Distinct up-regulation of myogenin in skeletal muscle of WT and Plg-deficient mice after freeze-crush injury.

RNA and tissue extracts were obtained from the gastrocnemious muscle of WT and Plg^−/− mice at 0 days AI (C, control) or 4 days AI (W, wound). (A) Analysis of myogenin messenger RNA in regenerating muscle of WT and Plg^−/− mice. Northern analysis was performed to detect expression of myogenin and 18S. Myogenin transcript levels were induced in regenerating muscle of WT mice. Expression of myogenin was lower in regenerating muscle of Plg-deficient mice compared with regenerating muscle of WT mice, whereas levels of 18S were similar in all lanes. (B) Analysis of myogenin protein in regenerating muscle of WT and Plg^−/− mice. Western analysis was performed to detect expression of myogenin using an antimyogenin antibody. Ponceau Red staining was performed to check for equal protein loading. Myogenin was induced in both WT and Plg-deficient mice, although induction was greater in the former mice. (C) PCR genotyping of Plg^+/+, Plg^−/−, and Plg^+/− mice. PCR products of 450 and 480 bp correspond to WT Plg allele and targeted allele, respectively.