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Mutagenesis and Functional Analysis of Ion Channels Heterologously Expressed in Mammalian Cells
15:28

Mutagenesis and Functional Analysis of Ion Channels Heterologously Expressed in Mammalian Cells

Published on: October 1, 2010

Mutagenesis in mammalian cells can be modulated by radiation-induced voltage-dependent potassium channels

A H Saad1, L Y Zhou, E K Lambe

  • 1Department of Radiation Oncology, Stanford University, CA 94305.

Mutation Research
|August 1, 1994
PubMed

Insights

Ionizing radiation increases mutation frequency in mammalian cells by activating potassium (K+) currents. Blocking these currents with specific blockers prevents radiation-induced mutagenesis, highlighting a novel role for membrane potential in DNA damage response.

Area of Science:

  • Cell Biology
  • Radiation Biology
  • Molecular Biology

Background:

  • The initial molecular events following ionizing radiation exposure in mammalian cells, leading to mutagenesis or DNA repair, remain largely unknown.
  • The potential role of the plasma membrane as an initiator of these cellular pathways is not understood.

Purpose of the Study:

  • To investigate the role of membrane voltage-dependent potassium (K+) currents in radiation-induced mutagenesis.
  • To determine if blocking these K+ currents can prevent mutagenesis following ionizing radiation exposure.

Main Methods:

  • Mammalian cells were exposed to 800 cGy of ionizing radiation.
  • Mutation frequency at the HGPRT locus was assessed.
  • Cells were treated with potassium channel blockers (CsCl, BaCl2) or a non-blocker (RbCl) post-irradiation.

Main Results:

  • Ionizing radiation significantly increased mutation frequency from 1.5 to 37.6 per 100,000 survivors.
  • Treatment with CsCl or BaCl2 completely abolished the radiation-induced increase in mutation frequency.
  • RbCl, which does not block K+ channels, was ineffective in preventing mutagenesis, while CsCl and BaCl2 did not affect radiation-induced cell killing.

Conclusions:

  • Membrane voltage-dependent potassium (K+) currents play a significant role in radiation mutagenesis.
  • Blocking these K+ currents represents a potential strategy to mitigate mutagenesis after radiation exposure.
  • These findings reveal a novel mechanism involving plasma membrane ion channels in the cellular response to DNA damage.

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