Résumé :
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Communication n° 485 Oculopharyngeal muscular dystrophy (OPMD) is an autosomal dominant late onset neuromuscular degenerative disease characterised by proximal muscle weakness, ptosis and swallowing disorders. The genetic abnormality is an expansion located on the chromosome 14, consisting of 2-7 additional repeats on the (GCG)6 sequence of the poly(A) binding protein nuclear 1 gene (PABPN1). It results in an increase in length of the polyalanine tract from 10 to 12-17 residues. Cultures of myoblasts from patients with OPMD have been performed in order to study the effect of the expanded repeat, (GCG)8-13 located on the poly(A) binding protein nuclear 1 (PABPN1), on satellite cell phenotype. The expression of PABPN1 in cultures of myoblasts and myotubes isolated from affected (cricopharyngeal muscles, ie CPM) and non affected muscles (quadriceps, sternocleidomastoid muscles), from 6 OPMD patients, have been studied and results were compared with healthy control subjects. The PABPN1 was localized in nuclei and cytoplasm of myotubes, but was predominant in the nuclei of OPMD myoblasts, co-localising with the Hoescht signal. It was found exclusively in the nuclei of myoblasts in the CPM of OMPD patients. In contrast, in unaffected muscles (ie quadriceps, sternocleidomastoid muscles), the PABPN1 was localised both in the nuclei and in the cytoplasm of myoblasts. In the myotubes from CPM from both unaffected and OPMD patients, the PABPN1 was visualized both in the nuclei and in the cytoplasm. In order to study the expression of the PABPN1 and to determine the markers of the OPMD, a proteome analysis of these cultures will be carried out.
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