title: Four functionally distinct C-type natriuretic peptides found in fish reveal evolutionary history of the natriuretic peptide system.
abstract: Natriuretic peptides (NPs) are major cardiovascular and osmoregulatory hormones in vertebrates. Although tetrapods generally have three subtypes, atrial NP (ANP), B-type NP (BNP), and C-type NP (CNP), some teleosts lack BNP, and sharks and hagfish have only one NP. Thus, NPs have diverged during fish evolution, possibly reflecting changes in osmoregulatory systems. In this study, we found, by cDNA cloning, four distinct CNPs (1 through 4) in the medaka (Oryzias latipes) and puffer fish (Takifugu rubripes), although to our knowledge no more than two CNPs have been isolated from a vertebrate species. Predicted mature CNP-1 was most similar, and CNP-4 was most dissimilar, to mammalian CNPs. However, synthetic CNP-4 most potently activated OlGC1, a medaka CNP-specific receptor (NPR-B) expressed in cultured cells, whereas CNP-1 and CNP-3 most activated OlGC7 and OlGC2, two medaka homologues of the ANP/BNP receptor (NPR-A), respectively. Linkage mapping in medaka followed by comparative genomic analyses among fishes and humans located four CNP genes in separate medaka chromosomes corresponding to human chromosomes 1, 2, 12, and 17. From conserved synteny, the following evolutionary history of NPs was evoked: (i) four CNP genes were generated by chromosomal duplications before the divergence of elasmobranchs; (ii) the CNP-3 gene generated ANP and BNP genes through tandem duplication before the divergence of tetrapods and teleosts; (iii) CNP-1 and -2 genes were retained in the teleost lineage but not in the tetrapod lineage; (iv) the CNP-3 gene disappeared from the tetrapod lineage after divergence of amphibians; and (v) the CNP-4 gene is retained in humans as CNP.
authors.affiliation: Ocean Research Institute, University of Tokyo, 1-15-1 Minamidai, Nakano, Tokyo 164-8639, Japan. inouek@ori.u-tokyo.ac.jp
authors.forename: Koji
authors.initials: K
authors.lastname: Inoue
authors.forename: Kiyoshi
authors.initials: K
authors.lastname: Naruse
authors.forename: Sayaka
authors.initials: S
authors.lastname: Yamagami
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Mitani
authors.forename: Norio
authors.initials: N
authors.lastname: Suzuki
authors.forename: Yoshio
authors.initials: Y
authors.lastname: Takei
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D009320:Atrial Natriuretic Factor / Q000235:genetics; D001483:Base Sequence; D002874:Chromosome Mapping; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000235:genetics; D019143:Evolution, Molecular; D005260:Female; D005399:Fishes / Q000235:genetics*; D020440:Gene Duplication; D006801:Humans; D008297:Male; D008969:Molecular Sequence Data; D020097:Natriuretic Peptide, Brain / Q000235:genetics; D020098:Natriuretic Peptide, C-Type / Q000235:genetics* / Q000502:physiology; D009990:Oryzias / Q000235:genetics; D010802:Phylogeny; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D018013:Receptors, Neuropeptide / Q000187:drug effects / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D023741:Takifugu / Q000235:genetics; D014018:Tissue Distribution
chemical_list: D018076:DNA, Complementary; D012333:RNA, Messenger; D018013:Receptors, Neuropeptide; D020097:Natriuretic Peptide, Brain; D020098:Natriuretic Peptide, C-Type; D009320:Atrial Natriuretic Factor