title: Expression of the hyperpolarization-activated cyclic nucleotide-gated cation channel HCN4 during mouse heart development.
abstract: HCN4 is a hyperpolarization-activated nucleotide-gated cation channel involved in the generation of the I(f) current that drives cardiac pacemaker activity. Previous studies have demonstrated that HCN4 is highly expressed in a restricted manner in adult sinoatrial (SA) node [Eur. J. Biochem. 268 (2001) 1646]. However, its developmental expression pattern is unknown. We have examined expression of HCN4 mRNA during mouse heart development. HCN4 mRNA was first detected in the cardiac crescent at embryonic day (ED) 7.5. At ED 8 it was symmetrically located in the most caudal portion of the heart tube, the sinus venosus where pacemaker activity has previously been reported [Am. J. Physiol. 212 (1967) 407]. With further development, HCN4 expression became asymmetrically distributed, occupying the dorsal wall of the right atria, and was progressively restricted to the junction of the right atrial appendage and the superior vena cava. The site of HCN4 expression in late embryonic heart coincided with the location of the SA node in postnatal and adult heart [Cardiovasc. Res. 52 (2001) 51]. Our results suggest that HCN4 may be a unique marker of the developing SA node.
authors.affiliation: Institute of Molecular Medicine and Department of Medicine, University of California at San Diego, La Jolla, CA 92093-0613, USA.
authors.forename: Cristina
authors.initials: C
authors.lastname: Garcia-Frigola
authors.forename: Yunqing
authors.initials: Y
authors.lastname: Shi
authors.forename: Sylvia M
authors.initials: SM
authors.lastname: Evans
mesh_terms: D000818:Animals; D054815:Cyclic Nucleotide-Gated Cation Channels; D015870:Gene Expression; D006321:Heart / Q000033:anatomy & histology / Q000196:embryology*; D064428:Hyperpolarization-Activated Cyclic Nucleotide-Gated Channels; D017403:In Situ Hybridization; D007473:Ion Channels / Q000235:genetics / Q000378:metabolism*; D051379:Mice / Q000196:embryology* / Q000235:genetics / Q000378:metabolism; D009206:Myocardium / Q000378:metabolism; D012333:RNA, Messenger / Q000032:analysis / Q000378:metabolism
chemical_list: D054815:Cyclic Nucleotide-Gated Cation Channels; D064428:Hyperpolarization-Activated Cyclic Nucleotide-Gated Channels; D007473:Ion Channels; D012333:RNA, Messenger