【摘要】 TFAR19基因 (TF 1cellapoptosisrelatedgene 19)是北京大学人类疾病基因中心从人白血病细胞株TF 1细胞中克隆到的凋亡相关新基因之一 (GenBank登记号AF0 1495 5 )。初步研究发现 ,该基因在细胞凋亡时高表达 ,并且表达产物具有抑制肿瘤细胞生长和促进凋亡作用。但是其确切的作用机制不明。线粒体膜完整性破坏所导致促凋亡因子 (如细胞色素c等因子 )的释放是细胞凋亡关键性的控制因素。线粒体膜通透性转运孔 (PTP) ,对线粒体膜完整性具有重要的调控作用。研究了重组人TFAR19蛋白在体外条件下 ,对线粒体PTP、跨膜电位 ,以及细胞色素c释放的影响。结果表明 ,TFAR19蛋白使分离的小鼠肝线粒体PTP开放、线粒体跨膜电位下降 ,以及细胞色素c释放。TFAR19对线粒体的上述作用是通过促进PTP开放起作用的。实验结果提示 ,TFAR19对线粒体凋亡信号有正反馈放大作用 ,并进一步揭示了TFAR19促进细胞凋亡的机制更多还原

【Abstract】 TFAR19(TF-1 cell apoptosis related gene 19)is a novel apoptosis-related gene cloned from human leukemia cell line TF-1 cells undergoing apoptosis in 1999 (accession number AF014955 in GenBank). The human TFAR19 encodes a protein which shares significant homology to the corresponding proteins of species ranging from yeast to mice. TFAR19 exhibits a ubiquitous expression pattern and its expression is upregulated in tumor cells undergoing apoptosis. Overexpression of TFAR19 could enhance apoptosis of some tumor cells induced by growth factor withdrawal or serum deprivation. But the exact mechanism of TFAR19 is unclear. Mitochondria not only provides energy for the cell, but also plays a critical role on cell death or survival. The release of apoptosis promoting factor, such as cytochrome c from mitochondria, resulted by the damage of mitochondrial membrane integrity, is the key factor controlling apoptosis. The permeability transition pore (PTP) of mitochondria is a protein complex located between the mitochondrial membranes, and it plays an important role in regulating the integrity of mitochondrial membrane. In this study, the effect of recombinant TFAR19 on isolated mitochondrial PTP, membrane potential, and release of cytochrome c was investigated in vitro. The results indicated that recombinant TFAR19 facilitated the isolated mitochondrial PTP opening, decreased the membrane potential, and promoted the release of cytochrome c. The effect of TFAR19 on mitochondria is implemented by opening the mitochondrial PTP. Experimental results implicate that TFAR19 may positively feedback apoptosis signal of mitochondria, forming a positive loop to promote apoptosis.更多还原