1
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Korb A, Tajbakhsh S, Comai GE. Functional specialisation and coordination of myonuclei. Biol Rev Camb Philos Soc 2024. [PMID: 38477382 DOI: 10.1111/brv.13063] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2023] [Revised: 01/30/2024] [Accepted: 02/02/2024] [Indexed: 03/14/2024]
Abstract
Myofibres serve as the functional unit for locomotion, with the sarcomere as fundamental subunit. Running the entire length of this structure are hundreds of myonuclei, located at the periphery of the myofibre, juxtaposed to the plasma membrane. Myonuclear specialisation and clustering at the centre and ends of the fibre are known to be essential for muscle contraction, yet the molecular basis of this regionalisation has remained unclear. While the 'myonuclear domain hypothesis' helped explain how myonuclei can independently govern large cytoplasmic territories, novel technologies have provided granularity on the diverse transcriptional programs running simultaneously within the syncytia and added a new perspective on how myonuclei communicate. Building upon this, we explore the critical cellular and molecular sources of transcriptional and functional heterogeneity within myofibres, discussing the impact of intrinsic and extrinsic factors on myonuclear programs. This knowledge provides new insights for understanding muscle development, repair, and disease, but also opens avenues for the development of novel and precise therapeutic approaches.
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Affiliation(s)
- Amaury Korb
- Institut Pasteur, Université Paris Cité, CNRS UMR 3738, Stem Cells & Development Unit, 25 rue du Dr. Roux, Institut Pasteur, Paris, F-75015, France
| | - Shahragim Tajbakhsh
- Institut Pasteur, Université Paris Cité, CNRS UMR 3738, Stem Cells & Development Unit, 25 rue du Dr. Roux, Institut Pasteur, Paris, F-75015, France
| | - Glenda E Comai
- Institut Pasteur, Université Paris Cité, CNRS UMR 3738, Stem Cells & Development Unit, 25 rue du Dr. Roux, Institut Pasteur, Paris, F-75015, France
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2
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Zhu Y, Zhou Z, Huang T, Zhang Z, Li W, Ling Z, Jiang T, Yang J, Yang S, Xiao Y, Charlier C, Georges M, Yang B, Huang L. Mapping and analysis of a spatiotemporal H3K27ac and gene expression spectrum in pigs. SCIENCE CHINA. LIFE SCIENCES 2022; 65:1517-1534. [PMID: 35122624 DOI: 10.1007/s11427-021-2034-5] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/09/2021] [Accepted: 10/29/2021] [Indexed: 12/12/2022]
Abstract
The limited knowledge of genomic noncoding and regulatory regions has restricted our ability to decipher the genetic mechanisms underlying complex traits in pigs. In this study, we characterized the spatiotemporal landscape of putative enhancers and promoters and their target genes by combining H3K27ac-targeted ChIP-Seq and RNA-Seq in fetal (prenatal days 74-75) and adult (postnatal days 132-150) tissues (brain, liver, heart, muscle and small intestine) sampled from Asian aboriginal Bama Xiang and European highly selected Large White pigs of both sexes. We identified 101,290 H3K27ac peaks, marking 18,521 promoters and 82,769 enhancers, including peaks that were active across all tissues and developmental stages (which could indicate safe harbor locus for exogenous gene insertion) and tissue- and developmental stage-specific peaks (which regulate gene pathways matching tissue- and developmental stage-specific physiological functions). We found that H3K27ac and DNA methylation in the promoter region of the XIST gene may be involved in X chromosome inactivation and demonstrated the utility of the present resource for revealing the regulatory patterns of known causal genes and prioritizing candidate causal variants for complex traits in pigs. In addition, we identified an average of 1,124 super-enhancers per sample and found that they were more likely to show tissue-specific activity than ordinary peaks. We have developed a web browser to improve the accessibility of the results ( http://segtp.jxau.edu.cn/pencode/?genome=susScr11 ).
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Affiliation(s)
- Yaling Zhu
- State Key Laboratory of Pig Genetic Improvement and Production Technology, Jiangxi Agricultural University, Nanchang, 330045, China
- Laboratory Animal Research Center, School of Basic Medical Sciences, Anhui Medical University, Hefei, 230032, China
| | - Zhimin Zhou
- State Key Laboratory of Pig Genetic Improvement and Production Technology, Jiangxi Agricultural University, Nanchang, 330045, China
| | - Tao Huang
- State Key Laboratory of Pig Genetic Improvement and Production Technology, Jiangxi Agricultural University, Nanchang, 330045, China
| | - Zhen Zhang
- State Key Laboratory of Pig Genetic Improvement and Production Technology, Jiangxi Agricultural University, Nanchang, 330045, China
| | - Wanbo Li
- State Key Laboratory of Pig Genetic Improvement and Production Technology, Jiangxi Agricultural University, Nanchang, 330045, China
| | - Ziqi Ling
- State Key Laboratory of Pig Genetic Improvement and Production Technology, Jiangxi Agricultural University, Nanchang, 330045, China
| | - Tao Jiang
- State Key Laboratory of Pig Genetic Improvement and Production Technology, Jiangxi Agricultural University, Nanchang, 330045, China
| | - Jiawen Yang
- State Key Laboratory of Pig Genetic Improvement and Production Technology, Jiangxi Agricultural University, Nanchang, 330045, China
| | - Siyu Yang
- State Key Laboratory of Pig Genetic Improvement and Production Technology, Jiangxi Agricultural University, Nanchang, 330045, China
| | - Yanyuan Xiao
- State Key Laboratory of Pig Genetic Improvement and Production Technology, Jiangxi Agricultural University, Nanchang, 330045, China
| | - Carole Charlier
- State Key Laboratory of Pig Genetic Improvement and Production Technology, Jiangxi Agricultural University, Nanchang, 330045, China
- Unit of Animal Genomics, GIGA-Institute and Faculty of Veterinary Medicine, University of Liege, 4000, Liege, Belgium
| | - Michel Georges
- State Key Laboratory of Pig Genetic Improvement and Production Technology, Jiangxi Agricultural University, Nanchang, 330045, China
- Unit of Animal Genomics, GIGA-Institute and Faculty of Veterinary Medicine, University of Liege, 4000, Liege, Belgium
| | - Bin Yang
- State Key Laboratory of Pig Genetic Improvement and Production Technology, Jiangxi Agricultural University, Nanchang, 330045, China.
| | - Lusheng Huang
- State Key Laboratory of Pig Genetic Improvement and Production Technology, Jiangxi Agricultural University, Nanchang, 330045, China.
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3
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Zhou Z, Jiang T, Zhu Y, Ling Z, Yang B, Huang L. A comparative investigation on
H3K27ac
enhancer activities in the brain and liver tissues between wild boars and domesticated pigs. Evol Appl 2022; 15:1281-1290. [PMID: 36051459 PMCID: PMC9423090 DOI: 10.1111/eva.13461] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2022] [Revised: 06/28/2022] [Accepted: 07/20/2022] [Indexed: 11/29/2022] Open
Abstract
Dramatic phenotypic differences between domestic pigs and wild boars (Sus scrofa) provide opportunities to investigate molecular mechanisms underlying the formation of complex traits, including morphology, physiology and behaviour. Most studies comparing domestic pigs and wild boars have focused on variations in DNA sequences and mRNA expression, but not on epigenetic changes. Here, we present a genome‐wide comparative study on H3K27ac enhancer activities and the corresponding mRNA profiling in the brain and liver tissues of adult Bama Xiang pigs (BMXs) and Chinese wild boars (CWBs). We identified a total of 1,29,487 potential regulatory elements, among which 11,241 H3K27ac peaks showed differential activity between CWBs and BMXs in at least one tissue. These peaks were overrepresented by binding motifs of FOXA1, JunB, ATF3 and BATF, and overlapped with differentially expressed genes that are involved in female mating behaviour, response to growth factors and hormones, and lipid metabolism. We also identified 4118 nonredundant super‐enhancers from ChIP‐Seq data on H3K27ac. Notably, we identified differentially active peaks located close to or within candidate genes, including TBX19, MSTN, AHR and P2RY1, which were identified in DNA sequence‐based population differentiation studies. This study generates a valuable dataset on H3K27ac profiles of the brain and liver from domestic pigs and wild boars, which helps gain insights into the changes in enhancer activities from wild boars to domestic pigs.
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Affiliation(s)
- Zhimin Zhou
- State Key Laboratory of Swine Genetic Improvement and Production Technology Jiangxi Agricultural University Nanchang P.R. China
| | - Tao Jiang
- State Key Laboratory of Swine Genetic Improvement and Production Technology Jiangxi Agricultural University Nanchang P.R. China
| | - Yaling Zhu
- State Key Laboratory of Swine Genetic Improvement and Production Technology Jiangxi Agricultural University Nanchang P.R. China
| | - Ziqi Ling
- State Key Laboratory of Swine Genetic Improvement and Production Technology Jiangxi Agricultural University Nanchang P.R. China
| | - Bin Yang
- State Key Laboratory of Swine Genetic Improvement and Production Technology Jiangxi Agricultural University Nanchang P.R. China
| | - Lusheng Huang
- State Key Laboratory of Swine Genetic Improvement and Production Technology Jiangxi Agricultural University Nanchang P.R. China
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4
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Rodríguez Cruz PM, Cossins J, Beeson D, Vincent A. The Neuromuscular Junction in Health and Disease: Molecular Mechanisms Governing Synaptic Formation and Homeostasis. Front Mol Neurosci 2020; 13:610964. [PMID: 33343299 PMCID: PMC7744297 DOI: 10.3389/fnmol.2020.610964] [Citation(s) in RCA: 73] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2020] [Accepted: 10/30/2020] [Indexed: 12/28/2022] Open
Abstract
The neuromuscular junction (NMJ) is a highly specialized synapse between a motor neuron nerve terminal and its muscle fiber that are responsible for converting electrical impulses generated by the motor neuron into electrical activity in the muscle fibers. On arrival of the motor nerve action potential, calcium enters the presynaptic terminal, which leads to the release of the neurotransmitter acetylcholine (ACh). ACh crosses the synaptic gap and binds to ACh receptors (AChRs) tightly clustered on the surface of the muscle fiber; this leads to the endplate potential which initiates the muscle action potential that results in muscle contraction. This is a simplified version of the events in neuromuscular transmission that take place within milliseconds, and are dependent on a tiny but highly structured NMJ. Much of this review is devoted to describing in more detail the development, maturation, maintenance and regeneration of the NMJ, but first we describe briefly the most important molecules involved and the conditions that affect their numbers and function. Most important clinically worldwide, are myasthenia gravis (MG), the Lambert-Eaton myasthenic syndrome (LEMS) and congenital myasthenic syndromes (CMS), each of which causes specific molecular defects. In addition, we mention the neurotoxins from bacteria, snakes and many other species that interfere with neuromuscular transmission and cause potentially fatal diseases, but have also provided useful probes for investigating neuromuscular transmission. There are also changes in NMJ structure and function in motor neuron disease, spinal muscle atrophy and sarcopenia that are likely to be secondary but might provide treatment targets. The NMJ is one of the best studied and most disease-prone synapses in the nervous system and it is amenable to in vivo and ex vivo investigation and to systemic therapies that can help restore normal function.
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Affiliation(s)
- Pedro M Rodríguez Cruz
- Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom.,Neurosciences Group, Weatherall Institute of Molecular Medicine, University of Oxford, The John Radcliffe Hospital, Oxford, United Kingdom
| | - Judith Cossins
- Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom.,Neurosciences Group, Weatherall Institute of Molecular Medicine, University of Oxford, The John Radcliffe Hospital, Oxford, United Kingdom
| | - David Beeson
- Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom.,Neurosciences Group, Weatherall Institute of Molecular Medicine, University of Oxford, The John Radcliffe Hospital, Oxford, United Kingdom
| | - Angela Vincent
- Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom.,Neurosciences Group, Weatherall Institute of Molecular Medicine, University of Oxford, The John Radcliffe Hospital, Oxford, United Kingdom
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5
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The NMJ as a model synapse: New perspectives on formation, synaptic transmission and maintenance: Acetylcholinesterase at the neuromuscular junction. Neurosci Lett 2020; 735:135157. [PMID: 32540360 DOI: 10.1016/j.neulet.2020.135157] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2020] [Revised: 06/10/2020] [Accepted: 06/11/2020] [Indexed: 12/28/2022]
Abstract
Acetylcholinesterase (AChE) is an essential enzymatic component of the neuromuscular junction where it is responsible for terminating neurotransmission by the cholinergic motor neurons. The enzyme at the neuromuscular junction (NMJ) is contributed primarily by the skeletal muscle where it is produced at higher levels in the post-synaptic region of the fibers. The major form of AChE at the NMJ is a large asymmetric form consisting of three tetramers covalently attached to a three-stranded collagen-like tail which is responsible for anchoring it to the synaptic basal lamina. Its location and expression is regulated to a large extent by the motor neurons and occurs at the transcriptional, translational and post-translational levels. While its expression can be quite rapid in tissue cultured cells, its half-life in vivo appears to be quite long, about three weeks, although more rapidly turning over pools have been described. Finally the essential nature of this enzyme is underscored by the fact that no naturally occurring null mutations of the catalytic subunit have been described in higher organisms and the few dozen humans carrying mutations in the collagen tail responsible for anchoring the enzyme at the NMJ are severely affected.
