Molecular cloning of a putative voltage- and cyclic nucleotide-gated ion channel present in the antennae and eyes of Drosophila melanogaster

Abstract

The amino acid sequence BCNG-1 (brain cyclic nucleotide gated 1, of the mouse), the first member of mamalian I(h) channels, was used to construct a set of polymerase chain reaction (PCR) primers from possibly conserved regions. Reverse transcription-PCR with Drosophila melanogaster mRNA yielded in a PCR product, which exhibited a high homology to BCNG-1. Using these PCR products to screen a D. melanogaster head cDNA library we isolated a cDNA encoding a member of a new class of putative voltage- and cyclic nucleotide-gated potassium channels from D. melanogaster. The most important features of the amino acid sequence predicted from the cDNA were a C-terminal cyclic nucleotide-binding region, an S4-voltage sensor and a putative potassium-selective pore-forming motif. The high homology of 51% to the sea urchin I(h) channel, which belongs to the same class of ion channels as BCNG-1, leads us to suggest that the Drosophila cDNA is the first insect member of a new class of hyperpolarization-activated and cyclic nucleotide-gated channels. As shown by in situ hybridization, a pronounced mRNA expression was detected in neuronal tissue, including sensory tissue like the compound eyes, and the olfactory and the auditory organs.

Functional expression and characterization of a Drosophila odorant receptor in a heterologous cell system

“…Although components of the cyclic nucleotide and phosphatidylinositol signaling pathway have been identified in Drosophila (22)(23)(24)(25), an essential role for either pathway has not emerged. The fact that the G␣ 15 subunit couples the activity of vertebrate seven-transmembrane receptors to the phospholipase C͞inositol 1,4,5-trisphosphate pathway (12,15), the functionality of this pathway in the heterologous system does not necessarily imply that this pathway functions in Drosophila ORNs in situ.…”

Hyperpolarization-Activated Cation Channels: From Genes to Function

“…Analysis of genomic sequences suggests that HCN2-4 genes underwent duplications in the fish lineage increasing the number of potential HCN species (194). HCN homologs have also been cloned from several invertebrates including arthropods [e.g., spiny lobster (157), insects (158,211,251)] and sea urchins (149,153). The overall characteristics of the I h currents from these species are strikingly similar to I h currents from mammals.…”

“…The ion channels underlying I h have been discovered about a decade ago (153,192,211,227,228,251,332,333,341,344,400). With reference to their complex dual gating mode (7,93,112), these proteins were termed hyperpolarization-activated cyclic nucleotide-gated (HCN) channels.…”

Functional study of hyperpolarization activated channel (I h ) in Drosophila behavior

“…In Drosophila melanogaster, there is only one I h channel gene [8,9]. Drosophila I h was reported to be strongly expressed in the compound eyes, the second segments and third segments of the antennae [9].…”