Mashima J, Nakada K, Yao Y, Miyazaki J, Hirabayashi T
Institute of Biological Sciences, University of Tsukuba, Ibaraki, Japan.
Zoolog Sci. 1996 Aug;13(4):571-6. doi: 10.2108/zsj.13.571.
Cells prepared from chicken skeletal muscles of different developmental stages were cultured to study their troponin T isoform expression, using antisera specific to the fast- and slow-muscle-type isoforms. We found that the cultured myogenic cells from chickens and chick embryos were classified into two types, fast type and fast/slow type in which fast- and slow-muscle-type isoforms were coexpressed. Cells expressing only slow-muscle-type troponin T isoforms could not be found. Most cells prepared from pectoralis major (fast muscle) and gastrocnemius (mixed muscle) of 11-day old embryos belonged to the latter, with only a small fraction belonging to the former. The percentage of fast type cells in those cells prepared from pectoralis major increased along development to over 90% by the 17th day of incubation, while, in the cells prepared from gastrocnemius, it reached a plateau of 30-40% by the 13th day of incubation. All the cells from anterior latissimus dorsi (slow muscle) belonged to the fast/slow type. Ratios of these two types of muscle cells varied depending on their origins and stages. The in vitro expression of troponin T isoforms was different from the in vivo expression, and each muscle seems to be determined differently in the composition of cell types during the developmental course.
利用针对快肌型和慢肌型肌钙蛋白T同工型的抗血清，培养来自不同发育阶段鸡骨骼肌的细胞，以研究它们的肌钙蛋白T同工型表达。我们发现，来自鸡和鸡胚胎的培养成肌细胞分为两种类型，即快肌型和快/慢肌型，其中快肌型和慢肌型同工型共同表达。未发现仅表达慢肌型肌钙蛋白T同工型的细胞。从11日龄胚胎的胸大肌（快肌）和腓肠肌（混合肌）制备的大多数细胞属于后者，只有一小部分属于前者。从胸大肌制备的细胞中快肌型细胞的百分比随着发育增加，到孵化第17天时超过90%，而在从腓肠肌制备的细胞中，到孵化第13天时达到30-40%的平台期。背阔肌前部（慢肌）的所有细胞都属于快/慢肌型。这两种类型的肌肉细胞比例因起源和阶段而异。肌钙蛋白T同工型的体外表达与体内表达不同，并且在发育过程中每种肌肉在细胞类型组成上的决定方式似乎也不同。
