title: Connexin-36 contributes to control function of insulin-producing cells.
abstract: Connexin-36 (Cx36) is a gap junction protein expressed by the insulin-producing beta-cells. We investigated the contribution of this protein in normal beta-cell function by using a viral gene transfer approach to alter Cx36 content in the insulin-producing line of INS-1E cells and rat pancreatic islets. Transcripts for Cx43, Cx45, and Cx36 were detected by reverse transcriptase-PCR in freshly isolated pancreatic islets, whereas only a transcript for Cx36 was detected in INS-1E cells. After infection with a sense viral vector, which induced de novo Cx36 expression in the Cx-defective HeLa cells we used to control the transgene expression, Western blot, immunofluorescence, and freeze-fracture analysis showed a large increase of Cx36 within INS-1E cell membranes. In contrast, after infection with an antisense vector, Cx36 content was decreased by 80%. Glucose-induced insulin release and insulin content were decreased, whether infected INS-1E cells expressed Cx36 levels that were largely higher or lower than those observed in wild-type control cells. In both cases, basal insulin secretion was unaffected. Comparable observations on basal secretion and insulin content were made in freshly isolated rat pancreatic islets. The data indicate that large changes in Cx36 alter insulin content and, at least in INS-1E cells, also affect glucose-induced insulin release.
authors.affiliation: Department of Internal Medicine, University Hospital, CHUV-1011 Lausanne, Switzerland.
authors.forename: Sabine
authors.initials: S
authors.lastname: Le Gurun
authors.forename: David
authors.initials: D
authors.lastname: Martin
authors.forename: Andrea
authors.initials: A
authors.lastname: Formenton
authors.forename: Pierre
authors.initials: P
authors.lastname: Maechler
authors.forename: Dorothee
authors.initials: D
authors.lastname: Caille
authors.forename: Gérard
authors.initials: G
authors.lastname: Waeber
authors.forename: Paolo
authors.initials: P
authors.lastname: Meda
authors.forename: Jacques-Antoine
authors.initials: JA
authors.lastname: Haefliger
mesh_terms: D000256:Adenoviridae / Q000235:genetics; D000595:Amino Acid Sequence; D000818:Animals; D002118:Calcium / Q000378:metabolism; D002460:Cell Line; D017630:Connexins / Q000502:physiology*; D007328:Insulin / Q000032:analysis / Q000378:metabolism*; D000078790:Insulin Secretion; D007515:Islets of Langerhans / Q000502:physiology*; D008969:Molecular Sequence Data; D051381:Rats; D000097004:Gap Junction delta-2 Protein
chemical_list: D002118:Calcium; D017630:Connexins; D007328:Insulin; D000097004:Gap Junction delta-2 Protein