Fig. 8. Creatine kinase (CK) isoforms are differentially regulated in muscle classes during development. qPCR analysis of hindlimb, cardiac and extraocular muscle (EOM) was performed with the Roche LightCycler and SYBR green reagent. qPCR analysis of E18 to P45 muscles used primers specific for CK-M (A), sCK (B), CK-B (C) and ubiquitous mitochondrial CK (D) transcripts. These data established tissue-specific regulation patterns for each isoform during development.