A polymerase chain reaction screening strategy for the promoter of the canine dystrophin gene

Objective:To develop a polymerase chain reaction (PCR) strategy to screen t he dystrophin promoter(s) in dogs with cardiac and skeletal myopathies. Animals-9 Doberman Pinschers; 1 Dalmation, and ? Saint Bernard with dilated cardiomyopathy (DCM)1 Irish Terrier with muscular dystrophy; and 2 dystrop hin-deficient German Shorthaired Pointers (GSHP). Procedure-For each of the 3 unique exons associated with the muscle (M), Pu rkinje (P), and cortical (C) promoters of the dystrophin gene, each first e xon, and the M promoter plus its first exon, were amplified, cloned, and se quenced. The M dystrophin transcript was amplified by reverse transcriptase PCR from skeletal and cardiac muscle RNA of 1 Doberman Pinscher and from s keletal muscle RNA of 1 GSHP. Results-The M, P,and C first exons were amplified from all dogs except the 2 GSHP, which had a deletion encompassing-the entire M, P, and C dystrophin promoter region. The M transcript could not be amplified from muscles of-t he GSHP, but was amplified from skeletal and cardiac muscle of the Doberman Pinscher. Sequencing of the product representing the M promoter and its fi rst exon revealed no differences between clinically normal dogs and the Dob erman' Pinscher with DCM. Conclusions and Clinical Relevance-We have ruled out a major rearrangement of the dystrophin promoter region as the universal cause of DCM in Doberman Pinschers or of Irish Terrier myopathy. Use of the strategy identified a l arge deletion of this region in muscle from the GSHP.