1
|
Asong-Fontem N, Panisello-Rosello A, Beghdadi N, Lopez A, Rosello-Catafau J, Adam R. Pre-Ischemic Hypothermic Oxygenated Perfusion Alleviates Protective Molecular Markers of Ischemia-Reperfusion Injury in Rat Liver. Transplant Proc 2022; 54:1954-1969. [PMID: 35961798 DOI: 10.1016/j.transproceed.2022.05.026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2021] [Revised: 04/26/2022] [Accepted: 05/22/2022] [Indexed: 11/16/2022]
Abstract
To expand the pool of organs, hypothermic oxygenated perfusion (HOPE), one of the most promising perfusion protocols, is currently performed after cold storage (CS) at transplant centers (HOPE-END). We investigated a new timing for HOPE, hypothesizing that performing HOPE before CS (HOPE-PRE) could boost mitochondrial protection allowing the graft to better cope with the accumulation of oxidative stress during CS. We analyzed liver injuries at 3 different levels. Histologic analysis demonstrated that, compared to classical CS (CTRL), the HOPE-PRE group showed significantly less ischemic necrosis compared to CTRL vs HOPE-END. From a biochemical standpoint, transaminases were lower after 2 hours of reperfusion in the CTRL vs HOPE-PRE group, which marked decreased liver injury. qPCR analysis on 37 genes involved in ischemia-reperfusion injury revealed protection in HOPE-PRE and HOPE-END compared to CTRL mediated through similar pathways. However, the CTRL vs HOPE-PRE group demonstrated an increased transcriptional level for protective genes compared to the CTRL vs HOPE-END group. This study provides insights on novel biomarkers that could be used in the clinic to better characterize graft quality improving transplantation outcomes.
Collapse
Affiliation(s)
- Njikem Asong-Fontem
- Université Paris-Saclay, Faculté de Médecine, Unité Chronothérapie, Cancers et Transplantation, Kremlin-Bicêtre, France.
| | - Arnau Panisello-Rosello
- Experimental Hepatic Ischemia-Reperfusion Unit, Institut d'Investigacions Biomèdiques de Barcelona (IIBB), Spanish National Research Council (CSIC), Barcelona, Catalonia, Spain
| | - Nassiba Beghdadi
- Université Paris-Saclay, Faculté de Médecine, Unité Chronothérapie, Cancers et Transplantation, Kremlin-Bicêtre, France; Center Hépato-Biliaire, APHP Hôpital Universitaire Paul Brousse, Villejuif, France
| | - Alexandre Lopez
- Université Paris-Saclay, Faculté de Médecine, Unité Chronothérapie, Cancers et Transplantation, Kremlin-Bicêtre, France
| | - Joan Rosello-Catafau
- Experimental Hepatic Ischemia-Reperfusion Unit, Institut d'Investigacions Biomèdiques de Barcelona (IIBB), Spanish National Research Council (CSIC), Barcelona, Catalonia, Spain
| | - René Adam
- Université Paris-Saclay, Faculté de Médecine, Unité Chronothérapie, Cancers et Transplantation, Kremlin-Bicêtre, France; Center Hépato-Biliaire, APHP Hôpital Universitaire Paul Brousse, Villejuif, France
| |
Collapse
|
2
|
Qi W, Li Z, Xia L, Dai J, Zhang Q, Wu C, Xu S. LncRNA GABPB1-AS1 and GABPB1 regulate oxidative stress during erastin-induced ferroptosis in HepG2 hepatocellular carcinoma cells. Sci Rep 2019; 9:16185. [PMID: 31700067 PMCID: PMC6838315 DOI: 10.1038/s41598-019-52837-8] [Citation(s) in RCA: 138] [Impact Index Per Article: 27.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2018] [Accepted: 10/23/2019] [Indexed: 02/06/2023] Open
Abstract
Ferroptosis is a non-apoptotic, iron-dependent oxidative form of cell death that is specifically induced by erastin in RAS mutant cancer cells. Ferroptotic cell death is the result of membrane lipid peroxide damage caused by the accumulation of hydroxyl radicals derived from H2O2 by the Fenton reaction. Peroxidases are key cellular antioxidant enzymes that block such damaging processes. Few studies have examined the roles of long non-coding RNAs (lncRNAs) in the regulation of cellular oxidative stress, especially in ferroptosis. Here, we demonstrated that erastin upregulated the lncRNA GABPB1-AS1, which downregulated GABPB1 protein levels by blocking GABPB1 translation, leading to the downregulation of the gene encoding Peroxiredoxin-5 (PRDX5) peroxidase and the eventual suppression of the cellular antioxidant capacity. Such effects critically inhibited the cellular antioxidant capacity and cell viability. Additionally, high expression levels of GABPB1 were correlated with poor prognosis of hepatocellular carcinoma (HCC) Patients, while high GABPB1-AS1 levels in HCC patients correlated with improved overall survival. Collectively, these data demonstrate a mechanistic link between GABPB1 and its antisense lncRNA GABPB1-AS1 in erastin-induced ferroptosis and establish GABPB1 and GABPB1-AS1 as attractive therapeutic targets for HCC.
Collapse
Affiliation(s)
- Wenchuan Qi
- Key Laboratory of Bio-Resource and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, 610065, Chengdu, Sichuan, P.R. China
| | - Zhenhua Li
- Affiliated Hospital of Changchun University of Traditional Chinese Medicine, 130117, Changchun, Jilin, P.R. China
| | - Longjiang Xia
- Chengdu University of Traditional Chinese Medicine, 611130, Chengdu, Sichuan, P.R. China
| | - Jiangshan Dai
- Key Laboratory of Bio-Resource and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, 610065, Chengdu, Sichuan, P.R. China
| | - Qiao Zhang
- China-Japan Union Hospital of Jilin University, 130033, Changchun, Jilin, P.R. China
| | - Chuanfang Wu
- Key Laboratory of Bio-Resource and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, 610065, Chengdu, Sichuan, P.R. China
| | - Si Xu
- Key Laboratory of Bio-Resource and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, 610065, Chengdu, Sichuan, P.R. China.
- Sichuan Academy of Medical Sciences and Sichuan Provincial People's Hospital, 610072, Chengdu, Sichuan, P.R. China.
| |
Collapse
|
3
|
Hwang HJ, Lynn SG, Vengellur A, Saini Y, Grier EA, Ferguson-Miller SM, LaPres JJ. Hypoxia Inducible Factors Modulate Mitochondrial Oxygen Consumption and Transcriptional Regulation of Nuclear-Encoded Electron Transport Chain Genes. Biochemistry 2015; 54:3739-48. [PMID: 26030260 PMCID: PMC5957085 DOI: 10.1021/bi5012892] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Hypoxia inducible factor-1 (HIF1) is a stress-responsive nuclear transcription factor that is activated with a decrease in oxygen availability. HIF1 regulates the expression of genes involved in a cell's adaptation to hypoxic stress, including those with mitochondrial specific function. To gain a more comprehensive understanding of the role of HIF1 in mitochondrial homeostasis, we studied the link between hypoxia, HIF1 transactivation, and electron transport chain (ETC) function. We established immortalized mouse embryonic fibroblasts (MEFs) for HIF1α wild-type (WT) and null cells and tested whether HIF1α regulates mitochondrial respiration by modulating gene expressions of nuclear-encoded ETC components. High-throughput quantitative real-time polymerase chain reaction was performed to screen nuclear-encoded mitochondrial genes related to the ETC to identify those whose regulation was HIF1α-dependent. Our data suggest that HIF1α regulates transcription of cytochrome c oxidase (CcO) heart/muscle isoform 7a1 (Cox7a1) under hypoxia, where it is induced 1.5-2.5-fold, whereas Cox4i2 hypoxic induction was HIF1α-independent. We propose that adaptation to hypoxic stress of CcO as the main cellular oxygen consumer is mediated by induction of hypoxia-sensitive tissue-specific isoforms. We suggest that HIF1 plays a central role in maintaining homeostasis in cellular respiration during hypoxic stress via regulation of CcO activity.
Collapse
Affiliation(s)
- Hye Jin Hwang
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan 48824-1319, United States
- Center for Mitochondrial Science and Medicine, Michigan State University, East Lansing, Michigan 48824-1319, United States
| | - Scott G. Lynn
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan 48824-1319, United States
- Center for Integrative Toxicology, Michigan State University, East Lansing, Michigan 48824-1319, United States
| | - Ajith Vengellur
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan 48824-1319, United States
| | - Yogesh Saini
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan 48824-1319, United States
- Center for Integrative Toxicology, Michigan State University, East Lansing, Michigan 48824-1319, United States
| | - Elizabeth A. Grier
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan 48824-1319, United States
| | - Shelagh M. Ferguson-Miller
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan 48824-1319, United States
- Center for Mitochondrial Science and Medicine, Michigan State University, East Lansing, Michigan 48824-1319, United States
| | - John J. LaPres
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan 48824-1319, United States
- Center for Integrative Toxicology, Michigan State University, East Lansing, Michigan 48824-1319, United States
- Center for Mitochondrial Science and Medicine, Michigan State University, East Lansing, Michigan 48824-1319, United States
| |
Collapse
|
4
|
Iida R, Ueki M, Fujihara J, Takeshita H, Kimura-Kataoka K, Yasuda T. Three Nonsynonymous Single Nucleotide Polymorphisms in the RhitH Gene Cause Reduction of the Repression Activity That Leads to Upregulation of M-LPH, a Participant in Mitochondrial Function. Biores Open Access 2013; 2:440-7. [PMID: 24380054 PMCID: PMC3869441 DOI: 10.1089/biores.2013.0042] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Human Mpv17-like protein (M-LPH) has been suggested to play a role in mitochondrial function. In this study, we identified a RhitH (human regulator of heat-induced transcription) binding site in intron 1 of the M-LPH gene. Tissue distribution analysis showed that M-LPH was specifically distributed in tissues with high mitochondrial metabolism. Functional and genetic analyses of nonsynonymous single nucleotide polymorphisms (SNPs) in the RhitH gene revealed that p.Cys461Ser, p.Thr465Ala, and p.Leu495Gln, corresponding to substitutions in the zinc fingers, cause reductions in the repression activity that lead to upregulation of M-LPH expression. The analyses also showed that the minor allele frequencies of these SNPs are extremely low in worldwide populations.
