scholarly journals Myxococcus xanthus sasN Encodes a Regulator That Prevents Developmental Gene Expression during Growth

1998 ◽  
Vol 180 (23) ◽  
pp. 6215-6223 ◽  
Author(s):  
Di Xu ◽  
Chun Yang ◽  
Heidi B. Kaplan
Keyword(s):  
Cell Density ◽  
Fruiting Body ◽  
Growth And Development ◽  
High Cell Density ◽  
Myxococcus Xanthus ◽  
High Cell ◽  
Wild Type ◽  
Hydrophobic Region ◽  
Body Development ◽  
Fruiting Body Development

ABSTRACT Myxococcus xanthus multicellular fruiting body development is initiated by nutrient limitation at high cell density. Five clustered point mutations (sasB5, -14, -15, -16, and -17) can bypass the starvation and high-cell-density requirements for expression of the4521 developmental reporter gene. These mutants express4521 at high levels during growth and development in anasgB background, which is defective in generation of the cell density signal, A signal. A 1.3-kb region of the sasBlocus cloned from the wild-type chromosome restored the SasB+ phenotype to the five mutants. DNA sequence analysis of the 1.3-kb region predicted an open reading frame, designated SasN. The N terminus of SasN appears to contain a strongly hydrophobic region and a leucine zipper motif. SasN showed no significant sequence similarities to known proteins. A strain containing a newly constructedsasN-null mutation and Ω4521 Tn5lac in an otherwise wild-type background expressed 4521 at a high level during growth and development. A similar sasN-null mutant formed abnormal fruiting bodies and sporulated at about 10% the level of wild type. These data indicate that the wild-typesasN gene product is necessary for normal M. xanthus fruiting body development and functions as a critical regulator that prevents 4521 expression during growth.

Murein components rescue developmental sporulation of Myxococcus xanthus

1982 ◽  
Vol 152 (1) ◽  
pp. 462-470 ◽  
Author(s):  
L J Shimkets ◽  
D Kaiser
Keyword(s):  
Fruiting Body ◽  
High Cell Density ◽  
Myxococcus Xanthus ◽  
Sodium Dodecyl ◽  
Protein Composition ◽  
Diaminopimelic Acid ◽  
Nutrient Level ◽  
High Cell ◽  
Wild Type ◽  
Nutrient Rich Medium

Murein (peptidoglycan) components are able to rescue sporulation in certain sporulation-defective mutants of Myxococcus xanthus. N-Acetylglucosamine, N-acetylmuramic acid, diaminopimelic acid, and D-alanine each increase the number of spores produced by SpoC mutants. When all four components are included they have a synergistic effect, raising the number of spores produced by SpoC mutants to the wild-type level. Murein-rescued spores are resistant to heat and sonic oscillation and germinate when plated on a nutrient-rich medium. They appear to be identical to fruiting body spores in their ultrastructure, in their protein composition, and in their resistance to boiling sodium dodecyl sulfate. Murein rescue of sporulation, like fruiting body sporulation, requires high cell density, a low nutrient level, and a solid surface.

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.

scholarly journals EspC Is Involved in Controlling the Timing of Development in Myxococcus xanthus

2005 ◽  
Vol 187 (14) ◽  
pp. 5029-5031 ◽  
Author(s):  
Bongsoo Lee ◽  
Penelope I. Higgs ◽  
David R. Zusman ◽  
Kyungyun Cho
Keyword(s):  
Fruiting Body ◽  
Type Strain ◽  
Wild Type Strain ◽  
Myxococcus Xanthus ◽  
Null Mutation ◽  
Fruiting Bodies ◽  
Wild Type ◽  
Body Development ◽  
Fruiting Body Development

ABSTRACT The espC null mutation caused accelerated aggregation and formation of tiny fruiting bodies surrounded by spores, which were also observed in the espA mutant and in CsgA-overproducing cells in Myxococcus xanthus. In addition, the espC mutant appeared to produce larger amounts of the complementary C-signal than the wild-type strain. These findings suggest that EspC is involved in controlling the timing of fruiting body development in M. xanthus.

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 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 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 A ς54 Activator Protein Necessary for Spore Differentiation within the Fruiting Body ofMyxococcus xanthus

2000 ◽  
Vol 182 (9) ◽  
pp. 2438-2444 ◽  
Author(s):  
Lisa Gorski ◽  
Thomas Gronewold ◽  
Dale Kaiser
Keyword(s):  
Fruiting Body ◽  
Time Course ◽  
Type Number ◽  
Wild Type ◽  
Activator Proteins ◽  
Antibody Expression ◽  
Body Development ◽  
Fruiting Body Development ◽  
In The Wild ◽  
Dna Fragment

ABSTRACT Insertion of an internal DNA fragment into the act1gene, which encodes one of several ς54-activator proteins in Myxococcus xanthus, produced a mutant defective in fruiting body development. While fruiting-body aggregation appears normal in the mutant, it fails to sporulate (<10−6 the wild-type number of viable spores). The A and C intercellular signals, which are required for sporulation, are produced by the mutant. But, while it produces A-factor at levels as high as that of the wild type, the mutant produces much less C-signal than normal, as measured either by C-factor bioassay or by the total amount of C-factor protein detected with specific antibody. Expression of three C-factor-dependent reporters is altered in the mutant: the level of expression of Ω4414 is about 15% of normal, and Ω4459 and Ω4403 have alterations in their time course. Finally, the methylation of FrzCD protein is below normal in the mutant. It is proposed that Act1 protein responds to C-signal reception by increasing the expression of the csgAgene. This C-signal-dependent increase constitutes a positive feedback in the wild type. The act1 mutant, unable to raise the level of csgA expression, carries out only those developmental steps for which a low level of C-signaling is adequate.

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