MOLECULAR-CLONING, GENOMIC ORGANIZATION, AND DEVELOPMENTAL REGULATIONOF A NOVEL RECEPTOR FROM DROSOPHILA-MELANOGASTER STRUCTURALLY RELATEDTO MEMBERS OF THE THYROID-STIMULATING HORMONE, FOLLICLE-STIMULATING-HORMONE, LUTEINIZING-HORMONE CHORIOGONADOTROPIN RECEPTOR FAMILY FROM MAMMALS

Using oligonucleotide probes derived from consensus sequences for glyc oprotein hormone receptors, we have cloned an 831-amino acid residue-l ong receptor from Drosophila melanogaster that shows a striking struct ural homology with members of the glycoprotein hormone (thyroid-stimul ating hormone (TSH); follicle-stimulating hormone (FSH); luteinizing h ormone/choriogonadotropin (LH/CG)) receptor family from mammals. This homology includes a very large, extracellular N terminus (20% sequence identity with rat TSH, 19% with rat FSH, and 20% with the rat LH/CG r eceptor) and a seven transmembrane region (53% sequence identity with rat TSH, 50% with rat FSH, and 52% with the rat LH/CG receptor). The D rosophila receptor gene is >7.5 kilobase pairs long and contains 17 ex ons and 16 introns. Seven intron positions coincide with introns in th e mammalian glycoprotein hormone receptor genes and have the same intr on phasing. This indicates that the Drosophila receptor is evolutionar ily related to the mammalian receptors. The Drosophila receptor gene i s located at position 90C on the right arm of the third chromosome. Th e receptor is strongly expressed starting 8-16 h after oviposition, an d the expression stays high until after pupation. Adult male flies exp ress high levels of receptor mRNA, but female flies express about 6 ti mes less. The expression pattern in embryos and larvae suggests that t he receptor is involved in insect development. This is the first repor t on the molecular cloning of a glycoprotein hormone receptor family m ember from insects.