Collapse
Affiliation(s)
- Reiko Iida
- Division of Life Science, Faculty of Medical Sciences, University of Fukui , Fukui, Japan . ; Research and Education Program for Life Science, Faculty of Medical Sciences, University of Fukui , Fukui, Japan
| | - Misuzu Ueki
- Division of Medical Genetics & Biochemistry, Faculty of Medical Sciences, University of Fukui , Fukui, Japan
| | - Junko Fujihara
- Department of Legal Medicine, Center for Integrated Research in Science, Shimane University School of Medicine , Izumo, Japan
| | - Haruo Takeshita
- Department of Legal Medicine, Center for Integrated Research in Science, Shimane University School of Medicine , Izumo, Japan
| | - Kaori Kimura-Kataoka
- Department of Legal Medicine, Center for Integrated Research in Science, Shimane University School of Medicine , Izumo, Japan
| | - Toshihiro Yasuda
- Research and Education Program for Life Science, Faculty of Medical Sciences, University of Fukui , Fukui, Japan . ; Division of Medical Genetics & Biochemistry, Faculty of Medical Sciences, University of Fukui , Fukui, Japan
| |
Collapse
|
5
|
Wong-Riley MTT. Bigenomic regulation of cytochrome c oxidase in neurons and the tight coupling between neuronal activity and energy metabolism. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2012; 748:283-304. [PMID: 22729863 DOI: 10.1007/978-1-4614-3573-0_12] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Cytochrome c oxidase is the terminal enzyme of the mitochondrial electron transport chain, without which oxidative metabolism cannot be carried to completion. It is one of only four unique, bigenomic proteins in mammalian cells. The holoenzyme is made up of three mitochondrial-encoded and ten nuclear-encoded subunits in a 1:1 stoichiometry. The ten nuclear subunit genes are located in nine different chromosomes. The coordinated regulation of such a multisubunit, multichromosomal, bigenomic enzyme poses a challenge. It is especially so for neurons, whose mitochondria are widely distributed in extensive dendritic and axonal processes, resulting in the separation of the mitochondrial from the nuclear genome by great distances. Neuronal activity dictates COX activity that reflects protein amount, which, in turn, is regulated at the transcriptional level. All 13 COX transcripts are up- and downregulated by neuronal activity. The ten nuclear COX transcripts and those for Tfam and Tfbms important for mitochondrial COX transcripts are transcribed in the same transcription factory. Bigenomic regulation of all 13 transcripts is mediated by nuclear respiratory factors 1 and 2 (NRF-1 and NRF-2). NRF-1, in addition, also regulates critical neurochemicals of glutamatergic synaptic transmission, thereby ensuring the tight coupling of energy metabolism and neuronal activity at the molecular level in neurons.
Collapse
Affiliation(s)
- Margaret T T Wong-Riley
- Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, Milwaukee, WI 53226, USA.
| |
Collapse
|
6
|
Iida R, Ueki M, Yasuda T. Identification of Rhit as a novel transcriptional repressor of human Mpv17-like protein with a mitigating effect on mitochondrial dysfunction, and its transcriptional regulation by FOXD3 and GABP. Free Radic Biol Med 2012; 52:1413-22. [PMID: 22306510 DOI: 10.1016/j.freeradbiomed.2012.01.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/28/2011] [Revised: 12/22/2011] [Accepted: 01/04/2012] [Indexed: 12/20/2022]
Abstract
Mpv17-like protein (M-LP) is a protein that has been suggested to be involved in the metabolism of reactive oxygen species. To elucidate the molecular basis of M-LP expression, we recently searched for regulatory elements of M-LP and identified a novel mouse KRAB-containing protein, Rhit (regulator of heat-induced transcription), as a repressor of the transcriptional regulation of M-LP. In this study, we identified zinc-finger protein 205 as a candidate human Rhit (RhitH) and subsequently confirmed its participation in transcriptional regulation of human M-LP (M-LPH). To clarify the functions of RhitH and M-LPH, we searched for cis-regulatory elements in the promoter region of RhitH and identified two transcription factors: forkhead box D3, as a negative regulatory element, and GA-binding protein, one of the key regulators of the mitochondrial electron transport system, as a positive regulatory element. Additionally, it was demonstrated that knockdown of RhitH or overexpression of M-LPH reduces the generation of intracellular H(2)O(2) and loss of mitochondrial membrane potential caused by an inhibitor of the respiratory chain, antimycin A. These results suggest that M-LPH functions to protect cells from oxidative stress and/or initiation of the mitochondrial apoptotic cascade under stressed conditions.
Collapse
Affiliation(s)
- Reiko Iida
- Division of Life Science, Faculty of Medical Sciences, University of Fukui, Fukui 910-1193, Japan.
| | | | | |
Collapse
|
7
|
Fujioka H, Moghaddas S, Murdock DG, Lesnefsky EJ, Tandler B, Hoppel CL. Decreased cytochrome c oxidase subunit VIIa in aged rat heart mitochondria: immunocytochemistry. Anat Rec (Hoboken) 2011; 294:1825-33. [PMID: 21972221 DOI: 10.1002/ar.21486] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2010] [Revised: 03/29/2011] [Accepted: 07/24/2011] [Indexed: 12/26/2022]
Abstract
Aging decreases oxidative phosphorylation through cytochrome oxidase (COX) in cardiac interfibrillar mitochondria (IFM) in 24-month old (aged) rats compared to 6-month old adult Fischer 344 rats, whereas subsarcolemmal mitochondria (SSM) located beneath the plasma membrane remain unaffected. Immunoelectron microscopy (IEM) reveals in aged rats a 25% reduction in cardiac COX subunit VIIa in cardiac IFM, but not in SSM. In contrast, the content of subunit IV remains unchanged in both SSM and IFM, irrespective of age. These subunits are localized mainly on cristae membranes. In contrast, semi-quantitative immunoblotting, which detects denatured protein, indicates that the content of COX VIIa is similar in IFM and SSM from both aged and adult hearts. IEM provides a sensitive method for precise localizing and quantifying specific mitochondrial proteins. The lack of immunoreaction of COX VIIa subunit by IEM in aged IFM is not explained by a reduction in protein, but rather by a masking phenomenon or by an in situ change in protein structure affecting COX activity.
Collapse
Affiliation(s)
- Hisashi Fujioka
- Department of Pharmacology, School of Medicine, Case Western Reserve University, Cleveland, Ohio 44106, USA.
| | | | | | | | | | | |
Collapse
|
8
|
LeMoine CMR, Craig PM, Dhekney K, Kim JJ, McClelland GB. Temporal and spatial patterns of gene expression in skeletal muscles in response to swim training in adult zebrafish (Danio rerio). J Comp Physiol B 2009; 180:151-60. [DOI: 10.1007/s00360-009-0398-5] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2009] [Revised: 07/20/2009] [Accepted: 07/27/2009] [Indexed: 10/20/2022]
|
9
|
Scarpulla RC. Transcriptional paradigms in mammalian mitochondrial biogenesis and function. Physiol Rev 2008; 88:611-38. [PMID: 18391175 DOI: 10.1152/physrev.00025.2007] [Citation(s) in RCA: 1156] [Impact Index Per Article: 72.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Mitochondria contain their own genetic system and undergo a unique mode of cytoplasmic inheritance. Each organelle has multiple copies of a covalently closed circular DNA genome (mtDNA). The entire protein coding capacity of mtDNA is devoted to the synthesis of 13 essential subunits of the inner membrane complexes of the respiratory apparatus. Thus the majority of respiratory proteins and all of the other gene products necessary for the myriad mitochondrial functions are derived from nuclear genes. Transcription of mtDNA requires a small number of nucleus-encoded proteins including a single RNA polymerase (POLRMT), auxiliary factors necessary for promoter recognition (TFB1M, TFB2M) and activation (Tfam), and a termination factor (mTERF). This relatively simple system can account for the bidirectional transcription of mtDNA from divergent promoters and key termination events controlling the rRNA/mRNA ratio. Nucleomitochondrial interactions depend on the interplay between transcription factors (NRF-1, NRF-2, PPARalpha, ERRalpha, Sp1, and others) and members of the PGC-1 family of regulated coactivators (PGC-1alpha, PGC-1beta, and PRC). The transcription factors target genes that specify the respiratory chain, the mitochondrial transcription, translation and replication machinery, and protein import and assembly apparatus among others. These factors are in turn activated directly or indirectly by PGC-1 family coactivators whose differential expression is controlled by an array of environmental signals including temperature, energy deprivation, and availability of nutrients and growth factors. These transcriptional paradigms provide a basic framework for understanding the integration of mitochondrial biogenesis and function with signaling events that dictate cell- and tissue-specific energetic properties.
