EXPRESSION OF MYOTONIC-DYSTROPHY PROTEIN-KINASE GENE DURING IN-VIVO AND IN-VITRO MOUSE MYOGENESIS

Myotonic dystrophy (DM) is an autosomal dominant neuromuscular disorde r characterized by a great variability in its clinical manifestations. The mutational basis underlying DM consists of an unstable (CTG), tri nucleotide repeat in the 3' untranslated region of the myotonic dystro phy protein kinase gene (DMPK). Conflicting results on DMPK gene expre ssion in congenitally affected infants (CDM) have been published. More over, the prominence of satellite cells seen in muscle of CDM infants supports the notion that the congenital form is associated with an arr est in muscle development and suggests a role for the DMPK gene during differentiation and maturation of muscle. In order to clarify these f indings, a comparative study of DMPK and myogenic factor mRNA levels w as performed in developing mouse muscle tissues and cultured muscle ce lls at different developmental stages. Results show that DMPK gene exp ression is upregulated at a late stage of muscular development. This u pregulation does not seem to depend on a given muscle specific bHLH fa ctor.