Johnson K, Knust E, Skaer H
Department of Zoology, University of Cambridge, Downing Street, Cambridge, CB2 3EJ, United Kingdom.
Dev Biol. 1999 Aug 15;212(2):440-54. doi: 10.1006/dbio.1999.9351.
We have identified a novel member of the vertebrate sodium- and chloride-dependent neurotransmitter symporter family from Drosophila melanogaster. This gene, named bloated tubules (blot), shows significant sequence similarity to a subgroup of vertebrate orphan transporters. blot transcripts are maternally supplied and during embryogenesis exhibit a complex and dynamic pattern in a subset of ectodermally derived epithelia, notably in the Malpighian tubules, and in the nervous system. Animals mutant for this gene are larval lethals, in which the Malpighian tubule cells are distended with an enlarged and disorganised apical surface. Embryos lacking the maternal component of blot expression die during early stages of development. They show an inability to form actin filaments in the apical cortex, resulting in impaired syncytial nuclear divisions, severe defects in the organisation of the cortical cytoskeleton, and a failure to cellularise. For the first time, a neurotransmitter transporter-like protein has been implicated in a function outside the nervous system. The isolation of blot thus provides the basis for an analysis of the relationship between the function of this putative transporter and epithelial morphogenesis.
我们从黑腹果蝇中鉴定出脊椎动物钠和氯依赖性神经递质转运体家族的一个新成员。这个名为肿胀小管（blot）的基因与脊椎动物孤儿转运体的一个亚组具有显著的序列相似性。blot转录本由母体提供，在胚胎发育过程中，在外胚层来源的上皮细胞亚群中呈现出复杂而动态的模式，特别是在马氏小管和神经系统中。该基因的突变动物在幼虫期致死，其中马氏小管细胞因顶端表面扩大和无序而膨胀。缺乏blot表达母体成分的胚胎在发育早期死亡。它们表现出无法在顶端皮质形成肌动蛋白丝，导致合胞体核分裂受损、皮质细胞骨架组织严重缺陷以及无法细胞化。首次发现一种神经递质转运体样蛋白与神经系统外的功能有关。因此，blot的分离为分析这种假定转运体的功能与上皮形态发生之间的关系提供了基础。