Collapse
Affiliation(s)
- Richard C Scarpulla
- Department of Cell and Molecular Biology, Northwestern Medical School, Chicago, Illinois 60611, USA
| |
Collapse
|
10
|
Hayashi R, Ueda T, Farwell MA, Takeuchi N. Nuclear respiratory factor 2 activates transcription of human mitochondrial translation initiation factor 2 gene. Mitochondrion 2006; 7:195-203. [PMID: 17161026 DOI: 10.1016/j.mito.2006.10.005] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2006] [Revised: 10/20/2006] [Accepted: 10/26/2006] [Indexed: 11/18/2022]
Abstract
We studied the transcriptional regulation of the human mitochondrial translation initiation factor 2 (IF2mt) gene. The minimal promoter region for the human IF2mt gene contains binding sites for Nuclear Respiratory Factor 2 (NRF-2), which is often involved in the transcription of mitochondrial-related genes. Electrophoresis mobility shift assay (EMSA) analyses indicated that NRF-2alpha/beta binds to the IF2mt promoter. Reporter assays, where HEK293T cells were co-transfected with an NRF-2alpha/beta-expressing vector and/or an IF2mt promoter reporter vector, revealed that NRF-2 trans-activates the IF2mt promoter. NRF-2 sites were also found in the promoters of several other mitochondrial translation factors, which suggests NRF-2 may play a key role in the regulation of mitochondrial protein synthesis.
Collapse
Affiliation(s)
- Rippei Hayashi
- Department of Medical Genome Sciences, Graduate School of Frontier Sciences, The University of Tokyo, Building FSB-401, 5-1-5 Kashiwanoha, Kashiwa, Chiba Prefecture 277-8562, Japan
| | | | | | | |
Collapse
|
11
|
Tsuchimochi K, Yagishita N, Yamasaki S, Amano T, Kato Y, Kawahara KI, Aratani S, Fujita H, Ji F, Sugiura A, Izumi T, Sugamiya A, Maruyama I, Fukamizu A, Komiya S, Nishioka K, Nakajima T. Identification of a crucial site for synoviolin expression. Mol Cell Biol 2005; 25:7344-56. [PMID: 16055742 PMCID: PMC1190266 DOI: 10.1128/mcb.25.16.7344-7356.2005] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Synoviolin is an E3 ubiquitin ligase localized in the endoplasmic reticulum (ER) and serving as ER-associated degradation system. Analysis of transgenic mice suggested that synoviolin gene dosage is implicated in the pathogenesis of arthropathy. Complete deficiency of synoviolin is fatal embryonically. Thus, alternation of Synoviolin could cause breakdown of ER homeostasis and consequently lead to disturbance of cellular homeostasis. Hence, the expression level of Synoviolin appears to be important for its biological role in cellular homeostasis under physiological and pathological conditions. To examine the control of protein level, we performed promoter analysis to determine transcriptional regulation. Here we characterize the role of synoviolin transcription in cellular homeostasis. The Ets binding site (EBS), termed EBS-1, from position -76 to -69 of the proximal promoter, is responsible for synoviolin expression in vivo and in vitro. Interestingly, transfer of EBS-1 decoy into NIH 3T3 cells conferred not only the repression of synoviolin gene expression but also a decrease in cell number. Fluorescence-activated cell sorter analysis using annexin V staining confirmed the induction of apoptosis by EBS-1 decoy and demonstrated recovery of apoptosis by overexpression of Synoviolin. Our results suggest that transcriptional regulation of synoviolin via EBS-1 plays an important role in cellular homeostasis. Our study provides novel insight into the transcriptional regulation for cellular homeostasis.
Collapse
Affiliation(s)
- Kaneyuki Tsuchimochi
- Department of Genomic Science, Institute of Medical Science, St. Marianna University School of Medicine, Kawasaki, Kanagawa, Japan
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
12
|
O'Leary DA, Pritchard MA, Xu D, Kola I, Hertzog PJ, Ristevski S. Tissue-specific overexpression of the HSA21 gene GABPalpha: implications for DS. Biochim Biophys Acta Mol Basis Dis 2005; 1739:81-7. [PMID: 15607120 DOI: 10.1016/j.bbadis.2004.09.005] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2004] [Revised: 09/07/2004] [Accepted: 09/08/2004] [Indexed: 11/15/2022]
Abstract
The ETS transcription factor GABPalpha is encoded by a gene on HSA21 and interacts with an ankyrin repeat-containing beta subunit to form the GABP complex. GABP regulates expression of genes involved in mitochondrial respiration and neuromuscular signalling. When GABPalpha mRNA is overexpressed in human DS fibroblast cell lines, or by tranfection in NIH3T3 cells, no increase in protein level is detected. However, increased Gabpalpha gene dosage in the Ts65Dn segmental trisomy mouse model of DS (DS) results in elevated Gabpalpha protein levels in brain and skeletal muscle only. These findings suggest that GABPalpha protein levels are tightly regulated in a tissue-specific manner, and consequently GABP may play a role in DS pathologies in tissues where GABPalpha protein levels are elevated.
Collapse
Affiliation(s)
- Debra A O'Leary
- Centre for Functional Genomics and Human Disease, Monash Institute of Reproduction and Development, Monash University, Clayton, Victoria 3168, Australia
| | | | | | | | | | | |
Collapse
|
13
|
Grasberger H, Ye H, Mashima H, Bell GI. Dual promoter structure of ZFP106: regulation by myogenin and nuclear respiratory factor-1. Gene 2004; 344:143-59. [PMID: 15656981 DOI: 10.1016/j.gene.2004.09.035] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2004] [Revised: 08/02/2004] [Accepted: 09/17/2004] [Indexed: 11/25/2022]
Abstract
The WD40 repeats containing zinc finger protein 106 (ZFP106) is a conserved mammalian protein of unknown function. However, its cDNA shares an extended region of identity with the scr homology domain 3 binding protein 3 (Sh3bp3) cDNA encoding a protein implicated in the insulin signaling pathway. Asking, whether Zfp106 and Sh3bp3 are products of the same gene, we characterized the structures and transcriptional regulation of Zfp106 and its human homologue, ZFP106. A TATA-less, CpG island associated promoter (P1), was mapped by 5'-RACE to a region 19 kb upstream of the ZFP106 translation start site. P1 is active throughout development and at low levels in all adult tissues examined. A conserved cis-element in the proximal P1 region showed specific binding to nuclear respiratory factor-1 (NRF-1). Mutagenesis of this site and transfection of a dominant-negative NRF-1 both revealed the crucial role of NRF-1 in activation of P1. The broad tissue expression of P1 was in contrast to the high level of ZFP106 mRNA observed in striated muscle. This prompted additional 5'-RACE experiments that established a second, TATA box-containing promoter (P2) upstream of the third coding exon. P1 and P2 transcripts encode proteins with distinct N-terminal sequences, with Sh3bp3 corresponding to a rare, alternatively spliced P2 transcript. P2 initiated transcripts are specifically expressed in striated muscle and their level is strongly upregulated during myogenic, but not adipogenic differentiation. By deletion analysis, the region between nucleotides -296 to +96 was sufficient for robust P2 responsiveness to myogenic differentiation. This response is mediated by the additive effect of binding of myogenin to three critical E boxes within this region. In addition, transcriptional enhancer factor-1 family factors contribute to both basal and myogenesis induced P2 activity. In situ hybridization of mouse embryos confirmed predominant expression of Zfp106 in tissues with high developmental expression of either NRF-1 (brown fat and developing brain) or myogenin (striated muscle). Our results suggest distinct roles of tissue-specific ZFP106 isoforms in growth related metabolism and provide the foundation for further studies into the regulation and function of ZFP106.
Collapse
Affiliation(s)
- Helmut Grasberger
- Department of Biochemistry and Molecular Biology, University of Chicago, Chicago, IL 60637, USA.
| | | | | | | |
Collapse
|
14
|
Ongwijitwat S, Wong-Riley MTT. Functional analysis of the rat cytochrome c oxidase subunit 6A1 promoter in primary neurons. Gene 2004; 337:163-71. [PMID: 15276212 DOI: 10.1016/j.gene.2004.04.024] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2004] [Revised: 04/04/2004] [Accepted: 04/26/2004] [Indexed: 11/16/2022]
Abstract
Cytochrome c oxidase (COX) is a multimeric enzyme consisting of 13 subunits that are encoded in both mitochondrial and nuclear genomes. We analyzed the promoter of the rat gene encoding the liver isoform of COX subunit VIa. Using transiently transfected primary neuronal cultures as a model system, we found that the basal promoter activity of this gene is localized to a region between positions -244 and +58 relative to the transcriptional start site. This region contains putative binding sites for the transcription factors Sp1, NRF-1, and NRF-2. Two of the NRF-2 sites in this basal promoter are organized in a tandem repeat. A deletion that disrupted this tandem repeat reduced transcription to approximately 25% of the basal level. Additional small deletion series and point mutation experiments confirmed the presence of two functional NRF-2 sites arranged in a tandem repeat, as well as a NRF-1 site and an Sp1 site. In vivo binding of NRF-2 to the rCOX6A1 promoter was confirmed with chromatin immunoprecipitation assay (ChIP). We conclude that Sp1, NRF-1, and NRF-2 are important in activating transcription of the rat COX6A1 gene.
Collapse
Affiliation(s)
- Sakkapol Ongwijitwat
- Department of Cell Biology, Neurobiology, and Anatomy, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI 53226, USA
| | | |
Collapse
|
15
|
Ristevski S, O'Leary DA, Thornell AP, Owen MJ, Kola I, Hertzog PJ. The ETS transcription factor GABPalpha is essential for early embryogenesis. Mol Cell Biol 2004; 24:5844-9. [PMID: 15199140 PMCID: PMC480913 DOI: 10.1128/mcb.24.13.5844-5849.2004] [Citation(s) in RCA: 111] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The ETS transcription factor complex GABP consists of the GABPalpha protein, containing an ETS DNA binding domain, and an unrelated GABPbeta protein, containing a transactivation domain and nuclear localization signal. GABP has been shown in vitro to regulate the expression of nuclear genes involved in mitochondrial respiration and neuromuscular signaling. We investigated the in vivo function of GABP by generating a null mutation in the murine Gabpalpha gene. Embryos homozygous for the null Gabpalpha allele die prior to implantation, consistent with the broad expression of Gabpalpha throughout embryogenesis and in embryonic stem cells. Gabpalpha(+/-) mice demonstrated no detectable phenotype and unaltered protein levels in the panel of tissues examined. This indicates that Gabpalpha protein levels are tightly regulated to protect cells from the effects of loss of Gabp complex function. These results show that Gabpalpha function is essential and is not compensated for by other ETS transcription factors in the mouse, and they are consistent with a specific requirement for Gabp expression for the maintenance of target genes involved in essential mitochondrial cellular functions during early cleavage events of the embryo.
