scholarly journals Muscle LIM Proteins Are Associated with Muscle Sarcomeres and Require dMEF2 for Their Expression during DrosophilaMyogenesis

1999 ◽  
Vol 10 (7) ◽  
pp. 2329-2342 ◽  
Author(s):  
Beth E. Stronach ◽  
Patricia J. Renfranz ◽  
Brenda Lilly ◽  
Mary C. Beckerle
Keyword(s):  
Muscle Development ◽  
Target Genes ◽  
Striated Muscle ◽  
Myogenic Differentiation ◽  
Muscle Differentiation ◽  
Epistasis Analysis ◽  
Lim Proteins ◽  
Muscle Lim Proteins ◽  
Genetic Hierarchy

A genetic hierarchy of interactions, involving myogenic regulatory factors of the MyoD and myocyte enhancer-binding 2 (MEF2) families, serves to elaborate and maintain the differentiated muscle phenotype through transcriptional regulation of muscle-specific target genes. Much work suggests that members of the cysteine-rich protein (CRP) family of LIM domain proteins also play a role in muscle differentiation; however, the specific functions of CRPs in this process remain undefined. Previously, we characterized two members of the Drosophila CRP family, the muscle LIM proteins Mlp60A and Mlp84B, which show restricted expression in differentiating muscle lineages. To extend our analysis ofDrosophila Mlps, we characterized the expression of Mlps in mutant backgrounds that disrupt specific aspects of muscle development. We show a genetic requirement for the transcription factor dMEF2 in regulating Mlp expression and an ability of dMEF2 to bind, in vitro, to consensus MEF2 sites derived from those present inMlp genomic sequences. These data suggest that theMlp genes may be direct targets of dMEF2 within the genetic hierarchy controlling muscle differentiation. Mutations that disrupt myoblast fusion fail to affect Mlp expression. In later stages of myogenic differentiation, which are dedicated primarily to assembly of the contractile apparatus, we analyzed the subcellular distribution of Mlp84B in detail. Immunofluorescent studies revealed the localization of Mlp84B to muscle attachment sites and the periphery of Z-bands of striated muscle. Analysis of mutations that affect expression of integrins and α-actinin, key components of these structures, also failed to perturb Mlp84B distribution. In conclusion, we have used molecular epistasis analysis to position Mlp function downstream of events involving mesoderm specification and patterning and concomitant with terminal muscle differentiation. Furthermore, our results are consistent with a structural role for Mlps as components of muscle cytoarchitecture.

scholarly journals The LIM-only protein FHL2 interacts with β-catenin and promotes differentiation of mouse myoblasts

2002 ◽  
Vol 159 (1) ◽  
pp. 113-122 ◽  
Author(s):  
Bernd Martin ◽  
Richard Schneider ◽  
Stefanie Janetzky ◽  
Zoe Waibler ◽  
Petra Pandur ◽  
...  
Keyword(s):  
Mammalian Cells ◽  
Muscle Development ◽  
Target Genes ◽  
Myogenic Differentiation ◽  
Myoblast Differentiation ◽  
Lim Domains ◽  
Vitro Binding ◽  
Specific Proteins

FHL2 is a LIM-domain protein expressed in myoblasts but down-regulated in malignant rhabdomyosarcoma cells, suggesting an important role of FHL2 in muscle development. To investigate the importance of FHL2 during myoblast differentiation, we performed a yeast two-hybrid screen using a cDNA library derived from myoblasts induced for differentiation. We identified β-catenin as a novel interaction partner of FHL2 and confirmed the specificity of association by direct in vitro binding tests and coimmunoprecipitation assays from cell lysates. Deletion analysis of both proteins revealed that the NH2-terminal part of β-catenin is sufficient for binding in yeast, but addition of the first armadillo repeat is necessary for binding FHL2 in mammalian cells, whereas the presence of all four LIM domains of FHL2 is needed for the interaction. Expression of FHL2 counteracts β-catenin–mediated activation of a TCF/LEF-dependent reporter gene in a dose-dependent and muscle cell–specific manner. After injection into Xenopus embryos, FHL2 inhibited the β-catenin–induced axis duplication. C2C12 mouse myoblasts stably expressing FHL2 show increased myogenic differentiation reflected by accelerated myotube formation and expression of muscle-specific proteins. These data imply that FHL2 is a muscle-specific repressor of LEF/TCF target genes and promotes myogenic differentiation by interacting with β-catenin.

