cSlo encodes calcium-activated potassium channels in the chick's cochlea
cSlo encodes calcium-activated potassium channels in the chick's cochlea
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DOI：
10.1098/rspb.1997.0104
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发表时间：
1997-05-22
影响因子：
4.7
通讯作者：
Fuchs, PA
中科院分区：
文献类型：
--
作者：
Jiang, GJ;Zidanic, M;Fuchs, PA
大电导钙激活 (BK) 钾通道在耳蜗毛细胞的兴奋性中发挥着核心作用。在哺乳动物大脑中，一类通道被称为 Slo，由果蝇 Slowpoke' 基因的同源物编码。通过小鼠Slo cDNA同源性筛选，我们从鸡耳蜗cDNA文库中分离得到全长克隆（cSlo1）。 cSlo1 在氨基酸水平上与小鼠 Slo 具有超过 90% 的一致性，并且在氨基和羧基末端与人脑 Slo 匹配得更好。 cSlo1 没有在哺乳动物大脑的剪接变体中发现的额外外显子。使用逆转录酶聚合酶链反应 (RT-PCR) 显示显微解剖的毛细胞上皮（基底乳头）中 cSlo1 的表达。 HEK 293 细胞的瞬时转染表明，cSlo1 编码钾通道，在对称的 140 mM K+ 中，其电导率在 +60 mV 时平均为 224 pS。通过 cSlo1 通道的宏观电流被蝎子毒素或四乙基铵阻断，并且与电压和钙相关。 cSlo1 可能编码耳蜗毛细胞中的 BK 型钙激活钾通道。
Large conductance, calcium-activated (BK) potassium channels play a central role in the excitability of cochlear hair cells. In mammalian brains, one class of these channels, termed Slo, is encoded by homologues of the Drosophila slowpoke' gene. By homology screening with mouse Slo cDNA, we have isolated a full-length clone (cSlo1) from a chick's cochlear cDNA library. cSlo1 had greater than 90% identity with mouse Slo at the amino acid level, and was even better matched to a human brain Slo at the amino and carboxy termini. cSlo1 had none of the additional exons found in splice variants from mammalian brain. The reverse transcriptase polymerase chain reaction (RT-PCR) was used to show expression of cSlo1 in the microdissected hair cell epithelium (basilar papilla). Transient transfection of HEK 293 cells demonstrated that cSlo1 encoded a potassium channel whose conductance averaged 224 pS at +60 mV in symmetrical 140 mM K+. Macroscopic currents through cSlo1 channels were blocked by scorpion toxin or tetraethyl ammonium, and were voltage and calcium dependent. cSlo1 is likely to encode BK-type calcium-activated potassium channels in cochlear hair cells.