empty plasmids); positive control (pUT18Cmcp7/pKT25cheW7); + (pUT18CmcpM/pKT25cheW4b); ++ (pUT18Cmcp4/pKT25cheW4b); +++ (pKT25CmcpM/pUT18CcheW4b) are shown.
Figure 7
Figure 7.ΔcheA triple mutants have restored phenotypes as compared to single and double mutants.
(A) Motility was measured after 48 h. The colony spreading of each mutant was normalized with the one of aΔpilA strain completely incapable of S motility, to exclude cell growth effects. Error bars indicate standard deviations. The star corresponds top<0.005. (B)ΔcheA fruiting body formation images at 72 h are shown.
Figure 8
Figure 8. Schematic organization ofM. xanthus Che modules as depicted from phylogenetic, cell biology and protein interaction analyses.
For clarity, we omitted CheR and CheB proteins and do not specify the MCP-CheW interactions. MCPs in light green are the ones for which interactions with a CSS have not been demonstrated. The different color backgrounds indicate taxonomic Group 1 (green), Group 2 (blue) and Group 3 (pink). Group 1 was further divided in two subgroups labelled with light and dark green, based on the localization analysis.
See this image and copyright information in PMC

Similar articles

See all similar articles

Cited by

See all "Cited by" articles

References

    1. Wuichet K, Zhulin IB (2010) Origins and diversification of a complex signal transduction system in prokaryotes. Sci Signal 3: ra50 doi:10.1126/scisignal.2000724 - DOI - PMC - PubMed
    1. Porter SL, Wadhams GH, Armitage JP (2011) Signal processing in complex chemotaxis pathways. Nat Rev Microbiol 9: 153–165 doi:10.1038/nrmicro2505 - DOI - PubMed
    1. Roberts MAJ, Papachristodoulou A, Armitage JP (2010) Adaptation and control circuits in bacterial chemotaxis. Biochem Soc Trans 38: 1265–1269 doi:10.1042/BST0381265 - DOI - PubMed
    1. Sourjik V, Berg HC (2002) Binding of the Escherichia coli response regulator CheY to its target measured in vivo by fluorescence resonance energy transfer. Proc Natl Acad Sci USA 99: 12669–12674 doi:10.1073/pnas.192463199 - DOI - PMC - PubMed
    1. Kirby JR (2009) Chemotaxis-Like Regulatory Systems: Unique Roles in Diverse Bacteria. Annual Review of Microbiology 63: 45–59 doi:10.1146/annurev.micro.091208.073221 - DOI - PubMed

Publication types

MeSH terms

Related information

Grants and funding

LinkOut - more resources

Full text links
Public Library of Science full text link Public Library of Science Free PMC article
Cite
Send To

NCBI Literature Resources

MeSHPMCBookshelfDisclaimer

The PubMed wordmark and PubMed logo are registered trademarks of the U.S. Department of Health and Human Services (HHS). Unauthorized use of these marks is strictly prohibited.

[8]ページ先頭
©2009-2025 Movatter.jp