title: Cloning and functional expression of invertebrate connexins from Halocynthia pyriformis.
abstract: Unlike many other ion channels, unrelated gene families encode gap junctions in different animal phyla. Connexin and pannexin genes are found in deuterostomes, while protostomal species use innexin genes. Connexins are often described as vertebrate genes, despite the existence of invertebrate deuterostomes. We have cloned connexin sequences from an invertebrate chordate, Halocynthia pyriformis. Invertebrate connexins shared 25-40% sequence identity with human connexins, had extracellular domains containing six invariant cysteine residues, coding regions that were interrupted by introns, and formed functional channels in vitro. These data show that gap junction channels based on connexins are present in animals that predate vertebrate evolution.
authors.affiliation: Department of Physiology and Biophysics, State University of New York, BST 5-147, Stony Brook, NY 11794, USA. thomas.white@sunysb.edu
authors.forename: Thomas W
authors.initials: TW
authors.lastname: White
authors.forename: Huan
authors.initials: H
authors.lastname: Wang
authors.forename: Rickie
authors.initials: R
authors.lastname: Mui
authors.forename: Jennifer
authors.initials: J
authors.lastname: Litteral
authors.forename: Peter R
authors.initials: PR
authors.lastname: Brink
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D003001:Cloning, Molecular; D017630:Connexins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism / Q000502:physiology*; D004247:DNA; D006801:Humans; D008969:Molecular Sequence Data; D010802:Phylogeny; D017386:Sequence Homology, Amino Acid; D014561:Urochordata / Q000378:metabolism*
chemical_list: D017630:Connexins; D004247:DNA