Differential expression of the rat retinoid X receptor γ gene during skeletal muscle differentiation suggests a role in myogenesis
✍ Scribed by Pantelis Georgiades; Paul M. Brickell
- Publisher
- John Wiley and Sons
- Year
- 1997
- Tongue
- English
- Weight
- 375 KB
- Volume
- 210
- Category
- Article
- ISSN
- 1058-8388
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✦ Synopsis
Even though previous studies have shown that transcripts encoding the murine retinoid X receptor ␥ (RXR␥) are present in skeletal muscle of mouse embryos and that cultured myoblasts are induced to differentiate upon retinoid treatment, a function for RXR␥ and retinoids in mammalian myogenesis has not yet been identified. To begin to understand the possible role of RXR␥ during mammalian myogenesis we isolated novel rat RXR␥ cDNA sequences and examined in detail the spatio-temporal expression pattern of RXR␥ transcripts in relation to skeletal muscle differentiation in rat embryos and cultured myoblasts. We show that the onset of RXR␥ expression coincides with the differentiation of limb myoblasts in vivo. In vitro, RXR␥ is expressed in differentiating myoblasts, but not in proliferating myoblasts. In the myotome, however, RXR␥ is first expressed after myoblast differentiation, with RXR␥ transcripts being confined initially to its ventral region. Subsequently, RXR␥ becomes expressed throughout limb and myotomederived muscle masses, and by the end of the primary myogenic wave, RXR␥ transcripts are mainly confined to their periphery. This dynamic expression pattern of RXR␥ during myogenesis suggests its possible involvement in the differentiation of limb myoblasts but excludes a role in the differentiation of early myotomal myoblasts.