Cheng Shaohong, Shakespeare Teresa, Mui Rickie, White Thomas W, Valdimarsson Gunnar
Department of Zoology and Biochemistry and Medical Genetics, University of Manitoba, Winnipeg, Manitoba R3T 2N2, Canada.
J Biol Chem. 2004 Aug 27;279(35):36993-7003. doi: 10.1074/jbc.M401355200. Epub 2004 Jun 22.
Gap junctions are composed of connexin (Cx) proteins and mediate intercellular communication required for many developmental and physiological processes. Here we describe the isolation and characterization of Cx48.5, a zebrafish connexin with the highest sequence identity to mammalian Cx46. Expression analysis showed that Cx48.5 is expressed in the adult and embryonic lens and heart, adult testis, and transiently in the embryonic otic vesicles. Injection of Cx48.5 cRNA into Xenopus oocytes elicited intercellular electrical coupling with voltage sensitivity similar to mammalian Cx46. In single oocytes, Cx48.5 also induced large outward currents on depolarization, consistent with gap-junctional hemichannels. Disruption of Cx48.5 expression in embryos with antisense morpholino oligos (morpholinos) revealed that Cx48.5 has an essential role in the maintenance of lens homeostasis. The morpholino-treated embryos also developed small lenses and eyes as well as severe cardiovascular abnormalities.
