Two Drosophila innexins are expressed in overlapping domains and cooperate to form gap-junction channels.
Mol Biol Cell
; 11(7): 2459-70, 2000 Jul.
Article
em En
| MEDLINE
| ID: mdl-10888681
ABSTRACT
Members of the innexin protein family are structural components of invertebrate gap junctions and are analogous to vertebrate connexins. Here we investigate two Drosophila innexin genes, Dm-inx2 and Dm-inx3 and show that they are expressed in overlapping domains throughout embryogenesis, most notably in epidermal cells bordering each segment. We also explore the gap-junction-forming capabilities of the encoded proteins. In paired Xenopus oocytes, the injection of Dm-inx2 mRNA results in the formation of voltage-sensitive channels in only approximately 40% of cell pairs. In contrast, Dm-Inx3 never forms channels. Crucially, when both mRNAs are coexpressed, functional channels are formed reliably, and the electrophysiological properties of these channels distinguish them from those formed by Dm-Inx2 alone. We relate these in vitro data to in vivo studies. Ectopic expression of Dm-inx2 in vivo has limited effects on the viability of Drosophila, and animals ectopically expressing Dm-inx3 are unaffected. However, ectopic expression of both transcripts together severely reduces viability, presumably because of the formation of inappropriate gap junctions. We conclude that Dm-Inx2 and Dm-Inx3, which are expressed in overlapping domains during embryogenesis, can form oligomeric gap-junction channels.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Junções Comunicantes
/
Conexinas
/
Proteínas de Insetos
Limite:
Animals
Idioma:
En
Revista:
Mol Biol Cell
Assunto da revista:
BIOLOGIA MOLECULAR
Ano de publicação:
2000
Tipo de documento:
Article
País de afiliação:
Reino Unido