Nuclear poly(A) binding protein 1 (PABPN1) levels are increased duringmuscle regeneration in part due to increased levels in myoblasts. (A)Representative hematoxylin and eosin stained sections of gastrocnemius musclesat different times after BaCl2 injury are shown. (B) Lysateswere prepared from gastrocnemius muscles at different times after injury andwere immunoblotted with anti-PABPN1, PABPC1 or heat shock protein 90 (HSP90)antibodies (n = 3 per timepoint). (C) Total RNA was obtained fromuninjured and injured muscle tissue (three independent samples) as well asfluorescence-activated cell sorting (FACS)-sorted myoblasts and non-myogeniccells obtained 3 days after muscle injury (pooled from five mice). PABPN1 mRNAlevels were determined using real-time polymerase chain reaction (PCR) andhypoxanthine-guanine phosphoribosyltransferase (HPRT) mRNA was used as aninternal control. Amount of PABPN1 mRNA relative to uninjured muscle is shown;n = 3. Data are mean ± SD; *P <0.05 vs uninjured muscle.