Onoue S, Suzuki H, Nimura Y, Shimizu Y, Nagino M, Tanaka M, Ozawa T
First Department of Surgery, Nagoya University School of Medicine, Japan.
J Surg Res. 1996 May;62(2):172-8. doi: 10.1006/jsre.1996.0191.
In order to elucidate the mechanism of energy supply for liver regeneration after partial hepatectomy, we investigated mtDNA replication and transcription in regenerating rat liver. Changes of mtDNA-binding proteins, mtDNA, and mitochondrial mRNAs were monitored at 0, 12, 24, 48, 96, and 168 hr after the operation by gel mobility shift assay and Southern and Northern blot analyses, respectively. We focused on mtDNA-binding proteins specific for four different sequence elements possibly involved in regulation of mtDNA replication and transcription. Amounts of all the proteins sharply increased to maximum (4- to 10-fold of the preoperative level) 12 hr after partial hepatectomy and then decreased for 24 hr. After 24 hr, the amount of the respective binding protein changed diversely. Mitochondrial mRNA levels per gram tissue weight were unchanged during the first 12 hr after partial hepatectomy, but dramatically increased to maximum (4-fold) at 24 hr. In contrast, mtDNA content, expressed as a ratio of the nuclear cytochrome c1 gene, was unchanged during the first 48 hr and then started to increase, reaching maximum (1.5-fold) at 4 days. These results suggest that the energy supply in the early stage of the liver regeneration following hepatectomy is achieved mainly through enhancement of mtDNA transcription in which the mtDNA-binding proteins probably play regulatory roles.
为了阐明部分肝切除术后肝脏再生的能量供应机制，我们研究了再生大鼠肝脏中的线粒体DNA（mtDNA）复制和转录情况。分别通过凝胶迁移率变动分析以及Southern和Northern印迹分析，在术后0、12、24、48、96和168小时监测mtDNA结合蛋白、mtDNA和线粒体mRNA的变化。我们重点关注了四种可能参与mtDNA复制和转录调控的不同序列元件所特有的mtDNA结合蛋白。所有蛋白的量在部分肝切除术后12小时急剧增加至最大值（术前水平的4至10倍），然后在24小时内下降。24小时后，各自结合蛋白的量出现不同变化。部分肝切除术后的前12小时，每克组织重量的线粒体mRNA水平未发生变化，但在24小时时急剧增加至最大值（4倍）。相比之下，以核细胞色素c1基因的比例表示的mtDNA含量在最初48小时内未发生变化，然后开始增加，在4天时达到最大值（1.5倍）。这些结果表明，肝切除术后肝脏再生早期的能量供应主要通过增强mtDNA转录来实现，其中mtDNA结合蛋白可能发挥调控作用。
