title: Expression of the IKr components KCNH2 (rERG) and KCNE2 (rMiRP1) during late rat heart development.
abstract: To understand molecular mechanisms that regulate formation and maintenance of cardiac IKr (rapidly activating component of the delayed rectifier K+ current), we have investigated the spatiotemporal expression pattern of two rat potassium voltage-gated channels, namely subfamily H (eag-related), member2 (KCNH2) (alias name: rERG) and Isk-related family, member2 (KCNE2) (alias name: rMiRP1) during late embryonic development by means of the in situ hybridization technique. KCNE2 is transcribed predominantly in atrial und ventricular myocardium at stages E14.5-E18.5dpc and only a minor signal emerged in the tongue at E16.5dpc. In contrast, KCNH2 transcripts appeared in a less confined pattern with intense signals in atrial and ventricular myocardium, somites, spinal cord, bowel system, central nervous system and thymus at stages E14.5-E18.5dpc. Non-cardiac expression even exceeds the intensity of the cardiac signal, indicating that KCNH2 contributes to K+ currents in non-cardiac tissue as well. Transcription of the rat b-subunit KCNE2 is present in all regions of the fetal myocardium and co-distributes perfectly with transcription of the pore forming a-subunit KCNH2. It seems likely that KCNH2 and KCNE2 are linked to form cardiac IKr channels, associated to cardiogenesis and cardiomyocyte excitability.
authors.affiliation: AK St. Georg, Abteilung für Kardiologie, Lohmuhlenstrasse 5, 20099 Hamburg, Germany.
authors.forename: K R J
authors.initials: KR
authors.lastname: Chun
authors.forename: M
authors.initials: M
authors.lastname: Koenen
authors.forename: H A
authors.initials: HA
authors.lastname: Katus
authors.forename: J
authors.initials: J
authors.lastname: Zehelein
mesh_terms: D000818:Animals; D000072237:ERG1 Potassium Channel; D004622:Embryo, Mammalian / Q000737:chemistry; D047108:Embryonic Development; D051638:Ether-A-Go-Go Potassium Channels; D015870:Gene Expression; D006321:Heart / Q000196:embryology*; D017403:In Situ Hybridization; D009206:Myocardium / Q000737:chemistry / Q000378:metabolism*; D024642:Potassium Channels, Voltage-Gated / Q000096:biosynthesis* / Q000235:genetics; D051381:Rats
chemical_list: D000072237:ERG1 Potassium Channel; D051638:Ether-A-Go-Go Potassium Channels; C489621:KCNE2 protein, rat; C000606918:Kcnh2 protein, rat; D024642:Potassium Channels, Voltage-Gated