大鼠骨骼肌中MHC与肌钙蛋白C亚型组成关系的单纤维研究。
A single-fibre study of the relationship between MHC and TnC isoform composition in rat skeletal muscle.
作者信息
O'Connell Brett, Nguyen Long T, Stephenson Gabriela M M
机构信息
Muscle Cell Biochemistry Laboratory, School of Biomedical Sciences, Victoria University of Technology, P.O. Box 14428, MCMC, Melbourne, VIC 8001, Australia.
出版信息
Biochem J. 2004 Feb 15;378(Pt 1):269-74. doi: 10.1042/BJ20031170.
In the present study, we investigated the possibility that MHC (myosin heavy chain) and TnC (troponin C) isoforms exist in specific combinations in rat-skeletal-muscle fibres. Single fibres (numbering 245) from soleus (predominantly slow-twitch) and sternomastoid (predominantly fast-twitch) muscles of adult rats were analysed for MHC and TnC isoform composition, using alanine-SDS/PAGE for separating MHC isoforms, and a novel method (based on the previously reported influence of Ca2+ on the mobility of Ca2+-binding proteins in SDS gels) for unequivocal identification of TnC isoforms in single-fibre segments. In this study, all fibres that contained only one MHC isoform (slow or fast) contained only the matching TnC isoform and all fibres that contained multiple fast MHC isoforms contained only the fast TnC isoform. Fibres expressing both slow and fast MHC isoforms displayed either both TnC isoforms or only one TnC isoform of a type depending on the relative proportion of fast/slow MHC present. Our results suggest a close relationship between MHC and TnC isoform composition in non-transforming skeletal muscles of adult rat.
在本研究中，我们调查了大鼠骨骼肌纤维中MHC（肌球蛋白重链）和TnC（肌钙蛋白C）亚型以特定组合形式存在的可能性。使用丙氨酸-SDS/PAGE分离MHC亚型，并采用一种新方法（基于先前报道的Ca2+对SDS凝胶中Ca2+结合蛋白迁移率的影响）明确鉴定单纤维段中的TnC亚型，对成年大鼠比目鱼肌（主要是慢肌纤维）和胸锁乳突肌（主要是快肌纤维）的单根纤维（共245根）进行了MHC和TnC亚型组成分析。在本研究中，所有仅含有一种MHC亚型（慢型或快型）的纤维只含有匹配的TnC亚型，所有含有多种快型MHC亚型的纤维只含有快型TnC亚型。同时表达慢型和快型MHC亚型的纤维，根据快/慢MHC的相对比例，要么同时显示两种TnC亚型，要么只显示一种类型的TnC亚型。我们的结果表明，成年大鼠非转化骨骼肌中MHC和TnC亚型组成之间存在密切关系。
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