title: Human connexin31.9, unlike its orthologous protein connexin30.2 in the mouse, is not detectable in the human cardiac conduction system.
abstract: In the human heart connexin(Cx)40, Cx43 and Cx45-containing gap junctional channels electrically couple cardiomyocytes, forming a functional syncytium. In the mouse heart, additionally, Cx30.2-containing gap junctions have been detected in the atrioventricular node where they are implicated, together with Cx45, in impulse delay. However, whether the human ortholog of Cx30.2, Cx31.9, is expressed in the human heart has not previously been investigated. We therefore generated Cx31.9 specific antibodies to test for the expression of Cx31.9 in the human heart. These antibodies recognized the Cx31.9 protein in HeLaCx31.9 transfectants by immunofluorescence and immunoblot analyses. However, we did not find punctate Cx31.9 specific immunofluorescence signals in the working myocardium or in the impulse generation and conduction system of adult or fetal human heart. Complementary immunoblot analyses did not reveal Cx31.9 protein in the adult atrial or ventricular myocardium. We conclude that the Cx31.9 protein, unlike its counterpart in the mouse, is not expressed in detectable quantities and is thus unlikely to contribute to the impulse generation and conduction system or the working myocardium of the human heart.
authors.affiliation: Institute of Genetics, University of Bonn, Bonn, Germany. k-ooishi@aist.go.jp
authors.forename: Maria M
authors.initials: MM
authors.lastname: Kreuzberg
authors.forename: Marcus
authors.initials: M
authors.lastname: Liebermann
authors.forename: Sara
authors.initials: S
authors.lastname: Segschneider
authors.forename: Radoslaw
authors.initials: R
authors.lastname: Dobrowolski
authors.forename: Halina
authors.initials: H
authors.lastname: Dobrzynski
authors.forename: Riyaz
authors.initials: R
authors.lastname: Kaba
authors.forename: Giselle
authors.initials: G
authors.lastname: Rowlinson
authors.forename: Emmanuel
authors.initials: E
authors.lastname: Dupont
authors.forename: Nicholas J
authors.initials: NJ
authors.lastname: Severs
authors.forename: Klaus
authors.initials: K
authors.lastname: Willecke
mesh_terms: D000818:Animals; D000918:Antibody Specificity; D017630:Connexins / Q000737:chemistry* / Q000378:metabolism*; D016616:Cryoultramicrotomy; D005455:Fluorescent Antibody Technique; D006367:HeLa Cells; D006329:Heart Conduction System / Q000378:metabolism*; D006801:Humans; D015151:Immunoblotting; D051379:Mice; D018613:Microscopy, Confocal; D017386:Sequence Homology, Amino Acid; D014162:Transfection
chemical_list: D017630:Connexins; C468137:GJD3 protein, human; C510757:connexin 30.2, mouse