A missense mutation in <i>rpoD</i> results in an A‐signalling defect in <i>Myxococcus xanthus</i>

Davis, John M.; Mayor, Jocelyne; Plamann, Lynda

doi:10.1111/j.1365-2958.1995.18050943.x

Cited by 40 publications

(36 citation statements)

References 52 publications

(93 reference statements)

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“…Mutations in asgA cause decreased A-signal production and aborted development (Kuspa & Kaiser, 1989). A defect in AsgC, a homologue of the vegetative sigma factor RpoD that is predicted to have a variety of effects on gene expression (Davis et al, 1995;Hernandez & Cashel, 1995), is similarly defective for Asignal production and development (Kuspa & Kaiser, 1989). AsgE, which is homologous to amidohydrolases that cleave heterocyclic compounds (Garza et al, 2000), is believed to function downstream of AsgA: while extracts from asgE cells can partly rescue the asgA sporulation defect, the reciprocal rescue of asgE cells by asgA cells does not occur.…”

Section: Predation and Developmentmentioning

confidence: 99%

Mutations affecting predation ability of the soil bacterium Myxococcus xanthus

Pham¹,

Shebelut²,

Diodati³

et al. 2005

Microbiology

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Myxococcus xanthus genetic mutants with characterized phenotypes were analysed for the ability to prey on susceptible bacteria. Quantification of predatory ability was scored by a newly developed method under conditions in which prey bacteria provided the only source of nutrients. These results were corroborated by data derived using a previously published protocol that measures predation in the presence of limited external nutrients. First, early developmental regulatory mutants were examined, because their likely functions in assessing the local nutrient status were predicted to be also important for predation. The results showed that predation efficiency is reduced by 64-80 % for mutants of three A-signalling components, AsgA, AsgC and AsgE, but not for AsgB. This suggests that an Asg regulon function that is separate from A-signal production is needed for predation. Besides the Asg components, mutations in the early developmental genes sdeK and csgA were also consistently observed to reduce predatory efficacy by 36 and 33 %, respectively. In contrast, later developmental components, such as DevRS, 4406 and PhoP4, did not appear to play significant roles in predation. The predatory abilities of mutants defective for motility were also tested. The data showed that adventurous, but not social, motility is required for predation in the assay. Also, mutants for components in the chemotaxis-like Frz system were found to be reduced in predation efficiency by between 62 and 85 %. In sum, it was demonstrated here that defects in development and development-related processes affect the ability of M. xanthus to prey on other bacteria.

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Section: Predation and Developmentmentioning

confidence: 99%

Mutations affecting predation ability of the soil bacterium Myxococcus xanthus

Pham¹,

Shebelut²,

Diodati³

et al. 2005

Microbiology

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“…1A). Amino acid sequences and molecular masses of three tryptic peptides from the spot 10 protein corresponded to the product of a hypothetical gene tentatively designated dru (downstream of rpsU) located in the rpsU operon of M. xanthus (28). The rpsU operon consists of, in order, rpsU, dru, dnaG, rpoD, and ogt genes.…”

Section: Comparison Of Patterns Of Protein Synthesis Among M Xanthusmentioning

confidence: 99%

Role of fruA and csgA Genes in Gene Expression during Development of Myxococcus xanthus

Horiuchi¹,

Taoka²,

Isobe³

et al. 2002

Journal of Biological Chemistry

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Two genes, fruA and csgA, encoding a putative transcription factor and C-factor, respectively, are essential for fruiting body formation of Myxococcus xanthus. To investigate the role of fruA and csgA genes in developmental gene expression, developing cells as well as vegetative cells of M. xanthus wild-type, fruA::Tc, and csgA731 strains were pulse-labeled with [35 S]methionine, and the whole cell proteins were analyzed using two-dimensional immobilized pH gradient/SDS-PAGE. Differences in protein synthesis patterns among more than 700 protein spots were detected during development of the three strains. Fourteen proteins showing distinctly different expression patterns in mutant cells were analyzed in more detail. Five of the 14 proteins were identified as elongation factor Tu (EF-Tu), Dru, DofA, FruA, and protein S by immunoblot analysis and mass spectroscopy. A gene encoding DofA was cloned and sequenced. Although both fruA and csgA genes regulate early development of M. xanthus, they were found to differently regulate expression of several developmental genes. The production of six proteins, including DofA and protein S, was dependent on fruA, whereas the production of two proteins was dependent on csgA, and one protein was dependent on both fruA and csgA. To explain the present findings, a new model was presented in which different levels of FruA phosphorylation may distinctively regulate the expression of two groups of developmental genes.

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“…Through extensive genetic and biochemical studies, a number of regulatory proteins thought to be involved in cellular aggregation and sporulation, including two-component proteins, such as histidine kinases and response regulators, serine threonine kinases, sigma factors and their associated transcriptional factors, and other proteins with no homology to known proteins, have been identified (2,7,8,9,10,13,14,33,42,47). In this study we have focused on a putative 54 activator that may play an important role in M. xanthus developmental gene regulation.…”

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confidence: 99%

Genetic Studies ofmrp, a Locus Essential for Cellular Aggregation and Sporulation ofMyxococcus xanthus

2001

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Under starvation conditions, Myxococcus xanthus undergoes a complex developmental process which includes cellular aggregation and sporulation. A transposon insertion mutant (the Tn5-⍀280 mutant) with defects in both aggregation and sporulation was analyzed in this study. The Tn5-⍀280 mutant was found to have a disrupted NtrC-like response regulator designated Myxococcus regulatory protein B (mrpB). Further sequencing analyses revealed a histidine kinase homolog (mrpA) immediately upstream of mrpB and a cyclic AMP receptor protein-like transcriptional regulator (mrpC) downstream of mrpB. In-frame deletion analyses revealed that both the mrpB and mrpC genes were required for cellular aggregation and sporulation but that only mrpA was required for sporulation only. Site-specific mutagenesis of the putative phosphorylation site of MrpB, D58, showed that a D58A mutation caused defects in both aggregation and sporulation but that a D58E mutation resulted in only a sporulation defect. Further genetic and molecular analyses with reporter genes and reverse transcription-PCR indicated that mrpA and mrpB are cotranscribed but that mrpC is transcribed independently and that all of these genes are developmentally regulated. In addition, MrpB is essential for transcription of mrpC and MrpC regulates its own transcription. These data indicate that Mrp proteins are important components required for M. xanthus development. The complicated interaction between Mrp proteins may play an important role in regulating developmental gene expression in M. xanthus.

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A missense mutation in rpoD results in an A‐signalling defect in Myxococcus xanthus

Cited by 40 publications

References 52 publications

Mutations affecting predation ability of the soil bacterium Myxococcus xanthus

Mutations affecting predation ability of the soil bacterium Myxococcus xanthus

Role of fruA and csgA Genes in Gene Expression during Development of Myxococcus xanthus

Genetic Studies ofmrp, a Locus Essential for Cellular Aggregation and Sporulation ofMyxococcus xanthus

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