The Fast TnT Isoforms Specifically Expressed in Avian Adult Pectoral Muscles of Galliforms and Physiological Significance
鸡形目鸟类成熟胸肌中特异性表达的fTnT同工异构型及其生理学意义

Three homologous genes have evolved to encode the cardiac,slow and fast skeletal muscle troponin Ts(TnTs) in the vertebrate. Multiple isoforms in each type of TnT are generated through alternative mRNA splicing during the development and the modality of the fast skeletal TnT isoforms is the most complex. The TnT isoforms specifically expressed in avian adult fast skeletal muscle (especially in the adult pectoral muscle) of Galliforms have been characterized as follows: 1. There exist a cluster of transition metal ion binding sites generally 4-7 repeats of a sequence motif His-(Glu/Ala)- Glu-Ala-His, designated as Tx] in the NH2-terminal variable region. 2. Compared with mammalian TnT and the neonatal or young avian TnT, these avian pectoral muscle TnTs prefer to express exon 16 in the COOH-terminal variable region. Furthermore,possible effects of the pectoral fTnT isoforms on the physiological activity are discussed in this article.