Figure 2. Characterization of the ΔT5304 deletion in the tRNA^Tyr gene.

(A) The mutation deleted the A of the innermost base pair of the TΨC stem, as indicated in the cloverleaf structure of tRNA^Tyr. (B) A quantitative oligonucleotide ligation assay (qOLA) was used to estimate the relation between wild-type and mutant molecules in blood samples from golden retrievers. W represents 71 unrelated golden retriever dogs that all show 100% wt molecules. The green bars represent the degree of heteroplasmy of distant relatives (34.8 (22.0); mean (SD)), yellow bars stand for close relatives (5.1 (2.8)) and the red bars represent affected dogs (4.9 (3.5)). (C) Northern blot analyses using probes for mt tRNA^Tyr, mt tRNA^Cys and mt tRNA^Gln and RNA from three SAN-affected golden retrievers and two unaffected dogs; one dachshund (Control 1) and one golden retriever (Control 2). The values given at the bottom of the blots for mt tRNA^Tyr and mt tRNA^Cys is the relative hybridization intensity normalized using the hybridization intensity for mt tRNA^Gln. The sample with the highest normalized hybridization intensity was given the value 1.00.