We have studied the contribution of the endogenous production of insulin-like growth factor II (IGFII) and of the muscle regulatory factor, MyoD, to the autonomy of differentiation in isolated skeletal myoblasts. Inhibition of MyoD and IGFII gene expression in myoblasts of the mouse myogenic cell line, C2, was achieved by transfection and selection of stably transfected cells (anti-MyoD and ant...

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...

Facioscapulohumeral muscular dystrophy (FSHD) is caused by contractions of D4Z4 repeats at 4q35.2 thought to induce misregulation of nearby genes, one of which, DUX4, is actually localized within each repeat. A conserved ORF (mDUX), embedded within D4Z4-like repeats, encoding a double-homeodomain protein, was recently identified on mouse chromosome 10. We show here that high level mDUX expressi...

The co-factor Vestigial-like 2 (Vgl-2), in association with the Scalloped/Tef/Tead transcription factors, has been identified as a component of the myogenic program in the C2C12 cell line. In order to understand Vgl-2 function in embryonic muscle formation, we analysed Vgl-2 expression and regulation during chick embryonic development. Vgl-2 expression was associated with all known sites of ske...

The formation of skeletal muscle during development occurs via a series of cellular and molecular steps that lead to the formation of multinucleated myofibers. are key regulators in skeletal muscle ontogeny. MyoD and Myf5 are expressed during myogenesis and are markers of commitment to a muscle fiber fate (Braun et al. The onset of the terminal differentiation process is characterized in part b...

Diploid and triploid rainbow trout weighing approximately 3g were either fed for five weeks, or feed deprived for one week, followed by refeeding. During feed deprivation gastrointestinal somatic index decreased in diploids, but not triploids, and during refeeding, carcass growth rate recovered more quickly in triploids. Although not affected by ploidy, liver ghr2 and igfbp2b expression increas...

Cytokine interleukin-6 (IL-6) is an essential regulator of satellite cell-mediated hypertrophic muscle growth through the transcription factor signal transducer and activator of transcription 3 (STAT3). The importance of this pathway linked to the modulation of myogenic regulatory factors expression in rat skeletal muscle undergoing hypertrophy following resistance exercise, has not been invest...

A single bout of high-intensity resistance exercise is capable of activating the expression of various genes in skeletal muscle involved in hypertrophy such as myosin heavy chain (MHC) isoforms, myogenic regulatory factors (MRFs), and growth factors. However, the specific role exercise intensity plays on the expression of these genes is not well defined. The purpose of this study was to investi...

We have employed the hybrid hammerhead ribozyme-based gene discovery system for identification of genes functionally involved in muscle differentiation using in vitro myoblast differentiation assay. The major muscle regulatory genes (MyoD1, Mylk, myosin, myogenin, and Myf5) were identified endorsing the validity of this method. Other gene targets included tumor suppressors and cell cycle regula...

The development of skeletal muscle in vertebrate embryos is controlled by a transcriptional cascade involving the four myogenic regulatory factors. In the somites of the mouse embryo the order of expression is thought to be Myf5, Myogenin, Mrf4 and MyoD. We have re-examined the expression pattern of Mrf4 and show that in the hypaxial domain of thoracic somites (the somitic bud) Mrf4 expression ...