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Elongation factor P restricts Salmonella's growth by controlling translation of a Mg2+ transporter gene during

Eunna Choi1, Soomin Choi1, Daesil Nam2

  • 1Department of Genetic Engineering and Graduate School of Biotechnology, College of Life Sciences, Kyung Hee University, Yongin 17104, South Korea.

Scientific Reports
|February 10, 2017
PubMed

Insights

Salmonella Typhimurium uses translation factor EF-P to regulate virulence gene expression. EF-P is crucial for translating proline codons, impacting MgtB protein levels and bacterial survival in macrophages.

Area of Science:

  • Microbiology
  • Molecular Biology
  • Genetics

Background:

  • Ribosome stalling occurs at difficult-to-translate codons, such as consecutive proline codons.
  • Elongation factor P (EF-P) is essential for resolving ribosome stalling at these proline-rich sequences.
  • The intracellular pathogen Salmonella Typhimurium regulates virulence gene expression, including the mgtCBR operon.

Purpose of the Study:

  • To investigate the role of EF-P in the translation of the mgtB gene within the mgtCBR virulence operon in Salmonella Typhimurium.
  • To understand how EF-P influences MgtB protein levels and the MgtC/MgtB ratio.
  • To determine the significance of EF-P-mediated translational control for Salmonella's survival in host macrophages.

Main Methods:

  • Analysis of mgtB gene translation in Salmonella lacking EF-P.
  • Investigating the impact of consecutive proline codons on MgtB protein levels.
  • Comparing transcription and translation levels of the mgtCBR operon.
  • Site-directed mutagenesis to substitute proline codons with alanine codons.
  • Assessing Salmonella survival within macrophages under varying EF-P conditions.

Main Results:

  • Salmonella lacking EF-P exhibits decreased MgtB protein levels, dependent on consecutive proline codons in the mgtB gene.
  • EF-P deficiency alters the MgtC/MgtB protein ratio due to translational control, despite increased mgtCBR operon transcription.
  • Mutating proline codons to alanine codons abolishes EF-P-dependent regulation of mgtB during infection.
  • EF-P-mediated control is critical for Salmonella survival in macrophages, where EF-P levels are low.

Conclusions:

  • Salmonella Typhimurium employs EF-P to regulate the translation of the virulence gene mgtB, particularly at proline-rich regions.
  • This translational control mechanism allows coordination of virulence gene expression in response to environmental cues, such as low EF-P availability within macrophages.
  • The pathogen utilizes EF-P-dependent translation to adapt and survive within the host environment.

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