Two Drosophila Innexins Are Expressed in Overlapping Domains and Cooperate to Form Gap-Junction Channels
| Autor: | Pauline Phelan, Jane A. Davies, Jonathan P. Bacon, Martin G. Todman, Lucy A. Stebbings |
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| Jazyk: | angličtina |
| Rok vydání: | 2000 |
| Předmět: |
DNA
Complementary Protein family Xenopus Molecular Sequence Data Gene Expression Genes Insect Innexin Biology Article Connexins Protein structure Protein biosynthesis Genes Overlapping Animals Drosophila Proteins Amino Acid Sequence Molecular Biology Base Sequence Gap junction Gap Junctions Cell Biology biology.organism_classification Molecular biology Cell biology Protein Structure Tertiary Protein Biosynthesis Oocytes Insect Proteins Ectopic expression Drosophila Drosophila Protein |
| Popis: | 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. |
| Databáze: | OpenAIRE |
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