Structure and developmental expression of the D alpha 2 gene encoding a novel nicotinic acetylcholine receptor protein of Drosophila melanogaster

Nicotinic acetylcholine receptors (nAChRs) represent a heterogeneous group of excitatory neurotransmitter receptors in the insect brain. We have characterized the D alpha 2 gene of Drosophila melanogaster, a new member of the nAChR gene family. The protein coding region is interrupted by six introns. The positions of three of these introns are shared with all other nAChR genes. The deduced D alpha 2 protein shows the structural features of ligand-binding nAChR alpha-subunits. Cytogenetically, the D alpha 2 gene maps at position 96A of the 3rd chromosome, close to the ALS gene which also encodes an alpha-like nAChR subunit. D alpha 2 transcripts are predominantly expressed in late embryos and in fly heads.