Figure 1. Conditional KO of Prmt5 in embryonic myoblasts (Prmt5^MKO) reduces muscle mass, impairs muscle function, and leads to pre-term death in adult mice.

(A and B) Growth curve (A) and total body weight gain over 6 weeks (B) in 4-week-old WT and Prmt5^MKO mice (n = 7/group).

(C) Survival of adult WT and Prmt5^MKO mice; all KO mice died before reaching 18 weeks old (n = 15).

(D) Lean and fat mass of 8-week-old WT and Prmt5^MKO mice (n = 6) measured by EchoMRI body composition analyzer.

(E) Weight of soleus (SOL), extensor digitorum longus (EDL), tibialis anterior (TA), gastrocnemius (GAS), and quadriceps (QU) muscles in adult WT and Prmt5^MKO mice (n = 3).

(F) Myofiber morphology outlined by sarcolemma dystrophin immunofluorescence of TA muscle sections from WT and Prmt5^MKO mice (n = 4). Scale bar, 100 μm.

(G) Frequency distribution of TA muscle myofiber cross-sectional area (CSA) in adult WT and Prmt5^MKO mice (n = 4).

(H and I) Average myofiber CSA (H) and total myofiber number (I) per TA muscle of WT and Prmt5^MKO mice (n = 4).

(J–L) Running time (J), maximum speed (K), and running distance (L) of adult WT and Prmt5^MKO mice measured by treadmill exhaustion test (n = 5–7).

(M) Grip strength test normalized to body weight in adult WT and Prmt5^MKO mice (n = 5–8).

(N and O) Absolute contractile force as a function of frequency of electric stimulation (left) and maximal absolute force (right) measured in the EDL (N) and SOL (O) muscles isolated from adult WT and Prmt5^MKO mice (n = 4).

(P and Q) Specific force as a function of frequency (left) and maximal specific force (right) of EDL (P) and SOL (Q) muscles isolated from adult WT and Prmt5^MKO mice (n = 4).

Values are expressed as mean ± SEM. *p < 0.05, **p < 0.01, ***p < 0.001, ****p < 0.0001 by t tests. See also Figure S1.