Splicing of a retained intron within ROMK K+ channel RNA generates a novel set of isoforms in rat kidney
Splicing of a retained intron within ROMK K+ channel RNA generates a novel set of isoforms in rat kidney
复制标题
DOI：
10.1152/ajpcell.1999.276.3.c585
复制
发表时间：
1999-03-01
影响因子：
5.5
通讯作者：
White, SJ
中科院分区：
文献类型：
--
作者：
Beesley, AH;Ortega, B;White, SJ
肾外髓质K+通道（ROMK）家族的K+通道可能构成了远端肾单位K+分泌的主要途径。迄今为止，该基因的四种主要亚型已在大鼠中被鉴定，它们仅在其NH 2末端氨基酸上不同，并且共享一个共同的决定剩余蛋白质序列的“核心外显子”。使用RT-PCR，我们已经确定了一组新的ROMK亚型在大鼠肾脏中产生的ROMK核心序列内的一个区域，可识别为一个典型的哺乳动物内含子的删除。通过检测用ROMK 2基因稳定转染的Madin-Darby犬肾（MDCK）细胞中缺失的ROMK mRNA，证明该剪接事件在体外是可重现的。ROMK 2的缺失变体的翻译在体外被证实，并且在用增强的绿色荧光蛋白标签瞬时转染后在MDCK细胞中可视化。预测在该核心区域中的缺失将产生亲水性蛋白，其大小约为天然ROMK的三分之一并且缺乏跨膜结构域。
The renal outer medulla K+ channel (ROMK) family of K+ channels may constitute a major pathway for K+ secretion in the distal nephron. To date, four main isoforms of this gene have been identified in the rat that differ only in their NH2-terminal amino acids and that share a common "core exon" that determines the remaining protein sequence. Using RT-PCR, we have identified a new set of ROMK isoforms in rat kidney that are generated by the deletion of a region within the ROMK core sequence that is identifiable as a typical mammalian intron. This splicing event was shown to be reproducible in vitro by detection of deleted ROMK mRNA in Madin-Darby canine kidney (MDCK) cells stably transfected with the gene for ROMK2. Translation of the deletion variant of ROMK2 was confirmed in vitro and visualized in MDCK cells following transient transfection with an enhanced green fluorescent protein tag. The deletion in this core region is predicted to generate hydrophilic proteins that are approximately one-third of the size of native ROMK and lack membrane-spanning domains.