Dow J A, Goodwin S F, Kaiser K
Department of Cell Biology, University of Glasgow, UK.
Gene. 1992 Dec 15;122(2):355-60. doi: 10.1016/0378-1119(92)90226-f.
Vacuolar ATPases (V-ATPases), originally characterised as components of endomembranes, have also been implicated in epithelial ion transport, both in vertebrates and in insects. The ATPase is particularly noteworthy in lepidopteran larvae, where it generates large transepithelial potential differences and short-circuit currents across the midgut epithelium. A cDNA library from Manduca sexta larval midguts and Malpighian tubules was screened with a Drosophila melanogaster cDNA encoding the 16-kDa proteolipid subunit of the V-ATPase, and a 1.4-kb cDNA sequenced in its entirety. The sequence contains a long open reading frame, encoding a putative peptide of 156 amino acids (aa) and with an M(r) of 15,967, in close agreement with values previously suggested by sodium dodecyl sulfate-polyacrylamide gels of M. sexta midgut proteins. Correspondence of the deduced aa sequence with those of other species, particularly D. melanogaster, was extremely close. Northern blots of M. sexta midgut mRNA at high stringency revealed two transcripts of 1.4 and 1.9 kb, whereas genomic Southern blots suggest that there is only a single copy of the gene in M. sexta. The possibility that members of the 16-kDa gene family might serve multiple roles in transport and membrane communication is discussed.
液泡型ATP酶（V-ATP酶）最初被鉴定为内膜的组成成分，在脊椎动物和昆虫的上皮离子运输中也发挥作用。这种ATP酶在鳞翅目幼虫中尤为值得关注，它能在中肠上皮细胞间产生较大的跨上皮电位差和短路电流。用编码V-ATP酶16-kDa蛋白脂质亚基的黑腹果蝇cDNA筛选烟草天蛾幼虫中肠和马氏管的cDNA文库，并对一个1.4-kb的cDNA进行了全序列测定。该序列包含一个长开放阅读框，编码一个推定的156个氨基酸（aa）的肽段，分子量为15,967，与先前通过烟草天蛾中肠蛋白十二烷基硫酸钠-聚丙烯酰胺凝胶电泳得出的值非常一致。推导的氨基酸序列与其他物种，特别是黑腹果蝇的氨基酸序列极为相似。高严谨度下烟草天蛾中肠mRNA的Northern印迹显示有1.4 kb和1.9 kb两种转录本，而基因组Southern印迹表明烟草天蛾中该基因只有一个拷贝。文中讨论了16-kDa基因家族成员可能在运输和膜通讯中发挥多种作用的可能性。
