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Electrophoretic Mobility Shift Assay EMSA for the Study of RNA-Protein Interactions: The IRE/IRP Example
Published on: December 3, 2014
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Staphylococcal aconitase expression during iron deficiency is controlled by an sRNA-driven feedforward loop and
Maxime Barrault1, Svetlana Chabelskaya2, Rodrigo H Coronel-Tellez1
1Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198 Gif-sur-Yvette, France.
Nucleic Acids Research
|June 13, 2024
Summary
Staphylococcus aureus uses regulatory RNA IsrR to control iron metabolism during host infection. IsrR regulates the TCA cycle enzyme aconitase, which also acts as an RNA-binding protein to fine-tune metabolic gene expression.
Area of Science:
- Microbiology
- Molecular Biology
- Bacterial Pathogenesis
Background:
- Pathogenic bacteria, including Staphylococcus aureus, possess intricate mechanisms to survive metal ion deprivation within a host.
- Iron is crucial for bacterial growth and virulence, necessitating tight regulation of iron-dependent processes during scarcity.
- Regulatory RNA (sRNA) IsrR plays a vital role in Staphylococcus aureus fitness and virulence under iron-limiting conditions.
Purpose of the Study:
- To elucidate the role of IsrR in regulating the tricarboxylic acid (TCA) cycle during iron starvation in Staphylococcus aureus.
- To investigate the dual regulatory function of aconitase (CitB) as both an enzyme and an RNA-binding protein.
- To understand the impact of aconitase's moonlighting activity on metabolic compensation during iron deficiency.
Main Methods:
- Analysis of gene expression and protein activity under iron-deprived conditions.
- Investigating the interaction between IsrR, aconitase, and its regulators.
- Studying the impact of aconitase's regulatory role on downstream metabolic pathways.
Main Results:
- IsrR directly regulates aconitase (CitB) and its transcriptional regulator CcpE, establishing an RNA-driven feedforward loop.
- Aconitase exhibits moonlighting activity, functioning as an RNA-binding protein that negatively regulates its own expression.
- Aconitase's regulatory role upregulates pyruvate carboxylase, compensating for TCA cycle deficits caused by iron scarcity.
Conclusions:
- IsrR orchestrates a complex post-transcriptional regulatory network to manage Staphylococcus aureus central metabolism during iron deficiency.
- Aconitase's dual enzymatic and RNA-binding functions are critical for bacterial adaptation and survival under iron-limiting conditions.
- This study reveals a sophisticated RNA-mediated regulatory cascade essential for Staphylococcus aureus virulence and persistence.
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