A fourth human MEF2 transcription factor, hMEF2D, is an early marker of the myogenic lineage

Development ◽  
1993 ◽  
Vol 118 (4) ◽  
pp. 1095-1106 ◽  
Author(s):  
R.E. Breitbart ◽  
C.S. Liang ◽  
L.B. Smoot ◽  
D.A. Laheru ◽  
V. Mahdavi ◽  
...  
Keyword(s):  
Myogenic Differentiation ◽  
Specific Binding ◽  
Single Gene ◽  
Cell Types ◽  
Related Factor ◽  
Muscle Gene Expression ◽  
Molecular Events ◽  
Myogenic Lineage ◽  
Muscle Genes ◽  
Muscle Gene

The transition from multipotent mesodermal precursor to committed myoblast and its differentiation into a mature myocyte involve molecular events that enable the cell to activate muscle-specific genes. Among the participants in this process is the myocyte-specific enhancer factor 2 (MEF2) family of tissue-restricted transcription factors. These factors, which share a highly conserved DNA-binding domain including a MADS box, are essential for the expression of multiple muscle genes with cognate target MEF2 sites in cis. We report here a new human MEF2 factor, hMEF2D, which is unique among the members of this family in that it is present not only in myotubes but also in undifferentiated myoblasts, even before the appearance of myogenin. hMEF2D comprises several alternatively spliced products of a single gene, one of which is the human homolog of the Xenopus SRF-related factor SL-1. Like its relatives, cloned hMEF2D is capable of activating transcription via sequence-specific binding to the MEF2 site, recapitulating endogenous tissue-specific MEF2 activity. Indeed, while MEF2D mRNAs are ubiquitous, the protein is highly restricted to those cell types that contain this activity, implicating posttranscriptional mechanisms in the regulation of MEF2D expression. Alternative splicing may be important in this process: two alternative MEF2D domains, at least one of which is specifically included during myogenic differentiation, also correlate precisely with endogenous MEF2 activity. These findings provide compelling evidence that MEF2D is an integral link in the regulatory network for muscle gene expression. Its presence in undifferentiated myoblasts further suggests that it may be a mediator of commitment in the myogenic lineage.

scholarly journals Expression of muscle genes in heterokaryons depends on gene dosage.

1986 ◽  
Vol 102 (1) ◽  
pp. 124-130 ◽  
Author(s):  
G K Pavlath ◽  
H M Blau
Keyword(s):  
Gene Expression ◽  
Time Course ◽  
Gene Dosage ◽  
Cell Types ◽  
Threshold Concentration ◽  
Specific Gene ◽  
Mouse Muscle ◽  
Muscle Gene Expression ◽  
Muscle Genes ◽  
Muscle Gene

We report that gene dosage, or the ratio of nuclei from two cell types fused to form a heterokaryon, affects the time course of differentiation-specific gene expression. The rate of appearance of the human muscle antigen, 5.1H11, is significantly faster in heterokaryons with equal or near-equal numbers of mouse muscle and human fibroblast nuclei than in heterokaryons with increased numbers of nuclei from either cell type. By 4 d after fusion, a high frequency of gene expression is evident at all ratios and greater than 75% of heterokaryons express the antigen even when the nonmuscle nuclei greatly outnumber the muscle nuclei. The kinetic differences observed with different nuclear ratios suggest that the concentration of putative trans-acting factors significantly influences the rate of muscle gene expression: a threshold concentration is necessary, but an excess may be inhibitory.

Disruption of the coordinate expression of muscle genes in a transfected BC3H1 myoblast cell line producing a low level of the adenovirus E1A transforming protein

1992 ◽  
Vol 70 (10-11) ◽  
pp. 1268-1276 ◽  
Author(s):  
Joe S. Mymryk ◽  
Janice D. Oakes ◽  
Senthil K. Muthuswamy ◽  
Pietro D'Amico ◽  
Stanley T. Bayley ◽  
...  
Keyword(s):  
Myogenic Differentiation ◽  
Calf Serum ◽  
Adenovirus E1a ◽  
Myoblast Cell Line ◽  
Muscle Genes ◽  
E1a Gene ◽  
H1 Cells ◽  
Myoblast Cell ◽  
Muscle Gene ◽  
Adenovirus 5

