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Fusidic acid-resistant EF-G perturbs the accumulation of ppGpp

Macvanin, Mirjana; Johanson, Urban LU ; Ehrenberg, Måns and Hughes, Diarmaid (2000) In Molecular Microbiology 37(1). p.98-107
Abstract
Reductions in growth rate caused by fusidic acid-resistant EF-G mutants in Salmonella typhimurium correlate strongly with increased mean cell size. This is unusual because growth rate and cell size normally correlate positively. The global transcription regulator molecule ppGpp has a role in co-ordinating growth rate and division, and its basal level normally correlates inversely with cell size at division. We show that fusidic acid-resistant EF-G mutants have perturbed ppGpp basal levels during steady-state growth and perturbed induced levels during starvation. One mutation, fusA1, associated with the slowest growth rate and largest cell size, causes a reduction in the basal level of ppGpp to one-third of that found in the wild-type... (More)
Reductions in growth rate caused by fusidic acid-resistant EF-G mutants in Salmonella typhimurium correlate strongly with increased mean cell size. This is unusual because growth rate and cell size normally correlate positively. The global transcription regulator molecule ppGpp has a role in co-ordinating growth rate and division, and its basal level normally correlates inversely with cell size at division. We show that fusidic acid-resistant EF-G mutants have perturbed ppGpp basal levels during steady-state growth and perturbed induced levels during starvation. One mutation, fusA1, associated with the slowest growth rate and largest cell size, causes a reduction in the basal level of ppGpp to one-third of that found in the wild-type strain. Other fusA mutants with intermediate or wild-type growth rates and cell sizes have either normal or increased basal levels of ppGpp. There is an inverse relationship between the basal level of ppGpp in vivo and the degree to which translation dependent on mutant EF-G is inhibited by ppGpp in vitro. This enhanced interaction between mutant EF-G and ppGpp correlates with an increased KM for GTP. Our results suggest that mutant EF-G modulates the production of ppGpp by the RelA (PSI) pathway. In conclusion, fusidic acid-resistant EF-G mutations alter the level of ppGpp and break the normal relationship between growth rate and cell size at division. It would not be surprising if other phenotypes associated with these mutants, such as loss of virulence, were also related to perturbations in ppGpp levels effected through altered transcription patterns. (Less)
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organization
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Contribution to journal
publication status
published
subject
keywords
development/metabolism, Guanosine Tetraphosphate/*metabolism, Fusidic Acid/*pharmacology, Microbial, Anti-Bacterial Agents/*pharmacology, Drug Resistance, Mutation, Peptide Elongation Factor G/drug effects/genetics/*metabolism, Salmonella typhimurium/*drug effects/genetics/growth &, Protein Biosynthesis
in
Molecular Microbiology
volume
37
issue
1
pages
98 - 107
publisher
Wiley-Blackwell
external identifiers
  • scopus:0033925641
ISSN
1365-2958
DOI
10.1046/j.1365-2958.2000.01967.x
language
English
LU publication?
yes
id
76b493a6-bfc8-4608-be5c-0acce93f879e (old id 1428974)
alternative location
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=10931308
date added to LUP
2009-06-22 12:37:58
date last changed
2017-01-01 04:35:10
@article{76b493a6-bfc8-4608-be5c-0acce93f879e,
  abstract     = {Reductions in growth rate caused by fusidic acid-resistant EF-G mutants in Salmonella typhimurium correlate strongly with increased mean cell size. This is unusual because growth rate and cell size normally correlate positively. The global transcription regulator molecule ppGpp has a role in co-ordinating growth rate and division, and its basal level normally correlates inversely with cell size at division. We show that fusidic acid-resistant EF-G mutants have perturbed ppGpp basal levels during steady-state growth and perturbed induced levels during starvation. One mutation, fusA1, associated with the slowest growth rate and largest cell size, causes a reduction in the basal level of ppGpp to one-third of that found in the wild-type strain. Other fusA mutants with intermediate or wild-type growth rates and cell sizes have either normal or increased basal levels of ppGpp. There is an inverse relationship between the basal level of ppGpp in vivo and the degree to which translation dependent on mutant EF-G is inhibited by ppGpp in vitro. This enhanced interaction between mutant EF-G and ppGpp correlates with an increased KM for GTP. Our results suggest that mutant EF-G modulates the production of ppGpp by the RelA (PSI) pathway. In conclusion, fusidic acid-resistant EF-G mutations alter the level of ppGpp and break the normal relationship between growth rate and cell size at division. It would not be surprising if other phenotypes associated with these mutants, such as loss of virulence, were also related to perturbations in ppGpp levels effected through altered transcription patterns.},
  author       = {Macvanin, Mirjana and Johanson, Urban and Ehrenberg, Måns and Hughes, Diarmaid},
  issn         = {1365-2958},
  keyword      = {development/metabolism,Guanosine Tetraphosphate/*metabolism,Fusidic Acid/*pharmacology,Microbial,Anti-Bacterial Agents/*pharmacology,Drug Resistance,Mutation,Peptide Elongation Factor G/drug effects/genetics/*metabolism,Salmonella typhimurium/*drug effects/genetics/growth &,Protein Biosynthesis},
  language     = {eng},
  number       = {1},
  pages        = {98--107},
  publisher    = {Wiley-Blackwell},
  series       = {Molecular Microbiology},
  title        = {Fusidic acid-resistant EF-G perturbs the accumulation of ppGpp},
  url          = {http://dx.doi.org/10.1046/j.1365-2958.2000.01967.x},
  volume       = {37},
  year         = {2000},
}