Collapse
Affiliation(s)
- Sika Ristevski
- Centre for Functional Genomics and Human Disease, Monash Institute of Reproduction and Development, Monash University, Clayton, Victoria 3168, Australia.
| | | | | | | | | | | |
Collapse
|
16
|
Kelly DP, Scarpulla RC. Transcriptional regulatory circuits controlling mitochondrial biogenesis and function. Genes Dev 2004; 18:357-68. [PMID: 15004004 DOI: 10.1101/gad.1177604] [Citation(s) in RCA: 934] [Impact Index Per Article: 46.7] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Affiliation(s)
- Daniel P Kelly
- Center for Cardiovascula Research, Departments of Medicine, Molecular Biology & Pharmacology, and Pediatrics, Washington University School of Medicine, St. Louis, Missouri 63119, USA.
| | | |
Collapse
|
17
|
Marie S, Race V, Nassogne MC, Vincent MF, Van den Berghe G. Mutation of a nuclear respiratory factor 2 binding site in the 5' untranslated region of the ADSL gene in three patients with adenylosuccinate lyase deficiency. Am J Hum Genet 2002; 71:14-21. [PMID: 12016589 PMCID: PMC384970 DOI: 10.1086/341036] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2001] [Accepted: 04/01/2002] [Indexed: 11/03/2022] Open
Abstract
Adenylosuccinate lyase (ADSL; also called "adenylosuccinase") catalyzes two steps in the synthesis of purine nucleotides: (1) the conversion of succinylaminoimidazolecarboxamide ribotide into aminoimidazolecarboxamide ribotide and (2) the conversion of adenylosuccinate into adenosine monophosphate. ADSL deficiency, a recessively inherited disorder, causes variable-but most often severe-mental retardation, frequently accompanied by epilepsy and/or autism. It is characterized by the accumulation, in body fluids, of succinylaminoimidazolecarboxamide riboside and succinyladenosine, the dephosphorylated derivatives of the two substrates of the enzyme. Analysis of the ADSL gene of three unrelated patients with ADSL deficiency, in whom one of the ADSL alleles displayed a normal coding sequence, revealed a -49T-->C mutation in the 5' untranslated region of this allele. Measurements of the amount of mRNA transcribed from the latter allele showed that it was reduced to approximately 33% of that transcribed from the alleles mutated in their coding sequence. Further investigations showed that the -49T-->C mutation provokes a reduction to 25% of wild-type control of promoter function, as evaluated by luciferase activity and mRNA level in transfection experiments. The mutation also affects the binding of nuclear respiratory factor 2 (NRF-2), a known activator of transcription, as assessed by gel-shift studies. Our findings indicate that a mutation of a regulatory region of the ADSL gene might be an unusually frequent cause of ADSL deficiency, and they suggest a role for NRF-2 in the gene regulation of the purine biosynthetic pathway.
Collapse
Affiliation(s)
- S Marie
- Laboratory of Physiological Chemistry, Christian de Duve Institute of Cellular Pathology, and Université Catholique de Louvain, Brussels, Belgium
| | | | | | | | | |
Collapse
|
18
|
Scarpulla RC. Nuclear activators and coactivators in mammalian mitochondrial biogenesis. BIOCHIMICA ET BIOPHYSICA ACTA 2002; 1576:1-14. [PMID: 12031478 DOI: 10.1016/s0167-4781(02)00343-3] [Citation(s) in RCA: 447] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
The biogenesis of mitochondria requires the expression of a large number of genes, most of which reside in the nuclear genome. The protein-coding capacity of mtDNA is limited to 13 respiratory subunits necessitating that nuclear regulatory factors play an important role in governing nucleo-mitochondrial interactions. Two classes of nuclear transcriptional regulators implicated in mitochondrial biogenesis have emerged in recent years. The first includes DNA-binding transcription factors, typified by nuclear respiratory factor (NRF)-1, NRF-2 and others, that act on known nuclear genes that specify mitochondrial functions. A second, more recently defined class, includes nuclear coactivators typified by PGC-1 and related family members (PRC and PGC-1 beta). These molecules do not bind DNA but rather work through their interactions with DNA-bound transcription factors to regulate gene expression. An important feature of these coactivators is that their expression is responsive to physiological signals mediating thermogenesis, cell proliferation and gluconeogenesis. Thus, they have the ability to integrate the action of multiple transcription factors in orchestrating programs of gene expression essential to cellular energetics. The interplay of these nuclear factors appears to be a major determinant in regulating the biogenesis of mitochondria.
Collapse
Affiliation(s)
- Richard C Scarpulla
- Department of Cell and Molecular Biology, Northwestern Medical School, 303 East Chicago Avenue, Searle 4-458, Chicago, IL 60611, USA.
| |
Collapse
|
19
|
Siciliano G, Monzani F, Manca ML, Tessa A, Caraccio N, Tozzi G, Piemonte F, Mancuso M, Santorelli FM, Ferrannini E, Murri L. Human Mitochondrial Transcription Factor A Reduction and Mitochondrial Dysfunction in Hashimoto’s Hypothyroid Myopathy. Mol Med 2002. [DOI: 10.1007/bf03402159] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
|
20
|
Yu M, Jaradat SA, Grossman LI. Genomic organization and promoter regulation of human cytochrome c oxidase subunit VII heart/muscle isoform (COX7AH). BIOCHIMICA ET BIOPHYSICA ACTA 2002; 1574:345-53. [PMID: 11997101 DOI: 10.1016/s0167-4781(02)00228-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
We have isolated and characterized the human gene (COX7AH) for the contractile muscle isoform of cytochrome c oxidase (COX) subunit VIIa. This subunit is one of the 10 nuclear encoded subunits of the 13-subunit holoenzyme that carries out the terminal step in the electron transport chain. Using transient transfection assays, we have located a 5'-flanking region sufficient to direct high level, skeletal myotube-specific reporter gene expression. This 792 bp basal promoter, which contains the single transcription start but no canonical TATA or CCAAT boxes, contains one MEF2 site, three E boxes, and an Sp1 site that show binding to their cognate factors, and are all required for full expression. Mutation and transactivation analysis suggest that there is functional interaction between these binding sites.
Collapse
Affiliation(s)
- Minghuan Yu
- Center for Molecular Medicine and Genetics, Wayne State University School of Medicine, Detroit, MI 48201, USA
| | | | | |
Collapse
|
21
|
Takahashi Y, Kako K, Arai H, Ohishi T, Inada Y, Takehara A, Fukamizu A, Munekata E. Characterization and identification of promoter elements in the mouse COX17 gene. BIOCHIMICA ET BIOPHYSICA ACTA 2002; 1574:359-64. [PMID: 11997103 DOI: 10.1016/s0167-4781(01)00374-8] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Cox17p, essential for the assembly of functional cytochrome c oxidase (CCO) in Saccharomyces cerevisiae, has been believed to deliver copper ions to the mitochondrion for insertion into the enzyme. We have recently isolated an approximately 20 kb genomic fragment of the mouse COX17. Reporter assay experiments have shown that most of the promoter activity was restricted to a 0.85 kb fragment flanking the first exon. Further intensive deletion and detailed mutation analysis suggested that the minimal essential region for transactivation was located at bases -155 to -70. This 5'-flanking region did not possess a TATA box, but contained putative Sp1, NRF-1 and NRF-2 binding sites. COX17 basal promoter activity was abrogated by site-directed mutagenesis of Sp1, NRF-1 and NRF-2 binding sites. Electrophoretic mobility shift assays with AtT-20 and NIH3T3 cell nuclear extract revealed that this region binds both a Sp1-like protein and NRF-1 transcription factors. These results indicated that Sp1, NRF-1 and NRF-2 are involved in basal transcription of the COX17 gene, similar to the transcription mechanism of other CCO-related genes.
Collapse
Affiliation(s)
- Yoshinori Takahashi
- Institute of Applied Biochemistry, University of Tsukuba, Ibaraki 305-8572, Tsukuba, Japan
| | | | | | | | | | | | | | | |
Collapse
|
22
|
Lescuyer P, Martinez P, Lunardi J. YY1 and Sp1 activate transcription of the human NDUFS8 gene encoding the mitochondrial complex I TYKY subunit. BIOCHIMICA ET BIOPHYSICA ACTA 2002; 1574:164-74. [PMID: 11955626 DOI: 10.1016/s0167-4781(01)00377-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Complex I is the most complicated of the multimeric enzymes that constitute the mitochondrial respiratory chain. It is encoded by both mitochondrial and nuclear genomes. We have previously characterized the human NDUFS8 gene that encodes the TYKY subunit. This essential subunit is thought to participate in the electron transfer and proton pumping activities of complex I. Here, we have analyzed the transcriptional regulation of the NDUFS8 gene. Using primer extension assays, we have identified two transcription start sites. The basal promoter was mapped to a 247 bp sequence upstream from the main transcription start site by reporter gene analysis in HeLa cells and in differentiated or non-differentiated C2C12 cells. Three Sp1 sites and one YY1 site were identified in this minimal promoter. Through gel shift analysis, all sites were shown to bind to their cognate transcription factors. Site-directed mutagenesis revealed that the YY1 site and two upstream adjacent Sp1 sites drive most of the promoter activity. This work represents the first promoter analysis for a complex I gene. Together with previous studies, our results indicate that YY1 and Sp1 control the expression of genes encoding proteins that are involved in almost all steps of the oxidative phosphorylation metabolism.
