Fig. 1

A robust transgenic model for tracing myogenesis. a Schematic of doxycylcline-inducible tracing system for perpetual labeling of skeletal muscle myocytes. In ActaLable mice, rtTA is expressed only in skeletal muscle myocytes where ACTA1 promoter is activated. Upon the presence of doxycycline, rtTA drives the expression of Cre recombinase. Then the loxP-floxed transcriptional stop cassette is excised and LacZ expression is activated. b β-gal staining of representative transections of LD, GA, RF, TA and EDL. Two-month-old male mice were fed with food and water either with or without doxycycline for 5 days before being analyzed. (Scale bar: 200 μm; n = 3 mice per group). c Detection of transgene expression specialty in ActaLabel mice. 60-day-old ActaLabel mice were induced with Dox for 5 days and then qPCR analysis was performed to examine the expression levels of Cre and LacZ in the indicated tissues. Gapdh was used as internal control. (n = 3 littermates per group, Data present as mean ± SD). d Detection for washout time of Dox in mice. 60-day-old ActaLabel mice were administrated with Dox with for 7 days, following 12 h, 24 h and 96 h Dox removal respectively. Then qPCR analysis was performed to examine the expression levels of Cre and LacZ in skeletal muscle. Gapdh was used as internal control. (n = 3 littermates per group, Data present as mean ± SD)