DECREASED MYOTONIN-PROTEIN KINASE IN THE SKELETAL AND CARDIAC MUSCLESIN MYOTONIC-DYSTROPHY

To investigate the role of myotonin-protein kinase (MT-PK) in the path ophysiology of myotonic dystrophy (DM), we developed specific antibodi es against synthetic MT-PK peptides. The antibody identified a 53kDa p rotein in skeletal muscle and recognized decreases in the amount of th e protein in both adult and congenital DM patients, compared with amou nts in controls and in patients with other muscle diseases. In cardiac muscle, this antibody identified a 62kDa protein, and in brain, both the 53 and 62kDa proteins were detected. These results suggest the pre sence of tissue-specific isoforms of MT-PK. (C) 1994 Academic Press, I nc.