Collapse
Affiliation(s)
- Pierre Lescuyer
- Laboratoire BECP-EA2943 UJF/LRA6V CEA-DBMS, CEA Grenoble, 17 rue des Martyrs, 38054 Cedex 9, Grenoble, France.
| | | | | |
Collapse
|
23
|
Scarpulla RC. Transcriptional activators and coactivators in the nuclear control of mitochondrial function in mammalian cells. Gene 2002; 286:81-9. [PMID: 11943463 DOI: 10.1016/s0378-1119(01)00809-5] [Citation(s) in RCA: 258] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The biogenesis and function of mitochondria rely upon the regulated expression of nuclear genes. Recent evidence points to both transcriptional activators and coactivators as important mediators of mitochondrial maintenance and proliferation. Several sequence-specific activators including NRF-1, NRF-2, Sp1, YY1, CREB and MEF-2/E-box factors, among others, have been implicated in respiratory chain expression. Notably, recognition sites for NRF-1, NRF-2 and Sp1 are common to most nuclear genes encoding respiratory subunits, mitochondrial transcription and replication factors, as well as certain heme biosynthetic enzymes and components of the protein import machinery. Moreover, genetic evidence supports a role for NRF-1 in the maintenance of mtDNA during embryonic development. Despite these advances, the means by which multiple transcription factors are integrated into a program of mitochondrial biogenesis remains an open question. New insight into this problem came with the discovery of the transcriptional coactivator, PGC-1. This cofactor is cold inducible in brown fat and interacts with multiple transcription factors to orchestrate a program of adaptive thermogenesis. As part of this program, PGC-1 can up-regulate nuclear genes that are required for mitochondrial biogenesis in part through a direct interaction with NRF-1. Ectopic expression of PGC-1 induces the expression of respiratory subunit mRNAs and leads to mitochondrial proliferation in both cultured cells and transgenic mice. More recently, PRC was characterized as a novel coactivator that shares certain structural similarities with PGC-1 including an activation domain, an RS domain and an RNA recognition motif. However, unlike PGC-1, PRC is not induced significantly during thermogenesis but rather is cell-cycle regulated in cultured cells under conditions where PGC-1 is not expressed. PRC has a transcriptional specificity that is very similar to PGC-1, especially in its interaction with NRF-1 and in the activation of NRF-1 target genes. These regulated coactivators may provide a means for integrating sequence-specific activators in the biogenesis and function of mitochondria under diverse physiological conditions.
Collapse
Affiliation(s)
- Richard C Scarpulla
- Department of Cell and Molecular Biology, Northwestern Medical School, 303 East Chicago Avenue, Chicago, IL 60611, USA.
| |
Collapse
|
24
|
Takahashi Y, Kako K, Ohmura K, Tsumori K, Ohmasa Y, Kashiwabara S, Baba T, Munekatat E. Genomic structure of mouse copper chaperone, COX17. DNA SEQUENCE : THE JOURNAL OF DNA SEQUENCING AND MAPPING 2001; 12:305-18. [PMID: 11913776 DOI: 10.3109/10425170109084454] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Coxl7p was first cloned as a cytoplasmic copper chaperone from yeast mutant and recent works suggested the existence of mammalian homologues. Previous report has shown that a gel filtration fraction of heart extract containing porcine Coxl7p peptide promoted the survival of NIH3T3 fibroblast cells. In the present study, we first cloned DNA fragments of the mouse COX17 gene. The mouse COX17 spans approximately 6kb and consists of three exons. It was mapped to the center of chromosome 16, using a radiation hybrid-mapping panel. The major transcription start site is 80 bp upstream of the ATG initiation codon as determined by rapid amplification of cDNA ends (5'-RACE) analysis. Two potential polyadenylation sites are 3233 and 3293 bp downstream of the termination codon, respectively. Transient transfection of reporter plasmids containing portions of the mouse COX17 5'-flanking region into AtT-20 and NIH3T3 cells allowed the localization of the essential promoter to a 0.8 kb region upstream of the transcription starting site. Furthermore, the transfected luciferase activity was much higher in AtT-20 than NIH3T3. According to sequence analysis of the approximately 0.8kb 5'-flanking region, GC rich segments including consensus sequences for binding of the transcription factor Sp1, but no TATA/CAAT boxes, exist in the region of the transcription start site. Besides the GC box, binding sites for NRF-1 and 2 known as specific transcription factors for COX subunits are also localized around the transcription starting site.
Collapse
Affiliation(s)
- Y Takahashi
- Institute of Applied Biochemistry, University of Tsukuba, Ibaraki, Japan
| | | | | | | | | | | | | | | |
Collapse
|
25
|
Chantrel-Groussard K, Delpy L, Ratinaud MH, Cogné M. Characterization of the murine gene for subunit VIIaL of cytochrome c oxidase. COMPTES RENDUS DE L'ACADEMIE DES SCIENCES. SERIE III, SCIENCES DE LA VIE 2001; 324:1117-23. [PMID: 11803812 DOI: 10.1016/s0764-4469(01)01398-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Mammalian cytochrome c oxidase consists of thirteen subunits, ten encoded by the nuclear genome and three by the mitochondrial DNA. In several species, two isoforms have been isolated for nuclear-encoded subunits VIa, VIIa and VIII: an ubiquitous L (liver) form and a heart- and skeletal-muscle specific H form. The gene for murine cytochrome c oxidase subunit VIIa-L (Cox7aL) and its promoter region were isolated, sequenced and analysed. The coding region is split in four exons spanning 4.1 kbp and the promoter carries potential binding sites for Sp1, NRF1 and NRF2 transcription factors. Transcriptional activity of the promoter in reporter assays suggested an ubiquitous expression in mouse tissues.
Collapse
|
26
|
Kain KH, Popov VL, Herzog NK. Alterations in mitochondria and mtTFA in response to LPS-induced differentiation of B-cells. BIOCHIMICA ET BIOPHYSICA ACTA 2000; 1494:91-103. [PMID: 11072072 DOI: 10.1016/s0167-4781(00)00223-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Stimulation of immune cells results in altered cell function and metabolism, which must be recognized by and coordinated with energy production from mitochondria. Mitochondria contain their own DNA genome encoding 13 polypeptides that combine with nuclear-derived subunits to create functional enzyme complexes of the electron transport chain. Therefore, coordination of mitochondrial and nuclear transcription is necessary to achieve a sustained elevation in mitochondrial ATP production. Pre-B-lymphocytes stimulated with lipopolysaccharide exhibit increased activity levels of the mitochondrial enzymes, succinate dehydrogenase and cytochrome c oxidase. Immunoblot analyses of purified mitochondria indicate an increase in the mitochondrial transcription factor (mtTFA) levels in mitochondria induced by cell stimulation. This increase is consistent with increased mtTFA production in the cytoplasm. In addition, mitochondrial protein extracts indicate an increase in protein binding to a mtTFA-DNA binding site from the mitochondrial genome, subsequent to cell stimulation. These results indicate that mitochondrial activity changes during B-lymphocyte stimulation, and mtTFA may contribute to the coordination of respiration with cellular energy demand.
Collapse
Affiliation(s)
- K H Kain
- Department of Pathology, The WHO Collaborating Center for Tropical Diseases, The University of Texas Medical Branch, 301 University Avenue, Galveston, TX 77555-0609, USA
| | | | | |
Collapse
|
27
|
Hüttemann M, Mühlenbein N, Schmidt TR, Grossman LI, Kadenbach B. Isolation and sequence of the human cytochrome c oxidase subunit VIIaL gene. BIOCHIMICA ET BIOPHYSICA ACTA 2000; 1492:252-8. [PMID: 11004498 DOI: 10.1016/s0167-4781(00)00087-7] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
The gene for human cytochrome c oxidase subunit VIIa liver isoform (COX7AL) was isolated and its sequence determined and analyzed. The three introns of the gene are considerably larger than those of the heart isoform of subunit VIIa (COX7AH), but the position of the introns relative to the cDNA sequences is homologous between the two genes. Comparison with other isolated COX7AL genes suggests that the promoter region binding motifs for transcription factors have evolved along with the coding region. In fibroblasts cultured originally from a Leigh's disease patient, a shortened COX7AL cDNA was identified by RT-PCR, consisting of exon I joined to exon IV, omitting exons II and III. No mutation could be identified in COX7AL of the patient, suggesting that the shortened cDNA is due to an alteration of the genome during cell culture. A surprising transcription of COX7AH was observed in cultured fibroblasts, suggesting a potential utility of these cells for study of its gene expression.
Collapse
Affiliation(s)
- M Hüttemann
- Fachbereich Chemie, Philipps-Universität, D35032 Marburg, Germany
| | | | | | | | | |
Collapse
|
28
|
Wong-Riley M, Guo A, Bachman NJ, Lomax MI. Human COX6A1 gene: promoter analysis, cDNA isolation and expression in the monkey brain. Gene 2000; 247:63-75. [PMID: 10773445 DOI: 10.1016/s0378-1119(00)00121-9] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
The human COX6A1 gene encodes the ubiquitous isoform of cytochrome c oxidase (COX) subunit VIa (VIa-L), and is located in a CpG island on chromosome 12q24.2. We compared the COX6A1 gene with the published cDNA and several ESTs and concluded that subunit COX VIa-L is synthesized as a preprotein, as are other COX subunits. The same transcription start sites were identified by primer extension analysis of human brain and lymphoblastoid RNA. Analysis of the COX6A1 promoter revealed several conserved sequence elements found in other COX genes, namely binding sites for nuclear respiratory factor 1 (NRF-1), nuclear respiratory factor 2/GA binding protein (NRF-2/GABP), and ying-yang protein 1 (YY1). These conserved elements were shown to bind nuclear proteins from HeLa nuclear extracts. COX6A1 cDNA was isolated from a human brain cDNA library, and the sequence was identical to that of human liver. The expression of this gene was demonstrated by in-situ hybridization in monkey brain sections with our human brain cDNA. Monocular impulse blockade in adult monkeys induced a downregulation of COX6A1 expression in deprived visual neurons, suggesting that this subunit gene is regulated by neuronal activity.
