Animals|Culture Techniques|DNA-Binding Proteins|Embryo, Mammalian|Fractals|Gene Expression Profiling|Gene Expression Regulation|Image Interpretation, Computer-Assisted|Imaging, Three-Dimensional|In Situ Hybridization, Fluorescence|Mice|Microscopy, Fluorescence|Muscle Proteins|Myogenic Regulatory Factor 5|Numerical Analysis, Computer-Assisted|Pattern Recognition, Automated|Tissue Distribution|Trans-Activators|Transcriptional Activation