Normalized expression of NOMO1 in tibialis anterior muscle biopsies and C2C12 differentiation in NOMO knockout cells. (A) Dorsiflexion strength was measured in control and DM1 patients against NOMO transcript levels (R = −0.59). proto-DM1, an intermediate form of DM1 corresponding to fewer CTG repeats (50–100) than DM1 (>100) or healthy controls (<30). (B) Myogenesis was performed as in Fig. 6 A and immunostained for Myhc and stained for DNA with DAPI. (C) Immunoblot of control or NOMO-depleted (siNomo) myoblasts during indicated days of differentiation. (D) Assay performed as in B, with myoblasts stably expressing either WT (F-NOMO^WT) or 4-Mut (F-NOMO^4-Mut) constructs in Nomo knockout lines. (E) Quantification of myogenesis under indicated conditions, scored by fusion index. n = 21 frames, 2,433 nuclei (Ctrl), n = 10 frames, 1,411 nuclei (Nomo KO), n = 16 frames, 1,207 nuclei (Nomo KO, WT rescue), and n = 16 frames, 1,717 nuclei (Nomo KO, 4-Mut rescue). (F) Immunoblot comparing protein levels in control (Ctrl) and Nomo knockdown (siNomo) conditions during differentiation. Samples were collected at multiple time points up to day 3 of differentiation. Immunoblot analysis of myogenic markers in control and siNomo-treated cells over 4 days. (G) cDNA obtained from the indicated treated myotubes during day 1 or day 3 of differentiation, amplified via PCR using XBP-1–specific primers, separated by agarose, and stained with SYBR Safe. (H and I) Immunoblot of siRNA knockdown efficiency for Climp-63 and calnexin. GAPDH serves as a loading control. (J) Immunoblot analysis of nra-4 in Ctrl (L4440) and knockdown conditions and probed with anti-NOMO antibody. Statistical analyses were performed using an ordinary one-way ANOVA test; ****P < 0.0001, *P < 0.05, and ns, not significant. Error bars show min. to max. point range. All scale bars, 50 μm. Source numerical data and unprocessed blots are available in source data. Source data are available for this figure: SourceData FS4.