TEAD transcription factors are required for normal primary myoblast differentiation in vitro and muscle regeneration in vivo

Myostatin, a member of the transforming growth factor (TGF)-β family, plays an important role in regulating skeletal muscle growth and differentiation. Here we examined the role of FoxO1 and SMAD transcription factors in regulating myostatin gene expression and myoblast differentiation in C2C12 myotubes in vitro. Both myostatin and FoxO1 mRNA expression were greater in fast- vs. slow-twitch skeletal muscles in vivo. Moreover, expression of a constitutively active form of FoxO1 increased myostatin mRNA and increased activity of a myostatin promoter reporter construct in differentiated C2C12 myotubes. Mutagenesis of highly conserved FoxO or SMAD binding sites significantly decreased myostatin promoter activity, and binding assays showed that both FoxO1 and SMADs bind to their respective sites in the myostatin promoter. Treatment with TGF-β and/or overexpression of SMAD2, -3, or -4 also resulted in a significant increase in myostatin promoter activity. Treatment with TGF-β along with overexpression of SMAD2 and FoxO1 resulted in the largest increase in myostatin promoter activity. Finally, TGF-β treatment and SMAD2 overexpression greatly potentiated FoxO1-mediated suppression of myoblast differentiation. Together these data demonstrate that FoxO1 and SMAD transcription factors regulate the expression of myostatin and contribute to the control of muscle cell growth and differentiation.

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c-Abl Kinase Is Required for Satellite Cell Function Through Pax7 Regulation

Frontiers in Cell and Developmental Biology ◽

10.3389/fcell.2021.606403 ◽

2021 ◽

Vol 9 ◽

Author(s):

Fabián Montecino ◽

Natalia González ◽

Natasha Blanco ◽

Manuel J. Ramírez ◽

Adrián González-Martín ◽

...

Keyword(s):

Transcription Factors ◽

Muscle Regeneration ◽

Cell Function ◽

Mapk Pathway ◽

Skeletal Muscle Regeneration ◽

Acute Injury ◽

Loss Of Function ◽

Adult Skeletal Muscle

Satellite cells (SCs) are tissue-specific stem cells responsible for adult skeletal muscle regeneration and maintenance. SCs function is critically dependent on two families of transcription factors: the paired box (Pax) involved in specification and maintenance and the Muscle Regulatory Factors (MRFs), which orchestrate myogenic commitment and differentiation. In turn, signaling events triggered by extrinsic and intrinsic stimuli control their function via post-translational modifications, including ubiquitination and phosphorylation. In this context, the Abelson non-receptor tyrosine kinase (c-Abl) mediates the activation of the p38 α/β MAPK pathway, promoting myogenesis. c-Abl also regulates the activity of the transcription factor MyoD during DNA-damage stress response, pausing differentiation. However, it is not clear if c-Abl modulates other key transcription factors controlling SC function. This work aims to determine the role of c-Abl in SCs myogenic capacity via loss of function approaches in vitro and in vivo. Here we show that c-Abl inhibition or deletion results in a down-regulation of Pax7 mRNA and protein levels, accompanied by decreased Pax7 transcriptional activity, without a significant effect on MRF expression. Additionally, we provide data indicating that Pax7 is directly phosphorylated by c-Abl. Finally, SC-specific c-Abl ablation impairs muscle regeneration upon acute injury. Our results indicate that c-Abl regulates myogenic progression in activated SCs by controlling Pax7 function and expression.

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Per1/Per2–Igf2 axis–mediated circadian regulation of myogenic differentiation

The Journal of Cell Biology ◽

10.1083/jcb.202101057 ◽

2021 ◽

Vol 220 (7) ◽

Author(s):

Nobuko Katoku-Kikyo ◽

Ellen Paatela ◽

Daniel L. Houtz ◽

Britney Lee ◽

Dane Munson ◽

...

Keyword(s):

Rna Polymerase Ii ◽

Muscle Regeneration ◽

Time Window ◽

Myogenic Differentiation ◽

Myoblast Differentiation ◽

Cell Proliferation And Differentiation ◽

Circadian Control ◽

Proliferation And Differentiation

Circadian rhythms regulate cell proliferation and differentiation, but circadian control of tissue regeneration remains elusive at the molecular level. Here, we show that proper myoblast differentiation and muscle regeneration are regulated by the circadian master regulators Per1 and Per2. Depletion of Per1 or Per2 suppressed myoblast differentiation in vitro and muscle regeneration in vivo, demonstrating their nonredundant functions. Both Per1 and Per2 were required for the activation of Igf2, an autocrine promoter of myoblast differentiation, accompanied by Per-dependent recruitment of RNA polymerase II, dynamic histone modifications at the Igf2 promoter and enhancer, and the promoter–enhancer interaction. This circadian epigenetic priming created a preferred time window for initiating myoblast differentiation. Consistently, muscle regeneration was faster if initiated at night, when Per1, Per2, and Igf2 were highly expressed compared with morning. This study reveals the circadian timing as a significant factor for effective muscle cell differentiation and regeneration.

