Molecular cloning and characterization of novel tissue-specific isoforms of the human vacuolar H⁺-ATPase C, G and d subunits, and their evaluation in autosomal recessive distal renal tubula

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• 作者：Smith ; Annabel N. ; Borthwick¹ ; Katherine J. ; Karet ; Fiona E.
• 关键词：Vacuolar-type proton-translocating ATPase ; Proton pump ; Kidney ; Distal renal tubular acidosis ; BAC ; bacterial artificial chromosome ; bp ; base pair(s) ; cDNA ; DNA complementary to RNA ; dRTA ; distal renal tubular acidosis ; EST ; expressed sequence tag ; kb ; ki
• 刊名：Gene
• 出版年：2002
• 出版时间：September 4, 2002
• 年：2002
• 卷：297
• 期：1-2
• 页码：169-177
• 全文大小：519 K

文摘

Several of the 13 subunits comprising mammalian H⁺-ATPases have multiple isoforms, encoded by separate genes and with differing tissue expression patterns, which may play an important role in the intracellular localization and activity of H⁺-ATPases. Here we report the cloning of three previously uncharacterized human genes, ATP6V1C2, ATP6V1G3 and ATP6V0D2, encoding novel H⁺-ATPase subunit isoforms C2, G3 and d2, respectively. We demonstrate that these novel genes are expressed in kidney and few other tissues, and confirm previous reports that the C1, G1 and d1 isoforms are ubiquitously expressed, while G2 is brain-specific. Previously we have shown that mutations in two kidney-specific genes, ATP6V1B1 and ATP6V0A4, encoding the H⁺-ATPase B1 and a4 subunit isoforms, cause recessive distal renal tubular acidosis (dRTA). As the genes reported here are expressed mainly in kidney, we assessed their candidacy as causative genes for recessive dRTA in eight kindreds unlinked to either known disease locus. Although no potential disease-causing mutations were seen in this cohort, this does not rule out a role for these genes in other families. The identification of these three novel tissue-specific isoforms supports the hypothesis that subunit differences may play a key role in the structure, site and function of H⁺-ATPases within the cell.