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6
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Belotti E, Schaeffer L. Regulation of Gene expression at the neuromuscular Junction. Neurosci Lett 2020; 735:135163. [PMID: 32553805 DOI: 10.1016/j.neulet.2020.135163] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2020] [Revised: 06/11/2020] [Accepted: 06/14/2020] [Indexed: 01/08/2023]
Abstract
Gene expression in skeletal muscle is profoundly changed upon innervation. 50 years of research on the neuromuscular system have greatly increased our understanding of the mechanisms underlying these changes. By controlling the expression and the activity of key transcription factors, nerve-evoked electrical activity in the muscle fiber positively and negatively regulates the expression of hundreds of genes. Innervation also compartmentalizes gene expression into synaptic and extra-synaptic regions of muscle fibers. In addition, electrically-evoked, release of several factors (e.g. Agrin, Neuregulin, Wnt ligands) induce the clustering of synaptic proteins and of a few muscle nuclei. The sub-synaptic nuclei acquire a particular chromatin organization and develop a specific gene expression program dedicated to building and maintaining a functional neuromuscular synapse. Deciphering synapse-specific, transcriptional regulation started with the identification of the N-box, a six base pair element present in the promoters of the acetylcholine δ and ε subunits. Most genes with synapse-specific expression turned out to contain at least one N-box in their promoters. The N-box is a response element for the synaptic signals Agrin and Neuregulins as well as a binding site for transcription factors of the Ets family. The Ets transcription factors GABP and Erm are implicated in the activation of post-synaptic genes via the N-box. In muscle fibers, Erm expression is restricted to the NMJ whereas GABP is expressed in all muscle nuclei but phosphorylated and activated by the JNK and ERK signaling pathways in response to Agrin and Neuregulins. Post-synaptic gene expression also correlates with chromatin modifications at the genomic level as evidenced by the strong enrichment of decondensed chromatin and acetylated histones in sub-synaptic nuclei. Here we discuss these transcriptional pathways for synaptic specialization at NMJs.
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Affiliation(s)
- Edwige Belotti
- INMG, Inserm U1217, CNRS UMR5310, Université Lyon 1, Université De Lyon, Lyon, France
| | - Laurent Schaeffer
- INMG, Inserm U1217, CNRS UMR5310, Université Lyon 1, Université De Lyon, Lyon, France; Centre De Biotechnologie Cellulaire, Hospices Civils De Lyon, Lyon, France.
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7
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Xu ML, Luk WK, Liu EY, Kong XP, Wu QY, Xia YJ, Dong TT, Tsim KW. Differentiation of erythroblast requires the dimeric form of acetylcholinesterase: Interference with erythropoietin receptor. Chem Biol Interact 2019; 308:317-322. [DOI: 10.1016/j.cbi.2019.06.006] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2019] [Revised: 04/24/2019] [Accepted: 06/03/2019] [Indexed: 12/14/2022]
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8
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Xu ML, Luk WKW, Bi CWC, Liu EYL, Wu KQY, Yao P, Dong TTX, Tsim KWK. Erythropoietin regulates the expression of dimeric form of acetylcholinesterase during differentiation of erythroblast. J Neurochem 2018; 146:390-402. [PMID: 29675901 DOI: 10.1111/jnc.14448] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2017] [Revised: 03/11/2018] [Accepted: 03/27/2018] [Indexed: 01/28/2023]
Abstract
Acetylcholinesterase (AChE; EC 3.1.1.7) is known to hydrolyze acetylcholine at cholinergic synapses. In mammalian erythrocyte, AChE exists as a dimer (G2 ) and is proposed to play role in erythropoiesis. To reveal the regulation of AChE during differentiation of erythroblast, erythroblast-like cells (TF-1) were induced to differentiate by application of erythropoietin (EPO). The expression of AChE was increased in parallel to the stages of differentiation. Application of EPO in cultured TF-1 cells induced transcriptional activity of ACHE gene, as well as its protein product. This EPO-induced event was in parallel with erythrocytic proteins, for example, α- and β-globins. The EPO-induced AChE expression was mediated by phosphorylations of Akt and GATA-1; because the application of Akt kinase inhibitor blocked the gene activation. Erythroid transcription factor also known as GATA-1, a downstream transcription factor of EPO signaling, was proposed here to account for regulation of AChE in TF-1 cell. A binding sequence of GATA-1 was identified in ACHE gene promoter, which was further confirmed by chromatin immunoprecipitation (ChIP) assay. Over-expression of GATA-1 in TF-1 cultures induced AChE expression, as well as activity of ACHE promoter tagged with luciferase gene (pAChE-Luc). The deletion of GATA-1 sequence on the ACHE promoter, pAChEΔGATA-1 -Luc, reduced the promoter activity during erythroblastic differentiation. On the contrary, the knock-down of AChE in TF-1 cultures could lead to a reduction in EPO-induced expression of erythrocytic proteins. These findings indicated specific regulation of AChE during maturation of erythroblast, which provided an insight into elucidating possible mechanisms in regulating erythropoiesis.
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Affiliation(s)
- Miranda L Xu
- Division of Life Science and Center for Chinese Medicine, The Hong Kong University of Science and Technology, Hong Kong, China.,Shenzhen Key Laboratory of Edible and Medicinal Bioresourses, Shenzhen Research Institute, Shenzhen, China
| | - Wilson K W Luk
- Division of Life Science and Center for Chinese Medicine, The Hong Kong University of Science and Technology, Hong Kong, China
| | - Cathy W C Bi
- Division of Life Science and Center for Chinese Medicine, The Hong Kong University of Science and Technology, Hong Kong, China
| | - Etta Y L Liu
- Division of Life Science and Center for Chinese Medicine, The Hong Kong University of Science and Technology, Hong Kong, China
| | - Kevin Q Y Wu
- Division of Life Science and Center for Chinese Medicine, The Hong Kong University of Science and Technology, Hong Kong, China
| | - Ping Yao
- Division of Life Science and Center for Chinese Medicine, The Hong Kong University of Science and Technology, Hong Kong, China
| | - Tina T X Dong
- Division of Life Science and Center for Chinese Medicine, The Hong Kong University of Science and Technology, Hong Kong, China.,Shenzhen Key Laboratory of Edible and Medicinal Bioresourses, Shenzhen Research Institute, Shenzhen, China
| | - Karl W K Tsim
- Division of Life Science and Center for Chinese Medicine, The Hong Kong University of Science and Technology, Hong Kong, China.,Shenzhen Key Laboratory of Edible and Medicinal Bioresourses, Shenzhen Research Institute, Shenzhen, China
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9
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Curcumin administration suppress acetylcholinesterase gene expression in cadmium treated rats. Neurotoxicology 2017; 62:75-79. [DOI: 10.1016/j.neuro.2017.05.004] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2017] [Revised: 05/03/2017] [Accepted: 05/11/2017] [Indexed: 11/23/2022]
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10
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Liu WS, Ma JE, Li WX, Zhang JG, Wang J, Nie QH, Qiu FF, Fang MX, Zeng F, Wang X, Lin XR, Zhang L, Chen SH, Zhang XQ. The Long Intron 1 of Growth Hormone Gene from Reeves' Turtle (Chinemys reevesii) Correlates with Negatively Regulated GH Expression in Four Cell Lines. Int J Mol Sci 2016; 17:543. [PMID: 27077853 PMCID: PMC4848999 DOI: 10.3390/ijms17040543] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2015] [Revised: 04/05/2016] [Accepted: 04/06/2016] [Indexed: 11/16/2022] Open
Abstract
Turtles grow slowly and have a long lifespan. Ultrastructural studies of the pituitary gland in Reeves’ turtle (Chinemys reevesii) have revealed that the species possesses a higher nucleoplasmic ratio and fewer secretory granules in growth hormone (GH) cells than other animal species in summer and winter. C. reevesii GH gene was cloned and species-specific similarities and differences were investigated. The full GH gene sequence in C. reevesii contains 8517 base pairs (bp), comprising five exons and four introns. Intron 1 was found to be much longer in C. reevesii than in other species. The coding sequence (CDS) of the turtle’s GH gene, with and without the inclusion of intron 1, was transfected into four cell lines, including DF-1 chicken embryo fibroblasts, Chinese hamster ovary (CHO) cells, human embryonic kidney 293FT cells, and GH4C1 rat pituitary cells; the turtle growth hormone (tGH) gene mRNA and protein expression levels decreased significantly in the intron-containing CDS in these cell lines, compared with that of the corresponding intronless CDS. Thus, the long intron 1 of GH gene in Reeves’ turtle might correlate with downregulated gene expression.
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Affiliation(s)
- Wen-Sheng Liu
- Department of Animal Genetics, Breeding and Reproduction, College of Animal Science, South China Agricultural University, Guangzhou 510642, China.
- Guangdong Provincial Key Lab of Agro-Animal Genomics and Molecular Breeding, South China Agricultural University, Guangzhou 510642, China.
- Key Lab of Chicken Genetics, Breeding and Reproduction, Ministry of Agriculture, South China Agricultural University, Guangzhou 510642, China.
- College of Marine Sciences, South China Agricultural University, Guangzhou 510642, China.
| | - Jing-E Ma
- Department of Animal Genetics, Breeding and Reproduction, College of Animal Science, South China Agricultural University, Guangzhou 510642, China.
- Guangdong Provincial Key Lab of Agro-Animal Genomics and Molecular Breeding, South China Agricultural University, Guangzhou 510642, China.
- Key Lab of Chicken Genetics, Breeding and Reproduction, Ministry of Agriculture, South China Agricultural University, Guangzhou 510642, China.
| | - Wei-Xia Li
- Department of Animal Genetics, Breeding and Reproduction, College of Animal Science, South China Agricultural University, Guangzhou 510642, China.
- Guangdong Provincial Key Lab of Agro-Animal Genomics and Molecular Breeding, South China Agricultural University, Guangzhou 510642, China.
- Key Lab of Chicken Genetics, Breeding and Reproduction, Ministry of Agriculture, South China Agricultural University, Guangzhou 510642, China.
| | - Jin-Ge Zhang
- Department of Animal Genetics, Breeding and Reproduction, College of Animal Science, South China Agricultural University, Guangzhou 510642, China.
- Guangdong Provincial Key Lab of Agro-Animal Genomics and Molecular Breeding, South China Agricultural University, Guangzhou 510642, China.
- Key Lab of Chicken Genetics, Breeding and Reproduction, Ministry of Agriculture, South China Agricultural University, Guangzhou 510642, China.
| | - Juan Wang
- Department of Animal Genetics, Breeding and Reproduction, College of Animal Science, South China Agricultural University, Guangzhou 510642, China.
- Guangdong Provincial Key Lab of Agro-Animal Genomics and Molecular Breeding, South China Agricultural University, Guangzhou 510642, China.
- Key Lab of Chicken Genetics, Breeding and Reproduction, Ministry of Agriculture, South China Agricultural University, Guangzhou 510642, China.
| | - Qing-Hua Nie
- Department of Animal Genetics, Breeding and Reproduction, College of Animal Science, South China Agricultural University, Guangzhou 510642, China.
- Guangdong Provincial Key Lab of Agro-Animal Genomics and Molecular Breeding, South China Agricultural University, Guangzhou 510642, China.
- Key Lab of Chicken Genetics, Breeding and Reproduction, Ministry of Agriculture, South China Agricultural University, Guangzhou 510642, China.
| | - Feng-Fang Qiu
- Department of Animal Genetics, Breeding and Reproduction, College of Animal Science, South China Agricultural University, Guangzhou 510642, China.
- Guangdong Provincial Key Lab of Agro-Animal Genomics and Molecular Breeding, South China Agricultural University, Guangzhou 510642, China.
- Key Lab of Chicken Genetics, Breeding and Reproduction, Ministry of Agriculture, South China Agricultural University, Guangzhou 510642, China.
| | - Mei-Xia Fang
- Department of Animal Genetics, Breeding and Reproduction, College of Animal Science, South China Agricultural University, Guangzhou 510642, China.
- Guangdong Provincial Key Lab of Agro-Animal Genomics and Molecular Breeding, South China Agricultural University, Guangzhou 510642, China.
- Key Lab of Chicken Genetics, Breeding and Reproduction, Ministry of Agriculture, South China Agricultural University, Guangzhou 510642, China.
| | - Fang Zeng
- Department of Animal Genetics, Breeding and Reproduction, College of Animal Science, South China Agricultural University, Guangzhou 510642, China.
- Guangdong Provincial Key Lab of Agro-Animal Genomics and Molecular Breeding, South China Agricultural University, Guangzhou 510642, China.
- Key Lab of Chicken Genetics, Breeding and Reproduction, Ministry of Agriculture, South China Agricultural University, Guangzhou 510642, China.
| | - Xing Wang
- Department of Animal Genetics, Breeding and Reproduction, College of Animal Science, South China Agricultural University, Guangzhou 510642, China.
- Guangdong Provincial Key Lab of Agro-Animal Genomics and Molecular Breeding, South China Agricultural University, Guangzhou 510642, China.
- Key Lab of Chicken Genetics, Breeding and Reproduction, Ministry of Agriculture, South China Agricultural University, Guangzhou 510642, China.
| | - Xi-Ran Lin
- Department of Animal Genetics, Breeding and Reproduction, College of Animal Science, South China Agricultural University, Guangzhou 510642, China.
- Guangdong Provincial Key Lab of Agro-Animal Genomics and Molecular Breeding, South China Agricultural University, Guangzhou 510642, China.
- Key Lab of Chicken Genetics, Breeding and Reproduction, Ministry of Agriculture, South China Agricultural University, Guangzhou 510642, China.
| | - Li Zhang
- Department of Animal Genetics, Breeding and Reproduction, College of Animal Science, South China Agricultural University, Guangzhou 510642, China.
- Guangdong Provincial Key Lab of Agro-Animal Genomics and Molecular Breeding, South China Agricultural University, Guangzhou 510642, China.
- Key Lab of Chicken Genetics, Breeding and Reproduction, Ministry of Agriculture, South China Agricultural University, Guangzhou 510642, China.
| | - Shao-Hao Chen
- Department of Animal Genetics, Breeding and Reproduction, College of Animal Science, South China Agricultural University, Guangzhou 510642, China.