Collapse
MESH Headings
- Amino Acid Sequence
- Animals
- Base Sequence
- Binding Sites
- Brain/enzymology
- DNA, Complementary/genetics
- DNA, Complementary/isolation & purification
- DNA-Binding Proteins/metabolism
- Electron Transport Complex IV/genetics
- Electron Transport Complex IV/metabolism
- Electrophoresis, Polyacrylamide Gel
- Gene Expression Regulation, Enzymologic/drug effects
- Genes/genetics
- Geniculate Bodies/drug effects
- Geniculate Bodies/enzymology
- HeLa Cells
- Humans
- In Situ Hybridization
- Isoenzymes/genetics
- Isoenzymes/metabolism
- Macaca
- Molecular Sequence Data
- Oligonucleotides/genetics
- Oligonucleotides/metabolism
- Promoter Regions, Genetic/genetics
- RNA, Messenger/drug effects
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
- Rats
- Regulatory Sequences, Nucleic Acid
- Sequence Alignment
- Sequence Analysis, DNA
- Sequence Homology, Amino Acid
- Tetrodotoxin/pharmacology
- Transcription, Genetic
Collapse
Affiliation(s)
- M Wong-Riley
- Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, Milwaukee, WI 53226, USA.
| | | | | | | |
Collapse
|
29
|
Zhang C, Wong-Riley MT. Depolarizing stimulation upregulates GA-binding protein in neurons: a transcription factor involved in the bigenomic expression of cytochrome oxidase subunits. Eur J Neurosci 2000; 12:1013-23. [PMID: 10762332 DOI: 10.1046/j.1460-9568.2000.00997.x] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Neurons are unique in having dendrites that extend far away from their cell bodies. Mitochondria located in the dendrites can be separated from the nucleus for long distances. The mechanism of bigenomic coordination is of particular importance to cytochrome oxidase (CO), which has subunits that are encoded in both the nuclear and mitochondrial DNA. GA-binding protein (GABP) is a transcription factor that is required for the promoter activity of mitochondrial transcription factor A as well as several nuclear-encoded CO subunits. Thus, GABP may play a key role in coordinating the transcription of both mitochondrial and nuclear-encoded subunits of CO. The goal of the present study was to determine if GABP was expressed in neurons and whether and how it responded to increased neuronal activity. Using primary neuronal cultures, the beta-subunit of GABP was localized immunocytochemically to both the cytoplasm and the nucleus, whereas the alpha-subunit was expressed mainly in the nucleus. In KCl-treated cultures, immunoreactivity for both alpha- and beta-subunits was significantly increased in the nucleus compared with untreated sister cultures. The induction of GABP preceded that of CO gene expression from the two genomes, which, in turn, preceded that of CO activity. Thus, our data suggest that neuronal activity regulates subunit concentrations of GABP in the nucleus, and GABP may be a critical sensor of changes in neuronal activity. Our data are also consistent with the postulated role of GABP as a coordinator of both mitochondrial and nuclear transcription for subunits of CO in neurons.
Collapse
Affiliation(s)
- C Zhang
- Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, Milwaukee, WI 53226, USA
| | | |
Collapse
|
30
|
Guo A, Nie F, Wong-Riley M. Human nuclear respiratory factor 2 alpha subunit cDNA: isolation, subcloning, sequencing, and in situ hybridization of transcripts in normal and monocularly deprived macaque visual system. J Comp Neurol 2000; 417:221-32. [PMID: 10660899 DOI: 10.1002/(sici)1096-9861(20000207)417:2<221::aid-cne7>3.0.co;2-4] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Nuclear respiratory factor 2 (NRF-2) has been shown to contribute to the transcriptional regulation of a number of subunits of respiratory chain enzymes, including cytochrome c oxidase (CO). Our recent study demonstrated a parallel distribution of the alpha subunit proteins of NRF-2 (NRF-2 alpha) with CO in the monkey striate cortex, and that it can be regulated by neuronal activity. To determine whether this regulation is at the transcriptional level, the present study examined the expression of NRF-2 alpha mRNA in normal and monocularly deprived adult monkeys. A partial NRF-2 alpha cDNA was isolated from a human brain cDNA library. Sequence analysis revealed that it shared 99% identity with the published sequence from human HeLa cells. Riboprobes of NRF-2 alpha was generated and labeled with digoxigenin-11-UTP for in situ hybridization. The expression pattern of NRF-2 alpha mRNA in the normal striate cortex paralleled that of CO activity. It was highly expressed in layers IVC and VI, which contained high levels of CO, and more densely expressed in puffs of layers II and III than in interpuffs. In monkeys monocularly treated with tetrodotoxin for 1 day to 2 weeks, both NRF-2 alpha expression and CO activity were reduced in deprived ocular dominance columns of the visual cortex and in deprived layers of the lateral geniculate nucleus. These data indicate that, in the normal and visually deprived adult monkeys, NRF-2 alpha is regulated by neuronal activity at the transcriptional level.
Collapse
Affiliation(s)
- A Guo
- Department of Cell Biology, Neurobiology, and Anatomy, Medical College of Wisconsin, Milwaukee 53226, USA
| | | | | |
Collapse
|
31
|
Enríquez JA, Fernández-Sílva P, Montoya J. Autonomous regulation in mammalian mitochondrial DNA transcription. Biol Chem 1999; 380:737-47. [PMID: 10494823 DOI: 10.1515/bc.1999.094] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
The regulation of the oxidative phosphorylation system (OXPHOS) biogenesis in eukaryotic cells is unique since it involves the expression of two genomes, the mitochondrial DNA (mtDNA) and the nuclear DNA (nDNA). The considerable effort done in collecting information on the factors that influence the expression of the genes encoded in mtDNA and nDNA has revealed that a multiplicity of regulatory options are available in mammalian cells to perform this task. Thus, at least three archetypal situations can be distinguished: mitochondrial proliferation, mitochondrial differentiation, and mitochondrial local tuning (MLT). Each of them seems to be predominantly under the control of specific strategies of regulation, although the description of the detailed molecular mechanisms involved is still in its beginnings. In the present review, we focus on the evidence supporting the existence of mechanisms for autonomous regulation of mtDNA transcription and its role in the integrated regulation of the OXPHOS system biogenesis.
Collapse
Affiliation(s)
- J A Enríquez
- Departamento de Bioquímica y Biología Molecular y Celular, Universidad de Zaragova, Spain
| | | | | |
Collapse
|
32
|
Lenka N, Vijayasarathy C, Mullick J, Avadhani NG. Structural organization and transcription regulation of nuclear genes encoding the mammalian cytochrome c oxidase complex. PROGRESS IN NUCLEIC ACID RESEARCH AND MOLECULAR BIOLOGY 1998; 61:309-44. [PMID: 9752724 DOI: 10.1016/s0079-6603(08)60830-2] [Citation(s) in RCA: 102] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Cytochrome c Oxidase (COX) is the terminal component of the bacterial as well as the mitochondrial respiratory chain complex that catalyzes the conversion of redox energy to ATP. In eukaryotes, the oligomeric enzyme is bound to mitochondrial innermembrane with subunits ranging from 7 to 13. Thus, its biosynthesis involves a coordinate interplay between nuclear and mitochondrial genomes. The largest subunits, I, II, and III, which represent the catalytic core of the enzyme, are encoded by the mitochondrial DNA and are synthesized within the mitochondria. The rest of the smaller subunits implicated in the regulatory function are encoded on the nuclear DNA and imported into mitochondria following their synthesis in the cytosol. Some of the nuclear coded subunits are expressed in tissue and developmental specific isologs. The ubiquitous subunits IV, Va, Vb, VIb, VIc, VIIb, VIIc, and VIII (L) are detected in all the tissues, although the mRNA levels for the individual subunits vary in different tissues. The tissue specific isologs VIa (H), VIIa (H), and VIII (H) are exclusive to heart and skeletal muscle. cDNA sequence analysis of nuclear coded subunits reveals 60 to 90% conservation among species both at the amino acid and nucleotide level, with the exception of subunit VIII, which exhibits 40 to 80% interspecies homology. Functional genes for COX subunits IV, Vb, VIa 'L' & 'H', VIIa 'L' & 'H', VIIc and VIII (H) from different mammalian species and their 5' flanking putative promoter regions have been sequenced and extensively characterized. The size of the genes range from 2 to 10 kb in length. Although the number of introns and exons are identical between different species for a given gene, the size varies across the species. A majority of COX genes investigated, with the exception of muscle-specific COXVIII(H) gene, lack the canonical 'TATAA' sequence and contain GC-rich sequences at the immediate upstream region of transcription start site(s). In this respect, the promoter structure of COX genes resemble those of many house-keeping genes. The ubiquitous COX genes show extensive 5' heterogeneity with multiple transcription initiation sites that bind to both general as well as specialized transcription factors such as YY1 and GABP (NRF2/ets). The transcription activity of the promoter in most of the ubiquitous genes is regulated by factors binding to the 5' upstream Sp1, NRF1, GABP (NRF2), and YY1 sites. Additionally, the murine COXVb promoter contains a negative regulatory region that encompasses the binding motifs with partial or full consensus to YY1, GTG, CArG, and ets. Interestingly, the muscle-specific COX genes contain a number of striated muscle-specific regulatory motifs such as E box, CArG, and MEF2 at the proximal promoter regions. While the regulation of COXVIa (H) gene involves factors binding to both MEF2 and E box in a skeletal muscle-specific fashion, the COXVIII (H) gene is regulated by factors binding to two tandomly duplicated E boxes in both skeletal and cardiac myocytes. The cardiac-specific factor has been suggested to be a novel bHLH protein. Mammalian COX genes provide a valuable system to study mechanisms of coordinated regulation of nuclear and mitochondrial genes. The presence of conserved sequence motifs common to several of the nuclear genes, which encode mitochondrial proteins, suggest a possible regulatory function by common physiological factors like heme/O2/carbon source. Thus, a well-orchestrated regulatory control and cross talks between the nuclear and mitochondrial genomes in response to changes in the mitochondrial metabolic conditions are key factors in the overall regulation of mitochondrial biogenesis.
