Downregulation of Connexin 45 Gene Products During Mouse Heart Development

The electrical activity in heart is generated in the sinoatrial node and then propagates to the atrial and ventricular tissues. The gap junction channels that couple the myocytes are responsible for this propagation process. The gap junction channels are dodecamers of transmembrane proteins of the c...

Full description

Saved in:
Bibliographic Details
Published in:Circulation research 1999-06, Vol.84 (12), p.1365-1379
Main Authors: Alcoléa, Sébastien, Théveniau-Ruissy, Magali, Jarry-Guichard, Thérèse, Marics, Irène, Tzouanacou, Elena, Chauvin, Jean-Paul, Briand, Jean-Paul, Moorman, Antoon F.M, Lamers, Wouter H, Gros, Daniel B
Format: Article
Language:English
Subjects:
Amino Acid Sequence
Animals
Antisense Elements (Genetics)
Biological and medical sciences
Connexins - analysis
Connexins - genetics
Connexins - immunology
Down-Regulation - genetics
Female
Fetus - cytology
Fluorescent Antibody Technique
Fundamental and applied biological sciences. Psychology
Gene Expression Regulation, Developmental
Heart
Heart - embryology
HeLa Cells
Humans
In Situ Hybridization
Liver - cytology
Mice
Microscopy, Electron
Molecular Sequence Data
Myocardium - chemistry
Myocardium - metabolism
Ovary - chemistry
Ovary - ultrastructure
Rabbits
Rats
Reverse Transcriptase Polymerase Chain Reaction
Transcription, Genetic - physiology
Vertebrates: cardiovascular system
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:The electrical activity in heart is generated in the sinoatrial node and then propagates to the atrial and ventricular tissues. The gap junction channels that couple the myocytes are responsible for this propagation process. The gap junction channels are dodecamers of transmembrane proteins of the connexin (Cx) family. Three members of this family have been demonstrated to be synthesized in the cardiomyocytesCx40, Cx43, and Cx45. In addition, each of them has been shown to form channels with unique and specific electrophysiological properties. Understanding the conduction phenomenon requires detailed knowledge of the spatiotemporal expression pattern of these Cxs in heart. The expression patterns of Cx40 and Cx43 have been previously described in the adult heart and during its development. Here we report the expression of Cx45 gene products in mouse heart from the stage of the first contractions (8.5 days postcoitum [dpc]) to the adult stage. The Cx45 gene transcript was demonstrated by reverse transcriptase-polymerase chain reaction experiments to be present in heart at all stages investigated. Between 8.5 and 10.5 dpc it was shown by in situ hybridization to be expressed in low amounts in all cardiac compartments (including the inflow and outflow tracts and the atrioventricular canal) and then to be downregulated from 11 to 12 dpc onward. At subsequent fetal stages, the transcript was weakly detected in the ventricles, with the most distinct expression in the outflow tract. Cx45 protein was demonstrated by immunofluorescence microscopy to be expressed in the myocytes of young embryonic hearts (8.5 to 9.5 dpc). However, beyond 10.5 dpc the protein was no longer detected with this technique in the embryonic, fetal, or neonatal working myocardium, although it could be shown by immunoblotting that the protein was still synthesized in neonatal heart. In the major part of adult heart, Cx45 was undetectable. It was, however, clearly seen in the anterior regions of the interventricular septum and in trace amounts in some small foci dispersed in the ventricular free walls. Cx45 gene is the first Cx gene so far demonstrated to be activated in heart at the stage of the first contractions. The coordination of myocytes during the slow peristaltic contractions that occur at this stage would thus appear to be controlled by the Cx45 channels.
ISSN:0009-7330
1524-4571
DOI:10.1161/01.res.84.12.1365