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

We report the sequence, expression pattern and mutant phenotype of Malvolio (mvl), the Drosophila homologue of mammalian natural resistance-associated macrophage proteins (NRAMPs), In the mouse, this novel transporter is encoded by Beg, a dominant gene that confers natural resistance to intracellular parasites. mvl was identified in a screen for mutants that affect taste behaviour. We show that loss-of-function as well as insertional mutants in mvl display defects in taste behaviour with no alterations in the physiology of the sensory neurons. Activity of 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 similarity (65% identity) with human NRAMP with almost complete identity in a conserved consensus motif found in a number of ATP-coupled transporters, Based on its phenotype and expression pattern as well as its structural similarities to NRAMPs and a nitrate transporter in Aspergillus nidulans, we discuss a possible role for MVL in nitrite/nitrate transport and its implications.