In situ hybridization reveals extensive diversity of K+ channel mRNA in isolated ferret cardiac myocytes
In situ hybridization reveals extensive diversity of K+ channel mRNA in isolated ferret cardiac myocytes
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DOI：
10.1161/01.res.78.6.1083
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发表时间：
1996-06-01
影响因子：
20.1
通讯作者：
Strauss, HC
中科院分区：
文献类型：
--
作者：
Brahmajothi, MV;Morales, MJ;Strauss, HC
在心脏中产生复极化的K+电流的分子基础是不确定的。这在一定程度上反映了不同K+通道克隆在异源表达时所表现出的相似功能特性，以及电压门控K+通道家族的分子多样性。为了确定雪貂心脏中表达的电压敏感K+通道mRNA亚基的身份、区域分布和细胞分布，我们使用荧光标记的寡核苷酸探针对酶解分离的窦房结、左右心房、左右心室、房间隔和室间隔的肌细胞进行原位杂交研究。在雪貂心脏中分布最广泛的K+通道转录本是Kv1.5（存在于69.3%至85.6%的测试肌细胞中，取决于分离肌细胞的解剖区域）和Kv1.4(46.1%至93.7%)，其次是Kv1.2、Kv2.1和Kv4.2。令人惊讶的是，许多肌细胞含有Kv1.3、Kv2.2、Kv4.1、Kv5.1和Kv3家族成员的转录本。Kv1.1、Kv1.6和Kv6.1在工作肌细胞中很少表达，而在SA结细胞中更常表达。IRK在心室细胞（84.3% ~ 92.8%）和心房细胞（52.4% ~ 64.0%）中表达，但在SA结细胞中几乎不表达（6.6%）；minK最常在SA结细胞中表达（33.7%），而在工作肌细胞中表达（10.3%至29.3%）。与长qt综合征相关的两个基因产物ERG和KvLQT1在所有解剖区域都很常见（分别为41.1%至58.2%和52.1%至71.8%）。这些结果表明，心脏中K+通道mRNA的多样性比以前所怀疑的要大，并且K+通道的分子基础可能在心脏不同区域和主要解剖区域内的细胞之间有所不同。
The molecular basis of K+ currents that generate repolarization in the heart is uncertain. In part, this reflects the similar functional properties different K+ channel clones display when heterologously expressed, in addition to the molecular diversity of the voltage-gated K+ channel family. To determine the identity, regional distribution, and cellular distribution of voltage-sensitive K+ channel mRNA subunits expressed in ferret heart, we used fluorescent labeled oligonucleotide probes to perform in situ hybridization studies on enzymatically isolated myocytes from the sinoatrial (SA) node, right and left atria, right and left ventricles, and interatrial and interventricular septa. The most widely distributed K+ channel transcripts in the ferret heart were Kv1.5 (present in 69.3% to 85.6% of myocytes tested, depending on the anatomic region from which myocytes were isolated) and Kv1.4 (46.1% to 93.7%), followed by Kv1.2, Kv2.1, and Kv4.2. Surprisingly, many myocytes contain transcripts for Kv1.3, Kv2.2, Kv4.1, Kv5.1, and members of the Kv3 family. Kv1.1, Kv1.6, and Kv6.1, which were rarely expressed in working myocytes, were more commonly expressed in SA nodal cells. IRK was expressed in ventricular (84.3% to 92.8%) and atrial (52.4% to 64.0%) cells but was nearly absent (6.6%) in SA nodal cells; minK was most frequently expressed in SA nodal cells (33.7%) as opposed to working myocytes (10.3% to 29.3%). Two gene products implicated in long-QT syndrome, ERG and KvLQT1, were common in all anatomic regions (41.1% to 58.2% and 52.1% to 71.8%, respectively). These results show that the diversity of K+ channel mRNA in heart is greater than previously suspected and that the molecular basis of K+ channels may vary from cell to cell within distinct regions of the heart and also between major anatomic regions.