Kimura F, Nakada K, Yonemura I, Hirabayashi T, Miyazaki J I
Institute of Biological Sciences, University of Tsukuba, Tsukuba, Ibaraki 305-8572, Japan.
Biochim Biophys Acta. 1999 Feb 2;1426(3):505-12. doi: 10.1016/s0304-4165(98)00173-1.
In order to show the tissue-specific distribution of troponin T (TnT) isoforms in avian skeletal muscles, their expression was examined by electrophoresis of the breast and leg muscles of seven avian species and immunoblotting with the antiserum against fast skeletal muscle TnT. It has been reported in the chicken that breast-muscle-type (B-type) and leg-muscle-type (L-type) TnT isoforms are expressed specifically in the adult breast and leg muscles, respectively. Their differential expression patterns were confirmed in all birds examined in this study. The expression of a segment encoded by the exon x series of TnT was also examined by immunoblotting with the antiserum against a synthetic peptide derived from the exon x3 sequence, because the segment has been shown to be included exclusively in the B-type, but not in the L-type TnT. The expression of the segment was found only in the breast muscle, but not in the leg muscle of all birds examined. TnT cDNA sequences from the duck breast and leg muscles were determined and showed that only B-type TnT had an exon x-related sequence, suggesting that the expression of B-type TnT containing the exon x-derived segment is conserved consistently in the birds.
为了显示肌钙蛋白T（TnT）同工型在禽类骨骼肌中的组织特异性分布，通过对7种禽类的胸肌和腿肌进行电泳，并使用抗快速骨骼肌TnT的抗血清进行免疫印迹分析，检测了它们的表达情况。据报道，在鸡中，胸肌型（B型）和腿肌型（L型）TnT同工型分别在成年胸肌和腿肌中特异性表达。在本研究中检测的所有鸟类中都证实了它们的差异表达模式。还用抗源自外显子x3序列的合成肽的抗血清进行免疫印迹分析，检测了由TnT外显子x系列编码的一个片段的表达情况，因为该片段已被证明仅包含在B型TnT中，而不包含在L型TnT中。在所检测的所有鸟类中，该片段仅在胸肌中表达，而在腿肌中未表达。测定了鸭胸肌和腿肌的TnT cDNA序列，结果显示只有B型TnT具有与外显子x相关的序列，这表明含有源自外显子x片段的B型TnT的表达在鸟类中一直是保守的。