- Guangdong Provincial Key Lab of Agro-Animal Genomics and Molecular Breeding, South China Agricultural University, Guangzhou 510642, China.
- Key Lab of Chicken Genetics, Breeding and Reproduction, Ministry of Agriculture, South China Agricultural University, Guangzhou 510642, China.
| | - Xi-Quan Zhang
- Department of Animal Genetics, Breeding and Reproduction, College of Animal Science, South China Agricultural University, Guangzhou 510642, China.
- Guangdong Provincial Key Lab of Agro-Animal Genomics and Molecular Breeding, South China Agricultural University, Guangzhou 510642, China.
- Key Lab of Chicken Genetics, Breeding and Reproduction, Ministry of Agriculture, South China Agricultural University, Guangzhou 510642, China.
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11
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Zhu W, Swaminathan G, Plowey ED. GA binding protein augments autophagy via transcriptional activation of BECN1-PIK3C3 complex genes. Autophagy 2014; 10:1622-36. [PMID: 25046113 DOI: 10.4161/auto.29454] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Macroautophagy is a vesicular catabolic trafficking pathway that is thought to protect cells from diverse stressors and to promote longevity. Recent studies have revealed that transcription factors play important roles in the regulation of autophagy. In this study, we have identified GA binding protein (GABP) as a transcriptional regulator of the combinatorial expression of BECN1-PIK3C3 complex genes involved in autophagosome initiation. We performed bioinformatics analyses that demonstrated highly conserved putative GABP sites in genes that encode BECN1/Beclin 1, several BECN1 interacting proteins, and downstream autophagy proteins including the ATG12-ATG5-ATG16L1 complex. We demonstrate that GABP binds to the promoter regions of BECN1-PIK3C3 complex genes and activates their transcriptional activities. Knockdown of GABP reduced BECN1-PIK3C3 complex transcripts, BECN1-PIK3C3 complex protein levels and autophagy in cultured cells. Conversely, overexpression of GABP increased autophagy. Nutrient starvation increased GABP-dependent transcriptional activity of BECN1-PIK3C3 complex gene promoters and increased the recruitment of GABP to the BECN1 promoter. Our data reveal a novel function of GABP in the regulation of autophagy via transcriptional activation of the BECN1-PIK3C3 complex.
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Affiliation(s)
- Wan Zhu
- Department of Pathology; Stanford University School of Medicine; Stanford, CA USA
| | - Gayathri Swaminathan
- Department of Pathology; Stanford University School of Medicine; Stanford, CA USA
| | - Edward D Plowey
- Department of Pathology; Stanford University School of Medicine; Stanford, CA USA
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12
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Bronicki LM, Jasmin BJ. Trans-acting factors governing acetylcholinesterase mRNA metabolism in neurons. Front Mol Neurosci 2012; 5:36. [PMID: 22461767 PMCID: PMC3309972 DOI: 10.3389/fnmol.2012.00036] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2012] [Accepted: 03/06/2012] [Indexed: 11/13/2022] Open
Abstract
The most characterized function of acetylcholinesterase (AChE) is to terminate cholinergic signaling at neuron-neuron and neuro-muscular synapses. In addition, AChE is causally or casually implicated in neuronal development, stress-response, cognition, and neurodegenerative diseases. Given the importance of AChE, many studies have focused on identifying the molecular mechanisms that govern its expression. Despite these efforts, post-transcriptional control of AChE mRNA expression is still relatively unclear. Here, we review the trans-acting factors and cis-acting elements that are known to control AChE pre-mRNA splicing, mature mRNA stability and translation. Moreover, since the Hu/ELAV family of RNA-binding proteins (RBPs) have emerged in recent years as “master” post-transcriptional regulators, we discuss the possibility that predominantly neuronal ELAVs (nELAVs) play multiple roles in regulating splicing, stability, localization, and translation of AChE mRNA.
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Affiliation(s)
- Lucas M Bronicki
- Faculty of Medicine, Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa ON, Canada
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13
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Cenik C, Derti A, Mellor JC, Berriz GF, Roth FP. Genome-wide functional analysis of human 5' untranslated region introns. Genome Biol 2010; 11:R29. [PMID: 20222956 PMCID: PMC2864569 DOI: 10.1186/gb-2010-11-3-r29] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2010] [Accepted: 03/11/2010] [Indexed: 12/19/2022] Open
Abstract
BACKGROUND Approximately 35% of human genes contain introns within the 5' untranslated region (UTR). Introns in 5'UTRs differ from those in coding regions and 3'UTRs with respect to nucleotide composition, length distribution and density. Despite their presumed impact on gene regulation, the evolution and possible functions of 5'UTR introns remain largely unexplored. RESULTS We performed a genome-scale computational analysis of 5'UTR introns in humans. We discovered that the most highly expressed genes tended to have short 5'UTR introns rather than having long 5'UTR introns or lacking 5'UTR introns entirely. Although we found no correlation in 5'UTR intron presence or length with variance in expression across tissues, which might have indicated a broad role in expression-regulation, we observed an uneven distribution of 5'UTR introns amongst genes in specific functional categories. In particular, genes with regulatory roles were surprisingly enriched in having 5'UTR introns. Finally, we analyzed the evolution of 5'UTR introns in non-receptor protein tyrosine kinases (NRTK), and identified a conserved DNA motif enriched within the 5'UTR introns of human NRTKs. CONCLUSIONS Our results suggest that human 5'UTR introns enhance the expression of some genes in a length-dependent manner. While many 5'UTR introns are likely to be evolving neutrally, their relationship with gene expression and overrepresentation among regulatory genes, taken together, suggest that complex evolutionary forces are acting on this distinct class of introns.
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Affiliation(s)
- Can Cenik
- Harvard Medical School, Department of Biological Chemistry and Molecular Pharmacology, 250 Longwood Avenue, SGMB-322, Boston, MA 02115, USA.
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14
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Darikova YA, Sherbakov DY. Evolution of a phosphofructokinase gene intron in gastropods of the family Baicaliidae. Mol Biol 2009. [DOI: 10.1134/s0026893309050094] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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15
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Girousse A, Tavernier G, Tiraby C, Lichtenstein L, Iacovoni JS, Mairal A, Villarroya F, Langin D. Transcription of the human uncoupling protein 3 gene is governed by a complex interplay between the promoter and intronic sequences. Diabetologia 2009; 52:1638-46. [PMID: 19468707 DOI: 10.1007/s00125-009-1385-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/23/2009] [Accepted: 04/17/2009] [Indexed: 11/24/2022]
Abstract
AIMS/HYPOTHESIS Uncoupling protein (UCP) 3 is an inner mitochondrial membrane transporter mainly produced in skeletal muscle in humans. UCP3 plays a role in fatty acid metabolism and energy homeostasis and modulates insulin sensitivity. In humans, UCP3 content is higher in fast-twitch glycolytic muscle than in slow-twitch oxidative muscle and is dysregulated in type 2 diabetes. Here, we studied the molecular mechanisms determining human UCP3 levels in skeletal muscle and their regulation by fasting in transgenic mice. METHODS We produced a series of transgenic lines with constructs bearing different putative regulatory regions of the human UCP3 gene, including promoter and intron sequences. UCP3 mRNA and reporter gene expression and activity were measured in different skeletal muscles and tissues. RESULTS The profile of expression and the response to fasting and thyroid hormone of human UCP3 mRNA in transgenic mice with 16 kb of the human UCP3 gene were similar to that of the endogenous human gene. Various parts of the UCP3 promoter did not confer expression in transgenic lines. Inclusion of intron 1 resulted in an expression profile in skeletal muscle that was identical to that of human UCP3 mRNA. Further dissection of intron 1 revealed that distinct regions were involved in skeletal muscle expression, distribution among fibre types and response to fasting. CONCLUSIONS/INTERPRETATION The control of human UCP3 transcription in skeletal muscle is not solely conferred by the promoter, but depends on several cis-acting elements in intron 1, suggesting a complex interplay between the promoter and intronic sequences.
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Affiliation(s)
- A Girousse
- Inserm U858, Institut de Médecine Moléculaire de Rangueil, Laboratoire de recherches sur les obésités, Equipe 4, 31432 Toulouse Cedex 4, France
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16
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Guo X, Silva JC. Properties of non-coding DNA and identification of putative cis-regulatory elements in Theileria parva. BMC Genomics 2008; 9:582. [PMID: 19055776 PMCID: PMC2612703 DOI: 10.1186/1471-2164-9-582] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2008] [Accepted: 12/03/2008] [Indexed: 01/24/2023] Open
Abstract
Background Parasites in the genus Theileria cause lymphoproliferative diseases in cattle, resulting in enormous socio-economic losses. The availability of the genome sequences and annotation for T. parva and T. annulata has facilitated the study of parasite biology and their relationship with host cell transformation and tropism. However, the mechanism of transcriptional regulation in this genus, which may be key to understanding fundamental aspects of its parasitology, remains poorly understood. In this study, we analyze the evolution of non-coding sequences in the Theileria genome and identify conserved sequence elements that may be involved in gene regulation of these parasitic species. Results Intergenic regions and introns in Theileria are short, and their length distributions are considerably right-skewed. Intergenic regions flanked by genes in 5'-5' orientation tend to be longer and slightly more AT-rich than those flanked by two stop codons; intergenic regions flanked by genes in 3'-5' orientation have intermediate values of length and AT composition. Intron position is negatively correlated with intron length, and positively correlated with GC content. Using stringent criteria, we identified a set of high-quality orthologous non-coding sequences between T. parva and T. annulata, and determined the distribution of selective constraints across regions, which are shown to be higher close to translation start sites. A positive correlation between constraint and length in both intergenic regions and introns suggests a tight control over length expansion of non-coding regions. Genome-wide searches for functional elements revealed several conserved motifs in intergenic regions of Theileria genomes. Two such motifs are preferentially located within the first 60 base pairs upstream of transcription start sites in T. parva, are preferentially associated with specific protein functional categories, and have significant similarity to know regulatory motifs in other species. These results suggest that these two motifs are likely to represent transcription factor binding sites in Theileria. Conclusion Theileria genomes are highly compact, with selection seemingly favoring short introns and intergenic regions. Three over-represented sequence motifs were independently identified in intergenic regions of both Theileria species, and the evidence suggests that at least two of them play a role in transcriptional control in T. parva. These are prime candidates for experimental validation of transcription factor binding sites in this single-celled eukaryotic parasite. Sequences similar to two of these Theileria motifs are conserved in Plasmodium hinting at the possibility of common regulatory machinery across the phylum Apicomplexa.
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Affiliation(s)
- Xiang Guo
- The Institute for Genomic Research/J. Craig Venter Institute, 9712 Medical Center Drive, Rockville, MD 20850, USA.
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17
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Old and new questions about cholinesterases. Chem Biol Interact 2008; 175:30-44. [DOI: 10.1016/j.cbi.2008.04.039] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2007] [Revised: 04/25/2008] [Accepted: 04/28/2008] [Indexed: 01/21/2023]
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18
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Camp S, De Jaco A, Zhang L, Marquez M, De La Torre B, Taylor P. Acetylcholinesterase expression in muscle is specifically controlled by a promoter-selective enhancesome in the first intron. J Neurosci 2008; 28:2459-70. [PMID: 18322091 PMCID: PMC2692871 DOI: 10.1523/jneurosci.4600-07.2008] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2007] [Revised: 01/09/2008] [Accepted: 01/17/2008] [Indexed: 11/21/2022] Open
Abstract
Mammalian acetylcholinesterase (AChE) gene expression is exquisitely regulated in target tissues and cells during differentiation. An intron located between the first and second exons governs a approximately 100-fold increase in AChE expression during myoblast to myotube differentiation in C2C12 cells. Regulation is confined to 255 bp of evolutionarily conserved sequence containing functional transcription factor consensus motifs that indirectly interact with the endogenous promoter. To examine control in vivo, this region was deleted by homologous recombination. The knock-out mouse is virtually devoid of AChE activity and its encoding mRNA in skeletal muscle, yet activities in brain and spinal cord innervating skeletal muscle are unaltered. The transcription factors MyoD and myocyte enhancer factor-2 appear to be responsible for muscle regulation. Selective control of AChE expression by this region is also found in hematopoietic lineages. Expression patterns in muscle and CNS neurons establish that virtually all AChE activity at the mammalian neuromuscular junction arises from skeletal muscle rather than from biosynthesis in the motoneuron cell body and axoplasmic transport.
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Affiliation(s)
- Shelley Camp
- Department of Pharmacology, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, California 92093-0650
| | - Antonella De Jaco
- Department of Pharmacology, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, California 92093-0650
| | - Limin Zhang
- Department of Pharmacology, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, California 92093-0650
| | - Michael Marquez
- Department of Pharmacology, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, California 92093-0650
| | - Brian De La Torre
- Department of Pharmacology, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, California 92093-0650
| | - Palmer Taylor
- Department of Pharmacology, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, California 92093-0650
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Chakkalakal JV, Miura P, Bélanger G, Michel RN, Jasmin BJ. Modulation of utrophin A mRNA stability in fast versus slow muscles via an AU-rich element and calcineurin signaling. Nucleic Acids Res 2008; 36:826-38. [PMID: 18084024 PMCID: PMC2241908 DOI: 10.1093/nar/gkm1107] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2007] [Revised: 11/19/2007] [Accepted: 11/26/2007] [Indexed: 12/12/2022] Open
Abstract
We examined the role of post-transcriptional mechanisms in controlling utrophin A mRNA expression in slow versus fast skeletal muscles. First, we determined that the half-life of utrophin A mRNA is significantly shorter in the presence of proteins isolated from fast muscles. Direct plasmid injection experiments using reporter constructs containing the full-length or truncated variants of the utrophin 3'UTR into slow soleus and fast extensor digitorum longus muscles revealed that a region of 265 nucleotides is sufficient to confer lower levels of reporter mRNA in fast muscles. Further analysis of this region uncovered a conserved AU-rich element (ARE) that suppresses expression of reporter mRNAs in cultured muscle cells. Moreover, stability of reporter mRNAs fused to the utrophin full-length 3'UTR was lower in the presence of fast muscle protein extracts. This destabilization effect seen in vivo was lost upon deletion of the conserved ARE. Finally, we observed that calcineurin signaling affects utrophin A mRNA stability through the conserved ARE. These results indicate that ARE-mediated mRNA decay is a key mechanism that regulates expression of utrophin A mRNA in slow muscle fibers. This is the first demonstration of ARE-mediated mRNA decay regulating the expression of a gene associated with the slow myogenic program.
