Fig. 1

Muscle phenotype in Mbnl1^ΔE3/ΔE3 and HSA^LR mice. A, B H&E coloration reveals moderate myopathic alterations in TA and gastrocnemius (GA) muscles from 3- and 9-month(M)-old Mbnl1^ΔE3/ΔE3 (A) and 3- and 12-month(M)-old HSA^LR mice (B). Asterisks and arrows point to internalized nuclei and vacuoles, respectively. Scale bar, 100 μm. C Late relaxation time upon stimulation is increased in EDL muscle from 3-month-old Mbnl1^ΔE3/ΔE3 and HSA^LR mice, as compared to control mice. n = 4 Ctrl / 3 Mbnl1^ΔE3/ΔE3; 9 Ctrl / 30 HSA^LR. D Specific tetanic force (sP0) of EDL muscle is unchanged in 3-month-old Mbnl1^ΔE3/ΔE3 (n = 4 Ctrl / 3 KO) and HSA^LR (n = 9 Ctrl / 30 HSA^LR) mice. E-G qPCR analysis of Clcn1 exon7a inclusion (E), Clcn1 total mRNA levels (F) and Atp2a1 exon22 inclusion (G) in TA muscle from Mbnl1^ΔE3/ΔE3 mice and gastrocnemius (GA) or TA muscle from HSA^LR mice. Expression is normalised on total mRNA expression for splice variants (E, G) or on Tbp expression (F). Levels are relative to control and expressed as log2(Fold Change). n = 4 Ctrl / 3 Mbnl1^ΔE3/ΔE3 (E, F); 6 Ctrl / 5 Mbnl1^ΔE3/ΔE3 (G); 4 Ctrl / 4 HSA^LR. All data represent mean ± SEM. **p < 0.01; ****p < 0.0001; unpaired two-tailed Student’s t test