Molecular characterization and nephron distribution of a family of transcripts encoding the pore-forming subunit of Ca2+ channels in the kidney.
Molecular characterization and nephron distribution of a family of transcripts encoding the pore-forming subunit of Ca2+ channels in the kidney.
复制标题
编码肾脏 Ca2 通道成孔亚基的转录本家族的分子特征和肾单位分布。
DOI：
10.1073/pnas.89.21.10494
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发表时间：
1992
影响因子：
11.1
通讯作者：
Lytton,J
中科院分区：
文献类型：
--
作者：
Yu,AS;Hebert,SC;Brenner,BM;Lytton,J
肾脏活性的跨上皮钙重吸收主要发生在远曲小管。最近的证据表明，钙离子通过与电压依赖性L型钙离子通道相似的通道进入顶膜可能是钙离子重吸收的速率决定步骤。为了确定肾脏电压依赖性钙通道(S)成孔亚单位的分子同源性，采用了基于同源性的聚合酶链式反应克隆策略。根据已发表的电压依赖性钙通道α1亚单位的保守序列设计非简并引物，从大鼠肾脏中扩增出c DNA，并对扩增产物进行亚克隆和测序。鉴定了一个分子物种家族，代表了编码这些通道亚基的四个已知基因的选择性剪接转录本。Northern杂交分析表明，这些基因在肾脏中的表达呈现出不同的空间分布。一个基因CaCH4主要在皮质表达，通过显微切割小管发现，聚合酶链式反应主要在远曲小管中被发现，这与该位置跨上皮细胞重吸收钙的作用一致。
Active, transepithelial, Ca2+ reabsorption in kidney occurs primarily in the distal convoluted tubule. Recent evidence suggests that entry of Ca2+ at the apical membrane through channels bearing resemblance to those of the voltage-dependent L type may be the rate-determining step in Ca2+ reabsorption. To determine the molecular identity of the pore-forming subunit of voltage-dependent Ca2+ channel(s) in the kidney, a homology-based PCR cloning strategy was employed. Nondegenerate primers, based on conserved regions of the published cDNA sequences of voltage-dependent Ca2+ channel alpha 1 subunits, were used to amplify cDNA from rat kidney, and the products were subcloned and sequenced. A family of molecular species was identified, representing alternatively spliced transcripts of four known genes encoding these channel subunits. Northern blot analysis indicated that the expression of each of the genes exhibits a distinct spatial distribution within the kidney. One gene, CaCh4, is expressed primarily in the cortex, and by microdissected-tubule PCR was found predominantly in the distal convoluted tubule, consistent with a role in transepithelial Ca2+ reabsorption at this site.