scholarly journals mef2c is activated directly by myogenic basic helix-loop-helix proteins during skeletal muscle development in vivo

2003 ◽  
Vol 120 (9) ◽  
pp. 1021-1032 ◽  
Author(s):  
Evdokia Dodou ◽  
Shan-Mei Xu ◽  
Brian L. Black
Keyword(s):  
Skeletal Muscle ◽  
Muscle Development ◽  
Skeletal Muscle Development ◽  
Basic Helix Loop Helix ◽  
Helix Loop Helix

The Mef2c gene is a direct transcriptional target of myogenic bHLH and MEF2 proteins during skeletal muscle development

Development ◽  
2001 ◽  
Vol 128 (22) ◽  
pp. 4623-4633 ◽  
Author(s):  
Da-Zhi Wang ◽  
M. Renee Valdez ◽  
John McAnally ◽  
James Richardson ◽  
Eric N. Olson
Keyword(s):  
Gene Expression ◽  
Skeletal Muscle ◽  
Transcription Factors ◽  
Binding Site ◽  
Control Region ◽  
Muscle Development ◽  
Regulatory Elements ◽  
Skeletal Muscle Development ◽  
Helix Loop Helix

Members of the MEF2 family of transcription factors are upregulated during skeletal muscle differentiation and cooperate with the MyoD family of myogenic basic helix-loop-helix (bHLH) transcription factors to control the expression of muscle-specific genes. To determine the mechanisms that regulate MEF2 gene expression during skeletal muscle development, we analyzed the mouse Mef2c gene for cis-regulatory elements that direct expression in the skeletal muscle lineage in vivo. We describe a skeletal muscle-specific control region for Mef2c that is sufficient to direct lacZ reporter gene expression in a pattern that recapitulates that of the endogenous Mef2c gene in skeletal muscle during pre- and postnatal development. This control region is a direct target for the binding of myogenic bHLH and MEF2 proteins. Mutagenesis of the Mef2c control region shows that a binding site for myogenic bHLH proteins is essential for expression at all stages of skeletal muscle development, whereas an adjacent MEF2 binding site is required for maintenance but not for initiation of Mef2c transcription. Our findings reveal the existence of a regulatory circuit between these two classes of transcription factors that induces, amplifies and maintains their expression during skeletal muscle development.

scholarly journals Regulation of Skeletal Muscle Sarcomere Integrity and Postnatal Muscle Function by Mef2c

2007 ◽  
Vol 27 (23) ◽  
pp. 8143-8151 ◽  
Author(s):  
Matthew J. Potthoff ◽  
Michael A. Arnold ◽  
John McAnally ◽  
James A. Richardson ◽  
Rhonda Bassel-Duby ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Transcription Factors ◽  
Muscle Development ◽  
Skeletal Muscle Development ◽  
Postnatal Maturation ◽  
Helix Loop Helix ◽  
Specific Proteins ◽  
Perinatal Lethality ◽  
Bhlh Transcription Factors

ABSTRACT Myocyte enhancer factor 2 (MEF2) transcription factors cooperate with the MyoD family of basic helix-loop-helix (bHLH) transcription factors to drive skeletal muscle development during embryogenesis, but little is known about the potential functions of MEF2 factors in postnatal skeletal muscle. Here we show that skeletal muscle-specific deletion of Mef2c in mice results in disorganized myofibers and perinatal lethality. In contrast, neither Mef2a nor Mef2d is required for normal skeletal muscle development in vivo. Skeletal muscle deficient in Mef2c differentiates and forms normal myofibers during embryogenesis, but myofibers rapidly deteriorate after birth due to disorganized sarcomeres and a loss of integrity of the M line. Microarray analysis of Mef2c null muscles identified several muscle structural genes that depend on MEF2C, including those encoding the M-line-specific proteins myomesin and M protein. We show that MEF2C directly regulates myomesin gene transcription and that loss of Mef2c in skeletal muscle results in improper sarcomere organization. These results reveal a key role for Mef2c in maintenance of sarcomere integrity and postnatal maturation of skeletal muscle.

scholarly journals Genetic analysis of alpha 4 integrin functions in the development of mouse skeletal muscle.

