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Updated: Jul 31, 2026

Electrophoretic Mobility Shift Assay (EMSA) for the Study of RNA-Protein Interactions: The IRE/IRP Example
12:44

Electrophoretic Mobility Shift Assay (EMSA) for the Study of RNA-Protein Interactions: The IRE/IRP Example

Published on: December 3, 2014

An IRP-like protein from Plasmodium falciparum binds to a mammalian iron-responsive element

M Loyevsky1, T LaVaute, C R Allerson

  • 1Howard University, Washington, DC, USA. mloyevsky@howard.edu

Blood
|October 6, 2001
PubMed

Insights

Researchers identified a novel iron-regulated protein (PfIRPa) in malaria parasites that binds to iron-responsive elements. This discovery suggests potential iron-dependent gene regulation in Plasmodium falciparum.

Area of Science:

  • Molecular Biology
  • Parasitology
  • Biochemistry

Background:

  • Iron metabolism is crucial for Plasmodium falciparum survival within red blood cells.
  • Iron-regulatory proteins (IRPs) control gene expression in response to iron levels in eukaryotes.
  • The presence and function of IRPs in malaria parasites remained largely uncharacterized.

Purpose of the Study:

  • To clone and characterize a putative iron-responsive element-binding protein (PfIRPa) from Plasmodium falciparum.
  • To investigate the iron-regulatory activity and expression of PfIRPa during the erythrocytic stage.
  • To determine if PfIRPa binds to mammalian iron-responsive elements (IREs).

Main Methods:

  • Complementary DNA (cDNA) cloning and sequencing of PfIRPa.
  • Sequence alignment with known IRPs, including human IRP1.
  • Electrophoretic mobility shift assays (EMSAs) to assess IRE-binding activity.
  • Western blot analysis to quantify PfIRPa levels under varying iron conditions.
  • Immunofluorescence microscopy to localize PfIRPa within infected red blood cells.

Main Results:

  • The cloned cDNA encoded PfIRPa, showing 47% sequence identity to human IRP1.
  • Plasmodium falciparum lysates exhibited iron-regulated IRE-binding activity.
  • PfIRPa levels increased significantly in desferrioxamine-treated (iron-depleted) cultures.
  • Anti-PfIRPa antibodies confirmed the presence of PfIRPa in the IRE-protein complex.
  • Immunofluorescence confirmed PfIRPa localization in infected red blood cells.

Conclusions:

  • Erythrocyte-stage Plasmodium falciparum possesses an iron-regulated protein (PfIRPa) capable of binding mammalian IRE sequences.
  • This finding suggests that malaria parasites may utilize IREs for iron-dependent post-transcriptional gene regulation.
  • PfIRPa represents a potential target for understanding and manipulating parasite iron homeostasis.

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