scholarly journals The SMYD3 methyltransferase promotes myogenesis by activating the myogenin regulatory network

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Roberta Codato ◽  
Martine Perichon ◽  
Arnaud Divol ◽  
Ella Fung ◽  
Athanassia Sotiropoulos ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Muscle Development ◽  
Myogenic Differentiation ◽  
Muscle Differentiation ◽  
Skeletal Muscle Differentiation ◽  
Skeletal Muscle Development ◽  
Genome Wide ◽  
Coordinated Expression

AbstractThe coordinated expression of myogenic regulatory factors, including MyoD and myogenin, orchestrates the steps of skeletal muscle development, from myoblast proliferation and cell-cycle exit, to myoblast fusion and myotubes maturation. Yet, it remains unclear how key transcription factors and epigenetic enzymes cooperate to guide myogenic differentiation. Proteins of the SMYD (SET and MYND domain-containing) methyltransferase family participate in cardiac and skeletal myogenesis during development in zebrafish, Drosophila and mice. Here, we show that the mammalian SMYD3 methyltransferase coordinates skeletal muscle differentiation in vitro. Overexpression of SMYD3 in myoblasts promoted muscle differentiation and myoblasts fusion. Conversely, silencing of endogenous SMYD3 or its pharmacological inhibition impaired muscle differentiation. Genome-wide transcriptomic analysis of murine myoblasts, with silenced or overexpressed SMYD3, revealed that SMYD3 impacts skeletal muscle differentiation by targeting the key muscle regulatory factor myogenin. The role of SMYD3 in the regulation of skeletal muscle differentiation and myotube formation, partially via the myogenin transcriptional network, highlights the importance of methyltransferases in mammalian myogenesis.

scholarly journals Protein arginine methyltransferase expression and activity during myogenesis

2018 ◽  
Vol 38 (1) ◽  
Author(s):  
Nicole Y. Shen ◽  
Sean Y. Ng ◽  
Stephen L. Toepp ◽  
Vladimir Ljubicic
Keyword(s):  
Skeletal Muscle ◽  
Muscle Development ◽  
Myogenic Differentiation ◽  
Muscle Differentiation ◽  
Type I ◽  
Protein Arginine Methyltransferases ◽  
Methyl Donors ◽  
Muscle Plasticity ◽  
Expression And Activity

Despite the emerging importance of protein arginine methyltransferases (PRMTs) in regulating skeletal muscle plasticity, PRMT biology during muscle development is complex and not completely understood. Therefore, our purpose was to investigate PRMT1, -4, and -5 expression and function in skeletal muscle cells during the phenotypic remodeling elicited by myogenesis. C2C12 muscle cell maturation, assessed during the myoblast (MB) stage, and during days 1, 3, 5, and 7 of differentiation, was employed as an in vitro model of myogenesis. We observed PRMT-specific patterns of expression and activity during myogenesis. PRMT4 and -5 gene expression was unchanged, while PRMT1 mRNA and protein content were significantly induced. Cellular monomethylarginines (MMAs) and symmetric dimethylarginines (SDMAs), indicative of global and type II PRMT activities, respectively, remained steady during development, while type I PRMT activity indicator asymmetric dimethylarginines (ADMAs) increased through myogenesis. Histone 4 arginine 3 (H4R3) and H3R17 contents were elevated coincident with the myonuclear accumulation of PRMT1 and -4. Collectively, this suggests that PRMTs are methyl donors throughout myogenesis and demonstrate specificity for their protein targets. Cells were then treated with TC-E 5003 (TC-E), a selective inhibitor of PRMT1 in order to specifically examine the enzymes role during myogenic differentiation. TC-E treated cells exhibited decrements in muscle differentiation, which were consistent with attenuated mitochondrial biogenesis and respiratory function. In summary, the present study increases our understanding of PRMT1, -4, and -5 biology during the plasticity of skeletal muscle development. Our results provide evidence for a role of PRMT1, via a mitochondrially mediated mechanism, in driving the muscle differentiation program.

scholarly journals The SMYD3 methyltransferase promotes myogenesis by activating the myogenin regulatory network

