Diversity of Ca2+-activated K+ channel transcripts in inner ear hair cells
Diversity of Ca2+-activated K+ channel transcripts in inner ear hair cells
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DOI：
10.1016/j.gene.2006.07.023
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发表时间：
2007-01-15
期刊：
影响因子：
3.5
通讯作者：
Davis, Robin L.
中科院分区：
文献类型：
--
作者：
Beisel, Kirk W.;Rocha-Sanchez, Sonia M.;Davis, Robin L.
毛细胞表达离子通道的补充，代表共享的和不同的通道，赋予每个细胞不同的电生理特征。这种多样性是通过在α亚基中使用选择性剪接、形成异四通道以及与β亚基的组合缔合而产生的。这些通道被认为在哺乳动物耳蜗中观察到的音调梯度中发挥作用。对小鼠Kcnma 1转录本、5'和3' EST以及基因组序列进行了检查，以确定小鼠转录组中可变剪接的利用率。比较基因组分析研究了KCNMA 1剪接位点的保守性。小鼠、大鼠、人、负鼠、鸡、青蛙和斑马鱼的基因组证实了KCNMA 1的外显子-内含子结构和选择性剪接机制是高度保守的，利用了6-7个剪接位点。鼠Kcnma 1利用了7个潜在剪接位点中的6个。使用鼠基因特异性寡核苷酸引物的RT-PCR实验分析了耳蜗和内耳毛细胞中Kcnma 1和Kcnmb 1 -4表达谱的范围和多样性。在耳蜗中，存在代表位点3、4、6和7的剪接变体，而位点I较少插入，位点2仅利用外显子10。但是，5号站点不存在。KCNMA 1转录本和蛋白质的检测表现出定量的纵向梯度与倒数梯度之间的内毛细胞和外毛细胞。在使用长形式的羧基末端尾中也观察到差异表达。这些结果表明，剪接变体的多样性存在于啮齿动物耳蜗毛细胞，这种多样性是类似于观察到的非哺乳动物脊椎动物毛细胞，如鸡和龟。(c)2006 Elsevier B. V.保留所有权利。
Hair cells express a complement of ion channels, representing shared and distinct channels that confer distinct electrophysiological signatures for each cell. This diversity is generated by the use of alternative splicing in the a subunit, formation of heterotetraineric channels, and combinatorial association with beta subunits. These channels are thought to play a role in the tonotopic gradient observed in the mammalian cochlea. Mouse Kcnma1 transcripts, 5' and 3' ESTs, and genomic sequences were examined for the utilization of alternative splicing in the mouse transcriptome. Comparative genomic analyses investigated the conservation of KCNMA1 splice sites. Genomes of mouse, rat, human, opossum, chicken, frog and zebrafish established that the exon-intron structure and mechanism of KCNMA1 alternative splicing were highly conserved with 6-7 splice sites being utilized. The murine Kcnma1 utilized 6 out of 7 potential splice sites. RT-PCR experiments using murine gene-specific oligonucleotide primers analyzed the scope and variety of Kcnma1 and Kcnmb1-4 expression profiles in the cochlea and inner ear hair cells. In the cochlea splice variants were present representing sites 3, 4, 6, and 7, while site I was insertion less and site 2 utilized only exon 10. However, site 5 was not present. Detection of KCNMA1 transcripts and protein exhibited a quantitative longitudinal gradient with a reciprocal gradient found between inner and outer hair cells. Differential expression was also observed in the usage of the long form of the carboxy-terminus tail. These results suggest that a diversity of splice variants exist in rodent cochlear hair cells and this diversity is similar to that observed for non-mammalian vertebrate hair cells, such as chicken and turtle. (c) 2006 Elsevier B.V. All rights reserved.