scholarly journals The stringent response in Myxococcus xanthus is regulated by SocE and the CsgA C-signaling protein

2000 ◽  
Vol 14 (4) ◽  
pp. 483-492 ◽  
Author(s):  
Eugene W. Crawford ◽  
Lawrence J. Shimkets
Keyword(s):  
Amino Acid ◽  
Myxococcus Xanthus ◽  
Growth Arrest ◽  
Stringent Response ◽  
Binding Pocket ◽  
Macromolecular Synthesis ◽  
New Members ◽  
Coenzyme Binding ◽  
Body Development ◽  
Fruiting Body Development

Myxococcus xanthus fruiting body development is induced by amino acid limitation. The decision to grow or develop is established by the RelA-dependent stringent response and A-signaling. We identified two new members of this regulatory hierarchy, socE and the C-signaling gene csgA. SocE depletion arrests growth and induces sporulation under conditions that normally favor growth as well as curtailing DNA and stable RNA synthesis, inhibiting cell elongation, and inducing accumulations of the stringent nucleotides ppGpp and pppGpp [(p)ppGpp]. This system separates C-signaling, which does not occur under these conditions, from CsgA enzyme activity. Amino acid substitutions in the CsgA coenzyme binding pocket or catalytic site eliminate growth arrest. relA mutation also eliminates growth arrest. Eleven pseudorevertants selected for growth following SocE depletion contained mutations in csgA or relA. These results suggest that CsgA induces the stringent response and while SocE inhibits it. Unlike the csgA mutant, wild-type and socE csgA cells maintained high levels of (p)ppGpp throughout development. We suggest that CsgA maintains growth arrest throughout development to divert carbon from A-signaling and other sources into developmental macromolecular synthesis.

scholarly journals The Myxococcus xanthus Nla4 Protein Is Important for Expression of Stringent Response-Associated Genes, ppGpp Accumulation, and Fruiting Body Development

2007 ◽  
Vol 189 (23) ◽  
pp. 8474-8483 ◽  
Author(s):  
Faisury Ossa ◽  
Michelle E. Diodati ◽  
Nora B. Caberoy ◽  
Krista M. Giglio ◽  
Mick Edmonds ◽  
...  
Keyword(s):  
Fruiting Body ◽  
Expression Patterns ◽  
Myxococcus Xanthus ◽  
Stringent Response ◽  
Fruiting Body Formation ◽  
Body Development ◽  
Normal Expression ◽  
Fruiting Body Development ◽  
Coordinated Expression ◽  
Low Levels

ABSTRACT Changes in gene expression are important for the landmark morphological events that occur during Myxococcus xanthus fruiting body development. Enhancer binding proteins (EBPs), which are transcriptional activators, play prominent roles in the coordinated expression of developmental genes. A mutation in the EBP gene nla4 affects the timing of fruiting body formation, the morphology of mature fruiting bodies, and the efficiency of sporulation. In this study, we showed that the nla4 mutant accumulates relatively low levels of the stringent nucleotide ppGpp. We also found that the nla4 mutant is defective for early developmental events and for vegetative growth, phenotypes that are consistent with a deficiency in ppGpp accumulation. Further studies revealed that nla4 cells produce relatively low levels of GTP, a precursor of RelA-dependent synthesis of (p)ppGpp. In addition, the normal expression patterns of all stringent response-associated genes tested, including the M. xanthus ppGpp synthetase gene relA, are altered in nla4 mutant cells. These findings indicate that Nla4 is part of regulatory pathway that is important for mounting a stringent response and for initiating fruiting body development.

scholarly journals Multicellular Development in Myxococcus xanthus Is Stimulated by Predator-Prey Interactions

2007 ◽  
Vol 189 (15) ◽  
pp. 5675-5682 ◽  
Author(s):  
James E. Berleman ◽  
John R. Kirby
Keyword(s):  
Fruiting Body ◽  
Prey Availability ◽  
Process Analysis ◽  
Myxococcus Xanthus ◽  
Stringent Response ◽  
Fruiting Bodies ◽  
Fruiting Body Formation ◽  
Multicellular Development ◽  
Body Formation ◽  
Body Development

