Terminal differentiation of distinct cell types requires the transcriptional activation of differentiation-specific genes and the suppression of genes associated with the precursor cell. For example, the expression of utrophin (Utrn) is suppressed during skeletal muscle differentiation, and it is replaced at the sarcolemma by the related dystrophin protein. The MyoD transcription factor directl...

Myogenin and MyoD belong to a family of muscle-specific helix-loop-helix (HLH) proteins that have the potential to activate muscle-specific genes in nonmyogenic cells. Peptide growth factors can block the ability of myogenin and MyoD to activate their target genes. Here, we show that the growth factor-inducible proto-oncogenes c-fos, c-jun, and junB mimic the effects of exogenous growth factors...

Skeletal muscle growth and regeneration are attributed to satellite cells - muscle stem cells resident beneath the basal lamina that surrounds each myofibre. Quiescent satellite cells express the transcription factor Pax7 and when activated, coexpress Pax7 with MyoD. Most then proliferate, downregulate Pax7 and differentiate. By contrast, others maintain Pax7 but lose MyoD and return to a state...

Myf-5 and MyoD are members of a family of musclespecific basic helix-loop-helix (bHLH) proteins that are fundamental for myogenic cell differentiation and transcriptional activation of muscle-specific genes. Here we report that elevated levels of the intracellular signaling molecule CAMP and overexpression of CAMP-dependent protein kinase (PKA) inhibit myogenic differentiation. PKA represses...

CDO, a member of the Ig/fibronectin type III repeat subfamily of transmembrane proteins that includes the axon guidance receptor Robo, was identified by virtue of its down-regulation by the ras oncogene. We report here that one prominent site of cdo mRNA expression during murine embryogenesis is the early myogenic compartment (newly formed somites, dermomyotome and myotome). CDO is expressed in...

In vertebrates, despite the evidence that extrinsic factors induce myogenesis in naive mesoderm, other experiments argue that the initiation of the myogenic program may take place independent of these factors. To resolve this discrepancy, we have re-addressed this issue, using short-term in vivo microsurgery and culture experiments in chick. Our results show that the initial expression of the m...

In developing vertebrate embryos, Pax3 is expressed in the neural tube and in the paraxial mesoderm that gives rise to skeletal muscles. Pax3 mutants develop muscular and neural tube defects; furthermore, Pax3 is essential for the proper activation of the myogenic determination factor gene, MyoD, during early muscle development and PAX3 chromosomal translocations result in muscle tumors, provid...

A MyoD family gene was identified in the ascidian Ciona intestinalis and designated CiMDF (Ciona intestinalis Muscle Determination Factor). Expression of CiMDF was restricted to the muscle cells of the developing embryo and the body-wall muscle of adults. Northern blots showed that two differentially regulated CiMDF transcripts were expressed during development. A 1.8 kb transcript (CiMDFa) app...

Background: The purpose of present study was to investigate whether Sphingosine 1-phosphate (S1P) levels and its receptors gene expressions are correlated with MyoD and myogenin following resistance training. Materials and Methods: 24 eight-week-old male Wistar rats (190-250 gr) were assigned randomly to a control (N = 12) or training (N = 12) group. Rats climbed a resistance training ladder...

The transcription factor MyoD is a master regulator of skeletal muscle differentiation. The finding that G9a, an enzyme principally involved in histone H3 lysine 9 di-methylation (H3K9me2), methylates MyoD, identifies previously unappreciated mechanisms by which chromatin modifiers regulate the transcriptional activity of non-histone substrates to control cellular differentiation programs.