2019 ◽  
Author(s):  
Roberta Codato ◽  
Martine Perichon ◽  
Arnaud Divol ◽  
Ella Fung ◽  
Athanassia Sotiropoulos ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Muscle Development ◽  
Myogenic Differentiation ◽  
Muscle Differentiation ◽  
Skeletal Muscle Differentiation ◽  
Skeletal Muscle Development ◽  
Genome Wide ◽  
Coordinated Expression

ABSTRACTThe coordinated expression of myogenic regulatory factors, including MyoD and myogenin, orchestrates the steps of skeletal muscle development, from myoblast proliferation and cell-cycle exit, to myoblast fusion and myotubes maturation. Yet, it remains unclear how key transcription factors and epigenetic enzymes cooperate to guide myogenic differentiation. Proteins of the SMYD (SET and MYND domain-containing) methyltransferase family participate in cardiac and skeletal myogenesis during development in zebrafish, Drosophila and mice. Here, we show that the mammalian SMYD3 methyltransferase coordinates skeletal muscle differentiation in vitro. Overexpression of SMYD3 in myoblasts promoted muscle differentiation and myoblasts fusion. Conversely, silencing of endogenous SMYD3 or its pharmacological inhibition impaired muscle differentiation. Genome-wide transcriptomic analysis of murine myoblasts, with silenced or overexpressed SMYD3, revealed that SMYD3 impacts skeletal muscle differentiation by targeting the key muscle regulatory factor myogenin. The role of SMYD3 in the regulation of skeletal muscle differentiation and myotube formation, partially via the myogenin transcriptional network, highlights the importance of methyltransferases in mammalian myogenesis.

BMP4 and WNT signaling interact to promote mouse tracheal mesenchyme morphogenesis

2021 ◽  
Author(s):  
Natalia Bottasso Arias ◽  
Lauren Leesman ◽  
Kaulini Burra ◽  
John Snowball ◽  
Ronak M Shah ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Wnt Signaling ◽  
Rna Sequencing ◽  
Muscle Development ◽  
Target Genes ◽  
Bmp Signaling ◽  
Embryonic Mouse ◽  
Tracheal Cartilage ◽  
Cartilage Formation

Tracheobronchomalacia and Complete Tracheal Rings are congenital malformations of the trachea associated with morbidity and mortality for which the etiology remains poorly understood. Epithelial expression of Wls (a cargo receptor mediating Wnt ligand secretion) by tracheal cells is essential for patterning the embryonic mouse trachea's cartilage and muscle. RNA sequencing indicated that Wls differentially modulated the expression of BMP signaling molecules. We tested whether BMP signaling, induced by epithelial Wnt ligands, mediates cartilage formation. Deletion of Bmp4 from respiratory tract mesenchyme impaired tracheal cartilage formation that was replaced by ectopic smooth muscle, recapitulating the phenotype observed after epithelial deletion of Wls in the embryonic trachea. Ectopic muscle was caused in part by anomalous differentiation and proliferation of smooth muscle progenitors rather than tracheal cartilage progenitors. Mesenchymal deletion of Bmp4 impaired expression of Wnt/β-catenin target genes, including targets of WNTsignaling: Notum, and Axin2. In vitro, rBMP4 rescued the expression of Notum in Bmp4 deficient tracheal mesenchymal cells and induced Notum promoter activity via SMAD1/5. RNA sequencing of Bmp4 deficient tracheas identified genes essential for chondrogenesis and muscle development co-regulated by BMP and WNT signaling. During tracheal morphogenesis, WNT signaling induces Bmp4 in mesenchymal progenitors to promote cartilage differentiation and restrict trachealis muscle. In turn, Bmp4 differentially regulates the expression of Wnt/β-catenin targets to attenuate mesenchymal WNT signaling and to further support chondrogenesis.