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Affiliation(s)
- Joe V. Chakkalakal
- Department of Cellular and Molecular Medicine and Centre for Neuromuscular Disease, Faculty of Medicine, University of Ottawa, Ottawa, ON, Canada K1H 8M5, Department of Chemistry and Biochemistry, Department of Exercise Science and Centre for Structural and Functional Genomics, Concordia University, The Richard J. Renaud Science Complex, Montreal, QC, Canada H4B 1R6 and Ottawa Health Research Institute, Molecular Medicine Program, Ottawa Hospital, General Campus, Ottawa, ON, Canada K1H 8L6
| | - Pedro Miura
- Department of Cellular and Molecular Medicine and Centre for Neuromuscular Disease, Faculty of Medicine, University of Ottawa, Ottawa, ON, Canada K1H 8M5, Department of Chemistry and Biochemistry, Department of Exercise Science and Centre for Structural and Functional Genomics, Concordia University, The Richard J. Renaud Science Complex, Montreal, QC, Canada H4B 1R6 and Ottawa Health Research Institute, Molecular Medicine Program, Ottawa Hospital, General Campus, Ottawa, ON, Canada K1H 8L6
| | - Guy Bélanger
- Department of Cellular and Molecular Medicine and Centre for Neuromuscular Disease, Faculty of Medicine, University of Ottawa, Ottawa, ON, Canada K1H 8M5, Department of Chemistry and Biochemistry, Department of Exercise Science and Centre for Structural and Functional Genomics, Concordia University, The Richard J. Renaud Science Complex, Montreal, QC, Canada H4B 1R6 and Ottawa Health Research Institute, Molecular Medicine Program, Ottawa Hospital, General Campus, Ottawa, ON, Canada K1H 8L6
| | - Robin N. Michel
- Department of Cellular and Molecular Medicine and Centre for Neuromuscular Disease, Faculty of Medicine, University of Ottawa, Ottawa, ON, Canada K1H 8M5, Department of Chemistry and Biochemistry, Department of Exercise Science and Centre for Structural and Functional Genomics, Concordia University, The Richard J. Renaud Science Complex, Montreal, QC, Canada H4B 1R6 and Ottawa Health Research Institute, Molecular Medicine Program, Ottawa Hospital, General Campus, Ottawa, ON, Canada K1H 8L6
| | - Bernard J. Jasmin
- Department of Cellular and Molecular Medicine and Centre for Neuromuscular Disease, Faculty of Medicine, University of Ottawa, Ottawa, ON, Canada K1H 8M5, Department of Chemistry and Biochemistry, Department of Exercise Science and Centre for Structural and Functional Genomics, Concordia University, The Richard J. Renaud Science Complex, Montreal, QC, Canada H4B 1R6 and Ottawa Health Research Institute, Molecular Medicine Program, Ottawa Hospital, General Campus, Ottawa, ON, Canada K1H 8L6
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20
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Gazave E, Marqués-Bonet T, Fernando O, Charlesworth B, Navarro A. Patterns and rates of intron divergence between humans and chimpanzees. Genome Biol 2007; 8:R21. [PMID: 17309804 PMCID: PMC1852421 DOI: 10.1186/gb-2007-8-2-r21] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2006] [Revised: 12/08/2006] [Accepted: 02/19/2007] [Indexed: 01/08/2023] Open
Abstract
An analysis of human-chimpanzee intron divergence shows strong correlations between intron length and divergence and GC-content. Background Introns, which constitute the largest fraction of eukaryotic genes and which had been considered to be neutral sequences, are increasingly acknowledged as having important functions. Several studies have investigated levels of evolutionary constraint along introns and across classes of introns of different length and location within genes. However, thus far these studies have yielded contradictory results. Results We present the first analysis of human-chimpanzee intron divergence, in which differences in the number of substitutions per intronic site (Ki) can be interpreted as the footprint of different intensities and directions of the pressures of natural selection. Our main findings are as follows: there was a strong positive correlation between intron length and divergence; there was a strong negative correlation between intron length and GC content; and divergence rates vary along introns and depending on their ordinal position within genes (for instance, first introns are more GC rich, longer and more divergent, and divergence is lower at the 3' and 5' ends of all types of introns). Conclusion We show that the higher divergence of first introns is related to their larger size. Also, the lower divergence of short introns suggests that they may harbor a relatively greater proportion of regulatory elements than long introns. Moreover, our results are consistent with the presence of functionally relevant sequences near the 5' and 3' ends of introns. Finally, our findings suggest that other parts of introns may also be under selective constraints.
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Affiliation(s)
- Elodie Gazave
- Unitat de Biologia Evolutiva, Departament de Ciències Experimentals i de la Salut, Universitat Pompeu Fabra, Carrer Dr Aiguader 88, 08003 Barcelona, Catalonia, Spain
| | - Tomàs Marqués-Bonet
- Unitat de Biologia Evolutiva, Departament de Ciències Experimentals i de la Salut, Universitat Pompeu Fabra, Carrer Dr Aiguader 88, 08003 Barcelona, Catalonia, Spain
| | - Olga Fernando
- Unitat de Biologia Evolutiva, Departament de Ciències Experimentals i de la Salut, Universitat Pompeu Fabra, Carrer Dr Aiguader 88, 08003 Barcelona, Catalonia, Spain
- Instituto de Tecnologia Química e Biológica (ITQB), Universidade Nova de Lisboa, Av. da República (EAN) 2781-901 Oeiras, Lisboa, Portugal
| | - Brian Charlesworth
- Institute of Evolutionary Biology, University of Edinburgh, West Mains Road, Edinburgh, Scotland, EH7 3JT, UK
| | - Arcadi Navarro
- Institucio Catalana de Recerca i Estudis Avancats (ICREA), Unitat de Biologia Evolutiva, Departament de Ciències Experimentals i de la Salut, Universitat Pompeu Fabra, Carrer Dr Aiguader 88, 08003 Barcelona, Catalonia, Spain
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Pregelj P, Trinkaus M, Zupan D, Trontelj JJ, Sketelj J. The role of muscle activation pattern and calcineurin in acetylcholinesterase regulation in rat skeletal muscles. J Neurosci 2007; 27:1106-13. [PMID: 17267565 PMCID: PMC6673202 DOI: 10.1523/jneurosci.4182-06.2007] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Acetylcholinesterase (AChE) expression in fast rat muscles is approximately fourfold higher than in slow muscles. We examined whether different muscle activation patterns are responsible for this difference and whether the calcineurin signaling pathway is involved in AChE regulation. The slow soleus and fast extensor digitorum longus (EDL) muscles were directly or indirectly stimulated by a tonic low-frequency or a phasic high-frequency pattern of electric impulses. The phasic, but not tonic, stimulation increased the AChE mRNA levels in denervated soleus muscles to those in the normal EDL and maintained high levels of AChE mRNA in denervated EDL muscles. Therefore, muscle activation pattern is the predominant regulator of extrajunctional AChE expression in rat muscles. Indirect phasic stimulation of innervated muscles, imposed on their natural pattern of neural activation, did not increase the AChE transcript levels in the soleus, whereas a 30% reduction was observed in the EDL muscles. A low number of impulses per day is therefore prerequisite for high AChE expression. Treatment by tacrolimus and cyclosporin A, two inhibitors of calcineurin (but not by a related substance rapamycin, which does not inhibit calcineurin), increased the levels of AChE transcripts in the control soleus muscles and in tonically electrically stimulated soleus and EDL muscles, even to reach those in the control EDL muscles. Therefore, tonic muscle activation reduces the extrajunctional levels of AChE transcripts by activating the calcineurin signaling pathway. In denervated soleus and EDL muscles, tacrolimus did not prevent the reduction of AChE mRNA levels, indicating that a calcineurin-independent suppressive mechanism was involved.
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Affiliation(s)
- Peter Pregelj
- Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, and
| | - Miha Trinkaus
- Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, and
| | - Daša Zupan
- Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, and
| | - Jože J. Trontelj
- Institute of Clinical Neurophysiology, Clinical Center, SI-1000 Ljubljana, Slovenia
| | - Janez Sketelj
- Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, and
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22
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O'Leary DA, Noakes PG, Lavidis NA, Kola I, Hertzog PJ, Ristevski S. Targeting of the ETS factor GABPalpha disrupts neuromuscular junction synaptic function. Mol Cell Biol 2007; 27:3470-80. [PMID: 17325042 PMCID: PMC1899955 DOI: 10.1128/mcb.00659-06] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
The GA-binding protein (GABP) transcription factor has been shown in vitro to regulate the expression of the neuromuscular proteins utrophin, acetylcholine esterase, and acetylcholine receptor subunits delta and epsilon through the N-box promoter motif (5'-CCGGAA-3'), but its in vivo function remains unknown. A single point mutation within the N-box of the gene encoding the acetylcholine receptor epsilon subunit has been identified in several patients suffering from postsynaptic congenital myasthenic syndrome, implicating the GA-binding protein in neuromuscular function and disease. Since conventional gene targeting results in an embryonic-lethal phenotype, we used conditional targeting to investigate the role of GABPalpha in neuromuscular junction and skeletal muscle development. The diaphragm and soleus muscles from mutant mice display alterations in morphology and distribution of acetylcholine receptor clusters at the neuromuscular junction and neurotransmission properties consistent with reduced receptor function. Furthermore, we confirmed decreased expression of the acetylcholine receptor epsilon subunit and increased expression of the gamma subunit in skeletal muscle tissues. Therefore, the GABP transcription factor aids in the structural formation and function of neuromuscular junctions by regulating the expression of postsynaptic genes.
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Affiliation(s)
- Debra A O'Leary
- Monash Institute of Medical Research, Monash University, Clayton, Victoria 3168, Australia
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23
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Zhu H, Gao W, Jiang H, Jin QH, Shi YF, Tsim KWK, Zhang XJ. Regulation of acetylcholinesterase expression by calcium signaling during calcium ionophore A23187- and thapsigargin-induced apoptosis. Int J Biochem Cell Biol 2007; 39:93-108. [PMID: 17000130 DOI: 10.1016/j.biocel.2006.06.012] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2006] [Revised: 06/06/2006] [Accepted: 06/13/2006] [Indexed: 11/23/2022]
Abstract
We have recently reported that acetylcholinesterase expression was induced during apoptosis in various cell types. In the current study we provide evidence to suggest that the induction of acetylcholinesterase expression during apoptosis is regulated by the mobilization of intracellular Ca(2+). During apoptosis, treatment of HeLa and MDA-MB-435s cells with the calcium ionophore A23187 resulted in a significant increase in acetylcholinesterase mRNA and protein levels. Chelation of intracellular Ca(2+) by BAPTA-AM (1,2-bis-(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid-acetoxymethyl ester), an intracellular Ca(2+) chelator, inhibited acetylcholinesterase expression. A23187 also enhanced the stability of acetylcholinesterase mRNA and increased the activity of acetylcholinesterase promoter, effects that were blocked by BAPTA-AM. Perturbations of cellular Ca(2+) homeostasis by thapsigargin resulted in the increase of acetylcholinesterase expression as well as acetylcholinesterase promoter activity during thapsigargin induced apoptosis in HeLa and MDA-MB-435s cells, effects that were also inhibited by BAPTA-AM. We further demonstrated that the transactivation of the human acetylcholinesterase promoter by A23187 and thapsigargin was partially mediated by a CCAAT motif within the -1270 to -1248 fragment of the human acetylcholinesterase promoter. This motif was able to bind to CCAAT binding factor (CBF/NF-Y). These results strongly suggest that cytosolic Ca(2+) plays a key role in acetylcholinesterase regulation during apoptosis induced by A23187 and thapsigargin.
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Affiliation(s)
- Hui Zhu
- Laboratory of Molecular Cell Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Graduate School of the Chinese Academy of Sciences, 320 YueYang Road, Shanghai 200031, China
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Cohen TV, Randall WR. The regulation of acetylcholinesterase by cis-elements within intron I in cultured contracting myotubes. J Neurochem 2006; 98:723-34. [PMID: 16787423 DOI: 10.1111/j.1471-4159.2006.03897.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
The onset of spontaneous contraction in rat primary muscle cultures coincides with an increase in acetylcholinesterase (AChE) activity. In order to establish whether contractile activity modulates the rate of AChE transcript synthesis, and what elements of the gene are determinant, we examined the promoter and intron I in contracting muscle cultures. Ache genomic fragments attached to a luciferase reporter were transfected into muscle cultures that were either electrically stimulated or paralyzed with tetrodotoxin to enhance or inhibit contractions, respectively. Cultures transfected with intron I-containing constructs showed a 2-fold increase in luciferase activity following electrical stimulation, compared to tetrodotoxin treatment, suggesting that this region contains elements responding to contractile activity. Deleting a 780 bp distal region within intron I, containing an N-box element at +890 bp, or introducing a 2-bp mutation within its core sequence, eliminated the contraction-induced response. In contrast, mutating an N-box element at +822 bp had no effect on the response. Furthermore, co-transfecting a dominant negative GA-binding protein (GABP), a transcription factor known to selectively bind N-box elements, reduced the stimulation-mediated increase. Our results suggest that the N-box within intron I at +890 bp is a regulatory element important in the transcriptional response of Ache to contractile activity in muscle.
