Properties of a nonjunctional current expressed from a rat connexin46 cDNA in Xenopus oocytes.
Properties of a nonjunctional current expressed from a rat connexin46 cDNA in Xenopus oocytes.
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DOI：
10.1085/jgp.102.1.59
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发表时间：
1993-07
影响因子：
3.8
通讯作者：
Steiner, E
中科院分区：
文献类型：
--
作者：
Ebihara, L;Steiner, E
连接蛋白46（connexin 46，cxn 46）是从大鼠透镜cDNA文库中克隆到的一种缝隙连接蛋白。孤爪蟾卵母细胞中cxn 46的表达导致了一个大的时间和电压依赖性电流的发展，这是没有观察到在noninjected控制卵母细胞或在卵母细胞注射cxn 43或cxn 32的mRNA。cxn 46诱导的电流在电位为正至-20 mV时激活。复极化至-40 mV时，电流在几秒钟内失活。去除外部钙引起的cxn 46诱导电流的幅度显着增加，移动的稳态激活曲线更负的电位，并改变激活和失活的动力学。增加外部钙有相反的效果。在卵母细胞对系统中测试cxn 46诱导细胞间通道形成的能力。卵母细胞对注射cxn 46 mRNA +爪蟾cxn 38反义寡核苷酸强烈耦合。相反，单独注射反义核酸的卵母细胞对没有显示偶联。差距连接通道的失活动力学与孤卵母细胞中cxn 46诱导电流的失活动力学相似。
Connexin46 (cxn46) is a gap junctional protein that was cloned from a rat lens cDNA library. Expression of cxn46 in solitary Xenopus oocytes resulted in the development of a large time- and voltage-dependent current that was not observed in noninjected control oocytes or in oocytes injected with mRNA for cxn43 or cxn32. The cxn46-induced current activated at potentials positive to -20 mV. On repolarization to -40 mV, the current deactivated over a period of several seconds. Removal of external calcium caused a marked increase in the amplitude of the cxn46-induced current, shifted the steady-state activation curve to more negative potentials, and altered the kinetics of activation and deactivation. Increasing external calcium had the opposite effect. The ability of cxn46 to induce the formation of cell-to-cell channels was tested in the oocyte pair system. Oocyte pairs injected with cxn46 mRNA + antisense oligonucleotides for Xenopus cxn38 were strongly coupled. In contrast, oocyte pairs injected with antisense alone showed no coupling. The inactivation kinetics of the gap junctional channels resembled the deactivation kinetics of the cxn46-induced current in solitary oocytes.