A C. elegans E/Daughterless bHLH protein marks neuronal but not striated muscle development

Development ◽  
1997 ◽  
Vol 124 (11) ◽  
pp. 2179-2189 ◽  
Author(s):  
M. Krause ◽  
M. Park ◽  
J.M. Zhang ◽  
J. Yuan ◽  
B. Harfe ◽  
...  
Keyword(s):  
Muscle Development ◽  
Striated Muscle ◽  
Bhlh Protein ◽  
E Proteins ◽  
Mobility Shift ◽  
C Elegans ◽  
Helix Loop Helix ◽  
Neuronal Precursors ◽  
Gel Mobility Shift

The E proteins of mammals, and the related Daughterless (DA) protein of Drosophila, are ubiquitously expressed helix-loop-helix (HLH) transcription factors that play a role in many developmental processes. We report here the characterization of a related C. elegans protein, CeE/DA, which has a dynamic and restricted distribution during development. CeE/DA is present embryonically in neuronal precursors, some of which are marked by promoter activity of a newly described Achaete-scute-like gene hlh-3. In contrast, we have been unable to detect CeE/DA in CeMyoD-positive striated muscle cells. In vitro gel mobility shift analysis detects dimerization of CeE/DA with HLH-3 while efficient interaction of CeE/DA with CeMyoD is not seen. These studies suggest multiple roles for CeE/DA in C. elegans development and provide evidence that both common and alternative strategies have evolved for the use of related HLH proteins in controlling cell fates in different species.

Caenorhabditis elegans twist plays an essential role in non-striated muscle development

Development ◽  
2000 ◽  
Vol 127 (10) ◽  
pp. 2041-2051 ◽  
Author(s):  
A.K. Corsi ◽  
S.A. Kostas ◽  
A. Fire ◽  
M. Krause
Keyword(s):  
Caenorhabditis Elegans ◽  
Essential Role ◽  
Muscle Development ◽  
Target Genes ◽  
Striated Muscle ◽  
Egg Laying ◽  
Bhlh Transcription Factor ◽  
Striated Muscles ◽  
Downstream Target ◽  
Mesodermal Development

The basic helix-loop-helix (bHLH) transcription factor Twist plays a role in mesodermal development in both invertebrates and vertebrates. In an effort to understand the role of the unique Caenorhabditis elegans Twist homolog, hlh-8, we analyzed mesodermal development in animals with a deletion in the hlh-8 locus. This deletion was predicted to represent a null allele because the HLH domain is missing and the reading frame for the protein is disrupted. Animals lacking CeTwist function were constipated and egg-laying defective. Both of these defects were rescued in transgenic mutant animals expressing wild-type hlh-8. Observing a series of mesoderm-specific markers allowed us to characterize the loss of hlh-8 function more thoroughly. Our results demonstrate that CeTwist performs an essential role in the proper development of a subset of mesodermal tissues in C. elegans. We found that CeTwist was required for the formation of three out of the four non-striated enteric muscles born in the embryo. In contrast, CeTwist was not required for the formation of the embryonically derived striated muscles. Most of the post-embryonic mesoderm develops from a single lineage. CeTwist was necessary for appropriate patterning in this lineage and was required for expression of two downstream target genes, but was not required for the expression of myosin, a marker of differentiation. Our results suggest that mesodermal patterning by Twist is an evolutionarily conserved function.

scholarly journals Defining Akt actions in muscle differentiation

2012 ◽  
Vol 303 (12) ◽  
pp. C1292-C1300 ◽  
Author(s):  
Samantha Gardner ◽  
Magdalena Anguiano ◽  
Peter Rotwein
Keyword(s):  
Growth Factors ◽  
Muscle Development ◽  
Muscle Growth ◽  
Muscle Differentiation ◽  
In Vivo Studies ◽  
Cell Contact ◽  
Muscle Repair ◽  
Complex Signals

Muscle development in childhood and muscle regeneration in adults are highly regulated processes that are necessary for reaching and maintaining optimal muscle mass and strength throughout life. Muscle repair after injury relies on stem cells, termed satellite cells, whose activity is controlled by complex signals mediated by cell-cell contact, by growth factors, and by hormones, which interact with genetic programs controlled by myogenic transcription factors. Insulin-like growth factors (IGFs) play key roles in muscle development and help coordinate muscle repair after injury, primarily by stimulating the phosphatidylinositol 3-kinase-Akt signaling pathway, and both in vitro and in vivo studies have shown that Akt kinase activity is critical for optimal muscle growth and regeneration. Here we find that of the two Akts expressed in muscle, Akt1 is essential for initiation of differentiation in culture and is required for normal myoblast motility, while Akt2 is dispensable. Although Akt2 deficiency did lead to diminished myotube maturation, as assessed by a decline in myofiber area and in fusion index, either Akt1 or Akt2 could restore these processes toward normal. Thus levels of Akt expression rather than distinct actions of individual Akt species are critical for normal myofiber development during the later stages of muscle differentiation.

