Fig. 2.

miR-501 expression is specific to myogenic progenitors and induced during skeletal muscle regeneration. (A) Expression of the selected miRNAs in MPs and FAPs sorted from normal (SM) or CTX-injected (SM+CTX) TA skeletal muscle, measured by qRT-PCR. miR-1 was measured as an adult-muscle-specific miRNA. n=4-6. acFAP, activated FAPs; acMP, activated MPs; quFAP, quiescent FAPs; quMP, quiescent MPs. (B) Expression of miR-501, miR-206 and miR-1 up to 9 days after CTX injection, measured as in A. n=3 for each time point. (C) Expression of miR-501 in different mouse tissues measured by qRT-PCR. n=5 for TA-CTX, n=3 for the other tissues. D3 CTX, day 3 after CTX treatment; Sm. Int., small intestine; WAT, white adipose tissue. (D) Confirmation of tissue-specific miR-501 expression in CTX-injected TA, primary myoblasts, and myotubes by northern blotting. Ethidium bromide staining of tRNA is shown as loading control. (E,F) The indicated muscle-specific miRNAs (E) or muscle differentiation markers (F) were measured during differentiation of mouse primary myoblasts after serum withdrawal for the indicated time points. n=3. Data were normalized to sno234 in A,B,C and E, and to 18S RNA in F and presented as mean±s.e.m. relative to normal TA muscle or undifferentiated myoblasts. *P<0.05, **P<0.01, ***P<0.001, Student's t-test. CTX, cardiotoxin; SM, skeletal muscle.