MOLECULAR-CLONING, GENOMIC ORGANIZATION AND DEVELOPMENTAL REGULATION OF A NOVEL RECEPTOR FROM DROSOPHILA-MELANOGASTER STRUCTURALLY RELATED TO GONADOTROPIN-RELEASING-HORMONE RECEPTORS FROM VERTEBRATES

After screening the data base of the Berkeley Drosophila Genome Projec t with a sequence coding for the transmembrane region of a G protein-c oupled receptor, we found that Drosophila might contain a gene coding for a receptor that is structurally related to the Gonadotropin-Releas ing Hormone (GnRH) receptors from vertebrates. Using the polymerase ch ain reaction, with Drosophila cDNA as a template, and oligonucleotide probes coding for the presumed exons of this gene, we were able to clo ne the cDNA coding for this receptor. The transmembrane region of the receptor shows 36% amino acid residue identity with the transmembrane region of the catfish and 31% amino acid residue identity with that of the rat GnRH receptor. The Drosophila receptor gene contains six intr ons, whereas the rat gene contains two; one intron in the Drosophila g ene occurs at exactly the same position and has the same intron phasin g as one intron in the rat gene, suggesting that the Drosophila and ma mmalian GnRH receptor genes are evolutionarily related. Northern blot analyses show that the Drosophila receptor gene is progressively expre ssed during larval development with a prominent maximum at the 3rd ins tar larval stage. Pupae contain low amounts of receptor mRNA, while ad ult flies contain higher levels, with males having about five times mo re receptor mRNA than female files. Southern blot analyses show that D rosophila contains only one copy of the receptor gene, which is locate d at position 27A2-B1 of chromosome 2. This paper is the first report on the molecular cloning of a member of the GnRH receptor family from invertebrates. (C) 1998 Academic Press.