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Affiliation(s)
- Tatiana V Cohen
- Department of Pharmacology and Experimental Therapeutics, School of Medicine University of Maryland, Baltimore, MD 21201-1559, USA
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25
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Chakkalakal JV, Michel SA, Chin ER, Michel RN, Jasmin BJ. Targeted inhibition of Ca2+/calmodulin signaling exacerbates the dystrophic phenotype in mdx mouse muscle. Hum Mol Genet 2006; 15:1423-35. [PMID: 16551657 DOI: 10.1093/hmg/ddl065] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
In this study, we crossbred mdx mice with transgenic mice expressing a small peptide inhibitor for calmodulin (CaM), known as the CaM-binding protein (CaMBP), driven by the slow fiber-specific troponin I slow promoter. This strategy allowed us to determine the impact of interfering with Ca(2+)/CaM-based signaling in dystrophin-deficient slow myofibers. Consistent with impairments in the Ca(2+)/CaM-regulated enzymes calcineurin and Ca(2+)/CaM-dependent kinase, the nuclear accumulation of nuclear factor of activated T-cell c1 and myocyte enhancer factor 2C was reduced in slow fibers from mdx/CaMBP mice. We also detected significant reductions in the levels of peroxisome proliferator gamma co-activator 1alpha and GA-binding protein alpha mRNAs in slow fiber-rich soleus muscles of mdx/CaMBP mice. In parallel, we observed significantly lower expression of myosin heavy chain I mRNA in mdx/CaMBP soleus muscles. This correlated with fiber-type shifts towards a faster phenotype. Examination of mdx/CaMBP slow muscle fibers revealed significant reductions in A-utrophin, a therapeutically relevant protein that can compensate for the lack of dystrophin in skeletal muscle. In accordance with lower levels of A-utrophin, we noted a clear exacerbation of the dystrophic phenotype in mdx/CaMBP slow fibers as exemplified by several pathological indices. These results firmly establish Ca(2+)/CaM-based signaling as key to regulating expression of A-utrophin in muscle. Furthermore, this study illustrates the therapeutic potential of using targets of Ca(2+)/CaM-based signaling as a strategy for treating Duchenne muscular dystrophy (DMD). Finally, our results further support the concept that strategies aimed at promoting the slow oxidative myofiber program in muscle may be effective in altering the relentless progression of DMD.
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Affiliation(s)
- Joe V Chakkalakal
- Department of Cellular and Molecular Medicine, Centre for Neuromuscular Diseases, Faculty of Medicine, University of Ottawa, Ottawa, Ont., Canada K1H 8M5
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Gardiner K. Transcriptional dysregulation in Down syndrome: predictions for altered protein complex stoichiometries and post-translational modifications, and consequences for learning/behavior genes ELK, CREB, and the estrogen and glucocorticoid receptors. Behav Genet 2006; 36:439-53. [PMID: 16502135 DOI: 10.1007/s10519-006-9051-1] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2005] [Accepted: 08/01/2005] [Indexed: 11/28/2022]
Abstract
The phenotype of Down syndrome, trisomy of chromosome 21, is hypothesized to be produced by the increased expression due to gene dosage of normal chromosome 21 genes. Chromosome 21 encodes a number of proteins that, based on experimental evidence or domain composition, are classed as transcription factors or their co-regulators. Other chromosome 21 proteins contribute to post-translational modification of transcription factors, including their phosphorylation, dephosphorylation and sumoylation. Several of these chromosome 21 proteins and the pathways in which they function have overlapping transcription factor specificities. Thus, altered stoichiometry in complexes and altered levels of activation of individual transcription factors may contribute to the Down syndrome phenotype by perturbation of downstream gene expression. Here we review recent data on four chromosome 21 proteins: NRIP1, GABPA, DYRK1A and SUMO3. We discuss the implications for activation of ELK, CREB, C/EBP alpha, beta estrogen and glucocorticoid receptors, and for expression of BDNF. Each of these proteins is relevant to learning, behavior and/or development and therefore perturbation of their activation may contribute to the Down syndrome phenotype.
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Camp S, Zhang L, Marquez M, de la Torre B, Long JM, Bucht G, Taylor P. Acetylcholinesterase (AChE) gene modification in transgenic animals: functional consequences of selected exon and regulatory region deletion. Chem Biol Interact 2005; 157-158:79-86. [PMID: 16289062 DOI: 10.1016/j.cbi.2005.10.012] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
AChE is an alternatively spliced gene. Exons 2, 3 and 4 are invariantly spliced, and this sequence is responsible for catalytic function. The 3' alternatively spliced exons, 5 and 6, are responsible for AChE disposition in tissue [J. Massoulie, The origin of the molecular diversity and functional anchoring of cholinesterases. Neurosignals 11 (3) (2002) 130-143; Y. Li, S. Camp, P. Taylor, Tissue-specific expression and alternative mRNA processing of the mammalian acetylcholinesterase gene. J. Biol. Chem. 268 (8) (1993) 5790-5797]. The splice to exon 5 produces the GPI anchored form of AChE found in the hematopoietic system, whereas the splice to exon 6 produces a sequence that binds to the structural subunits PRiMA and ColQ, producing AChE expression in brain and muscle. A third alternative RNA species is present that is not spliced at the 3' end; the intron 3' of exon 4 is used as coding sequence and produces the read-through, unanchored form of AChE. In order to further understand the role of alternative splicing in the expression of the AChE gene, we have used homologous recombination in stem cells to produce gene specific deletions in mice. Alternatively and together exon 5 and exon 6 were deleted. A cassette containing the neomycin gene flanked by loxP sites was used to replace the exon(s) of interest. Tissue analysis of mice with exon 5 deleted and the neomycin cassette retained showed very low levels of AChE expression, far less than would have been anticipated. Only the read-through species of the enzyme was produced; clearly the inclusion of the selection cassette disrupted splicing of exon 4 to exon 6. The selection cassette was then deleted in exon 5, exon 6 and exons 5 + 6 deleted mice by breeding to Ella-cre transgenic mice. AChE expression in serum, brain and muscle has been analyzed. Another AChE gene targeted mouse strain involving a region in the first intron, found to be critical for AChE expression in muscle cells [S. Camp, L. Zhang, M. Marquez, B. delaTorre, P. Taylor, Knockout mice with deletions of alternatively spliced exons of Acetylcholinesterase, in: N.C. Inestrosa, E.O. Campus (Eds.), VII International Meeting on Cholinesterases, Pucon-Chile Cholinesterases in the Second Millennium: Biomolecular and Pathological Aspects. P. Universidad Catholica de Chile-FONDAP Biomedicina, 2004, pp. 43-48; R.Y.Y. Chan, C. Boudreau-Larivière, L.A. Angus, F. Mankal, B.J. Jasmin, An intronic enhancer containing an N-box motif is required for synapse- and tissue-specific expression of the acetylcholinesterase gene in skeletal muscle fibers. Proc. Natl. Acad. Sci. USA 96 (1999) 4627-4632], is also presented. The intronic region was floxed and then deleted by mating with Ella-cre transgenic mice. The deletion of this region produced a dramatic phenotype; a mouse with near normal AChE expression in brain and other CNS tissues, but no AChE expression in muscle. Phenotype and AChE tissue activities are compared with the total AChE knockout mouse [W. Xie, J.A. Chatonnet, P.J. Wilder, A. Rizzino, R.D. McComb, P. Taylor, S.H. Hinrichs, O. Lockridge, Postnatal developmental delay and supersensitivity to organophosphate in gene-targeted mice lacking acetylcholinesterase. J. Pharmacol. Exp. Ther. 293 (3) (2000) 896-902].
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Affiliation(s)
- Shelley Camp
- University of California, San Diego, 9500 Gilman Dr., Department of Pharmacology, La Jolla, CA 92093-0636, USA.
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Deschênes-Furry J, Bélanger G, Mwanjewe J, Lunde JA, Parks RJ, Perrone-Bizzozero N, Jasmin BJ. The RNA-binding protein HuR binds to acetylcholinesterase transcripts and regulates their expression in differentiating skeletal muscle cells. J Biol Chem 2005; 280:25361-8. [PMID: 15878846 DOI: 10.1074/jbc.m410929200] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
During myogenic differentiation, acetylcholinesterase (AChE) transcript levels are known to increase dramatically. Although this increase can be attributed in part to increased transcriptional activity, posttranscriptional mechanisms have also been implicated in the high levels of AChE mRNA in myotubes. In this study, we observed that transfection of a luciferase reporter construct containing the full-length AChE 3'-untranslated region (UTR) resulted in significantly higher (5-fold) luciferase activity in differentiated myotubes versus myoblasts. RNA-electrophoretic mobility shift assays (REMSAs) performed with a full-length AChE 3'-UTR probe and the AU-rich element revealed that the intensity of RNA-binding protein complexes increased as myogenic differentiation proceeded. Using several complementary approaches including supershift REMSA, mRNA-binding protein pull-down assays, and immunoprecipitation followed by reverse transcription-PCR, we found that the mRNA-stabilizing protein HuR interacts directly with AChE transcripts. Stable overexpression of HuR in C2C12 cells increased the expression of endogenous AChE transcripts as well as that of the luciferase reporter construct containing the AChE 3'-UTR. In vitro stability assays performed with protein extracts from these cells versus controls resulted in a slower rate of AChE mRNA decay. The down-regulation of HuR expression mediated through small interfering RNA further confirmed the role of HuR in the regulation of AChE mRNA levels. Taken together, these studies demonstrate that HuR interacts with the AChE 3'-UTR to regulate posttranscriptionally the expression of AChE mRNA during myogenic differentiation.
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Affiliation(s)
- Julie Deschênes-Furry
- Department of Cellular and Molecular Medicine, Faculty of Medicine, University of Ottawa, Ottawa, Ontario K1H 8M5, Canada
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Niu DK, Hou WR, Li SW. mRNA-mediated intron losses: evidence from extraordinarily large exons. Mol Biol Evol 2005; 22:1475-81. [PMID: 15788745 DOI: 10.1093/molbev/msi138] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Multicellular eukaryotes that have high intron density have their introns almost evenly distributed within genes, but unicellular eukaryotes that are generally intron poor have their introns asymmetrically distributed toward the 5' ends of genes. This was explained by homologous recombination of genomic DNA with the cDNA reverse transcribed from the 3' polyadenylated tail of spliced mRNA. This paper is to study whether mRNA-mediated intron losses have ever occurred in multicellular eukaryotes. If intron losses were mRNA-mediated, adjacent introns should be commonly lost together. A direct result is fusion of several previously adjacent exons and producing a large exon. We found that extraordinarily large exons (ELEs) are common not only in unicellular eukaryotes but also in multicellular eukaryotes. The percentage of genes having ELEs is negatively correlated with intron abundance. In addition, the number of lost introns estimated from the relative lengths of ELEs is negatively correlated with the number of extant introns. These results support mRNA-mediated intron losses in all eukaryotes. Moreover, we found that the ELEs of intron-common eukaryotes (with more than 0.5 intron per gene on average) are not only located at 3' ends but also at 5' ends and the middle of genes. This is contrary to what would be expected if the involved cDNAs were reverse transcribed from the 3' polyadenosine ends. A remarkable difference in intron distribution was revealed between intron-rare eukaryotes and intron-common eukaryotes. The intron-rare eukaryotes show very strong 5'-biased intron distribution, whereas the intron-common eukaryotes display even intron distribution or only weak 5'-biased distribution. We suspected that intron losses from 3' end of genes may be limited in intron-rare eukaryotes. The intron losses from intron-common eukaryotes should have other priming mechanism, like self-primed reverse transcription.
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Affiliation(s)
- Deng-Ke Niu
- Ministry of Education Key Laboratory for Biodiversity Science and Ecological Engineering, College of Life Sciences, Beijing Normal University, Beijing, China.
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30
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Meng F, Zolova O, Kokorina NA, Dobretsova A, Wight PA. Characterization of an intronic enhancer that regulates myelin proteolipid protein (Plp) gene expression in oligodendrocytes. J Neurosci Res 2005; 82:346-56. [PMID: 16155935 DOI: 10.1002/jnr.20640] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
The myelin proteolipid protein (Plp) gene is expressed in oligodendrocytes and encodes the most abundant protein (approximately 50%) present in mature myelin from the central nervous system (CNS). Plp gene activity is low to nonexistent early in development but sharply increases, concurrently with the active myelination period of CNS development. Work from our laboratory suggests that the temporal regulation of Plp gene expression in mice is mediated by a positive regulatory element located within Plp intron 1 DNA. We have termed this regulatory element/region ASE (for antisilencer/enhancer). The ASE is situated approximately 1 kb downstream of exon 1 DNA and encompasses nearly 100 bp. To understand the mechanisms by which the ASE augments Plp gene expression in oligodendrocytes, Plp-lacZ constructs were generated and transfected into a mouse oligodendroglial cell line (N20.1). Results presented here demonstrate that upstream regulatory elements in the Plp promoter/5'-flanking DNA are not required for ASE activity; the ASE worked perfectly well when the thymidine kinase (TK) promoter was substituted for the Plp promoter. However, the relative location of the ASE appears to be important. When placed upstream of 2.4 kb of Plp 5'-flanking DNA, or downstream of the lacZ expression cassette, the ASE was no longer effective. Thus, the ASE might have to be in the context of the intron in order to function. To begin to identify the crucial nucleotides within the ASE, orthologous sequences from rat, human, cow, and pig Plp genes were swapped for the mouse sequence. Results presented here demonstrate that the orthologous sequence from rat can substitute for the mouse ASE, unlike those from human, cow, or pig.
