title: Electrophysiological properties of mouse and epitope-tagged human cardiac sodium channel Na v1.5 expressed in HEK293 cells.
abstract: BACKGROUND
  The pore-forming subunit of the cardiac sodium channel, Na v1.5, has been previously found to be mutated in genetically determined arrhythmias. Na v1.5 associates with many proteins that regulate its function and cellular localisation. In order to identify more in situ Na v1.5 interacting proteins, genetically-modified mice with a high-affinity epitope in the sequence of Na v1.5 can be generated.
  
  
  METHODS
  In this short study, we (1) compared the biophysical properties of the sodium current (I Na) generated by the mouse Na v1.5 (mNa v1.5) and human Na v1.5 (hNa v1.5) constructs that were expressed in HEK293 cells, and (2) investigated the possible alterations of the biophysical properties of the human Na v1.5 construct that was modified with specific epitopes.
  
  
  RESULTS
  The biophysical properties of mNa v1.5 were similar to the human homolog. Addition of epitopes either up-stream of the N-terminus of hNa v1.5 or in the extracellular loop between the S5 and S6 transmembrane segments of domain 1, significantly decreased the amount of I Na and slightly altered its biophysical properties. Adding green fluorescent protein (GFP) to the N-terminus did not modify any of the measured biophysical properties of hNa v1.5.
  
  
  CONCLUSIONS
  These findings have to be taken into account when planning to generate genetically-modified mouse models that harbour specific epitopes in the gene encoding mNa v1.5.
authors.affiliation: Department of Clinical Research, University of Bern, Bern, 3010, Switzerland ; Current address: Centre for Integrative Neuroscience, University of Tübingen, Tübingen, 72076, Germany.
authors.forename: Katja
authors.initials: K
authors.lastname: Reinhard
authors.affiliation: Department of Clinical Research, University of Bern, Bern, 3010, Switzerland.
authors.forename: Jean-Sébastien
authors.initials: JS
authors.lastname: Rougier
authors.affiliation: Department of Clinical Research, University of Bern, Bern, 3010, Switzerland.
authors.forename: Jakob
authors.initials: J
authors.lastname: Ogrodnik
authors.affiliation: Department of Clinical Research, University of Bern, Bern, 3010, Switzerland.
authors.forename: Hugues
authors.initials: H
authors.lastname: Abriel