Molecular characterization of the zebrafish P2X receptor subunit gene family

• Published in: Neuroscience 2003-01, Vol.121 (4), p.935-945
• Main Authors: Kucenas, S, Li, Z, Cox, J.A, Egan, T.M, Voigt, M.M
• Format: Article
• Language: English
• Subjects: Adenosine Triphosphate - metabolism; Adenosinic and purinergic receptors; Animals; ATP; Biological and medical sciences; Cell Line; Cell receptors; Cell structures and functions; Cloning, Molecular; Danio rerio; DNA, Complementary - analysis; DNA, Complementary - genetics; embryo; Embryo, Nonmammalian - cytology; Embryo, Nonmammalian - metabolism; Freshwater; Fundamental and applied biological sciences. Psychology; Gene Expression Regulation, Developmental - genetics; Humans; Ion Channel Gating - physiology; ligand-gated channel; Molecular and cellular biology; Molecular Sequence Data; Multigene Family; Nervous System - cytology; Nervous System - embryology; Nervous System - metabolism; Neurons, Afferent - cytology; Neurons, Afferent - metabolism; nucleotide; Phenotype; Phylogeny; Protein Subunits - genetics; Protein Subunits - isolation & purification; purine; Purines - metabolism; Receptors, Purinergic P2 - genetics; Receptors, Purinergic P2 - isolation & purification; Receptors, Purinergic P2X; Sequence Homology, Amino Acid; Sequence Homology, Nucleic Acid; Zebrafish; Zebrafish Proteins - genetics; Zebrafish Proteins - isolation & purification
• ISSN: 0306-4522; 1873-7544
• DOI: 10.1016/S0306-4522(03)00566-9

P2X receptors are non-selective cation channels gated by extracellular ATP and are encoded by a family of seven subunit genes in mammals. These receptors exhibit high permeabilities to calcium and in the mammalian nervous system they have been linked to modulation of neurotransmitter release. Previously, three complementary DNAs (cDNAs) encoding members of the zebrafish gene family have been described. We report here the cloning and characterization of an additional six genes of this family. Sequence analysis of all nine genes suggests that six are orthologs of mammalian genes, two are paralogs of previously described zebrafish subunits, and one remains unclassified. All nine subunits were physically mapped onto the zebrafish genome using radiation hybrid analysis. Of the nine gene products, seven give functional homo-oligomeric receptors when recombinantly expressed in human embryonic kidney cell line 293 cells. In addition, these subunits can form hetero-oligomeric receptors with phenotypes distinct from the parent subunits. Analysis of gene expression patterns was carried out using in situ hybridization, and seven of the nine genes were found to be expressed in embryos at 24 and 48 h post-fertilization. Of the seven that were expressed, six were present in the nervous system and four of these demonstrated considerable overlap in cells present in the sensory nervous system. These results suggest that P2X receptors might play a role in the early development and/or function of the sensory nervous system in vertebrates.