MALVOLIO, THE DROSOPHILA HOMOLOG OF MOUSE NRAMP-1 (BCG), IS EXPRESSEDIN MACROPHAGES AND IN THE NERVOUS-SYSTEM AND IS REQUIRED FOR NORMAL TASTE BEHAVIOR

We report the sequence, expression pattern and mutant phenotype of Mal volio (mvl), the Drosophila homologue of mammalian natural resistance- associated macrophage proteins (NRAMPs), In the mouse, this novel tran sporter is encoded by Beg, a dominant gene that confers natural resist ance to intracellular parasites. mvl was identified in a screen for mu tants that affect taste behaviour. We show that loss-of-function as we ll as insertional mutants in mvl display defects in taste behaviour wi th no alterations in the physiology of the sensory neurons. Activity o f the reporter enzyme beta-galactosidase, that reflects the expression pattern of mvl, is seen in mature sensory neurons and in macrophages, The conceptual translation of the mvl cDNA shows a striking similarit y (65% identity) with human NRAMP with almost complete identity in a c onserved consensus motif found in a number of ATP-coupled transporters , Based on its phenotype and expression pattern as well as its structu ral similarities to NRAMPs and a nitrate transporter in Aspergillus ni dulans, we discuss a possible role for MVL in nitrite/nitrate transpor t and its implications.