scholarly journals Activation of Utrophin Promoter by Heregulin via theets-related Transcription Factor Complex GA-binding Protein α/β

1999 ◽  
Vol 10 (6) ◽  
pp. 2075-2086 ◽  
Author(s):  
Tejvir S. Khurana ◽  
Alan G. Rosmarin ◽  
Jing Shang ◽  
Thomas O. B. Krag ◽  
Saumya Das ◽  
...  
Keyword(s):  
Gene Expression ◽  
Skeletal Muscle ◽  
Transcription Factors ◽  
Neuromuscular Junction ◽  
Muscle Cell ◽  
Cell Cultures ◽  
Binding Protein ◽  
Duchenne's Muscular Dystrophy ◽  
Ga Binding Protein

Utrophin/dystrophin-related protein is the autosomal homologue of the chromosome X-encoded dystrophin protein. In adult skeletal muscle, utrophin is highly enriched at the neuromuscular junction. However, the molecular mechanisms underlying regulation of utrophin gene expression are yet to be defined. Here we demonstrate that the growth factor heregulin increases de novo utrophin transcription in muscle cell cultures. Using mutant reporter constructs of the utrophin promoter, we define the N-box region of the promoter as critical for heregulin-mediated activation. Using this region of the utrophin promoter for DNA affinity purification, immunoblots, in vitro kinase assays, electrophoretic mobility shift assays, and in vitro expression in cultured muscle cells, we demonstrate thatets-related GA-binding protein α/β transcription factors are activators of the utrophin promoter. Taken together, these results suggest that the GA-binding protein α/β complex of transcription factors binds and activates the utrophin promoter in response to heregulin-activated extracellular signal–regulated kinase in muscle cell cultures. These findings suggest methods for achieving utrophin up-regulation in Duchenne’s muscular dystrophy as well as mechanisms by which neurite-derived growth factors such as heregulin may influence the regulation of utrophin gene expression and subsequent enrichment at the neuromuscular junction of skeletal muscle.

scholarly journals Single-nucleus RNA-seq and FISH identify coordinated transcriptional activity in mammalian myofibers

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Matthieu Dos Santos ◽  
Stéphanie Backer ◽  
Benjamin Saintpierre ◽  
Brigitte Izac ◽  
Muriel Andrieu ◽  
...  
Keyword(s):  
Gene Expression ◽  
Skeletal Muscle ◽  
Transcription Factors ◽  
Neuromuscular Junction ◽  
Heavy Chain ◽  
Transcriptional Activity ◽  
Rna Seq ◽  
Hybrid Fibers ◽  
Adult Mice ◽  
Single Nucleus

Abstract Skeletal muscle fibers are large syncytia but it is currently unknown whether gene expression is coordinately regulated in their numerous nuclei. Here we show by snRNA-seq and snATAC-seq that slow, fast, myotendinous and neuromuscular junction myonuclei each have different transcriptional programs, associated with distinct chromatin states and combinations of transcription factors. In adult mice, identified myofiber types predominantly express either a slow or one of the three fast isoforms of Myosin heavy chain (MYH) proteins, while a small number of hybrid fibers can express more than one MYH. By snRNA-seq and FISH, we show that the majority of myonuclei within a myofiber are synchronized, coordinately expressing only one fast Myh isoform with a preferential panel of muscle-specific genes. Importantly, this coordination of expression occurs early during post-natal development and depends on innervation. These findings highlight a previously undefined mechanism of coordination of gene expression in a syncytium.

scholarly journals Induction of utrophin gene expression by heregulin in skeletal muscle cells: Role of the N-box motif and GA binding protein

1999 ◽  
Vol 96 (6) ◽  
pp. 3223-3227 ◽  
Author(s):  
A. O. Gramolini ◽  
L. M. Angus ◽  
L. Schaeffer ◽  
E. A. Burton ◽  
J. M. Tinsley ◽  
...  
Keyword(s):  
Gene Expression ◽  
Skeletal Muscle ◽  
Binding Protein ◽  
Muscle Cells ◽  
Skeletal Muscle Cells ◽  
Ga Binding Protein

scholarly journals Functional Interaction between the CoactivatorDrosophila CREB-Binding Protein and ASH1, a Member of the Trithorax Group of Chromatin Modifiers

2000 ◽  
Vol 20 (24) ◽  
pp. 9317-9330 ◽  
Author(s):  
Frédéric Bantignies ◽  
Richard H. Goodman ◽  
Sarah M. Smolik
Keyword(s):  
Gene Expression ◽  
Transcription Factors ◽  
Chromatin Structure ◽  
Binding Protein ◽  
Polytene Chromosomes ◽  
Open Chromatin ◽  
Creb Binding Protein ◽  
Trithorax Group ◽  
Chromatin Modifiers

