Met-tRNA(fMet) binding in murine dystrophy

Dystrophic mice of the C57B1 dy (2J)dy (2J) strain and of the ReJ 129 dy dy strain and littermate controls were used to prepare met-tRNA(fMet) binding factors. The tissues were homogenized and fractions were obtained which contained ribosomes. The binding factors were assayed by the binding of [(35)S]methionyl-tRNA to control liver ribosomes. The binding, i.e. eukaryotic initiation factor 2 (elF 2) activity, was measured in brain, liver and muscle and in all of these tissues there was a significant decrease in the dystrophic mice. This decrease in initiation factor activity of hindleg muscle resembled, in the direction of the effect, the decrease in elongation factor activity of hindleg muscle resembled, in the of dy dy mice previously reported by our laboratory. Thus these two defects, taken together may help to explain the marked wasting of the muscles. The decrease in brain in both strains provides evidence for nervous tissue involvement in genetic dystrophy.