| Budget Amount *help |
¥6,600,000 (Direct Cost: ¥6,600,000)
Fiscal Year 1993: ¥1,500,000 (Direct Cost: ¥1,500,000)
Fiscal Year 1992: ¥5,100,000 (Direct Cost: ¥5,100,000)
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| Research Abstract |
In this study, we realized that Mt element-binding protenis (MtEBPs) with the samne recognition capability are present in the nuclei and mitochondrial of human, bovine, and rat cells, possibly and mitochondria with Mt element-specific DNA affinity chromatography contained 4 different polypeptides, respectivey. A UV-induced DNA cross-linking study showed that 47- ir 55-kDa of the nuclear MtEBP recongnizes Mt element in the 5'-flanking region of the human cytochrome cl gene and that 140- and 180-kDa polypeptides of the mitochondrial MtEBP do Mt elements in the human mitochondrial promoter region. Mitochondrial MtEBP recognized a sequence homologous to Mt4 element within the mitochondrial transcription factor-1 binding site for the heavy-strand promoter but not for the light-stand promoter. These results suggest a MtEBP-mediated coordination mechanism between nuclear and mitochondrial genetic systems.
We demonstrated the presence of four different rat and human mitochondrial D-loop-binding
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proteins each of which is specific for a DNA fragment containing an inter-specifically conserved sequence ; TAS, Mt5, B block, and a A+T-rich sequence overlapping the conserved sequence block II.UV-induced DNA crosslinking visualized mtDNA-binding protein as a new one.
We investigated the mitochondrial DNA replication and transcription in regenerating rat liver induced by partial hepatectomy (PH) or portal branch ligation (PBL). Amounts of all the mtDNA-binding proteins tested sharply increased maximum (4 to 10-fold of the preoperative level) 12 h after the operation. Mitochondrial mRNA levels dramatically increased maximum (2 to 4-fold) after 24 h. In the PH-induced liver regeneration, mtDNA content was slightly reduced to 80% of the preoperative level during the first 48 h, while in the liver regeneration induced by PBL, mtDNA content increased maximum (3.9-fold) at 24 h. These sequential alterations suggest that the energy supply in the early stage of the liver regeneration is achieved through enhancement of the mtDNA replication and/or transcription in which the mtDNA-binding proteins probably play regulatory roles. Less
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