cDNA sequence, tissue-specific expression, and chromosomal mapping of the human slow-twitch skeletal muscle isoform of troponin I

Genomics. 1990 Jul;7(3):346-57. doi: 10.1016/0888-7543(90)90168-t.


Troponin I (TnI) is a myofibrillar protein involved in the calcium-mediated regulation of striated muscle contraction. Three isoforms of TnI are known and each is expressed in a muscle fiber-type-specific manner. TnI-fast and TnI-slow are expressed exclusively in fast-twitch and slow-twitch skeletal muscle myofibers, respectively, while a third isoform, TnI-card, is expressed in both the atrium and the ventricle of the heart. An explanation of the myofiber-type-restricted expression of the troponin I multigene family will further aid in understanding how various types of striated muscle fibers are established. To initiate the study of TnI isoform gene expression, we have isolated a full-length cDNA representing the human slow-twitch skeletal muscle isoform of troponin I. Sequence comparisons demonstrate that the TnI-slow protein is highly conserved between species. Therefore, the cDNA was used as a probe to investigate the tissue-specific and developmental regulation of the TnI-slow gene in both rodent and human myogenic cells. TnI-slow message appears to be restricted to muscle tissue containing slow-twitch skeletal muscle myofibers. TnI-slow gene expression is induced in differentiated cultures of primary human muscle cells and several (but not all) myogenic cell lines. In addition, a human-specific probe prepared from the 3' untranslated region of the cDNA has been used to probe a panel of human/mouse somatic cell hybrid lines, resulting in the assignment of the human TnI-slow gene to the q12----qter region of chromosome 1. The locus is designated TNNI1.

Publication types

  • Research Support, U.S. Gov't, Non-P.H.S.
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Base Sequence
  • Cell Line
  • Chromosome Mapping*
  • DNA / genetics
  • Genes
  • Humans
  • Mice
  • Molecular Sequence Data
  • Muscles / metabolism*
  • Organ Specificity / genetics
  • RNA, Messenger / analysis
  • Rabbits
  • Rats
  • Restriction Mapping
  • Sequence Homology, Nucleic Acid
  • Troponin / genetics*
  • Troponin I


  • RNA, Messenger
  • Troponin
  • Troponin I
  • DNA

Associated data

  • GENBANK/J04760