Fig. 3.

MS spectra of selected proteins with differential modulation in dystrophin-deficient muscle. Gastrocnemius muscle was obtained from SILAC-labeled C57BL/6 and unlabeled mdx-52 mice, and MS analysis was performed. A, B, a representative mass spectrum for labeled and unlabeled peptide of dystrophin protein and its elution profile, indicating a complete absence of dystrophin peptide in mdx mice. C, D, a representative mass spectrum for labeled and unlabeled peptide of glyceraldehyde 3 phosphate dehydrogenase (GAPDH) and its elution profile, indicating no change in its level between C57BL/6 and mdx mice. E, F, a representative mass spectrum for labeled and unlabeled peptide of talin-1 protein, indicating its up-regulation in mdx relative to C57BL/6 mice. All peptide ions shown were detected as doubly charged species at their respective m/z values, with a mass error < 10 ppm.