Molecular characterization of renal calcium channel beta-subunit transcripts.
Molecular characterization of renal calcium channel beta-subunit transcripts.
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肾钙通道β亚基转录物的分子特征。
DOI：
10.1152/ajprenal.1995.268.3.f525
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发表时间：
1995
期刊：
影响因子：
--
通讯作者：
Lytton,J
中科院分区：
文献类型：
--
作者：
Yu,AS;Boim,M;Hebert,SC;Castellano,A;Perez-Reyes,E;Lytton,J
远端曲管和/或连接小管 (DCT/CNT) 中的顶端激素调节钙进入通道被认为在控制肾钙排泄方面发挥着重要作用。我们之前鉴定了编码钙通道（α1A或CaCh4）的成孔α1亚基的基因转录本，它可能是此类分子的候选者。已知电压依赖性钙通道的特性受其 β 亚基调节。为了鉴定DCT/CNT钙通道的附属β亚基，利用基于已发表的β亚基序列的简并引物，通过聚合酶链式反应(PCR)扩增大鼠肾脏cDNA，并对产物进行亚克隆和测序。鉴定了三个β亚基基因（β2、β3和β4）的选择性剪接转录本。 Northern印迹分析表明β4亚基优先在肾皮质中表达。通过 PCR 在显微解剖的肾单位片段中检测到所有三个 β 亚基基因的转录本，但在 DCT/CNT 中仅发现 β 4 亚基。由于 β 4 和 α 1A 亚基共定位于 DCT/CNT，我们假设它们可能是受激素调节的肾钙通道的组成亚基。
An apical, hormone-regulated, calcium entry channel in the distal convoluted tubule and/or connecting tubule (DCT/CNT) is thought to play an important role in controlling renal calcium excretion. We previously identified a gene transcript encoding the pore-forming alpha 1-subunit of a calcium channel (alpha 1A, or CaCh4) which may be a candidate for such a molecule. The properties of voltage-dependent calcium channels are known to be modulated by their beta-subunits. To identify the accessory beta-subunit of DCT/CNT calcium channels, degenerate primers based on published beta-subunit sequences were used to amplify rat kidney cDNA by the polymerase chain reaction (PCR), and the products were subcloned and sequenced. Alternatively spliced transcripts of three beta-subunit genes (beta 2, beta 3, and beta 4) were identified. Northern blot analysis indicated that beta 4-subunit is preferentially expressed in kidney cortex. Transcripts of all three beta-subunit genes were detected by PCR in microdissected nephron segments, but only beta 4-subunit was found in DCT/CNT. As the beta 4- and alpha 1A-subunits colocalize to the DCT/CNT, we hypothesize that they may be constituent subunits of a renal calcium channel regulated by a hormone(s).