Matsuoka M, Wispriyono B, Igisu H
Department of Environmental Toxicology, University of Occupational and Environmental Health, Kitakyyushu, Japan.
Chem Biol Interact. 1997 Dec 12;108(1-2):95-106. doi: 10.1016/s0009-2797(97)00097-5.
The c-fos, a member of the immediate early genes, has been reported to be expressed in the renal proximal tubule in response to ischemic and toxic injury. In the present study, effects of mercury chloride (HgCl2) on the expression of c-fos were examined in LLC-PK1 cells. The reverse transcription polymerase chain reaction (RT-PCR) analysis for the semi-quantification of mRNA showed that the treatment of 20 microM HgCl2, markedly increased c-fos mRNA levels. The level of c-fos mRNA began to increase after a 30-min exposure, peaked at 1 h and then returned to the control level at 8 h. The HgCl2-induced c-fos expression was abolished completely by actinomycin-D, indicating it was due to transcriptional activation of the gene. Western blotting immunodetection revealed accumulation of c-Fos protein after 1 h exposure to 20 microM HgCl2. The cytotoxicity of HgCl2 as assayed by mitochondrial dehydrogenase activity (MTT conversion) was observed after 18 h exposure but not at 0.5-8 h. Also, the decrease in cell viability was accompanied with DNA fragmentation, which is characteristic of apoptosis. The present results showed that HgCl2 could induce the early expression of c-fos gene in a renal epithelial cell line.
即刻早期基因的成员之一c-fos，据报道在肾近端小管中因缺血和毒性损伤而表达。在本研究中，检测了氯化汞（HgCl2）对LLC-PK1细胞中c-fos表达的影响。用于mRNA半定量的逆转录聚合酶链反应（RT-PCR）分析表明，20微摩尔HgCl2处理显著增加了c-fos mRNA水平。c-fos mRNA水平在暴露30分钟后开始升高，1小时达到峰值，然后在8小时回到对照水平。放线菌素-D完全消除了HgCl2诱导的c-fos表达，表明这是由于该基因的转录激活。蛋白质免疫印迹检测显示，暴露于20微摩尔HgCl2 1小时后c-Fos蛋白积累。暴露18小时后观察到HgCl2的细胞毒性（通过线粒体脱氢酶活性测定，MTT转化），但在0.5 - 8小时未观察到。此外，细胞活力的降低伴随着DNA片段化，这是凋亡的特征。目前的结果表明，HgCl2可诱导肾上皮细胞系中c-fos基因的早期表达。
