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Ribosome modulation factor, an important protein for cell viability encoded by the polyamine modulon

Yusuke Terui1, Yuzuru Tabei, Mariko Akiyama

  • 1Faculty of Pharmacy, Chiba Institute of Science, 15-8 Shiomi-cho, Choshi, Chiba 288-0025, Japan.

The Journal of Biological Chemistry
|July 15, 2010
PubMed

Insights

Polyamines enhance Escherichia coli cell viability by boosting ribosome modulation factor (RMF) synthesis during stationary phase. This effect is linked to translation regulation and mRNA structure.

Area of Science:

  • Microbiology
  • Molecular Biology
  • Biochemistry

Background:

  • Polyamines are essential for bacterial growth and viability.
  • Cellular processes, including protein synthesis, are regulated by polyamines, especially during stationary phase.
  • Escherichia coli mutants requiring polyamines exhibit decreased viability under polyamine deficiency.

Purpose of the Study:

  • To identify proteins whose synthesis is enhanced by polyamines in Escherichia coli at the stationary phase.
  • To elucidate the mechanism by which polyamines regulate protein synthesis, specifically ribosome modulation factor (RMF).
  • To investigate the role of RMF in maintaining cell viability under polyamine deficiency.

Main Methods:

  • Utilized a polyamine-requiring Escherichia coli mutant.
  • Analyzed the translational regulation of RMF synthesis.
  • Investigated the effect of Shine-Dalgarno sequence position on RMF synthesis and polyamine stimulation.
  • Examined structural changes in the rmf mRNA initiation site.
  • Assessed the impact of a modified rmf gene on cell viability.

Main Results:

  • Polyamines strongly enhance ribosome modulation factor (RMF) synthesis at the translational level during stationary phase.
  • The position of the Shine-Dalgarno sequence in rmf mRNA influences polyamine stimulation.
  • Polyamine stimulation is attributed to specific structural alterations in the rmf mRNA initiation site.
  • Overexpression of a modified rmf gene, independent of polyamines, rescues cell viability.

Conclusions:

  • Polyamines enhance Escherichia coli cell viability, at least partially, through the upregulation of RMF synthesis.
  • RMF plays a critical role in maintaining cell viability during stationary phase under conditions of polyamine deficiency.
  • Translational control mechanisms involving mRNA structure are key to polyamine-mediated regulation of RMF synthesis.

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