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Affiliation(s)
- Fanxue Meng
- Department of Physiology and Biophysics, University of Arkansas for Medical Sciences, Little Rock, Arkansas 72205, USA
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31
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Rodova M, Brownback K, Werle MJ. Okadaic acid augments utrophin in myogenic cells. Neurosci Lett 2004; 363:163-7. [PMID: 15172107 DOI: 10.1016/j.neulet.2004.04.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2004] [Revised: 03/05/2004] [Accepted: 04/01/2004] [Indexed: 11/21/2022]
Abstract
Duchenne muscular dystrophy is a fatal childhood disease caused by mutations that abolish the expression of dystrophin in muscle. Utrophin is a paralogue of dystrophin and can functionally replace it in skeletal muscle. A potential therapeutic approach is to increase utrophin levels in muscle. One way to achieve this aim is to increase the expression of the utrophin gene at a transcriptional level via promoter activation. In this study, we have shown that utrophin A mRNA levels can be induced by okadaic acid in murine myogenic C2C12 cells. We have found that a utrophin A promoter reporter can be induced by Sp1 in C2C12 myoblasts, but not in myotubes. This activation can be enhanced by okadaic acid treatment. Our data suggest that this induction is due to Sp1 phosphorylation during myogenesis and thus, utrophin expression in muscle could be regulated by treatment with phosphatase inhibitors. Control of utrophin promoter activation could then be used to increase the expression of utrophin, and thus ameliorate the symptoms of Duchenne muscular dystrophy.
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MESH Headings
- Animals
- Base Sequence/genetics
- Cell Differentiation/drug effects
- Cell Differentiation/genetics
- Cell Line
- Cytoskeletal Proteins/genetics
- Enzyme Inhibitors/pharmacology
- Enzyme Inhibitors/therapeutic use
- Gene Expression Regulation, Developmental/drug effects
- Gene Expression Regulation, Developmental/genetics
- Humans
- Membrane Proteins/genetics
- Mice
- Molecular Sequence Data
- Muscle Fibers, Skeletal/drug effects
- Muscle Fibers, Skeletal/metabolism
- Muscular Dystrophy, Duchenne/genetics
- Muscular Dystrophy, Duchenne/metabolism
- Muscular Dystrophy, Duchenne/therapy
- Myoblasts, Skeletal/drug effects
- Myoblasts, Skeletal/metabolism
- Okadaic Acid/pharmacology
- Phosphoric Monoester Hydrolases/antagonists & inhibitors
- Phosphoric Monoester Hydrolases/metabolism
- Phosphorylation
- Promoter Regions, Genetic/genetics
- RNA, Messenger/drug effects
- RNA, Messenger/metabolism
- Sp1 Transcription Factor/genetics
- Sp1 Transcription Factor/metabolism
- Sp1 Transcription Factor/pharmacology
- Up-Regulation/drug effects
- Up-Regulation/genetics
- Utrophin
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Affiliation(s)
- Marianna Rodova
- Department of Anatomy and Cell Biology, University of Kansas Medical Center, Kansas City, KS 66160, USA
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Tung EKK, Choi RCY, Siow NL, Jiang JXS, Ling KKY, Simon J, Barnard EA, Tsim KWK. P2Y2 receptor activation regulates the expression of acetylcholinesterase and acetylcholine receptor genes at vertebrate neuromuscular junctions. Mol Pharmacol 2004; 66:794-806. [PMID: 15258260 DOI: 10.1124/mol.104.003269] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
At the vertebrate neuromuscular junction (nmj), ATP is known to be coreleased with acetylcholine from the synaptic vesicles. We have previously shown that the P2Y1 receptor is localized at the nmj. Here, we extend the findings to show that another nucleotide receptor, P2Y2, is also localized there and with P2Y1 jointly mediates trophic responses to ATP. The P2Y2 receptor mRNA in rat muscle increased during development and peaked in adulthood. The P2Y2 receptor protein was shown to become restricted to the nmjs during embryonic development, in chick and in rat. In both rat and chick myotubes, P2Y1 and P2Y2 are expressed, increasing with differentiation, but P2Y4 is absent. The P2Y2 agonist UTP stimulated there inositol trisphosphate production and phosphorylation of extracellular signal-regulated kinases, in a dose-dependent manner. These UTP-induced responses were insensitive to the P2Y1-specific antagonist MRS 2179 (2'-deoxy-N6-methyl adenosine 3',5'-diphosphate diammonium salt). In differentiated myotubes, P2Y2 activation induced expression of acetylcholinesterase (AChE) protein (but not control alpha-tubulin). This was shown to arise from AChE promoter activation, mediated by activation of the transcription factor Elk-1. Two Elk-1-responsive elements, located in intron-1 of the AChE promoter, were found by mutation to act in this gene activation initiated at the P2Y2 receptor and also in that initiated at the P2Y1 receptor. Furthermore, the promoters of different acetylcholine receptor subunits were also stimulated by application of UTP to myotubes. These results indicate that ATP regulates postsynaptic gene expressions via a common pathway triggered by the activation of P2Y1 and P2Y2 receptors at the nmjs.
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Affiliation(s)
- Edmund K K Tung
- Department of Biology, The Hong Kong University of Science and Technology, Clear Water Bay Rd., Hong Kong SAR, China
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33
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Chamary JV, Hurst LD. Similar rates but different modes of sequence evolution in introns and at exonic silent sites in rodents: evidence for selectively driven codon usage. Mol Biol Evol 2004; 21:1014-23. [PMID: 15014158 DOI: 10.1093/molbev/msh087] [Citation(s) in RCA: 75] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
In mammals divergence at fourfold degenerate sites in codons (K(4)) and intronic sequence (K(i)) are both used to estimate the mutation rate, under the supposition that both evolve neutrally. Does it matter which of these we use? Using either class of sequence can be defended because (1) K(4) is the same as K(i) (at least in rodents) and (2) there is no selectively driven codon usage (hence no systematic selection on third sites). Here we re-examine these findings using 560 introns (for 136 genes) in the mouse-rat comparison, aligned by eye and using a new maximum likelihood protocol. We find that the rate of evolution at fourfold sites and at intronic sites is similar in magnitude, but only after eliminating putatively constrained sites from introns (first introns and sites flanking intron-exon junctions). Any approximate congruence between the two rates is not, however, owing to an underlying similarity in the mode of sequence evolution. Some dinucleotides are hypermutable and differently abundant in exons and introns (e.g., CpGs). More importantly, after controlling for relative abundance, all dinucleotides starting with A or T are more prevalent in mismatches in exons than in introns, whereas C-starting dinucleotides (except CG) are more common in introns. Although C content at intronic sites is lower than at flanking fourfold sites, G content is similar, demonstrating that there exists a strong strand-specific preference for C nucleotides that is unique to exons. Transcription-coupled mutational processes and biased gene conversion cannot explain this, as they should affect introns and flanking exons equally. Therefore, by elimination, we propose this to be strong evidence for selectively driven codon usage in mammals.
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Affiliation(s)
- Jean-Vincent Chamary
- Department of Biology and Biochemistry, University of Bath, Bath, United Kingdom
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Sunesen M, Huchet-Dymanus M, Christensen MO, Changeux JP. Phosphorylation-elicited quaternary changes of GA binding protein in transcriptional activation. Mol Cell Biol 2003; 23:8008-18. [PMID: 14585962 PMCID: PMC262348 DOI: 10.1128/mcb.23.22.8008-8018.2003] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Enrichment of nicotinic acetylcholine receptors (nAChR) on the tip of the subjunctional folds of the postsynaptic membrane is a central event in the development of the vertebrate neuromuscular junction. This is attained, in part, through a selective transcription in the subsynaptic nuclei, and it has recently been shown that the GA binding protein (GABP) plays an important role in this compartmentalized expression. The neural factor heregulin (HRG) activates nAChR transcription in cultured cells by stimulating a signaling cascade of protein kinases. Hence, it is speculated that GABP becomes activated by phosphorylation, but the mechanism has remained elusive. To fully understand the consequences of GABP phosphorylation, we examined the effect of heregulin-elicited GABP phosphorylation on cellular localization, DNA binding, transcription, and mobility. We demonstrate that HRG-elicited phosphorylation dramatically changes the transcriptional activity and mobility of GABP. While phosphorylation of GABPbeta seems to be dispensable for these changes, phosphorylation of GABPalpha is crucial. Using fluorescence resonance energy transfer, we furthermore showed that phosphorylation of threonine 280 in GABPalpha triggers reorganizations of the quaternary structure of GABP. Taken together, these results support a model in which phosphorylation-elicited structural changes of GABP enable engagement in certain interactions leading to transcriptional activation.
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Affiliation(s)
- Morten Sunesen
- Laboratoire Récepteurs et Cognition, CNRS URA 2182, Institut Pasteur, 25 rue du Dr. Roux, 75724 Paris Cedex 15, France
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Méjat A, Ravel-Chapuis A, Vandromme M, Schaeffer L. Synapse-specific gene expression at the neuromuscular junction. Ann N Y Acad Sci 2003; 998:53-65. [PMID: 14592863 DOI: 10.1196/annals.1254.008] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Agrin is the key neural factor that controls muscle postsynaptic differentiation, including the induction of synapse-specific transcription via neuregulins. In 1995, the promoter element responsible for the targeting of AChR delta and epsilon gene transcription to the skeletal muscle subsynaptic area was identified. This element, named N-box, recruits the Ets-related transcription factor GABP to AChR delta and epsilon promoters, and both the N-box and GABP are required to obtain transcriptional stimulation by neuregulins. The physiological importance of the N-box has been definitively established with the discovery of myasthenic families carrying single-point mutations in the N-box of the AChR epsilon gene promoter and showing reduced levels of AChR epsilon subunit expression. The control of synapse-specific transcription by agrin and neuregulins through the N-box and GABP is not restricted to the case of AChR genes. The same regulation holds true for the ACh esterase and utrophin genes, thus showing that nerve-induced transcriptional activation of several synapse-specific genes is triggered by a common mechanism involving agrin, neuregulins, and ultimately the N-box and Ets-related transcription factors.
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Affiliation(s)
- Alexandre Méjat
- Equipe Différenciation Neuromusculaire, UMR 5161 CNRS/ENS, Ecole Normale Supérieure de Lyon, Lyon, France
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36
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Jiang JXS, Choi RCY, Siow NL, Lee HHC, Wan DCC, Tsim KWK. Muscle induces neuronal expression of acetylcholinesterase in neuron-muscle co-culture: transcriptional regulation mediated by cAMP-dependent signaling. J Biol Chem 2003; 278:45435-44. [PMID: 12963741 DOI: 10.1074/jbc.m306320200] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Presynaptic motor neuron synthesizes and secretes acetylcholinesterase (AChE) at vertebrate neuromuscular junctions. In order to determine the retrograde role of muscle in regulating the expression of AChE in motor neuron, a chimeric co-culture of NG108-15 cell, a cholinergic cell line that resembles motor neuron, with chick myotube was established to mimic the neuromuscular contact in vitro. A DNA construct of human AChE promoter tagged with luciferase (pAChE-Luc) was stably transfected into NG108-15 cells. The co-culture with myotubes robustly stimulated the promoter activity as well as the endogenous expression of AChE in pAChE-Luc stably transfected NG108-15 cells. Muscle extract derived from chick embryos when applied onto pAChE-Luc-expressing NG108-15 cells induced expressions of AChE promoter and endogenous AChE. The cAMP-responsive element mutation on human AChE promoter blocked the muscle-induced AChE transcriptional activity in cultured NG108-15 cells either in co-culturing with myotube or in applying muscle extract. The accumulation of intracellular cAMP and the phosphorylation of cAMP-responsive element-binding protein in cultured NG108-15 cells were stimulated by applied muscle extract. Part of the muscle-induced signaling was mimicked by application of calcitonin gene-related peptide in cultured NG108-15 cells. These results suggest the muscle-induced neuronal AChE expression in the co-culture is mediated by a cAMP-dependent signaling.
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Affiliation(s)
- Joy X S Jiang
- Department of Biology and Molecular Neuroscience Center, The Hong Kong University of Science and Technology, Clear Water Bay Road, Kowloon, Hong Kong, China
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37
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Takahashi K, Nishiyama C, Hasegawa M, Akizawa Y, Ra C. Regulation of the human high affinity IgE receptor beta-chain gene expression via an intronic element. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2003; 171:2478-84. [PMID: 12928396 DOI: 10.4049/jimmunol.171.5.2478] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The high affinity IgE receptor, FcepsilonRI, is a key regulatory molecule in the allergic reaction. By screening for cis-acting elements over the entire region of the human FcepsilonRI beta-chain gene, a sequence located in the fourth intron was revealed to serve as a repressor element. This element was recognized by a transcription factor, myeloid zinc finger protein 1 (MZF-1). Introduction of MZF-1 antisense inhibited the suppressive effect of the element on the beta-chain promoter and increased the mRNA for the beta-chain in KU812 cells, indicating that MZF-1 repressed human FcepsilonRI beta-chain gene expression via the element in the fourth intron. Furthermore, it was suggested that a cofactor binding with MZF-1, whose expression level was different among the cell types, was required for transcriptional repression by MZF-1.
