Hypertonicity stimulates transcription of gene for Na(+)-myo-inositol cotransporter in MDCK cells.
Hypertonicity stimulates transcription of gene for Na(+)-myo-inositol cotransporter in MDCK cells.
复制标题
高渗性刺激 MDCK 细胞中 Na(+)-肌醇协同转运蛋白基因的转录。
DOI：
10.1152/ajprenal.1993.264.1.f20
复制
发表时间：
1993
期刊：
影响因子：
--
通讯作者：
Handler,JS
中科院分区：
文献类型：
--
作者：
Yamauchi,A;Uchida,S;Preston,AS;Kwon,HM;Handler,JS
肌醇是高渗肾髓质和高渗培养的狗肾(MDCK)细胞中积累的一种主要的亲和性渗透调节物质。肌醇通过Na(+)偶联转运蛋白被MDCK细胞摄取，该转运蛋白的活性在细胞切换到高渗介质后24小时增加6倍。为了探讨高渗对共转运体的调节机制，我们利用我们最近克隆的犬Na(+)-肌醇共转运体的编码基因，测定了该共转运体在渗透压变化后的mRNA丰度及其转录速率。当MDCK细胞从等渗培养转变为高渗培养时，共转运蛋白基因的转录在16h内增加了10倍，转录也增加，16h后达到峰值，约为等渗培养细胞的15倍。当细胞切换回等渗介质时，该基因的mRNA丰度和转录在8h内恢复到等渗水平，转运速率在48h恢复到等渗水平，因此转录似乎是高渗调节肌醇运输的主要步骤。
Myo-inositol is a major compatible osmolyte accumulated in the hypertonic renal medulla and in Madin-Darby canine kidney (MDCK) cells cultured in hypertonic media. Myo-inositol is taken up by MDCK cells on a Na(+)-coupled transporter whose activity increases sixfold 24 h after cells are switched to hypertonic medium. To investigate the mechanism of regulation of the cotransporter by hypertonicity, we used the cDNA encoding the canine Na(+)-myo-inositol cotransporter that we recently cloned to measure the abundance of the mRNA for the cotransporter and its rate of transcription after changes in osmolality. When MDCK cells were switched from isotonic to hypertonic medium, cotransporter mRNA abundance rose 10-fold in 16 h. Transcription of the cotransporter gene also rose and 16 h after the switch reached a peak approximately 15-fold that in isotonic cells. When cells were switched back to isotonic medium, mRNA abundance and transcription of the gene returned to isotonic levels in 8 h and transport rate reached isotonic levels in 48 h. Thus transcription appears to be the primary step in regulation of myo-inositol transport by hypertonicity.