Sarcosin (Krp1) in skeletal muscle differentiation: gene expression profiling and knockdown experiments

Int J Dev Biol. 2012;56(4):301-9. doi: 10.1387/ijdb.113327lp.


SARCOSIN, also named Krp1, has been identified as a protein exclusively expressed in striated muscle tissue. Here we report on the role of SARCOSIN in skeletal muscle development and differentiation. We demonstrate, by means of whole-mount in situ hybridization, that Sarcosin mRNA is expressed in the myotome part of the mature somites in mouse embryos from embryonic day 9.5 onwards. Sarcosin is not expressed in the developing heart at these embryonic stages, and in adult tissues the mRNA expression levels are five times lower in the heart than in skeletal muscle. SARCOSIN protein partially co-localizes with the M-band protein myomesin and between and below laterally fusing myofibrils in adult skeletal muscle tissue. RNA interference mediated knock-down of SARCOSIN in the C2C12 myoblast cell line appeared to be stimulatory in the early phase of differentiation, but inhibitory at a later phase of differentiation.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cell Differentiation / genetics*
  • Cell Line
  • Connectin
  • Embryo, Mammalian / cytology
  • Embryo, Mammalian / embryology
  • Embryo, Mammalian / metabolism
  • Female
  • Gene Expression Profiling
  • Gene Expression Regulation, Developmental
  • Immunoblotting
  • In Situ Hybridization
  • Male
  • Mice
  • Mice, Inbred C57BL
  • Microscopy, Fluorescence
  • Muscle Development / genetics*
  • Muscle Fibers, Skeletal / cytology
  • Muscle Fibers, Skeletal / metabolism
  • Muscle Proteins / genetics*
  • Muscle Proteins / metabolism
  • Muscle, Skeletal / cytology
  • Muscle, Skeletal / embryology
  • Muscle, Skeletal / metabolism*
  • Myoblasts / cytology
  • Myoblasts / metabolism
  • RNA Interference
  • Reverse Transcriptase Polymerase Chain Reaction
  • Somites / embryology
  • Somites / metabolism
  • Time Factors


  • Connectin
  • Muscle Proteins
  • sarcosin protein, mouse