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Affiliation(s)
- Kyoko Takahashi
- Division of Molecular Cell Immunology and Allergology, Nihon University Graduate School of Medical Sciences, 30-1 Oyaguchi, Kami-machi, Itabashi-ku, Tokyo 173-8610, Japan
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38
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Bélanger G, Stocksley MA, Vandromme M, Schaeffer L, Furic L, DesGroseillers L, Jasmin BJ. Localization of the RNA-binding proteins Staufen1 and Staufen2 at the mammalian neuromuscular junction. J Neurochem 2003; 86:669-77. [PMID: 12859680 DOI: 10.1046/j.1471-4159.2003.01883.x] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Staufen is an RNA-binding protein, first identified for its role in oogenesis and CNS development in Drosophila. Two mammalian homologs of Staufen have been identified and shown to bind double-stranded RNA and tubulin, and to function in the somatodendritic transport of mRNA in neurons. Here, we examined whether Staufen proteins are expressed in skeletal muscle in relation to the neuromuscular junction. Immunofluorescence experiments revealed that Staufen1 (Stau1) and Staufen2 (Stau2) accumulate preferentially within the postsynaptic sarcoplasm of muscle fibers as well as at newly formed ectopic synapses. Western blot analyses showed that the levels of Stau1 and Stau2 are greater in slow muscles than in fast-twitch muscles. Muscle denervation induced a significant increase in the expression of Stau1 and Stau2 in the extrasynaptic compartment of both fast and slow muscles. Consistent with these observations, we also demonstrated that expression of Stau1 and Stau2 is increased during myogenic differentiation and that treatment of myotubes with agrin and neuregulin induces a further increase in the expression of both Staufen proteins. We propose that Stau1 and Stau2 are key components of the postsynaptic apparatus in muscle, and that they contribute to the maturation and plasticity of the neuromuscular junction.
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MESH Headings
- Agrin/pharmacology
- Animals
- Blotting, Western
- Cell Differentiation/drug effects
- Cell Differentiation/physiology
- Cell Line
- Mice
- Mice, Inbred C57BL
- Muscle Denervation
- Muscle Fibers, Fast-Twitch/chemistry
- Muscle Fibers, Fast-Twitch/metabolism
- Muscle Fibers, Skeletal/cytology
- Muscle Fibers, Skeletal/drug effects
- Muscle Fibers, Skeletal/metabolism
- Muscle Fibers, Slow-Twitch/chemistry
- Muscle Fibers, Slow-Twitch/metabolism
- Muscle, Skeletal/chemistry
- Muscle, Skeletal/cytology
- Muscle, Skeletal/metabolism
- Myoblasts/cytology
- Myoblasts/metabolism
- Nerve Tissue Proteins/analysis
- Nerve Tissue Proteins/biosynthesis
- Neuregulins/pharmacology
- Neuromuscular Junction/metabolism
- RNA-Binding Proteins/analysis
- RNA-Binding Proteins/biosynthesis
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Affiliation(s)
- Guy Bélanger
- Department of Cellular and Molecular Medicine, and Center for Neuromuscular Disease, Faculty of Medicine, University of Ottawa, Ottawa, Ontario, Canada
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39
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ATP acts via P2Y1 receptors to stimulate acetylcholinesterase and acetylcholine receptor expression: transduction and transcription control. J Neurosci 2003. [PMID: 12805285 DOI: 10.1523/jneurosci.23-11-04445.2003] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
At the vertebrate neuromuscular junction ATP is known to stabilize acetylcholine in the synaptic vesicles and to be co-released with it. We have shown previously that a nucleotide receptor, the P2Y1 receptor, is localized at the junction, and we propose that this mediates a trophic role for synaptic ATP there. Evidence in support of this and on its mechanism is given here. With the use of chick or mouse myotubes expressing promoter-reporter constructs from genes of acetylcholinesterase (AChE) or of the acetylcholine receptor subunits, P2Y1 receptor agonists were shown to stimulate the transcription of each of those genes. The pathway to activation of the AChE gene was shown to involve protein kinase C and intracellular Ca 2+ release. Application of dominant-negative or constitutively active mutants, or inhibitors of specific kinases, showed that it further proceeds via some of the known intermediates of extracellular signal-regulated kinase phosphorylation. In both chick and mouse myotubes this culminates in activation of the transcription factor Elk-1, confirmed by gel mobility shift assays and by the nuclear accumulation of phosphorylated Elk-1. All of the aforementioned activations by agonist were amplified when the content of P2Y1 receptors was boosted by transfection, and the activations were blocked by a P2Y1-selective antagonist. Two Elk-1 binding site sequences present in the AChE gene promoter were jointly sufficient to drive ATP-induced reporter gene transcription. Thus ATP regulates postsynaptic gene expression via a pathway to a selective transcription factor activation.
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40
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Choi RCY, Siow NL, Cheng AWM, Ling KKY, Tung EKK, Simon J, Barnard EA, Tsim KWK. ATP acts via P2Y1 receptors to stimulate acetylcholinesterase and acetylcholine receptor expression: transduction and transcription control. J Neurosci 2003; 23:4445-56. [PMID: 12805285 PMCID: PMC6740789] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/03/2023] Open
Abstract
At the vertebrate neuromuscular junction ATP is known to stabilize acetylcholine in the synaptic vesicles and to be co-released with it. We have shown previously that a nucleotide receptor, the P2Y1 receptor, is localized at the junction, and we propose that this mediates a trophic role for synaptic ATP there. Evidence in support of this and on its mechanism is given here. With the use of chick or mouse myotubes expressing promoter-reporter constructs from genes of acetylcholinesterase (AChE) or of the acetylcholine receptor subunits, P2Y1 receptor agonists were shown to stimulate the transcription of each of those genes. The pathway to activation of the AChE gene was shown to involve protein kinase C and intracellular Ca 2+ release. Application of dominant-negative or constitutively active mutants, or inhibitors of specific kinases, showed that it further proceeds via some of the known intermediates of extracellular signal-regulated kinase phosphorylation. In both chick and mouse myotubes this culminates in activation of the transcription factor Elk-1, confirmed by gel mobility shift assays and by the nuclear accumulation of phosphorylated Elk-1. All of the aforementioned activations by agonist were amplified when the content of P2Y1 receptors was boosted by transfection, and the activations were blocked by a P2Y1-selective antagonist. Two Elk-1 binding site sequences present in the AChE gene promoter were jointly sufficient to drive ATP-induced reporter gene transcription. Thus ATP regulates postsynaptic gene expression via a pathway to a selective transcription factor activation.
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MESH Headings
- Acetylcholinesterase/genetics
- Acetylcholinesterase/metabolism
- Adenosine Diphosphate/analogs & derivatives
- Adenosine Diphosphate/pharmacology
- Adenosine Triphosphate/pharmacology
- Adenosine Triphosphate/physiology
- Animals
- Calcium/metabolism
- Cells, Cultured
- Chick Embryo
- Cytosol/metabolism
- DNA-Binding Proteins
- Gene Expression Regulation/drug effects
- Gene Expression Regulation/physiology
- Genes, Reporter
- Mice
- Mitogen-Activated Protein Kinases/metabolism
- Muscle Fibers, Skeletal/cytology
- Muscle Fibers, Skeletal/drug effects
- Muscle Fibers, Skeletal/metabolism
- Myoblasts/cytology
- Myoblasts/metabolism
- Neuromuscular Junction/metabolism
- Phosphorylation/drug effects
- Promoter Regions, Genetic/physiology
- Protein Kinase C/metabolism
- Proto-Oncogene Proteins/metabolism
- Receptors, Cholinergic/biosynthesis
- Receptors, Cholinergic/genetics
- Receptors, Purinergic P2/genetics
- Receptors, Purinergic P2/metabolism
- Receptors, Purinergic P2Y1
- Signal Transduction/drug effects
- Signal Transduction/physiology
- Thionucleotides/pharmacology
- Transcription Factors
- Transcription, Genetic/physiology
- Transduction, Genetic
- ets-Domain Protein Elk-1
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Affiliation(s)
- Roy C Y Choi
- Department of Biology and Molecular Neuroscience Center, Hong Kong University of Science and Technology, Hong Kong, China
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41
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Lacazette E, Le Calvez S, Gajendran N, Brenner HR. A novel pathway for MuSK to induce key genes in neuromuscular synapse formation. J Cell Biol 2003; 161:727-36. [PMID: 12756238 PMCID: PMC2199368 DOI: 10.1083/jcb.200210156] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
At the developing neuromuscular junction the Agrin receptor MuSK is the central organizer of subsynaptic differentiation induced by Agrin from the nerve. The expression of musk itself is also regulated by the nerve, but the mechanisms involved are not known. Here, we analyzed the activation of a musk promoter reporter construct in muscle fibers in vivo and in cultured myotubes, using transfection of multiple combinations of expression vectors for potential signaling components. We show that neuronal Agrin by activating MuSK regulates the expression of musk via two pathways: the Agrin-induced assembly of muscle-derived neuregulin (NRG)-1/ErbB, the pathway thought to regulate acetylcholine receptor (AChR) expression at the synapse, and via a direct shunt involving Agrin-induced activation of Rac. Both pathways converge onto the same regulatory element in the musk promoter that is also thought to confer synapse-specific expression to AChR subunit genes. In this way, a positive feedback signaling loop is established that maintains musk expression at the synapse when impulse transmission becomes functional. The same pathways are used to regulate synaptic expression of AChR epsilon. We propose that the novel pathway stabilizes the synapse early in development, whereas the NRG/ErbB pathway supports maintenance of the mature synapse.
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Affiliation(s)
- Eric Lacazette
- Department of Physiology, University of Basel, CH-4056 Basel, Switzerland
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42
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Pregelj P, Crne-Finderle N, Sketelj J. Effect of thyroid hormones on acetylcholinesterase mRNA levels in the slow soleus and fast extensor digitorum longus muscles of the rat. Neuroscience 2003; 116:657-67. [PMID: 12573709 DOI: 10.1016/s0306-4522(02)00693-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
In the rat, the level of acetylcholinesterase messenger RNA in the typical slow soleus muscles is only about 20-30% of that in the fast extensor digitorum longus muscles. The expression of contractile proteins in muscles is influenced by thyroid hormones and hyperthyroidism makes the slow soleus muscle faster. The influence of thyroid hormones on the levels of acetylcholinesterase messenger RNA level in the slow soleus and fast extensor digitorum longus muscle of the rat was studied in order to examine the effect of thyroid hormones on muscle acetylcholinesterase expression. Hyperthyroidism was induced in rats by daily thyroid hormone injection or thyroid hormone releasing tablet implantation. Hind-limb suspension was applied to produce muscle unloading. Muscle denervation or reinnervation was achieved by sciatic nerve transection or crush. Acetylcholinesterase messenger RNA levels were analyzed by Northern blots and evaluated densitometrically. Hyperthyroidism increased the levels of acetylcholinesterase messenger RNA in the slow soleus muscles close to the levels in the fast extensor digitorum longus. The effect was the same in the unloaded soleus muscles. Acetylcholinesterase expression increased also in the absence of innervation (denervation), in the presence of changed nerve activation pattern (reinnervation), and under enhanced tonic neural activation of the soleus muscle (electrical stimulation). However, the changes were substantially smaller than those observed in the control soleus muscles. Enhancement of acetylcholinesterase expression in the soleus muscles by the thyroid hormones is, therefore, at last in part due to hormonal effect on the muscle itself. On the contrary, increased level of the thyroid hormones had no influence on acetylcholinesterase expression in the normal fast extensor digitorum longus muscles. However, some enhancing influence was apparent whenever the total number of nerve-induced muscle activations per day in the extensor digitorum longus muscle was increased. Thyroid hormones seem to be an independent extrinsic factor of acetylcholinesterase regulation in the slow soleus muscle.
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Affiliation(s)
- P Pregelj
- Institute of Pathophysiology, School of Medicine, University of Ljubljana, Slovenia.
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43
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Deschenes-Furry J, Belanger G, Perrone-Bizzozero N, Jasmin BJ. Post-transcriptional regulation of acetylcholinesterase mRNAs in nerve growth factor-treated PC12 cells by the RNA-binding protein HuD. J Biol Chem 2003; 278:5710-7. [PMID: 12468554 DOI: 10.1074/jbc.m209383200] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Expression of acetylcholinesterase (AChE) is greatly enhanced during neuronal differentiation, but the nature of the molecular mechanisms remains to be fully defined. In this study, we observed that nerve growth factor treatment of PC12 cells leads to a progressive increase in the expression of AChE transcripts, reaching approximately 3.5-fold by 72 h. Given that the AChE 3'-untranslated region (UTR) contains an AU-rich element, we focused on the potential role of the RNA-binding protein HuD in mediating the increase in AChE mRNA seen in differentiating neurons. Using PC12 cells engineered to stably express HuD or an antisense to HuD, our studies indicate that HuD can regulate the abundance of AChE transcripts in neuronal cells. Furthermore, transfection of a reporter construct containing the AChE 3'-UTR showed that this 3'-UTR can increase expression of the reporter gene product in cells expressing HuD but not in cells expressing the antisense. RNA gel shifts and Northwestern blots revealed an increase in the binding of several protein complexes in differentiated neurons. Immunoprecipitation experiments demonstrated that HuD can bind directly AChE transcripts. These results show the importance of post-transcriptional mechanisms in regulating AChE expression in differentiating neurons and implicate HuD as a key trans-acting factor in these events.
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Affiliation(s)
- Julie Deschenes-Furry
- Department of Cellular and Molecular Medicine and Centre for Neuromuscular Disease, Faculty of Medicine, University of Ottawa, Ottawa, Ontario K1H 8M5, Canada
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44
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Chakkalakal JV, Jasmin BJ. Localizing synaptic mRNAs at the neuromuscular junction: it takes more than transcription. Bioessays 2003; 25:25-31. [PMID: 12508279 DOI: 10.1002/bies.10205] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The neuromuscular junction has been used for several decades as an excellent model system to examine the cellular and molecular events involved in the formation and maintenance of a differentiated chemical synapse. In this context, several laboratories have focused their efforts over the last 15 years on the important contribution of transcriptional mechanisms to the regulation of the development and plasticity of the postsynaptic apparatus in muscle fibers. Converging lines of evidence now indicate that post-transcriptional events, operating at the level of mRNA stability and targeting, are likely to also play key roles at the neuromuscular junction. Here, we present the recent findings highlighting the role of these additional molecular events and extend our review to include data showing that post-transcriptional events are also important in the control of the expression of genes encoding synaptic proteins in muscle cells placed under different conditions. Finally, we discuss the possibility that mis-regulation of post-transcriptional events can occur in certain neuromuscular diseases and cause abnormalities of the neuromuscular junction.
