© 1997 American Heart Association, Inc.
Articles |
Protean Patterns of Gene Expression in the Heart Conduction System
Correspondence to Dr Stefano Schiaffino, Department of Biomedical Sciences, Viale G. Colombo 3, 35121 Padova, Italy. E-mail schiaffi@civ.bio.unipd.it
Key Words: heart conduction tissue • gene regulation • myofibrillar protein • editorial
 |
Introduction |
|---|
The heart conduction system consists of different muscle cell populations specialized for the generation and propagation of the electrical impulse and responsible for the coordinated activation of atrial and ventricular myocardium. Cells present in the SA and AV nodes are generally smaller than ordinary myocardial cells and appear similar to embryonic cardiomyocytes with respect to morphology and electrophysiological properties, eg, slow conduction velocity. In contrast, the Purkinje cells of the ventricular conduction system are often larger than ordinary myocardial cells and are characterized by fast conduction velocity. There are considerable species variations in the morphology of conduction system cells and further heterogeneity within the nodes and the peripheral Purkinje fibers. Immunocytochemical and in situ hybridization analyses have added a new dimension of complexity by showing that heart conduction system cells express markers typical of skeletal muscle, in addition to markers typical of cardiac muscle. In the chicken, ventricular Purkinje cells contain a slow skeletal MHC, which is not present in the ordinary myocardium.1 2 In the adult rat heart, AV node cells contain slow skeletal TnI transcripts, whereas ordinary cardiomyocytes contain cardiac TnI transcripts.3 An MHC isoform immunologically similar to that expressed in embryonic skeletal muscle has been detected in bovine and rat nodal cells.4 5
In this issue of Circulation Research, Alyonycheva et
al6 report that another skeletal muscle protein,
thick-filament MyBP-H, is expressed in ventricular Purkinje
cells but not in ordinary myocardial cells of the chicken heart.
MyBP-H, like MyBP-C, belongs to a family of myofibrillar proteins with
a
This article has been cited by other articles:
 |
|
 |
|
  C. E. Hall, R. Hurtado, K. W. Hewett, M. Shulimovich, C. P. Poma, M. Reckova, C. Justus, D. J. Pennisi, K. Tobita, D. Sedmera, et al. Hemodynamic-dependent patterning of endothelin converting enzyme 1 expression and differentiation of impulse-conducting Purkinje fibers in the embryonic heart Development, February 1, 2004; 131(3): 581 - 592. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 A. F. M. MOORMAN and V. M. CHRISTOFFELS Cardiac Chamber Formation: Development, Genes, and Evolution Physiol Rev, October 1, 2003; 83(4): 1223 - 1267. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
D. L. Brutsaert Cardiac Endothelial-Myocardial Signaling: Its Role in Cardiac Growth, Contractile Performance, and Rhythmicity Physiol Rev, January 1, 2003; 83(1): 59 - 115. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
K Takebayashi-Suzuki, M Yanagisawa, R. Gourdie, N Kanzawa, and T Mikawa In vivo induction of cardiac Purkinje fiber differentiation by coexpression of preproendothelin-1 and endothelin converting enzyme-1 Development, January 8, 2000; 127(16): 3523 - 3532. [Abstract] [PDF]
|
|
|
|
 |
|
 A. C. Gittenberger-de Groot, M.-P. F.M. Vrancken Peeters, M. M.T. Mentink, R. G. Gourdie, and R. E. Poelmann Epicardium-Derived Cells Contribute a Novel Population to the Myocardial Wall and the Atrioventricular Cushions Circ. Res., June 1, 1998; 82(10): 1043 - 1052. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
A. F.M. Moorman, F. de Jong, M. M.F.J. Denyn, and W. H. Lamers Development of the Cardiac Conduction System Circ. Res., April 6, 1998; 82(6): 629 - 644. [Full Text] [PDF]
|
|