Collapse
Affiliation(s)
- N Lenka
- Department of Animal Biology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia 19104, USA
| | | | | | | |
Collapse
|
33
|
Transcriptional regulation of the GluR2 gene: neural-specific expression, multiple promoters, and regulatory elements. J Neurosci 1998. [PMID: 9712644 DOI: 10.1523/jneurosci.18-17-06723.1998] [Citation(s) in RCA: 104] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
To understand how neurons control the expression of the AMPA receptor subunit GluR2, we cloned the 5' proximal region of the rat gene and investigated GluR2 promoter activity by transient transfection. RNase protection and primer extension of rat brain mRNA revealed multiple transcription initiation sites from -340 to -481 bases upstream of the GluR2 AUG codon. The relative use of 5' start sites was different in cortex and cerebellum, indicating complexity of GluR2 transcript expression among different sets of neurons. When GluR2 promoter activity was investigated by plasmid transfection into cultured cortical neurons, cortical glia, and C6 glioma cells, the promoter construct with the strongest activity, per transfected cell, was 29.4-fold (+/- 3.7) more active in neurons than in non-neural cells. Immunostaining of cortical cultures showed that >97% of the luciferase-positive cells also expressed the neuronal marker MAP-2. Evaluation of internal deletion and substitution mutations identified a functional repressor element I RE1-like silencer and functional Sp1 and nuclear respiratory factor-1 (NRF-1) elements within a GC-rich proximal GluR2 promoter region. The GluR2 silencer reduced promoter activity in glia and non-neuronal cell lines by two- to threefold, was without effect in cortical neurons, and could bind the RE1-silencing transcription factor (REST) because cotransfection of REST into neurons reduced GluR2 promoter activity in a silencer-dependent manner. Substitution of the GluR2 silencer by the homologous NaII RE1 silencer further reduced GluR2 promoter activity in non-neuronal cells by 30-47%. Maximal positive GluR2 promoter activity required both Sp1 and NRF-1 cis elements and an interelement nucleotide bridge sequence. These results indicate that GluR2 transcription initiates from multiple sites, is highly neuronal selective, and is regulated by three regulatory elements in the 5' proximal promoter region.
Collapse
|
34
|
Grossman LI, Seelan RS, Jaradat SA. Transcriptional regulation of mammalian cytochrome c oxidase genes. Electrophoresis 1998; 19:1254-9. [PMID: 9694260 DOI: 10.1002/elps.1150190805] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The cytochrome c oxidase (COX) holoenzyme is a 13-subunit complex that carries out the terminal step in the electron transport chain. Three of the subunits, which contain the electron transfer function, are coded by mitochondrial DNA and the other ten subunits by nuclear DNA. Since the holoenzyme contains equivalent amounts of each subunit, we and others have examined transcriptional regulation of COX nuclear subunits to explore whether there is a common basis for co-regulation. Each gene is seen to have a unique pattern of recognition by regulatory factors; although some factors bind to more than one gene, not all COX genes seem to be regulated by the same set of factors. Current information about the COX promoters that have been examined is summarized, and the relation of promoter regulation to coordinate gene expression is discussed.
Collapse
Affiliation(s)
- L I Grossman
- Center for Molecular Medicine and Genetics, Wayne State University School of Medicine, Detroit, MI 48201, USA.
| | | | | |
Collapse
|
35
|
Biochemical and genetic controls exerted by plant mitochondria. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 1998. [DOI: 10.1016/s0005-2728(98)00080-2] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
|
36
|
Scheffler IE. Molecular genetics of succinate:quinone oxidoreductase in eukaryotes. PROGRESS IN NUCLEIC ACID RESEARCH AND MOLECULAR BIOLOGY 1998; 60:267-315. [PMID: 9594577 DOI: 10.1016/s0079-6603(08)60895-8] [Citation(s) in RCA: 89] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Succinate:quinone oxidoreductase is a membrane-associated complex in mitochondria, often referred to as complex II, based on the fractionation scheme developed by Y. Hatefi and colleagues. It consists of four peptides, two of which are integral membrane proteins (15 and 12-13 kDa, respectively) and two others that are peripheral membrane proteins, i.e., a flavoprotein (Fp, 70 kDa) and an iron-protein (Ip, 27 kDa). The mature, functional complex contains a cytochrome in association with the membrane proteins, a flavin linked covalently to the largest peptide, and three iron-sulfur clusters in the 27-kDa subunit. The present review touches only briefly on the biochemical and biophysical properties of this complex. Instead, the focus is on the molecular-genetic studies that have become possible since the first genes from eukaryotes were cloned in 1989. The evolutionary conservation of the amino acid sequence of both the Fp and the Ip peptides has facilitated the cloning of these genes from a large variety of eukaryotic organisms by PCR-based methods. The review addresses questions related to the regulation of the expression of these genes, with an emphasis on mammals and yeast, for which most of the information is available. Four different genes have to be co-ordinately regulated. Transcriptional as well as posttranscriptional regulatory mechanisms have been observed in diverse organisms. Intriguing observations have been made in studies of this enzyme during the life cycle of organisms existing alternately under aerobic and anaerobic conditions. Naturally occurring or induced mutations in these genes have shed light on several questions related to the assembly of this complex, and on the relationship between structure and function. Four different peptides are imported into the mitochondria. They have to be modified, folded, and assembled. The stage is set for the exploration of highly specific changes introduced by site-directed mutagenesis. Until recently the genes were believed to be exclusively nuclear in all eukaryotes, but exceptions have since been found. This finding has relevance in the discussion of the evolution of mitochondria from prokaryotes. A highly conserved set of genes is found in prokaryotes, and some informative comparisons on gene organization and expression in prokaryotes and eukaryotes have been included.
Collapse
Affiliation(s)
- I E Scheffler
- Department of Biology, University of California, San Diego 92093, USA
| |
Collapse
|
37
|
Villena JA, Viñas O, Mampel T, Iglesias R, Giralt M, Villarroya F. Regulation of mitochondrial biogenesis in brown adipose tissue: nuclear respiratory factor-2/GA-binding protein is responsible for the transcriptional regulation of the gene for the mitochondrial ATP synthase beta subunit. Biochem J 1998; 331 ( Pt 1):121-7. [PMID: 9512469 PMCID: PMC1219328 DOI: 10.1042/bj3310121] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The regulation of transcription of the gene for the beta subunit of the FoF1 ATP synthase (ATPsynbeta) in brown adipose tissue has been studied as a model to determine the molecular mechanisms for mitochondrial biogenesis associated with brown adipocyte differentiation. The expression of the ATPsynbeta mRNA is induced during the brown adipocyte differentiation that occurs during murine prenatal development or when brown adipocytes differentiate in culture. This induction occurs in parallel with enhanced gene expression for other nuclear and mitochondrially-encoded components of the respiratory chain/oxidative phosphorylation system (OXPHOS). Transient transfection assays indicated that the expression of the ATPsynbeta gene promoter is higher in differentiated HIB-1B brown adipocytes than in non-differentiated HIB-1B cells. A major transcriptional regulatory site was identified between nt -306 and -266 in the ATPsynbeta promoter. This element has a higher enhancer capacity in differentiated brown adipocyte HIB-1B cells than in non-differentiated cells. Electrophoretic shift analysis indicated that Sp1and nuclear respiratory factor-2/GA-binding protein (NRF2/GABP) were the main nuclear proteins present in brown adipose tissue that bind this site. Double-point mutant analysis indicated a major role for the NRF2/GABP site in the enhancer capacity of this element in brown fat cells. It is proposed that NRF2/GABP plays a pivotal role in the co-ordinated enhancement of OXPHOS gene expression associated with mitochondrial biogenesis in brown adipocyte differentiation.
Collapse
Affiliation(s)
- J A Villena
- Department of Biochemistry and Molecular Biology, University of Barcelona, Diagonal 645, 08028-Barcelona, Spain
| | | | | | | | | | | |
Collapse
|
38
|
Wolz W, Kress W, Mueller CR. Genomic sequence and organization of the human gene for cytochrome c oxidase subunit (COX7A1) VIIa-M. Genomics 1997; 45:438-42. [PMID: 9344674 DOI: 10.1006/geno.1997.4937] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Cytochrome c oxidase (COX, EC 1.9.3.1), the last component of the mitochondrial electron transfer chain, is built up by 13 polypeptides; 3 of them are encoded by the mitochondrial genome while the 10 smaller subunits are encoded by the nuclear genome. Several nuclear-encoded subunits occur in two different tissue-specific isoforms, a constitutive "L"-form and an "M"-form specific for skeletal and heart muscle. In this article, we describe the genomic sequence and organization of the human gene for COX subunit VIIa-M (COX7A1) located on chromosome 19q13.1 and compare it to its bovine homologue. The coding region of the gene extends over 1.45 kb of genomic sequence, organized in four exons. Intron-exon boundaries are well conserved between cattle and humans. Although it is a gene for a tissue-specific isoform, it has some features of a housekeeping gene: it is located in a CpG island, like its bovine homologue, and no TATA or CCAAT boxes were found in the 5' flanking sequence. Southern hybridization of COX7A1 to human genomic DNA revealed no pseudogenes. Putative binding sites for ubiquitous transcription factors like Sp1 and specific expression in skeletal as well as in heart muscle have been found. In contrast to the bovine gene, the human gene contains putative binding sites for nuclear respiratory factor 2 (NRF-2), which is implicated in the activation of other respiratory enzymes. Therefore, the human and the bovine genes, although well conserved in their coding regions, could differ in the tissue-specific regulation of gene expression. Knowledge of the gene structure will facilitate the analysis of the involvement of subunit VIIa in mitochondrial myopathies and may provide clues to the function of this subunit in a multicomponent enzyme.