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Affiliation(s)
- Joe V Chakkalakal
- Department of Cellular and Molecular Medicine, Faculty of Medicine, University of Ottawa, Ontario, Canada
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45
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Weill CO, Vorlová S, Berna N, Ayon A, Massoulié J. Transcriptional regulation of gene expression by the coding sequence: An attempt to enhance expression of human AChE. Biotechnol Bioeng 2002; 80:490-7. [PMID: 12355459 DOI: 10.1002/bit.10392] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
In a previous report, Morel and Massoulié showed that Bungarus AChE (bBAChE) is produced more efficiently than rat AChE in various expression systems, mainly because the Bungarus coding sequence exerts a stimulatory effect on transcription (Morel and Massoulié, 2000). They reported that a 5' Bungarus fragment could partially transfer this property to a CAT expression vector. This appeared to offer the possibility of increasing the production of recombinant proteins. In the present paper, we show that insertion of this fragment in the transcribed region, before the polyadenylation site, may have either stimulatory or inhibitory effects, depending on the vector and on the reporter gene. Since the stimulatory effect of Bungarus coding region could not be attached to a small number of discrete motifs, we reasoned that it might result from a general feature of the sequence. Therefore it might be possible to partially transfer this property to the very homologous human AChE (hHAChE) coding sequence by modifications based on synonymous codons, which increased nucleotide identity between the 5' fragment (721 nucleotides) of bBAChE and hHAChE from 71% to 85%. The production of human AChE in transfected COS cells was increased nearly 2-fold with this modified construct, but still remained about 4-fold smaller than that of Bungarus AChE. There was no change in expression level in transformed Pichia pastoris. We thus confirm that coding sequences can strongly influence gene expression, but in a manner that depends on the context and cannot yet be predicted.
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Affiliation(s)
- Claire O Weill
- Laboratoire de Neurobiologie Cellulaire et Moléculaire, ENS, CNRS UMR 8544, Paris, France
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46
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Perry C, Sklan EH, Birikh K, Shapira M, Trejo L, Eldor A, Soreq H. Complex regulation of acetylcholinesterase gene expression in human brain tumors. Oncogene 2002; 21:8428-41. [PMID: 12466963 DOI: 10.1038/sj.onc.1205945] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2002] [Revised: 07/31/2002] [Accepted: 08/07/2002] [Indexed: 11/09/2022]
Abstract
To study the regulation of acetylcholinesterase (AChE) gene expression in human brain tumors, 3' splice variants of AChE mRNA and potentially relevant transcription factor mRNAs were labeled in primary astrocytomas and melanomas. AChE-S and AChE-R mRNA, as well as Runx1/AML1 mRNA accumulated in astrocytomas in correlation with tumor aggressiveness, but neither HNF3beta nor c-fos mRNA was observed in melanoma and astrocytomas. Immunohistochemistry demonstrated nuclear Runx1/AML1 and cellular AChE-S and AChE-R in melanomas, however, only AChE-S, and not the secreted AChE-R variant, was retained in astrocyte tumor cells. Runx1/AML1 revealed weak linkage with ACHE promoter sequences, yet enhanced ACHE gene expression in co-transfected COS1 cells. The p300 co-activator and the ACHE promoter's distal enhancer facilitated this effect, which was independent of much of the Runx1/AML1 trans-activation domain. Surprisingly, GASP, a fusion product of green fluorescence protein (GFP) and ASP(67), a peptide composed of the 67 C-terminal amino acid residues of AChE-S, localized to COS1 cell nuclei. However, GARP, the corresponding fusion product of GFP with a peptide having the 51 C-terminal residues of AChE-E or GFP alone, remained cytoplasmic. Runx1/AML1 exhibited improved nuclear retention in GASP-expressing COS1 cells, suggesting modulated nuclear localization processes. Together, these findings reveal brain tumor-specific regulation of both expression and cellular retention of variant ACHE gene products.
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Affiliation(s)
- Chava Perry
- Department of Biological Chemistry, The Institute of Life Sciences, The Hebrew University of Jerusalem, Israel 91904
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47
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de Kerchove d'Exaerde A, Cartaud J, Ravel-Chapuis A, Seroz T, Pasteau F, Angus LM, Jasmin BJ, Changeux JP, Schaeffer L. Expression of mutant Ets protein at the neuromuscular synapse causes alterations in morphology and gene expression. EMBO Rep 2002; 3:1075-81. [PMID: 12393756 PMCID: PMC1307595 DOI: 10.1093/embo-reports/kvf220] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The localized transcription of several muscle genes at the motor endplate is controlled by the Ets transcription factor GABP. To evaluate directly its contribution to the formation of the neuromuscular junction, we generated transgenic mice expressing a general Ets dominant-negative mutant specifically in skeletal muscle. Quantitative RT-PCR analysis demonstrated that the expression of genes containing an Ets-binding site was severely affected in the mutant mice. Conversely, the expression of other synaptic genes, including MuSK and Rapsyn, was unchanged. In these animals, muscles expressing the mutant transcription factor developed normally, but examination of the post-synaptic morphology revealed marked alterations of both the primary gutters and secondary folds of the neuromuscular junction. Our results demonstrate that Ets transcription factors are crucial for the normal formation of the neuromuscular junction. They further show that Ets-independent mechanisms control the synaptic expression of a distinct set of synaptic genes.
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Affiliation(s)
- Alban de Kerchove d'Exaerde
- Laboratoire de Neurobiologie Moléculaire, CNRS URA 2182 'Récepteurs et Cognition' Institut Pasteur, 25 rue du Dr Roux, 75724 Paris cedex 15, France
- Laboratory of Neurophysiology, CP 601, Université Libre de Bruxelles, Faculty of Medicine, 808 route de Lennik, 1070 Brussels, Belgium
| | - Jean Cartaud
- Biologie Cellulaire des Membranes, Institut Jacques Monod, UMR7592 CNRS, Université Paris6 et Paris7, 75251 Paris, France
| | - Aymeric Ravel-Chapuis
- Equipe Différenciation Neuromusculaire, UMR 5665 CNRS/ENS, Ecole Normale Supérieure, 46 allée d'Italie 69364 Lyon cedex 07, France
| | - Thierry Seroz
- Laboratoire de Neurobiologie Moléculaire, CNRS URA 2182 'Récepteurs et Cognition' Institut Pasteur, 25 rue du Dr Roux, 75724 Paris cedex 15, France
| | - Fabien Pasteau
- Equipe Différenciation Neuromusculaire, UMR 5665 CNRS/ENS, Ecole Normale Supérieure, 46 allée d'Italie 69364 Lyon cedex 07, France
| | - Lindsay M. Angus
- Department of Cellular and Molecular Medicine and Centre for Neuromuscular Disease, Faculty of Medicine, University of Ottawa, 451 Smyth Road, Ottawa, ON, K1H 8M5, Canada
| | - Bernard J. Jasmin
- Department of Cellular and Molecular Medicine and Centre for Neuromuscular Disease, Faculty of Medicine, University of Ottawa, 451 Smyth Road, Ottawa, ON, K1H 8M5, Canada
| | - Jean-Pierre Changeux
- Laboratoire de Neurobiologie Moléculaire, CNRS URA 2182 'Récepteurs et Cognition' Institut Pasteur, 25 rue du Dr Roux, 75724 Paris cedex 15, France
- Tel: +33 1 45688805; Fax: +33 1 45688836;
| | - Laurent Schaeffer
- Equipe Différenciation Neuromusculaire, UMR 5665 CNRS/ENS, Ecole Normale Supérieure, 46 allée d'Italie 69364 Lyon cedex 07, France
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48
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Siow NL, Choi RCY, Cheng AWM, Jiang JXS, Wan DCC, Zhu SQ, Tsim KWK. A cyclic AMP-dependent pathway regulates the expression of acetylcholinesterase during myogenic differentiation of C2C12 cells. J Biol Chem 2002; 277:36129-36. [PMID: 12140295 DOI: 10.1074/jbc.m206498200] [Citation(s) in RCA: 63] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The expression of acetylcholinesterase (AChE) is markedly increased during myogenic differentiation of C2C12 myoblasts to myotubes; the expression is mediated by intrinsic factor(s) during muscle differentiation. In order to analyze the molecular mechanisms regulating AChE expression during myogenic differentiation, a approximately 2.2-kb human AChE promoter tagged with a luciferase reporter gene, namely pAChE-Luc, was stably transfected into C2C12 cells. The profile of promoter-driven luciferase activity during myogenic differentiation of C2C12 myotubes was found to be similar to that of endogenous expression of AChE catalytic subunit. The increase of AChE expression was reciprocally regulated by a cAMP-dependent signaling pathway. The level of intracellular cAMP, the activity of cAMP-dependent protein kinase, the phosphorylation of cAMP-responsive element binding protein and the activity of cAMP- responsive element (CRE) were down-regulated during the myotube formation. Mutating the CRE site of human AChE promoter altered the original myogenic profile of the promoter activity and its suppressive response to cAMP. In addition, the suppressive effect of the CRE site is dependent on its location on the promoter. Therefore, our results suggest that a cAMP-dependent signaling pathway serves as a suppressive element in regulating the expression of AChE during early myogenesis.
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Affiliation(s)
- Nina L Siow
- Department of Biology and Molecular Neuroscience Center, The Hong Kong University of Science and Technology, Clear Water Bay Road, Hong Kong, China
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49
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Perry C, Soreq H. Transcriptional regulation of erythropoiesis. Fine tuning of combinatorial multi-domain elements. EUROPEAN JOURNAL OF BIOCHEMISTRY 2002; 269:3607-18. [PMID: 12153557 DOI: 10.1046/j.1432-1033.2002.02999.x] [Citation(s) in RCA: 63] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Haematopoiesis, the differentiation of haematopoietic stem cells and progenitors into various lineages, involves complex interactions of transcription factors that modulate the expression of downstream genes and mediate proliferation and differentiation signals. Commitment of pluripotent haematopoietic stem cells to the erythroid lineage induces erythropoiesis, the production of red blood cells. This process involves a concerted progression through an erythroid burst forming unit (BFU-E), an erythroid colony forming unit (CFU-E), proerythroblast and an erythroblast. The terminally differentiated erythrocytes, in mammals, lose their nucleus yet function several more months. A well-coordinated cohort of transcription factors regulates the formation, survival, proliferation and differentiation of multipotent progenitor into the erythroid lineage. Here, we discuss broad-spectrum factors essential for self-renewal and/or differentiation of multipotent cells as well as specific factors required for proper erythroid development. These factors may operate solely or as part of transcriptional complexes, and exert activation or repression. Sequence comparisons reveal evolutionarily conserved modular composition for these factors; X-ray crystallography demonstrates that they include multidomain elements (e.g. HLH or zinc finger motifs), consistent with their complex interactions with other proteins. Finally, transfections and genomic studies show that the timing of each factor's expression during the hematopoietic process, the cell lineages affected and the existing combination of other factors determine the erythroid cell fate.
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Affiliation(s)
- Chava Perry
- Department of Biological Chemistry, The Institute of Life Sciences, The Hebrew University of Jerusalem, Israel
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50
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Abicht A, Stucka R, Schmidt C, Briguet A, Höpfner S, Song IH, Pongratz D, Müller-Felber W, Ruegg MA, Lochmüller H. A newly identified chromosomal microdeletion and an N-box mutation of the AChR epsilon gene cause a congenital myasthenic syndrome. Brain 2002; 125:1005-13. [PMID: 11960891 DOI: 10.1093/brain/awf095] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Congenital myasthenic syndromes (CMSs) are frequently caused by mutations of the coding region of the acetylcholine receptor epsilon subunit (AChRepsilon) gene leading to a reduced expression of the acetylcholine receptor (AChR) at the postsynaptic membrane. Two recent observations have linked two different N-box mutations of the human AChRepsilon promoter to a clinical CMS phenotype. N-boxes are regulatory sequence elements of mammalian promoters that confer synapse-specific expression of several genes, including the AChR subunit genes. Here, we report on a novel point mutation (epsilon-154G-->A) in the N-box of the AChRepsilon promoter in a German CMS pedigree. Semiquantitative analysis of AChRepsilon mRNA levels in the patient's muscle indicated significantly impaired AChRepsilon expression. We provide additional evidence of a pathogenic role for this mutation using the mutated promoter (epsilon-154G-->A) driving a heterologous gene (luciferase) in rat skeletal muscle. We show that agrin-induced gene expression is significantly reduced by the N-box mutant (mt) compared with the wild-type (wt) promoter. Refined haplotype analysis and direct sequencing revealed maternal inheritance of the mutant AChRepsilon promoter (epsilon-154G-->A) together with paternal inheritance of a chromosomal microdeletion (Delta1290 bp) encompassing the promoter and the first two exons of the AChRepsilon gene in the index patient. In conclusion, we provide genetic and functional evidence that a mutation of the AChRepsilon subunit promoter (epsilon-154G-->A) causes CMS due to the reduction of gene expression in skeletal muscle. Moreover, this is the first report of a chromosomal microdeletion affecting an AChR gene. This type of mutation may be missed in standard screening techniques of CMS patients.
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Affiliation(s)
- Angela Abicht
- Genzentrum and Friedrich-Baur-Institut, Ludwig-Maximilians-University Munich, Germany
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