Mouse BC3H1 myoblasts were stably transfected with the adenovirus 5 E1A gene. One clonal line, BC3E7, was found to differ in some important respects from those previously reported for E1A-transformed myoblasts. In contrast to BC3H1 cells which differentiate when confluent in medium containing 0.5% fetal calf serum (FCS), BC3E7 cells failed to elongate and align, to express acetylcholine receptor and creatine kinase, and to down-regulate expression of β- and γ-actins and tropomyosin isoform (TM) 1. However, increased synthesis of TMs 2, 3, and 4, and myosin light chain 1 associated with differentiation in BC3H1 still occurred in BC3E7 cells, and most surprisingly, α-actin was produced at a significant level in both proliferating and confluent BC3E7 cells. Interestingly, myogenin was expressed in confluent BC3E7 cells in 0.5% FCS, but not in 20%. The level of E1A expression in BC3E7 cells was found to be very low by analysis of mRNA, by immunoprecipitation of E1A protein, and by the ability of BC3E7 cells to complement the E1A-deficient adenovirus mutant dl312. These results suggest that different levels of E1A may be needed to repress different promoters and that E1A does not block myogenic differentiation by repressing myogenin expression, but represses each muscle gene independently.Key words: actin, adenovirus 5 E1A, BC3H1 myoblasts, myogenin.

scholarly journals PCAF Involvement in Lamin A/C-HDAC2 Interplay during the Early Phase of Muscle Differentiation

Cells ◽  
2020 ◽  
Vol 9 (7) ◽  
pp. 1735
Author(s):  
Spartaco Santi ◽  
Vittoria Cenni ◽  
Cristina Capanni ◽  
Giovanna Lattanzi ◽  
Elisabetta Mattioli
Keyword(s):  
Muscular Dystrophy ◽  
Early Phase ◽  
Myogenic Differentiation ◽  
Nuclear Lamina ◽  
Muscle Differentiation ◽  
Lamin A ◽  
Histone Deacetylase 2 ◽  
Muscle Gene Expression ◽  
Muscle Gene ◽  
Human Muscle Cells

Lamin A/C has been implicated in the epigenetic regulation of muscle gene expression through dynamic interaction with chromatin domains and epigenetic enzymes. We previously showed that lamin A/C interacts with histone deacetylase 2 (HDAC2). In this study, we deepened the relevance and regulation of lamin A/C-HDAC2 interaction in human muscle cells. We present evidence that HDAC2 binding to lamin A/C is related to HDAC2 acetylation on lysine 75 and expression of p300-CBP associated factor (PCAF), an acetyltransferase known to acetylate HDAC2. Our findings show that lamin A and farnesylated prelamin A promote PCAF recruitment to the nuclear lamina and lamin A/C binding in human myoblasts committed to myogenic differentiation, while protein interaction is decreased in differentiating myotubes. Interestingly, PCAF translocation to the nuclear envelope, as well as lamin A/C-PCAF interaction, are reduced by transient expression of lamin A mutated forms causing Emery Dreifuss muscular dystrophy. Consistent with this observation, lamin A/C interaction with both PCAF and HDAC2 is significantly reduced in Emery–Dreifuss muscular dystrophy myoblasts. Overall, these results support the view that, by recruiting PCAF and HDAC2 in a molecular platform, lamin A/C might contribute to regulate their epigenetic activity required in the early phase of muscle differentiation.

scholarly journals miR-155 Inhibits Expression of the MEF2A Protein to Repress Skeletal Muscle Differentiation

2011 ◽  
Vol 286 (41) ◽  
pp. 35339-35346 ◽  
Author(s):  
Hee Young Seok ◽  
Mariko Tatsuguchi ◽  
Thomas E. Callis ◽  
Aibin He ◽  
William T. Pu ◽  
...  
Keyword(s):  
Gene Expression ◽  
Small Rnas ◽  
Myogenic Differentiation ◽  
Regulation Of Gene Expression ◽  
Myoblast Differentiation ◽  
Transcriptional Level ◽  
Muscle Gene Expression ◽  
Important Regulator ◽  
Non Coding Rnas ◽  
Muscle Gene

microRNAs (miRNAs) are 21–23-nucleotide non-coding RNAs. It has become more and more evident that this class of small RNAs plays critical roles in the regulation of gene expression at the post-transcriptional level. MEF2A is a member of the MEF2 (myogenic enhancer factor 2) family of transcription factors. Prior report showed that the 3′-untranslated region (3′-UTR) of the Mef2A gene mediated its repression; however, the molecular mechanism underlying this intriguing observation was unknown. Here, we report that MEF2A is repressed by miRNAs. We identify miR-155 as one of the primary miRNAs that significantly represses the expression of MEF2A. We show that knockdown of the Mef2A gene by siRNA impairs myoblast differentiation. Similarly, overexpression of miR-155 leads to the repression of endogenous MEF2A expression and the inhibition of myoblast differentiation. Most importantly, reintroduction of MEF2A in miR-155 overexpressed myoblasts was able to partially rescue the miR-155-induced myoblast differentiation defect. Our data therefore establish miR-155 as an important regulator of MEF2A expression and uncover its function in muscle gene expression and myogenic differentiation.