ABSTRACT Myxococcus xanthus is a predatory bacterium that exhibits complex social behavior. The most pronounced behavior is the aggregation of cells into raised fruiting body structures in which cells differentiate into stress-resistant spores. In the laboratory, monocultures of M. xanthus at a very high density will reproducibly induce hundreds of randomly localized fruiting bodies when exposed to low nutrient availability and a solid surface. In this report, we analyze how M. xanthus fruiting body development proceeds in a coculture with suitable prey. Our analysis indicates that when prey bacteria are provided as a nutrient source, fruiting body aggregation is more organized, such that fruiting bodies form specifically after a step-down or loss of prey availability, whereas a step-up in prey availability inhibits fruiting body formation. This localization of aggregates occurs independently of the basal nutrient levels tested, indicating that starvation is not required for this process. Analysis of early developmental signaling relA and asgD mutants indicates that they are capable of forming fruiting body aggregates in the presence of prey, demonstrating that the stringent response and A-signal production are surprisingly not required for the initiation of fruiting behavior. However, these strains are still defective in differentiating to spores. We conclude that fruiting body formation does not occur exclusively in response to starvation and propose an alternative model in which multicellular development is driven by the interactions between M. xanthus cells and their cognate prey.

scholarly journals New Locus Important for Myxococcus Social Motility and Development

2007 ◽  
Vol 189 (21) ◽  
pp. 7937-7941 ◽  
Author(s):  
Cui-ying Zhang ◽  
Ke Cai ◽  
Hong Liu ◽  
Yong Zhang ◽  
Hong-wei Pan ◽  
...  
Keyword(s):  
Fruiting Body ◽  
Myxococcus Xanthus ◽  
Gliding Motility ◽  
Salt Tolerant ◽  
Fruiting Body Formation ◽  
Body Formation ◽  
Homologous Genes ◽  
Body Development ◽  
Fruiting Body Development ◽  
Social Motility

ABSTRACT The mts locus in salt-tolerant Myxococcus fulvus HW-1 was found to be critical for gliding motility, fruiting-body formation, and sporulation. The homologous genes in Myxococcus xanthus are also important for social motility and fruiting-body development. The mts genes were determined to be involved in cell-cell cohesion in both myxobacterial species.

scholarly journals New members of the brachyurins family in lobster include a trypsin-like enzyme with amino acid substitutions in the substrate-binding pocket

FEBS Journal ◽  
2010 ◽  
Vol 277 (17) ◽  
pp. 3489-3501 ◽  
Author(s):  
Erick Perera ◽  
Tirso Pons ◽  
Damir Hernandez ◽  
Francisco J. Moyano ◽  
Gonzalo Martínez-Rodríguez ◽  
...  
Keyword(s):  
Amino Acid ◽  
Substrate Binding ◽  
Binding Pocket ◽  
Amino Acid Substitutions ◽  
Substrate Binding Pocket ◽  
New Members

scholarly journals SdeK Is Required for Early Fruiting Body Development in Myxococcus xanthus

1998 ◽  
Vol 180 (17) ◽  
pp. 4628-4637 ◽  
Author(s):  
Anthony G. Garza ◽  
Jeffrey S. Pollack ◽  
Baruch Z. Harris ◽  
Albert Lee ◽  
Ingrid M. Keseler ◽  
...  
Keyword(s):  
Dna Sequence ◽  
Fruiting Body ◽  
Developmental Process ◽  
Transcriptional Start Site ◽  
Expression Patterns ◽  
Myxococcus Xanthus ◽  
Predicted Amino Acid Sequence ◽  
Developmental Program ◽  
Body Development ◽  
Fruiting Body Development

ABSTRACT Myxococcus xanthus cells carrying the Ω4408 Tn5lac insertion at the sde locus show defects in fruiting body development and sporulation. Our analysis ofsde expression patterns showed that this locus is induced early in the developmental program (0 to 2 h) and that expression increases approximately fivefold after 12 h of development. Further studies showed that expression of sde is induced as growing cells enter stationary phase, suggesting that activation of thesde locus is not limited to the developmental process. Because the peak levels of sde expression in both ansde + and an sde mutant background were similar, we conclude that the sde locus is not autoregulated. Characterization of the sde locus by DNA sequence analysis indicated that the Ω4408 insertion occurred within the sdeK gene. Primer extension analyses localized the 5′ end of sde transcript to a guanine nucleotide 307 bp upstream of the proposed start for the SdeK coding sequence. The DNA sequence in the −12 and −24 regions upstream of the sdetranscriptional start site shows similarity to the ς54family of promoters. The results of complementation studies suggest that the defects in development and sporulation caused by the Ω4408 insertion are due to an inactivation of sdeK. The predicted amino acid sequence of SdeK was found to have similarity to the sequences of the histidine protein kinases of two-component regulatory systems. Based on our results, we propose that SdeK may be part of a signal transduction pathway required for the activation and propagation of the early developmental program.

