Peter S Zammit

..This time course is similar to that observed in vivo following acute injury and indicates that cells other than satellite cells are not required for complete myofiber regeneration...

..Importantly, therefore, this promoter-specific activity directed by A17 reflects aspects of the expression profiles of the endogenous Myf5 and Mrf4 genes...

..Thus, beta-catenin signalling in proliferating satellite cells directs these cells towards the self-renewal pathway and, so, contributes to the maintenance of this stem-cell pool in adult skeletal muscle...

..Finally, the rapid progress in the age of molecular biology is briefly discussed, and some ongoing debates on satellite cell function highlighted...

..This Commentary seeks to integrate these interesting new findings into the wider context of satellite-cell biology, and to highlight some of the many outstanding questions...

..This is a fast-moving and dynamic field, however, and in this review we discuss the evidence that we think puts this enigmatic cell firmly back at the center of adult myogenesis...

..Therefore Pax7 may be involved in maintaining proliferation and preventing precocious differentiation, but does not promote quiescence...

..Satellite cells, therefore, are a functionally heterogeneous population, with many occupants of the niche exhibiting stem cell characteristics in both somite-derived and branchiomeric muscles...

..These studies are a first step towards identifying cognate transcription factors involved in muscle stem cell regulation...

..Thus, within a normally stable tissue, the satellite cell exhibits archetypal stem cell properties and is competent to form the basal origin of adult muscle regeneration...

..Conversely, Jagged-1, a Notch ligand, was not expressed in quiescent satellite cells but was induced upon activation. These findings further contribute to defining the molecular signature of muscle satellite cells...

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..Thus, the effectiveness of stem-cell-mediated muscle regeneration is determined by both extrinsic environmental influences and diversity in intrinsic potential of the stem cells themselves...

..Myotome asymmetry, therefore, is downstream of the iv mutation but upstream of, or unrelated to, the Pitx2c pathway...

..These observations suggest that satellite cells either differentiate or switch from terminal myogenesis to maintain the satellite cell pool...

..Thus, the expression of HB-EGF in myotome pairs is regulated by global cues that define the left-right body axis...

..Where myofibre hypertrophy during growth requires the addition of new myonuclei, these are supplied by muscle satellite cells, the resident stem cells of skeletal muscle...

..In the present paper, we review recent developments in genotype-phenotype correlations in laminopathies and discuss the factors that could influence pathology...

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..Taken together, our observations show that PS1 is a key player in the choice of satellite cell fate, acting through both gamma-secretase-dependent and gamma-secretase-independent mechanisms...

..Together these observations show that Myf5 activation in adult muscle is accomplished by a complex signalling pathway, and provides candidates that can be examined for their role in Myf5 regulation during development...

..Here, we review whether the pathogenic mutation can directly contribute to satellite cell dysfunction in a number of muscular dystrophies...

..Together, our results show that Pitx genes play a role in regulating satellite cell function during myogenesis in adult...

..Together, this study significantly augments the number of EDMD patients on the database and describes 15 novel mutations that underlie EDMD, which will contribute to establishing genotype-phenotype correlations...

..Therefore, we show that Myf5 is a regulator of regenerative myogenesis and homeostasis, with functions distinct from those of Myod and Mrf4...

..Together, our observations show that sphingolipid signaling is involved in the induction of proliferation in an adult stem cell and a key component of muscle regeneration...

..Together our observations provide insights into the regulation of fetal myogenesis and the mechanisms by which temporally distinct genetic programs are integrated at a single locus...

..Our observations show that quiescent satellite cells are characterized by high levels of sphingomyelin in their plasma membranes and that lysenin provides a novel marker of myogenic quiescence...