Characterization of sinoatrial node in four conduction system marker mice

S. Viswanathan, J. B.E. Burch, G. I. Fishman, I. P. Moskowitz, D. W. Benson

Research output: Contribution to journalArticlepeer-review

22 Scopus citations

Abstract

The specialized cardiac conduction system (CCS) consists of the sinoatrial node (SAN) and the atrioventricular (AV) conduction system (AVCS), which includes proximal (AV node, bundle of His and bundle branches) and distal (Purkinje fibers) components. In four CCS marker mice [two transgenic (cGATA6|lacZ, CCS|lacZ) and two targeted gene knock-in (minK|lacZ, Hop|lacZ)] the expression of the lacZ gene (β-gal) has been reported to mark portions of the proximal and distal AVCS; the expression of this marker in the adult SAN is unknown. The primary objective of this study was to analyze the utility of these marker mice in the identification of the SAN. Intercaval and interventricular septal regions, containing all the components of the CCS, were freshly dissected from adult mice based on the anatomical landmarks and sectioned. Immunohistochemical characterization was performed with SAN markers (Cx45, HCN4), compared to the reporter expression (β-gal) and markers of the working myocardium (Cx40 and Cx43). In all four of the CCS marker mice, we found that β-gal expression is consistently observed in the proximal and distal AVCS. However, the presence of lacZ gene expression in the working myocardium outside the CCS and/or the absence of this reporter expression in the SAN prevent the effective use of these mice to identify the SAN, leading us to conclude that none of the four CCS marker mice we studied specifically mark the SAN.

Original languageEnglish
Pages (from-to)946-953
Number of pages8
JournalJournal of Molecular and Cellular Cardiology
Volume42
Issue number5
DOIs
StatePublished - May 2007
Externally publishedYes

Keywords

  • Conduction system
  • Connexins
  • Histo(patho)logy
  • Sinus node
  • Transgenic animal models

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