Collapse
Affiliation(s)
- W Wolz
- Department of Human Genetics, Biocenter, Am Hubland, Wuerzburg, D-97074, Germany.
| | | | | |
Collapse
|
39
|
Affiliation(s)
- L I Grossman
- Center for Molecular Medicine and Genetics, Wayne State University School of Medicine, Detroit, MI 48201, USA.
| | | |
Collapse
|
40
|
Chen S, Nagy PL, Zalkin H. Role of NRF-1 in bidirectional transcription of the human GPAT-AIRC purine biosynthesis locus. Nucleic Acids Res 1997; 25:1809-16. [PMID: 9108165 PMCID: PMC146651 DOI: 10.1093/nar/25.9.1809] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
GPAT and AIRC encode enzymes for steps one and six plus seven respectively in the pathway for de novo purine nucleotide synthesis in vertebrates. The human GPAT and AIRC genes are divergently transcribed from a 558 bp intergenic promoter region. Cis-acting sites and transcription factors important for bidirectional expression were identified. A cluster of sites between nt 215 and 260 are essential, although not sufficient, for expression of both genes. Two proteins from HepG2 cell nuclear extract, identified as NRF-1 and Sp1, bound to the promoter at sites within the 215-260 region. NRF-1 was required for stable binding of Sp1. Deletion of a 5'promoter region including nt 215-260 resulted in decreased expression of GPAT and AIRC in transfected HepG2 cells. The decreased expression was accounted for by point mutations in an NRF-1 site and either of two flanking sites for Sp1. These transcription factors account in part for the coordinated expression of human GPAT and AIRC.
Collapse
Affiliation(s)
- S Chen
- Department of Biochemistry, Purdue University, West Lafayette, IN 47907, USA
| | | | | |
Collapse
|
41
|
Breen GA, Jordan EM. Regulation of the nuclear gene that encodes the alpha-subunit of the mitochondrial F0F1-ATP synthase complex. Activation by upstream stimulatory factor 2. J Biol Chem 1997; 272:10538-42. [PMID: 9099698 DOI: 10.1074/jbc.272.16.10538] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
We have previously identified several positive cis-acting regulatory regions in the promoters of the bovine and human nuclear-encoded mitochondrial F0F1-ATP synthase alpha-subunit genes (ATPA). One of these cis-acting regions contains the sequence 5'-CACGTG-3' (an E-box), to which a number of transcription factors containing a basic helix-loop-helix motif can bind. This E-box element is required for maximum activity of the ATPA promoter in HeLa cells. The present study identifies the human transcription factor, upstream stimulatory factor 2 (USF2), as a nuclear factor that binds to the ATPA E-box and demonstrates that USF2 plays a critical role in the activation of the ATPA gene in vivo. Evidence includes the following. Antiserum directed against USF2 recognized factors present in HeLa nuclear extracts that interact with the ATPA promoter in mobility shift assays. Wild-type USF2 proteins synthesized from expression vectors trans-activated the ATPA promoter through the E-box, whereas truncated USF2 proteins devoid of the amino-terminal activation domains did not. Importantly, expression of a dominant-negative mutant of USF2 lacking the basic DNA binding domain but able to dimerize with endogenous USF proteins significantly reduced the level of activation of the ATPA promoter caused by ectopically coexpressed USF2, demonstrating the importance of endogenous USF2 in activation of the ATPA gene.
Collapse
Affiliation(s)
- G A Breen
- Department of Molecular and Cell Biology, The University of Texas at Dallas, Richardson, Texas 75083-0688, USA.
| | | |
Collapse
|
42
|
Seelan RS, Grossman LI. Structural organization and promoter analysis of the bovine cytochrome c oxidase subunit VIIc gene. A functional role for YY1. J Biol Chem 1997; 272:10175-81. [PMID: 9092564 DOI: 10.1074/jbc.272.15.10175] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Cytochrome c oxidase (COX) subunit VIIc is one of the nuclear encoded subunits of the 13-subunit holoenzyme that carries out the terminal step in the electron transport chain. We have isolated the gene for this subunit, previously shown to be ubiquitously expressed from a single copy gene in the genome, and show that 167 base pairs of DNA surrounding the transcriptional start site contain the minimal promoter of this gene. This basal promoter contains two YY1 sites and at least one site for NRF-2, which show binding to their cognate factors. Mutation of both YY1 sites eliminates most of the promoter activity. Mutation at the upstream YY1 site significantly reduces the efficiency of transcript initiation at the major start site and thus plays the dominant role in COX7C regulation. COX7C is, thus, the second nuclear gene of COX that is regulated by YY1, suggesting that it is a third common factor, along with NRF-1 and NRF-2, to be associated with COX gene regulation.
Collapse
Affiliation(s)
- R S Seelan
- Center for Molecular Medicine and Genetics, Wayne State University School of Medicine, Detroit, Michigan 48201, USA
| | | |
Collapse
|
43
|
Abstract
The majority of gene products for mitochondrial respiratory function are encoded in the nuclear genome. These include most of the respiratory subunits and all of the proteins that regulate the mitochondrial genetic system. One approach to understanding nucleo-mitochondrial interactions in mammalian cells is to identify the nuclear transcription factors that are common to the expression of these gene products. This has led to the purification and molecular cloning of nuclear respiratory factors, NRF-1 and NRF-2. The DNA binding and transcriptional specificities of these proteins have implicated them in the expression of many respiratory subunits along with key components of the mitochondrial transcription, replication, and heme biosynthetic machinery. In addition, tissue-specific transcription factors have been linked to the coordinate synthesis of contractile proteins and muscle-specific respiratory subunits whereas other more ubiquitous factors may have a dual function in nuclear and mitochondrial gene activation. These findings provide a framework for further investigations of the nuclear genetic mechanisms that integrate the expression of the respiratory apparatus with that of other cellular systems during growth and development.
Collapse
Affiliation(s)
- R C Scarpulla
- Department of Cell and Molecular Biology, Northwestern Medical School, Chicago, Illinois 60611, USA
| |
Collapse
|
44
|
Gugneja S, Virbasius CM, Scarpulla RC. Nuclear respiratory factors 1 and 2 utilize similar glutamine-containing clusters of hydrophobic residues to activate transcription. Mol Cell Biol 1996; 16:5708-16. [PMID: 8816484 PMCID: PMC231571 DOI: 10.1128/mcb.16.10.5708] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Nuclear respiratory factors 1 and 2 (NRF-1 and NRF-2) are ubiquitous transcription factors that have been implicated in the control of nuclear genes required for respiration, heme biosynthesis, and mitochondrial DNA transcription and replication. Recently, both factors have been found to be major transcriptional determinants for a subset of these genes that define a class of simple promoters involved in respiratory chain expression. Here, functional domains required for transactivation by NRF-1 have been defined. An atypical nuclear localization signal resides in a conserved amino-terminal region adjacent to the DNA binding domain and consists of functionally redundant clusters of basic residues. A second domain in the carboxy-terminal half of the molecule is necessary for transcriptional activation. The activation domains of both NRF-1 and NRF-2 were extensively characterized by both deletion and alanine substitution mutagenesis. The results show that these domains do not fall into known classes defined by a preponderance of amino acid residues, including glutamines, prolines, or isoleucines, as found in other eukaryotic activators. Rather, in both factors, a series of tandemly arranged clusters of hydrophobic amino acids were required for activation. Although all of the functional clusters contain glutamines, the glutamines differ from the hydrophobic residues in that they are inconsequential for activation. Unlike the NRF-2 domain, which contains its essential hydrophobic motifs within 40 residues, the NRF-1 domain spans about 40% of the molecule and appears to have a bipartite structure. The findings indicate that NRF-1 and NRF-2 utilize similar hydrophobic structural motifs for activating transcription.
Collapse
Affiliation(s)
- S Gugneja
- Department of Cell and Molecular Biology, Northwestern University Medical School, Chicago, Illinois 60611, USA
| | | | | |
Collapse
|
45
|
Xia Y, Buja LM, McMillin JB. Change in expression of heart carnitine palmitoyltransferase I isoforms with electrical stimulation of cultured rat neonatal cardiac myocytes. J Biol Chem 1996; 271:12082-7. [PMID: 8662650 DOI: 10.1074/jbc.271.20.12082] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Electrical stimulation of neonatal rat cardiac myocytes in culture produces increases in myocyte size (hypertrophy) and organization of actin into myofibrillar arrays. The maturation of the cells is associated with enhanced contractile parameters and cellular calcium content. The numbers and intensity of cellular mitochondrial profiles increase, as measured by scanning laser confocal microscopy. Consistent with the hypertrophic response is increased cellular content of beta-myosin heavy chain and cytochrome oxidase subunit Va messages, as well as increases in cytochrome oxidase activity in the stimulated cardiac myocytes. Myocyte contractile capacity is associated with increased expression of the muscle carnitine palmitoyltransferase (CPT-I) isoform as measured by Northern analysis, immunoblotting, and altered sensitivity of CPT-I activity to malonyl-CoA in the stimulated cells. The data suggest that a switch from the liver isoform of CPT-I, prominent in the neonatal rat heart, to the muscle CPT-I which predominates in adult rat heart, takes place in the neonatal cardiac myocytes over the same time period as the hypertrophic-mediated changes in myofibrillar assembly and increased contractile activity.
Collapse
Affiliation(s)
- Y Xia
- Department of Pathology and Laboratory Medicine, University of Texas Medical School of Houston 77030, USA
| | | | | |
Collapse
|
46
|
|