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Circadian timing-dependent myoblast differentiation and muscle regeneration

10.1101/2020.07.29.209312 ◽

2020 ◽

Author(s):

Nobuko Katoku-Kikyo ◽

Ellen Paatela ◽

Daniel L. Houtz ◽

Britney Lee ◽

Dane Munson ◽

...

Keyword(s):

Rna Polymerase Ii ◽

Muscle Regeneration ◽

Time Window ◽

Myoblast Differentiation ◽

Circadian Timing ◽

Cell Proliferation And Differentiation ◽

Proliferation And Differentiation ◽

Redundant Functions

ABSTRACTCircadian rhythms regulate cell proliferation and differentiation but circadian control of tissue regeneration remains elusive at the molecular level. Here, we show that the circadian master regulators Per1 and Per2 are integral components defining the efficiency of myoblast differentiation and muscle regeneration. We found that the depletion of Per1 or Per2 suppressed myoblast differentiation in vitro and muscle regeneration in vivo, demonstrating their non-redundant functions. Both Per1 and Per2 directly activated Igf2, an autocrine promoter of myoblast differentiation, accompanied by Per-dependent recruitment of RNA polymerase II, dynamic histone modifications at the Igf2 promoter and enhancer, and the promoter-enhancer interaction. This circadian epigenetic oscillation created a preferred time window for initiating myoblast differentiation. Consistently, muscle regeneration was faster if initiated at night when Per1, Per2, and Igf2 were highly expressed compared with morning. This study reveals the circadian timing as a significant factor for effective muscle cell differentiation and regeneration.

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

Biochemistry and Cell Biology ◽

10.1139/o05-062 ◽

2005 ◽

Vol 83 (4) ◽

pp. 535-547 ◽

Cited By ~ 7

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.

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Regulation of sarcomagenesis by the empty spiracles homeobox genes EMX1 and EMX2

Cell Death and Disease ◽

10.1038/s41419-021-03801-w ◽

2021 ◽

Vol 12 (6) ◽

Author(s):

Manuel Pedro Jimenez-García ◽

Antonio Lucena-Cacace ◽

Daniel Otero-Albiol ◽

Amancio Carnero

Keyword(s):

Stem Cells ◽

Stem Cell ◽

Transcription Factors ◽

Neural Crest ◽

Tumor Suppressors ◽

Homeobox Genes ◽

Neuronal Cell ◽

Cell Gene Expression

AbstractThe EMX (Empty Spiracles Homeobox) genes EMX1 and EMX2 are two homeodomain gene members of the EMX family of transcription factors involved in the regulation of various biological processes, such as cell proliferation, migration, and differentiation, during brain development and neural crest migration. They play a role in the specification of positional identity, the proliferation of neural stem cells, and the differentiation of certain neuronal cell phenotypes. In general, they act as transcription factors in early embryogenesis and neuroembryogenesis from metazoans to higher vertebrates. The EMX1 and EMX2’s potential as tumor suppressor genes has been suggested in some cancers. Our work showed that EMX1/EMX2 act as tumor suppressors in sarcomas by repressing the activity of stem cell regulatory genes (OCT4, SOX2, KLF4, MYC, NANOG, NES, and PROM1). EMX protein downregulation, therefore, induced the malignance and stemness of cells both in vitro and in vivo. In murine knockout (KO) models lacking Emx genes, 3MC-induced sarcomas were more aggressive and infiltrative, had a greater capacity for tumor self-renewal, and had higher stem cell gene expression and nestin expression than those in wild-type models. These results showing that EMX genes acted as stemness regulators were reproduced in different subtypes of sarcoma. Therefore, it is possible that the EMX genes could have a generalized behavior regulating proliferation of neural crest-derived progenitors. Together, these results indicate that the EMX1 and EMX2 genes negatively regulate these tumor-altering populations or cancer stem cells, acting as tumor suppressors in sarcoma.

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Anti-glioma Efficacy and Mechanism of Action of Tripolinolate A from Tripolium pannonicum

Planta Medica ◽

10.1055/s-0044-101038 ◽

2018 ◽

Vol 84 (11) ◽

pp. 786-794

Author(s):

Weiyun Chai ◽

Lu Chen ◽

Xiao-Yuan Lian ◽

Zhizhen Zhang

Keyword(s):