ABSTRACT CREB-binding protein (CBP) is a coactivator for multiple transcription factors that transduce a variety of signaling pathways. Current models propose that CBP enhances gene expression by bridging the signal-responsive transcription factors with components of the basal transcriptional machinery and by augmenting the access of transcription factors to DNA through the acetylation of histones. To define the pathways and proteins that require CBP function in a living organism, we have begun a genetic analysis of CBP in flies. We have overproduced Drosophila melanogaster CBP (dCBP) in a variety of cell types and obtained distinct adult phenotypes. We used an uninflated-wing phenotype, caused by the overexpression of dCBP in specific central nervous system cells, to screen for suppressors of dCBP overactivity. Two genes with mutant versions that act as dominant suppressors of the wing phenotype were identified: thePKA-C1/DCO gene, encoding the catalytic subunit of cyclic AMP protein kinase, and ash1, a member of thetrithorax group (trxG) of chromatin modifiers. Using immunocolocalization, we showed that the ASH1 protein is specifically expressed in the majority of the dCBP-overexpressing cells, suggesting that these proteins have the potential to interact biochemically. This model was confirmed by the findings that the proteins interact strongly in vitro and colocalize at specific sites on polytene chromosomes. The trxG proteins are thought to maintain gene expression during development by creating domains of open chromatin structure. Our results thus implicate a second class of chromatin-associated proteins in mediating dCBP function and imply that dCBP might be involved in the regulation of higher-order chromatin structure.

scholarly journals Targeting of the ETS Factor Gabpα Disrupts Neuromuscular Junction Synaptic Function

2007 ◽  
Vol 27 (9) ◽  
pp. 3470-3480 ◽  
Author(s):  
Debra A. O'Leary ◽  
Peter G. Noakes ◽  
Nick A. Lavidis ◽  
Ismail Kola ◽  
Paul J. Hertzog ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Transcription Factor ◽  
Neuromuscular Junction ◽  
Acetylcholine Receptor ◽  
Neuromuscular Junctions ◽  
Binding Protein ◽  
Synaptic Function ◽  
Single Point Mutation ◽  
Structural Formation ◽  
Ga Binding Protein

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 δ and ε 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 ε 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 GABPα 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 ε subunit and increased expression of the γ 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.

scholarly journals Modeling the transport of nuclear proteins along single skeletal muscle cells

2020 ◽  
Vol 117 (6) ◽  
pp. 2978-2986 ◽  
Author(s):  
Hermes Taylor-Weiner ◽  
Christopher L. Grigsby ◽  
Duarte M. S. Ferreira ◽  
José M. Dias ◽  
Molly M. Stevens ◽  
...  
Keyword(s):  
Gene Expression ◽  
Skeletal Muscle ◽  
Molecular Weight ◽  
Transcription Factors ◽  
Protein Transport ◽  
Muscle Cells ◽  
Skeletal Muscle Cells ◽  
Nuclear Proteins ◽  
Transcriptional Responses

Skeletal muscle cells contain hundreds of myonuclei within a shared cytoplasm, presenting unique challenges for regulating gene expression. Certain transcriptional programs (e.g., postsynaptic machinery) are segregated to specialized domains, while others (e.g., contractile proteins) do not show spatial confinement. Furthermore, local stimuli, such as denervation, can induce transcriptional responses that are propagated along the muscle cells. Regulated transport of nuclear proteins (e.g., transcription factors) between myonuclei represents a potential mechanism for coordinating gene expression. However, the principles underlying the transport of nuclear proteins within multinucleated cells remain poorly defined. Here we used a mosaic transfection model to create myotubes that contained exactly one myonucleus expressing a fluorescent nuclear reporter and monitored its distribution among all myonuclei. We found that the transport properties of these model nuclear proteins in myotubes depended on molecular weight and nuclear import rate, as well as on myotube width. Interestingly, muscle hypertrophy increased the transport of high molecular weight nuclear proteins, while atrophy restricted the transport of smaller nuclear proteins. We have developed a mathematical model of nuclear protein transport within a myotube that recapitulates the results of our in vitro experiments. To test the relevance to nuclear proteins expressed in skeletal muscle, we studied the transport of two transcription factors—aryl hydrocarbon receptor nuclear translocator and sine oculis homeobox 1—and found that their distributions were similar to the reporter proteins with corresponding molecular weights. Together, these results define a set of variables that can be used to predict the spatial distributions of nuclear proteins within a myotube.

scholarly journals Troglitazone Downregulates  -6 Desaturase Gene Expression in Human Skeletal Muscle Cell Cultures

