MOLECULAR CHARACTERIZATION OF THE CINNABAR REGION OF DROSOPHILA-MELANOGASTER - IDENTIFICATION OF THE CINNABAR TRANSCRIPTION UNIT

Early studies of eye pigmentation in Drosophila melanogaster provided compelling evidence that the cinnabar ten) gene encodes the enzyme kyn urenine 3-monooxygenase (EC 1.14.13.9). Here we report the cloning of approximately 60 kb of DNA encompassing the cn gene by chromosome walk ing in the 43E6-F1 region of chromosome 2. An indication of the positi on of cn within the cloned region was obtained by molecular analysis o f mutants: 9 spontaneous cn mutants were found to have either DNA inse rtions or deletions within a 5 kb region. In addition, a 7.8 kb restri ction fragment encompassing the region altered in the mutants was obse rved to induce transient cn function when microinjected into cn(-) emb ryos. The cn transcription unit was identified by Northern blotting an d sequence analysis of cDNA and genomic clones from this region. The p redicted cn protein contains several sequence motifs common to aromati c monooxygenases and is consistent with the assignment of cn as encodi ng the structural gene for kynurenine 3-monooxygenase.