Notch signalling acts in postmitotic avian myogenic cells to control MyoD activation

Development ◽  
2001 ◽  
Vol 128 (1) ◽  
pp. 107-116 ◽  
Author(s):  
E. Hirsinger ◽  
P. Malapert ◽  
J. Dubrulle ◽  
M.C. Delfini ◽  
D. Duprez ◽  
...  
Keyword(s):  
Myogenic Differentiation ◽  
Muscle Differentiation ◽  
Detailed Examination ◽  
Notch Signalling ◽  
Myogenic Cells ◽  
Myogenic Markers ◽  
Notch Activation

During Drosophila myogenesis, Notch signalling acts at multiple steps of the muscle differentiation process. In vertebrates, Notch activation has been shown to block MyoD activation and muscle differentiation in vitro, suggesting that this pathway may act to maintain the cells in an undifferentiated proliferative state. In this paper, we address the role of Notch signalling in vivo during chick myogenesis. We first demonstrate that the Notch1 receptor is expressed in postmitotic cells of the myotome and that the Notch ligands Delta1 and Serrate2 are detected in subsets of differentiating myogenic cells and are thus in position to signal to Notch1 during myogenic differentiation. We also reinvestigate the expression of MyoD and Myf5 during avian myogenesis, and observe that Myf5 is expressed earlier than MyoD, consistent with previous results in the mouse. We then show that forced expression of the Notch ligand, Delta1, during early myogenesis, using a retroviral system, has no effect on the expression of the early myogenic markers Pax3 and Myf5, but causes strong down-regulation of MyoD in infected somites. Although Delta1 overexpression results in the complete lack of differentiated muscles, detailed examination of the infected embryos shows that initial formation of a myotome is not prevented, indicating that exit from the cell cycle has not been blocked. These results suggest that Notch signalling acts in postmitotic myogenic cells to control a critical step of muscle differentiation.

The muscle regulatory and structural protein MLP is a cytoskeletal binding partner of betaI-spectrin

2000 ◽  
Vol 113 (9) ◽  
pp. 1553-1564 ◽  
Author(s):  
M.J. Flick ◽  
S.F. Konieczny
Keyword(s):  
Structural Integrity ◽  
Striated Muscle ◽  
Myogenic Differentiation ◽  
Specific Factor ◽  
Contractile Apparatus ◽  
Structural Protein ◽  
Biochemical Analyses ◽  
Myogenic Program

Muscle LIM protein (MLP) is a striated muscle-specific factor that enhances myogenic differentiation and is critical to maintaining the structural integrity of the contractile apparatus. The ability of MLP to regulate myogenesis is particularly interesting since it exhibits multiple subcellular localizations, being found in both nuclear and cytoplasmic compartments. Despite extensive biochemical analyses on MLP, the mechanism(s) by which it influences the myogenic program remains largely undefined. To further examine the role of MLP as a positive myogenic regulator, a yeast two-hybrid screen was employed to identify cytoplasmic-associated MLP binding partners. From this screen, the cytoskeletal protein betaI-spectrin was isolated. Protein interaction assays demonstrate that MLP and betaI-spectrin associate with one another in vivo as well as when tested under several in vitro binding conditions. betaI-spectrin binds specifically to MLP but not to the MLP related proteins CRP1 and CRP2 or to other LIM domain containing proteins. The MLP:beta-spectrin interaction is mediated by the second LIM motif of MLP and by repeat 7 of beta-spectrin. Confocal microscopy studies also reveal that MLP co-localizes with beta-spectrin at the sarcolemma overlying the Z- and M-lines of myofibrils in both cardiac and skeletal muscle tissue. Given that beta-spectrin is a known costamere protein, we propose that sarcolemma-associated MLP also serves as a key costamere protein, stabilizing the association of the contractile apparatus with the sarcolemma by linking the beta-spectrin network to the alpha-actinin crosslinked actin filaments of the myofibril.

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