Cloning and functional expression of a novel gap junction channel from the retina of Danio aquipinnatus

• Published in: Visual neuroscience 1998-11, Vol.15 (6), p.1137-1144
• Main Authors: WAGNER, T.L.E., BEYER, E.C., McMAHON, D.G.
• Format: Article
• Language: English
• Subjects: Amino Acid Sequence; Animals; Biological and medical sciences; Cloning, Molecular; Connexin; Connexin 43 - genetics; Connexin 43 - metabolism; Connexins - chemistry; Connexins - genetics; Electrical synapse; Eye; Eye and associated structures. Visual pathways and centers. Vision; Fish; Fundamental and applied biological sciences. Psychology; Gap Junctions - metabolism; Mice; Molecular Sequence Data; Rats - genetics; Retina - metabolism; Sequence Homology, Amino Acid; Tumor Cells, Cultured; Vertebrates: nervous system and sense organs; Visual system; Zebrafish - genetics; Zebrafish - physiology
• ISSN: 0952-5238; 1469-8714
• DOI: 10.1017/S0952523898156146

Electrical synapses, or gap junctions, are widely distributed in the vertebrate retina and are thought to play critical roles in the transmission and coding of visual signals. To investigate the molecular basis of this form of neural communication in the retina, we have isolated, characterized, and functionally expressed a cDNA for a gap junction channel derived from the retina of the teleost fish Danio aquipinnatus (giant danio). The cDNA contained an open reading frame of 1146 nucleotides encoding a connexin with a predicted molecular mass of 43.3 kDa which shared extensive identity with Rattus norvegicus Cx43 (78%). This protein (DACX43) contained several consensus phosphorylation sequences in the c-terminal region, some of which are conserved among Cx43 orthologs. RNA blot hybridization revealed that DACX43 was expressed in the brain as well as in the retina. In addition, Southern analysis suggested that there are multiple copies of DACX43, or other closely related sequences, in the Danio aquipinnatus genome. When DACX43 was expressed by stable transfection in gap-junction-deficient mouse N2A neuroblastoma cells, functional gap junctions were formed as indicated by dual whole-cell recordings of electrical coupling. We conclude that DACX43 is a connexin43 ortholog, which is expressed in the retina of Danio aquipinnatus, and when translated is able to form functional gap junction channels.