title: Cloning, expression, and tissue localization of the calcium-sensing receptor in chicken (Gallus domesticus).
abstract: In previous studies, we characterized an extracellular Ca2+ (Cao(2+))-sensing receptor (CaR) that plays a central role in regulating parathyroid hormone secretion in mammals by sensing Cao2+. In the present study, we have cloned and characterized the chicken (Gallus domesticus) homolog of the CaR. The chicken parathyroid CaR shares a high degree of homology (84% amino acid identity) with the human CaR and displays a similar topology. Moreover, amino acid residues where mutations cause disorders of Cao(2+)-sensing in the human CaR share the wild-type human sequence in the chicken CaR. However, a single region in the extracellular domain of the chicken CaR differs substantially from its mammalian homologs. Xenopus laevis oocytes injected with chicken CaR cRNA respond to elevated ambient levels of Cao2+, extracellular Mg2+, or extracellular Gd3+ with the characteristic activation of inositol trisphosphate-dependent, intracellular Ca(2+)-induced Cl- currents elicited by mammalian CaRs as well as by G protein-linked receptors coupled to activation of phospholipase C. By in situ hybridization, clusters of cells in chicken parathyroid glands were shown to express CaR messenger RNA. Northern analysis and immunohistochemistry demonstrated expression of receptor transcripts and/or protein in kidney tubules and intestine as well as in brain. The close conservation of the amino acid sequence of the chicken CaR with its mammalian homologs as well as its similar tissue distribution suggest that the receptor may also play an important role in avian calcium homeostasis.
authors.affiliation: Department of Medicine, Brigham and Women's Hospital, Boston, Massachusetts, USA.
authors.forename: R
authors.initials: R
authors.lastname: Diaz
authors.forename: S
authors.initials: S
authors.lastname: Hurwitz
authors.forename: N
authors.initials: N
authors.lastname: Chattopadhyay
authors.forename: M
authors.initials: M
authors.lastname: Pines
authors.forename: Y
authors.initials: Y
authors.lastname: Yang
authors.forename: O
authors.initials: O
authors.lastname: Kifor
authors.forename: M S
authors.initials: MS
authors.lastname: Einat
authors.forename: R
authors.initials: R
authors.lastname: Butters
authors.forename: S C
authors.initials: SC
authors.lastname: Hebert
authors.forename: E M
authors.initials: EM
authors.lastname: Brown
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002135:Calcium-Binding Proteins / Q000032:analysis / Q000096:biosynthesis* / Q000737:chemistry; D002645:Chickens; D003001:Cloning, Molecular; D005260:Female; D006801:Humans; D006965:Hyperplasia; D007668:Kidney / Q000378:metabolism*; D008322:Mammals; D008969:Molecular Sequence Data; D009865:Oocytes / Q000502:physiology; D010280:Parathyroid Glands / Q000378:metabolism* / Q000473:pathology; D044169:Receptors, Calcium-Sensing; D011956:Receptors, Cell Surface / Q000032:analysis / Q000096:biosynthesis* / Q000737:chemistry; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D014808:Vitamin D Deficiency / Q000473:pathology / Q000503:physiopathology; D014982:Xenopus laevis
chemical_list: D002135:Calcium-Binding Proteins; D044169:Receptors, Calcium-Sensing; D011956:Receptors, Cell Surface