The classical notion of a centralized clock that governs circadian rhythmicity has been challenged with the discovery of peripheral oscillators that enable organisms to cope with daily changes in their environment. The present study aimed to identify the molecular clock components in Atlantic cod (Gadus morhua) and to investigate their daily gene expression in fast skeletal muscle. Atlantic cod...

Mitochondrial dysfunctions are frequently reported in cancer cells, but their direct involvement in tumorigenesis remains unclear. To understand this relation, we stimulated mitochondrial activity by overexpression of the mitochondrial triiodothyronine receptor (p43) in human dermal fibroblasts. In all clones, this stimulation induced morphologic changes and cell fusion in myotube-like structur...

Myogenic regulatory factors (MRFs), including Myf5, MyoD (Myod1) and Myog, are muscle-specific transcription factors that orchestrate myogenesis. Although MRFs are essential for myogenic commitment and differentiation, timely repression of their activity is necessary for the self-renewal and maintenance of muscle stem cells (satellite cells). Here, we define Ascl2 as a novel inhibitor of MRFs. ...

Muscle, a multinucleate syncytium formed by the fusion of mononuclear myoblasts, arises from quiescent progenitors (satellite cells) via activation of muscle-specific transcription factors (MyoD, Myf5, myogenin: MYOG, and MRF4). Subsequent to a decline in Pax7, induction in the expression of MYOG is a hallmark of myoblasts that have entered the differentiation phase following cell cycle withdra...

The pathophysiological mechanisms of both familial and sporadic Amyotrophic Lateral Sclerosis (ALS) are unknown, although growing evidence suggests that skeletal muscle tissue is a primary target of ALS toxicity. Skeletal muscle biopsies were performed on transgenic SOD1(G93A) mice, a mouse model of ALS, to determine genetic biomarkers of disease longevity. Mice were anesthetized with isofluran...

Skeletal myogenesis is associated with the activation of four muscle regulatory factors (MRFs): Myf5, MyoD, Myogenin and MRF4. Here we report that p38 mitogen-activated protein kinase represses the transcriptional activity of MRF4 (involved in late stages of myogenesis), resulting in downregulation of specific muscle genes. MRF4 is phosphorylated in vitro and in vivo by p38 on two serines (Ser3...

As a continuation of the previous study on palate development (Rot and Kablar, 2013), here we explore the relationship between the secondary cartilage mandibular condyles (parts of the temporomandibular joint) and the contributions (mechanical and secretory) from the adjacent skeletal musculature. Previous analysis of Myf5-/-:MyoD-/- mouse fetuses lacking skeletal muscle demonstrated the import...

Myogenesis is a tightly controlled process involving the transcriptional activation and repression of thousands of genes. Although many components of the transcriptional network regulating the later phases of myogenesis have been identified, relatively few studies have described the transcriptional landscape during the first 24 h, when myoblasts commit to differentiate. Through dense temporal p...