Transitin is required for the differentiation of avian QM7 myoblasts into myotubes

Abstract

*Transitin is a nestin-like intermediate filament protein co-expressed with vimentin in the precursor cells of the myogenic and neurogenic lineages of the avian embryo. To understand its role in myogenesis, stable cell lines expressing transitin-targeted siRNAs were derived from the quail muscle cell line QM7. When cells were cultured in differentiation medium, we found that transitin knockdown prevented myoblast fusion and myotube formation. MyoD mRNA could be detected in transitin siRNA-transfected cells, but upregulation of myogenin and desmin expression was impaired compared to control cells. In addition, transitin siRNA cells maintain high levels of Pax7 expression suggesting that QM7 myoblasts into which transitin expression has been attenuated display a muscle progenitor cell phenotype (Pax7). These observations indicate that transitin plays an important role in the initiation of the myogenic program in avian muscle progenitor cells in acting downstream of MyoD and upstream of myogenin during the lineage progression. V C

Foetal development of the human gluteus maximus muscle with special reference to its fascial insertion

“…All samples were counterstained with haematoxylin. We used nestin as a marker of embryonic striated muscle cells [7,11,12]. Desmin is well known as a marker of muscle fibres [1], but it is not available for specimens that have been preserved for long periods in fixatives (unpublished data).…”