Cell Cycle ◽

Transcription Factors ◽

Glioma Cells ◽

Inhibitory Effect ◽

Cell Cycle Regulators ◽

Expression Levels ◽

Multiple Tumor ◽

Glioma Growth

AbstractTripolinolate A as a new bioactive phenolic ester was previously isolated from a halophyte of Tripolium pannonicum. However, the in vitro and in vivo anti-glioma effects and mechanism of tripolinolate A have not been investigated. This study has demonstrated that (1) tripolinolate A inhibited the proliferation of different glioma cells with IC50 values of 7.97 to 14.02 µM and had a significant inhibitory effect on the glioma growth in U87MG xenograft nude mice, (2) tripolinolate A induced apoptosis in glioma cells by downregulating the expressions of antiapoptotic proteins and arrested glioma cell cycle at the G2/M phase by reducing the expression levels of cell cycle regulators, and (3) tripolinolate A also remarkably reduced the expression levels of several glioma metabolic enzymes and transcription factors. All data together suggested that tripolinolate A had significant in vitro and in vivo anti-glioma effects and the regulation of multiple tumor-related regulators and transcription factors might be responsible for the activities of tripolinolate A against glioma.

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Targeting of p38 Mitogen-Activated Protein Kinases to MEF2 Transcription Factors

Molecular and Cellular Biology ◽

10.1128/mcb.19.6.4028 ◽

1999 ◽

Vol 19 (6) ◽

pp. 4028-4038 ◽

Cited By ~ 172

Author(s):

Shen-Hsi Yang ◽

Alex Galanis ◽

Andrew D. Sharrocks

Keyword(s):

Transcription Factors ◽

Transcriptional Activation ◽

Cellular Response ◽

Map Kinases ◽

Biological Response ◽

Extracellular Signals ◽

Extracellular Signal ◽

Mitogen Activated Protein

ABSTRACT Mitogen-activated protein (MAP) kinase-mediated signalling to the nucleus is an important event in the conversion of extracellular signals into a cellular response. However, the existence of multiple MAP kinases which phosphorylate similar phosphoacceptor motifs poses a problem in maintaining substrate specificity and hence the correct biological response. Both the extracellular signal-regulated kinase (ERK) and c-Jun NH2-terminal kinase (JNK) subfamilies of MAP kinases use a second specificity determinant and require docking to their transcription factor substrates to achieve maximal substrate activation. In this study, we demonstrate that among the different MAP kinases, the MADS-box transcription factors MEF2A and MEF2C are preferentially phosphorylated and activated by the p38 subfamily members p38α and p38β2. The efficiency of phosphorylation in vitro and transcriptional activation in vivo of MEF2A and MEF2C by these p38 subtypes requires the presence of a kinase docking domain (D-domain). Furthermore, the D-domain from MEF2A is sufficient to confer p38 responsiveness on different transcription factors, and reciprocal effects are observed upon the introduction of alternative D-domains into MEF2A. These results therefore contribute to our understanding of signalling to MEF2 transcription factors and demonstrate that the requirement for substrate binding by MAP kinases is an important facet of three different subclasses of MAP kinases (ERK, JNK, and p38).

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Activating Signal Cointegrator 2 Belongs to a Novel Steady-State Complex That Contains a Subset of Trithorax Group Proteins

Molecular and Cellular Biology ◽

10.1128/mcb.23.1.140-149.2003 ◽

2003 ◽

Vol 23 (1) ◽

pp. 140-149 ◽

Cited By ~ 158

Author(s):

Young-Hwa Goo ◽

Young Chang Sohn ◽

Dae-Hwan Kim ◽

Seung-Whan Kim ◽

Min-Jung Kang ◽

...

Keyword(s):

Transcription Factors ◽

Steady State ◽

Nuclear Receptors ◽

Transcriptional Activation ◽

Retinoic Acid Receptor ◽

Dependent Manner ◽

Trithorax Group ◽

Trithorax Group Proteins

ABSTRACT Many transcription coactivators interact with nuclear receptors in a ligand- and C-terminal transactivation function (AF2)-dependent manner. These include activating signal cointegrator 2 (ASC-2), a recently isolated transcriptional coactivator molecule, which is amplified in human cancers and stimulates transactivation by nuclear receptors and numerous other transcription factors. In this report, we show that ASC-2 belongs to a steady-state complex of approximately 2 MDa (ASC-2 complex [ASCOM]) in HeLa nuclei. ASCOM contains retinoblastoma-binding protein RBQ-3, α/β-tubulins, and trithorax group proteins ALR-1, ALR-2, HALR, and ASH2. In particular, ALR-1/2 and HALR contain a highly conserved 130- to 140-amino-acid motif termed the SET domain, which was recently implicated in histone H3 lysine-specific methylation activities. Indeed, recombinant ALR-1, HALR, and immunopurified ASCOM exhibit very weak but specific H3-lysine 4 methylation activities in vitro, and transactivation by retinoic acid receptor appears to involve ligand-dependent recruitment of ASCOM and subsequent transient H3-lysine 4 methylation of the promoter region in vivo. Thus, ASCOM may represent a distinct coactivator complex of nuclear receptors. Further characterization of ASCOM will lead to a better understanding of how nuclear receptors and other transcription factors mediate transcriptional activation.

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