A model for the modulation of muscle cell determination and differentiation by growth factors

1989 ◽  
Vol 67 (9) ◽  
pp. 575-580 ◽  
Author(s):  
David J. Kelvin ◽  
Terry P. Yamaguchi ◽  
Gilles Simard ◽  
Helen H. Tai ◽  
Andrew I. Sue-A-Quan ◽  
...  
Keyword(s):  
Growth Factors ◽  
Muscle Cell ◽  
Nuclear Dna ◽  
Regulatory Sequences ◽  
Cis Acting ◽  
Muscle Gene Expression ◽  
Muscle Genes ◽  
Adult Organism ◽  
Muscle Gene

In an adult organism three principal types of muscle tissue can be found: skeletal, smooth, and cardiac. While each display subtle differences, for the most part they express a common set of genes that are representative of differentiated muscle. Several in vitro muscle cell lines have provided clues as to how the developmental programs of muscle cell proliferation, determination, and differentiation are controlled. In this paper we will explore recent advances in our understanding of how growth factors, acting through specific signal transduction pathways, control muscle gene expression. The transcription of muscle genes is controlled by specific cis-acting regulatory sequences. We will discuss how growth factors may exert their effects on muscle genes by modulating the expression of nuclear DNA-binding proteins that directly regulate muscle gene expression.Key words: determination, myogenesis, oncogene, fibroblast growth factor, myoD1.

scholarly journals Myogenin is required for assembly of the transcription machinery on muscle genes during skeletal muscle differentiation

PLoS ONE ◽  
2021 ◽  
Vol 16 (1) ◽  
pp. e0245618
Author(s):  
Abhinav Adhikari ◽  
William Kim ◽  
Judith Davie
Keyword(s):  
Gene Expression ◽  
Skeletal Muscle ◽  
Gene Activation ◽  
Gene Promoters ◽  
Muscle Gene Expression ◽  
Transcription Machinery ◽  
Muscle Genes ◽  
Muscle Gene

Skeletal muscle gene expression is governed by the myogenic regulatory family (MRF) which includes MyoD (MYOD1) and myogenin (MYOG). MYOD1 and MYOG are known to regulate an overlapping set of muscle genes, but MYOD1 cannot compensate for the absence of MYOG in vivo. In vitro, late muscle genes have been shown to be bound by both factors, but require MYOG for activation. The molecular basis for this requirement was unclear. We show here that MYOG is required for the recruitment of TBP and RNAPII to muscle gene promoters, indicating that MYOG is essential in assembling the transcription machinery. Genes regulated by MYOD1 and MYOG include genes required for muscle fusion, myomaker and myomerger, and we show that myomaker is fully dependent on activation by MYOG. We also sought to determine the role of MYOD1 in MYOG dependent gene activation and unexpectedly found that MYOG is required to maintain Myod1 expression. However, we also found that exogenous MYOD1 was unable to compensate for the loss of Myog and activate muscle gene expression. Thus, our results show that MYOD1 and MYOG act in a feed forward loop to maintain each other’s expression and also show that it is MYOG, and not MYOD1, that is required to load TBP and activate gene expression on late muscle gene promoters bound by both factors.

scholarly journals Modulation of Smooth Muscle Gene Expression by Association of Histone Acetyltransferases and Deacetylases with Myocardin

2005 ◽  
Vol 25 (1) ◽  
pp. 364-376 ◽  
Author(s):  
Dongsun Cao ◽  
Zhigao Wang ◽  
Chun-Li Zhang ◽  
Jiyeon Oh ◽  
Weibing Xing ◽  
...  
Keyword(s):  
Gene Expression ◽  
Smooth Muscle ◽  
Transcriptional Activation ◽  
Histone Deacetylases ◽  
Serum Response Factor ◽  
Gene Activation ◽  
Muscle Gene Expression ◽  
P300 Binding ◽  
Muscle Genes ◽  
Muscle Gene

