Nuclear HMGA1 nonhistone chromatin proteins directly influence mitochondrial transcription, maintenance, and function
Nuclear HMGA1 nonhistone chromatin proteins directly influence mitochondrial transcription, maintenance, and function
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DOI：
10.1016/j.yexcr.2006.09.014
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发表时间：
2007-01-01
影响因子：
3.7
通讯作者：
Reeves, Raymond
中科院分区：
文献类型：
--
作者：
Dement, Gregory A.;Maloney, Scott C.;Reeves, Raymond
我们先前已经证明HMGA 1蛋白从细胞核易位到线粒体，并在D环控制区与线粒体DNA（mtDNA）结合[G. A. Dement，N.R. Treff，N.S. Magnuson，V. Franceschi，R. Reeves，核转录因子HMGA 1的动态线粒体定位，Exp. 307（2005）388-401.] [11]第10段。为了阐明这种结合可能的生理作用，我们采用了一些方法来分析转基因人MCF-7细胞（HA 7 C）诱导过度表达HA标记的HMGA 1蛋白和对照（亲本）MCF-7细胞中mtDNA转录、线粒体维持和其他细胞器功能。定量实时（RT）PCR分析表明，mtDNA水平降低约2倍，在HMGA 1过表达HA 7 C细胞和流式细胞仪分析进一步揭示，线粒体质量显着减少，在这些细胞。HA 7 C细胞中细胞ATP水平也降低，存活研究显示对2-deOXY-D-葡萄糖（一种糖酵解特异性抑制剂）杀伤的敏感性增加。流式细胞术分析揭示了HA 7 C细胞中与癌性表型一致的另外的线粒体异常：即，增加的活性氧（ROS）和增加的线粒体膜电位（Δ psi（m））。额外的RT-PCR分析表明，来自线粒体DNA重链（ND 2、COXI、ATP 6）和轻链（ND 6）的基因转录本在HA 7 C细胞中上调约3倍。总之，这些线粒体变化与许多先前的报告一致，并揭示了HMGA 1过表达（自然发生的癌症的共同特征）可能影响肿瘤进展的几种可能机制。(c)2006年爱思唯尔公司All rights reserved.
We have previously demonstrated that HMGA1 proteins translocate from the nucleus to mitochondria and bind to mitochondrial DNA (mtDNA) at the D-loop control region [G.A. Dement, N.R. Treff, N.S. Magnuson, V. Franceschi, R. Reeves, Dynamic mitochondrial localization of nuclear transcription factor HMGA1, Exp. Cell Res. 307 (2005) 388-401.] [11]. To elucidate possible physiological roles for such binding, we employed methods to analyze mtDNA transcription, mitochondrial maintenance, and other organelle functions in transgenic human MCF-7 cells (HA7C) induced to over-express an HA-tagged HMGA1 protein and control (parental) MCF-7 cells. Quantitative real-time (RT) PCR analyses demonstrated that mtDNA levels were reduced approximately 2-fold in HMGA1 over-expressing HA7C cells and flow cytometric analyses further revealed that mitochondrial mass was significantly reduced in these cells. Cellular ATP levels were also reduced in HA7C cells and survival studies showed an increased sensitivity to killing by 2-deOXY-D-glucose, a glycolysis-specific inhibitor. Flow cytometric analyses revealed additional mitochondrial abnormalities in HA7C cells that are consistent with a cancerous phenotype: namely, increased reactive oxygen species (ROS) and increased mitochondrial membrane potential (Delta psi(m)). Additional RT-PCR analyses demonstrated that gene transcripts from both the heavy (ND2, COXI, ATP6) and light (ND6) strands of mtDNA were up-regulated approximately 3-fold in HA7C cells. Together, these mitochondrial changes are consistent with many previous reports and reveal several possible mechanisms by which HMGA1 over-expression, a common feature of naturally occurring cancers, may affect tumor progression. (c) 2006 Elsevier Inc. All rights reserved.