Diabetes ◽  
2002 ◽  
Vol 51 (4) ◽  
pp. 1060-1065 ◽  
Author(s):  
H. G. Wahl ◽  
C. Kausch ◽  
F. Machicao ◽  
K. Rett ◽  
M. Stumvoll ◽  
...  
Keyword(s):  
Gene Expression ◽  
Skeletal Muscle ◽  
Muscle Cell ◽  
Cell Cultures ◽  
Human Skeletal Muscle ◽  
Skeletal Muscle Cell ◽  
Desaturase Gene ◽  
Human Skeletal Muscle Cell

Subnuclear compartmentalization of sequence-specific transcription factors and regulation of eukaryotic gene expression

2005 ◽  
Vol 83 (4) ◽  
pp. 535-547 ◽  
Author(s):  
Gareth N Corry ◽  
D Alan Underhill
Keyword(s):  
Gene Expression ◽  
Transcription Factor ◽  
Transcription Factors ◽  
Transcriptional Activation ◽  
Current Knowledge ◽  
Nuclear Architecture ◽  
Subnuclear Localization ◽  
Modular Structures

To date, the majority of the research regarding eukaryotic transcription factors has focused on characterizing their function primarily through in vitro methods. These studies have revealed that transcription factors are essentially modular structures, containing separate regions that participate in such activities as DNA binding, protein–protein interaction, and transcriptional activation or repression. To fully comprehend the behavior of a given transcription factor, however, these domains must be analyzed in the context of the entire protein, and in certain cases the context of a multiprotein complex. Furthermore, it must be appreciated that transcription factors function in the nucleus, where they must contend with a variety of factors, including the nuclear architecture, chromatin domains, chromosome territories, and cell-cycle-associated processes. Recent examinations of transcription factors in the nucleus have clarified the behavior of these proteins in vivo and have increased our understanding of how gene expression is regulated in eukaryotes. Here, we review the current knowledge regarding sequence-specific transcription factor compartmentalization within the nucleus and discuss its impact on the regulation of such processes as activation or repression of gene expression and interaction with coregulatory factors.Key words: transcription, subnuclear localization, chromatin, gene expression, nuclear architecture.

Retinoic Acid Receptor Agonists Suppress Muscle Fatty Infiltration in Mice

2021 ◽  
Vol 49 (2) ◽  
pp. 332-339
Author(s):  
Hideyuki Shirasawa ◽  
Noboru Matsumura ◽  
Masaki Yoda ◽  
Kazumasa Okubo ◽  
Masayuki Shimoda ◽  
...  
Keyword(s):  
Gene Expression ◽  
Skeletal Muscle ◽  
Rotator Cuff ◽  
Rotator Cuff Tear ◽  
Gene Expression Analysis ◽  
Retinoic Acid Receptor ◽  
Adipogenic Differentiation ◽  
Fatty Infiltration ◽  
Cuff Tear

Background: The infiltration of fat tissue into skeletal muscle, a condition referred to as muscle fatty infiltration or fatty degeneration, is regarded as an irreversible event that significantly compromises the motor function of skeletal muscle. Purpose: To investigate the effect of retinoic acid receptor (RAR) agonists in suppressing the adipogenic differentiation of fibroadipogenic progenitors (FAPs) in vitro and fatty infiltration after rotator cuff tear in mice. Study Design: Controlled laboratory study. Methods: FAPs isolated from mouse skeletal muscle were cultured in adipogenic differentiation medium in the presence or absence of an RAR agonist. At the end of cell culture, adipogenic differentiation was evaluated by gene expression analysis and oil red O staining. A mouse model of fatty infiltration—which includes the resection of the rotator cuff, removal of the humeral head, and denervation the supraspinatus muscle—was used to induce fatty infiltration in the supraspinatus muscle. The mice were orally or intramuscularly administered with an RAR agonist after the surgery. Muscle fatty infiltration was evaluated by histology and gene expression analysis. Results: RAR agonists effectively inhibited the adipogenic differentiation of FAPs in vitro. Oral and intramuscular administration of RAR agonists suppressed the development of muscle fatty infiltration in the mice after rotator cuff tear. In accordance, we found a significant decrease in the number of intramuscular fat cells and suppressed expression in adipogenic markers. RAR agonists also increased the expression of the transcripts for collagens; however, an accumulation of collagenous tissues was not histologically evident in the present model. Conclusion: Muscle fatty infiltration can be alleviated by RAR agonists through suppressing the adipogenic differentiation of FAPs. The results also suggest that RAR agonists are potential therapeutic agents for treating patients who are at risk of developing muscle fatty infiltration. The consequence of the increased expression of collagen transcripts by RAR agonists needs to be clarified. Clinical Relevance: RAR agonists can be used to prevent the development of muscle fatty infiltration after rotator cuff tear. Nevertheless, further studies are mandatory in a large animal model to examine the safety and efficacy of intramuscular injection of RAR agonists.

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