1996 ◽  
Vol 135 (3) ◽  
pp. 829-835 ◽  
Author(s):  
J T Yang ◽  
T A Rando ◽  
W A Mohler ◽  
H Rayburn ◽  
H M Blau ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Muscle Development ◽  
Es Cells ◽  
Embryonic Stem ◽  
Chimeric Mice ◽  
Skeletal Muscle Development ◽  
Gene Encoding ◽  
Pure Cultures

It has been suggested, on the basis of immunolocalization studies in vivo and antibody blocking experiments in vitro, that alpha 4 integrins interacting with vascular cell adhesion molecule 1 (VCAM-1) are involved in myogenesis and skeletal muscle development. To test this proposal, we generated embryonic stem (ES) cells homozygous null for the gene encoding the alpha 4 subunit and used them to generate chimeric mice. These chimeric mice showed high contributions of alpha 4-null cells in many tissues, including skeletal muscle, and muscles lacking any detectable (< 2%) alpha 4-positive cells did not reveal any gross morphological abnormalities. Furthermore, assays for in vitro myogenesis using either pure cultures of alpha 4-null myoblasts derived from the chimeras or alpha 4-null ES cells showed conclusively that alpha 4 integrins are not essential for muscle cell fusion and differentiation. Taking these results together, we conclude that alpha 4 integrins appear not to play essential roles in normal skeletal muscle development.

Determination versus differentiation and the MyoD family of transcription factors

1995 ◽  
Vol 73 (9-10) ◽  
pp. 723-732 ◽  
Author(s):  
Lynn A. Megeney ◽  
Michael A. Rudnicki
Keyword(s):  
Skeletal Muscle ◽  
Transcription Factors ◽  
Sequence Homology ◽  
Expression Patterns ◽  
Myogenic Regulatory Factors ◽  
Basic Helix Loop Helix ◽  
Helix Loop Helix

The myogenic regulatory factors (MRFs) form a family of basic helix–loop–helix transcription factors consisting of Myf-5, MyoD, myogenin, and MRF4. The MRFs play key regulatory roles in the development of skeletal muscle during embryogenesis. Sequence homology, expression patterns, and genetargeting experiments have revealed a two-tiered subclassification within the MRF family. Myf-5 and MyoD are more homologous to one another than to the others, are expressed in myoblasts before differentiation, and are required for the determination or survival of muscle progenitor cells. By contrast, myogenin and MRF4 are more homologous to one another than to the others and are expressed upon differentiation, and myogenin is required in vivo as a differentiation factor while the role of MRF4 remains unclear. On this basis, MyoD and Myf-5 are classified as primary MRFs, as they are required for the determination of myoblasts, and myogenin and MRF4 are classified as secondary MRFs, as they likely function during terminal differentiation.Key words: MyoD, Myf-5, myogenin, MRF4, skeletal muscle.

scholarly journals Loss of splicing factor IK impairs normal skeletal muscle development

BMC Biology ◽  
2021 ◽  
Vol 19 (1) ◽  
Author(s):  
Hye In Ka ◽  
Hyemin Seo ◽  
Youngsook Choi ◽  
Joohee Kim ◽  
Mina Cho ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Muscle Development ◽  
Myogenic Differentiation ◽  
Mrna Splicing ◽  
C2c12 Cells ◽  
Splicing Factor ◽  
Skeletal Muscle Development

Abstract Background IK is a splicing factor that promotes spliceosome activation and contributes to pre-mRNA splicing. Although the molecular mechanism of IK has been previously reported in vitro, the physiological role of IK has not been fully understood in any animal model. Here, we generate an ik knock-out (KO) zebrafish using the CRISPR/Cas9 system to investigate the physiological roles of IK in vivo. Results The ik KO embryos display severe pleiotropic phenotypes, implying an essential role of IK in embryonic development in vertebrates. RNA-seq analysis reveals downregulation of genes involved in skeletal muscle differentiation in ik KO embryos, and there exist genes having improper pre-mRNA splicing among downregulated genes. The ik KO embryos display impaired neuromuscular junction (NMJ) and fast-twitch muscle development. Depletion of ik reduces myod1 expression and upregulates pax7a, preventing normal fast muscle development in a non-cell-autonomous manner. Moreover, when differentiation is induced in IK-depleted C2C12 myoblasts, myoblasts show a reduced ability to form myotubes. However, inhibition of IK does not influence either muscle cell proliferation or apoptosis in zebrafish and C2C12 cells. Conclusion This study provides that the splicing factor IK contributes to normal skeletal muscle development in vivo and myogenic differentiation in vitro.

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