scholarly journals σ54 Enhancer Binding Proteins and Myxococcus xanthus Fruiting Body Development

2004 ◽  
Vol 186 (13) ◽  
pp. 4361-4368 ◽  
Author(s):  
Jimmy S. Jakobsen ◽  
Lars Jelsbak ◽  
Lotte Jelsbak ◽  
Roy D. Welch ◽  
Craig Cummings ◽  
...  
Keyword(s):  
Fruiting Body ◽  
Binding Proteins ◽  
Myxococcus Xanthus ◽  
Fruiting Bodies ◽  
Knockout Mutant ◽  
Developmentally Regulated ◽  
Enhancer Binding Proteins ◽  
Developmental Program ◽  
Body Development ◽  
Fruiting Body Development

ABSTRACT A search of the M1genome sequence, which includes 97% of the Myxococcus xanthus genes, identified 53 sequence homologs of σ54-dependent enhancer binding proteins (EBPs). A DNA microarray was constructed from the M1genome that includes those homologs and 318 other M. xanthus genes for comparison. To screen the developmental program with this array, an RNA extract from growing cells was compared with one prepared from developing cells at 12 h. Previous reporter studies had shown that M. xanthus has initiated development and has begun to express many developmentally regulated genes by 12 h. The comparison revealed substantial increases in the expression levels of 11 transcription factors that may respond to environmental stimuli. Six of the 53 EBP homologs were expressed at significantly higher levels at 12 h of development than during growth. Three were previously unknown genes, and they were inactivated to look for effects on fruiting body development. One knockout mutant produced fruiting bodies of abnormal shape that depended on the composition of the medium.

scholarly journals Nla18, a Key Regulatory Protein Required for Normal Growth and Development of Myxococcus xanthus

2006 ◽  
Vol 188 (5) ◽  
pp. 1733-1743 ◽  
Author(s):  
Michelle E. Diodati ◽  
Faisury Ossa ◽  
Nora B. Caberoy ◽  
Ivy R. Jose ◽  
Wataru Hiraiwa ◽  
...  
Keyword(s):  
Gene Expression ◽  
Gene Regulation ◽  
Fruiting Body ◽  
Vegetative Growth ◽  
Growth And Development ◽  
Expression Patterns ◽  
Myxococcus Xanthus ◽  
Body Development ◽  
Fruiting Body Development ◽  
Mutant Cells

ABSTRACT NtrC-like activators regulate the transcription of a wide variety of adaptive genes in bacteria. Previously, we demonstrated that a mutation in the ntrC-like activator gene nla18 causes defects in fruiting body development in Myxococcus xanthus. In this report, we describe the effect that nla18 inactivation has on gene expression patterns during development and vegetative growth. Gene expression in nla18 mutant cells is altered in the early stages of fruiting body development. Furthermore, nla18 mutant cells are defective for two of the earliest events in development, production of the intracellular starvation signal ppGpp and production of A-signal. Taken together, these results indicate that the developmental program in nla18 mutant cells goes awry very early. Inactivation of nla18 also causes a dramatic decrease in the vegetative growth rate of M. xanthus cells. DNA microarray analysis revealed that the vegetative expression patterns of more than 700 genes are altered in nla18 mutant cells. Genes coding for putative membrane and membrane-associated proteins are among the largest classes of genes whose expression is altered by nla18 inactivation. This result is supported by our findings that the profiles of membrane proteins isolated from vegetative nla18 mutant and wild-type cells are noticeably different. In addition to genes that code for putative membrane proteins, nla18 inactivation affects the expression of many genes that are likely to be important for protein synthesis and gene regulation. Our data are consistent with a model in which Nla18 controls vegetative growth and development by activating the expression of genes involved in gene regulation, translation, and membrane structure.

Sign in / Sign up

Export Citation Format

Share Document