Related Experiment Video

Updated: Jul 8, 2026

A Non-Coding Small RNA MicC Contributes to Virulence in Outer Membrane Proteins in Salmonella Enteritidis
06:30

A Non-Coding Small RNA MicC Contributes to Virulence in Outer Membrane Proteins in Salmonella Enteritidis

Published on: January 27, 2021

Peptide-assisted degradation of the Salmonella MgtC virulence factor

Eric Alix1, Anne-Béatrice Blanc-Potard

  • 1Inserm, ESPRI 26, Nîmes, France.

The EMBO Journal
|January 18, 2008
PubMed

Insights

A novel peptide, MgtR, regulates the MgtC virulence factor in Salmonella by promoting its degradation. This discovery reveals a new bacterial regulatory mechanism and a potential target for combating intracellular pathogens.

Area of Science:

  • Microbiology
  • Molecular Biology
  • Pathogenesis

Background:

  • MgtC is a crucial virulence factor for intracellular pathogens, essential for survival within macrophages under magnesium-depleted conditions.
  • In Salmonella enterica, MgtC is co-transcribed with the MgtB magnesium transporter, with expression upregulated during magnesium deprivation.

Purpose of the Study:

  • To elucidate the mechanism behind the low detection of MgtC protein despite high transcriptional levels in magnesium-depleted Salmonella.
  • To investigate the role of the MgtR peptide in regulating MgtC expression and virulence.

Main Methods:

  • Bacterial two-hybrid assays to study MgtR and MgtC interactions.
  • Analysis of MgtR and MgtC mutant derivatives.
  • In vivo studies involving Salmonella replication rates in macrophages.

Main Results:

  • MgtR, a hydrophobic peptide encoded by the mgtCB operon, downregulates MgtC expression.
  • MgtR promotes the degradation of MgtC via the FtsH protease, establishing a negative feedback loop.
  • MgtR directly interacts with the MgtC protein, and specific mutations disrupt this interaction and regulation.
  • Overexpression of MgtR in macrophages reduced Salmonella replication.

Conclusions:

  • Peptides play significant roles in bacterial regulatory networks.
  • MgtR acts as a natural antagonist to the MgtC virulence factor, offering insights into pathogen control strategies.

More Related Videos

Generation of In-Frame Gene Deletion Mutants in Pseudomonas aeruginosa and Testing for Virulence Attenuation in a Simple Mouse Model of Infection08:34

Generation of In-Frame Gene Deletion Mutants in Pseudomonas aeruginosa and Testing for Virulence Attenuation in a Simple Mouse Model of Infection

Published on: January 8, 2020

Related Concept Videos

Regulation of Bacterial Virulence01:28

Regulation of Bacterial Virulence

Pathogenic bacteria employ a range of regulatory mechanisms to modulate the expression of virulence genes in response to environmental and host-derived signals. These mechanisms ensure that virulence factors are expressed only under favorable conditions, thereby optimizing infection and survival strategies.Mechanisms of Virulence RegulationKey regulatory strategies include:Two-Component Systems: These consist of a membrane-bound sensor kinase and a cytoplasmic response regulator. Environmental...
Determinants of Bacterial Pathogenicity and Virulence01:20

Determinants of Bacterial Pathogenicity and Virulence

Pathogenic bacteria employ a variety of strategies to establish infections, including the secretion of extracellular enzymes that act as potent virulence factors. These enzymes facilitate bacterial colonization of host tissues and help evade immune surveillance. By targeting structural components of host tissues and interfering with immune mechanisms, these enzymes play a pivotal role in disease progression.Extracellular Enzymes Facilitating Tissue Invasion: Several bacterial pathogens secrete...
Gene Regulation in Microbial Communities: Quorum Sensing01:28

Gene Regulation in Microbial Communities: Quorum Sensing

Quorum sensing is a mechanism of bacterial communication that enables coordinated gene expression in response to changes in population density. This facilitates collective behaviors that enhance survival, resource acquisition, and ecological adaptation. This process relies on small signaling molecules called autoinducers that accumulate as bacterial populations grow. When a critical threshold concentration of autoinducers is reached, bacterial cells collectively modify gene expression,...
Clinical Significance of Antibiotic Resistance01:25

Clinical Significance of Antibiotic Resistance

Methicillin-resistant Staphylococcus aureus (MRSA) presents a critical public health threat, arising from its capacity to resist β-lactam antibiotics due to acquisition of the mecA gene within the staphylococcal cassette chromosome mec (SCCmec). This gene encodes penicillin-binding protein 2a (PBP2a), which impairs binding efficacy of methicillin and other β-lactams. MRSA has evolved into distinct clonal lineages impacting humans and animals alike, reinforcing its significance within the One...
Bacterial Gastroenteritis01:18

Bacterial Gastroenteritis

Bacterial gastroenteritis, characterized by diarrhea, abdominal cramps, and vomiting, is often caused by ingestion of contaminated food or water and is frequently associated with pathogenic Escherichia coli strains. These microbes exploit two principal mechanisms to inflict disease.Shiga toxin–producing E. coli, also referred to as STEC—notably O157:H7—release Shiga toxins that target ribosomes, blocking protein synthesis. The B subunit of the toxin binds the host glycolipid receptor...