ABSTRACT Differentiation of smooth muscle cells is accompanied by the transcriptional activation of an array of muscle-specific genes controlled by serum response factor (SRF). Myocardin is a cardiac and smooth muscle-specific expressed transcriptional coactivator of SRF and is sufficient and necessary for smooth muscle gene expression. Here, we show that myocardin induces the acetylation of nucleosomal histones surrounding SRF-binding sites in the control regions of smooth muscle genes. The promyogenic activity of myocardin is enhanced by p300, a histone acetyltransferase that associates with the transcription activation domain of myocardin. Conversely, class II histone deacetylases interact with a domain of myocardin distinct from the p300-binding domain and suppress smooth muscle gene activation by myocardin. These findings point to myocardin as a nexus for positive and negative regulation of smooth muscle gene expression by changes in chromatin acetylation.

scholarly journals microRNA-1 regulates sarcomere formation and suppresses smooth muscle gene expression in the mammalian heart

eLife ◽  
2013 ◽  
Vol 2 ◽  
Author(s):  
Amy Heidersbach ◽  
Chris Saxby ◽  
Karen Carver-Moore ◽  
Yu Huang ◽  
Yen-Sin Ang ◽  
...  
Keyword(s):  
Gene Expression ◽  
Smooth Muscle ◽  
Striated Muscle ◽  
Muscle Gene Expression ◽  
Regulatory Myosin Light Chain ◽  
Myosin Light Chain 2 ◽  
Evolutionarily Conserved ◽  
Muscle Genes ◽  
Mammalian Genomes ◽  
Muscle Gene

microRNA-1 (miR-1) is an evolutionarily conserved, striated muscle-enriched miRNA. Most mammalian genomes contain two copies of miR-1, and in mice, deletion of a single locus, miR-1-2, causes incompletely penetrant lethality and subtle cardiac defects. Here, we report that deletion of miR-1-1 resulted in a phenotype similar to that of the miR-1-2 mutant. Compound miR-1 knockout mice died uniformly before weaning due to severe cardiac dysfunction. miR-1-null cardiomyocytes had abnormal sarcomere organization and decreased phosphorylation of the regulatory myosin light chain-2 (MLC2), a critical cytoskeletal regulator. The smooth muscle-restricted inhibitor of MLC2 phosphorylation, Telokin, was ectopically expressed in the myocardium, along with other smooth muscle genes. miR-1 repressed Telokin expression through direct targeting and by repressing its transcriptional regulator, Myocardin. Our results reveal that miR-1 is required for postnatal cardiac function and reinforces the striated muscle phenotype by regulating both transcriptional and effector nodes of the smooth muscle gene expression network.

scholarly journals MyoD induces myogenic differentiation through cooperation of its NH2- and COOH-terminal regions

2005 ◽  
Vol 171 (3) ◽  
pp. 471-482 ◽  
Author(s):  
Jeff Ishibashi ◽  
Robert L. Perry ◽  
Atsushi Asakura ◽  
Michael A. Rudnicki
Keyword(s):  
Transcription Factors ◽  
Target Genes ◽  
Myogenic Differentiation ◽  
Gene Activation ◽  
Proliferating Cells ◽  
Muscle Gene Expression ◽  
Helix Loop Helix ◽  
Myoblast Proliferation ◽  
Muscle Gene

MyoD and Myf5 are basic helix-loop-helix transcription factors that play key but redundant roles in specifying myogenic progenitors during embryogenesis. However, there are functional differences between the two transcription factors that impact myoblast proliferation and differentiation. Target gene activation could be one such difference. We have used microarray and polymerase chain reaction approaches to measure the induction of muscle gene expression by MyoD and Myf5 in an in vitro model. In proliferating cells, MyoD and Myf5 function very similarly to activate the expression of likely growth phase target genes such as L-myc, m-cadherin, Mcpt8, Runx1, Spp1, Six1, IGFBP5, and Chrnβ1. MyoD, however, is strikingly more effective than Myf5 at inducing differentiation-phase target genes. This distinction between MyoD and Myf5 results from a novel and unanticipated cooperation between the MyoD NH2- and COOH-terminal regions. Together, these results support the notion that Myf5 functions toward myoblast proliferation, whereas MyoD prepares myoblasts for efficient differentiation.

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