|
Slow skeletal muscle troponin T (sTnT) is a protein that in humans is encoded by the ''TNNT1'' gene.〔 The TNNT1 gene is located at 19q13.4 in the human chromosomal genome, encoding the slow twitch skeletal muscle isoform of troponin T (ssTnT). ssTnT is an ~32-kDa protein consisting of 262 amino acids (including the first methionine) with an isoelectric point (pI) of 5.95. It is the tropomyosin binding and thin filament anchoring subunit of the troponin complex in the sarcomeres of slow twitch skeletal muscle fibers.〔〔〔 TNNT1 gene is specifically expressed in slow skeletal muscle of vertebrates, with one exception that dry land toad (Bufo) cardiac muscle expresses ssTnT other than cardiac TnT.〔 == Evolution == thumb Three homologous genes have evolved in vertebrates, encoding three muscle type specific isoforms of TnT.〔 Each of the TnT isoform genes is linked to one of the three troponin I〔 isoform genes encoding the inhibitory subunit of the troponin complex, in chromosomal DNA to form three gene pairs: The fast skeletal muscle TnI (fsTnI)-fsTnT, ssTnI-cardiac (cTnT) and cTnI-ssTnT gene pairs. Sequence and epitope conservation studies suggested that genes encoding the muscle type specific TnT and TnI isoforms may have evolved from duplications of a fsTnI-like-fsTnT-like gene pair.〔 Evolutionary lineage of the three TnI-TnT gene pairs shows that cTnI-ssTnT is the newest〔 and most closely linked.〔 Protein sequence alignment demonstrated that TNNT1 genes are highly conserved among vertebrate species (Fig. 2), especially in the middle and C-terminal regions, while the three muscle type isoforms are significantly diverged among vertebrate species.〔〔 thumb 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「TNNT1」の詳細全文を読む スポンサード リンク
|
