Dow J A, Davies S A, Guo Y, Graham S, Finbow M E, Kaiser K
Division of Molecular Genetics, University of Glasgow, UK.
J Exp Biol. 1997 Jan;200(Pt 2):237-45. doi: 10.1242/jeb.200.2.237.
V-ATPases are phylogenetically widespread, highly conserved, multisubunit proton pumps. Originally characterised in endomembranes, they have been found to energise transport across plasma membranes in a range of animal cells and particularly in certain epithelia. While yeast is the model of choice for the rapid generation and identification of V-ATPase mutants, it does not allow their analysis in a plasma membrane context. For such purposes, Drosophila melanogaster is a uniquely suitable model. Accordingly, we have cloned and characterised genes encoding several V-ATPase subunits in D. melanogaster and, using P-element technology, we have succeeded in generating multiple new alleles. Reporter gene constructs reveal ubiquitous expression, but at particularly high levels in those epithelial thought to be energised by V-ATPases, and several of the alleles have lethal recessive phenotypes characterised by epithelial dysfunction. These results, while providing the first gene knockouts of V-ATPases in animals, also illustrate the general utility of D. melanogaster as a model for the genetic analysis of ion transport and its control in epithelia.
V-ATP酶在系统发育上分布广泛、高度保守，是多亚基质子泵。最初在内膜中被鉴定出来，现已发现它们能为一系列动物细胞尤其是某些上皮细胞的质膜转运提供能量。虽然酵母是快速生成和鉴定V-ATP酶突变体的首选模型，但它不适合在质膜环境中对其进行分析。出于此类目的，黑腹果蝇是一个特别合适的模型。因此，我们已经克隆并鉴定了黑腹果蝇中编码几种V-ATP酶亚基的基因，并且利用P因子技术成功产生了多个新的等位基因。报告基因构建体显示出普遍表达，但在那些被认为由V-ATP酶提供能量的上皮细胞中表达水平特别高，并且其中几个等位基因具有以上皮功能障碍为特征的致死隐性表型。这些结果不仅首次实现了动物中V-ATP酶的基因敲除，还说明了黑腹果蝇作为上皮细胞中离子转运及其调控的遗传分析模型的普遍实用性。
