bloated tubules (blot) encodes a Drosophila member of the neurotransmittertransporter family required for organisation of the apical cytocortex

We have identified a novel member of the vertebrate sodium- and chloride-de pendent neurotransmitter symporter family from Drosophila melanogaster. Thi s gene, named bloated tubules (blot), shows significant sequence similarity to a subgroup of vertebrate orphan transporters. blot transcripts are mate rnally supplied and during embryogenesis exhibit a complex and dynamic patt ern in a subset of ectodermally derived epithelia, notably in the Malpighia n tubules, and in the nervous system.; Animals mutant for this gene are lar val lethals, in which the Malpighian tubule cells are distended with an enl arged and disorganised apical surface. Embryos lacking the maternal compone nt of blot expression die during early stages of development. They show an inability to form actin filaments in the apical cortex, resulting in impair ed syncytial nuclear divisions, severe defects in the organisation of the c ortical cytoskeleton, and a failure to cellularise. For the first time, a n eurotransmitter transporter-like protein has been implicated in a function outside the nervous system. The isolation of blot thus provides the basis f or an analysis of the relationship between the function of this putative tr ansporter and epithelial morphogenesis. (C) 1999 Academic Press.