Salles-Mourlan A M, Guyot-Lenfant M, Saadi A, Gallien C L, Butler-Browne G
Laboratoire de Biologie du Développement, URA 1188, CNRS, Université René Descartes, Paris, France.
Int J Dev Biol. 1994 Dec;38(4):709-16.
Electrophoretic techniques adapted for the analysis of muscles of lower invertebrates reveal four myosin heavy chain isoforms in the dorsalis trunci of Pleurodeles waltlii: two fast (MHC-IIA, MHC-IIB), and one slow (MHC-I) in the adult and one isoform (MHC-La) in the larvae. Polyclonal antibodies were prepared against the larval (anti-MHC-La) and one of the fast myosin (MHC-IIA) isoforms and their specificity was confirmed by western blot analysis. An immunohistochemical analysis was then carried out on frozen sections of the dorsalis trunci of P. waltlii at different stages of development. From stage 44 it was possible to demonstrate the presence of MHC-IIA in the small diameter fibers at the periphery of the muscle; the number and diameter of these fibers increased from stage 44 to stage 56 when anatomical metamorphosis had finished. By stage 56 these fibers could also be readily identified using standard histochemical techniques as type IIA fibers. We conclude that fast IIA myosin is expressed well before the final adult muscle phenotype has been established and its expression is therefore independent of thyroid hormone.
适用于分析低等无脊椎动物肌肉的电泳技术揭示，在钝口螈的躯干背肌中有四种肌球蛋白重链异构体：成年个体中有两种快速型（MHC-IIA、MHC-IIB）和一种慢速型（MHC-I），幼虫中有一种异构体（MHC-La）。制备了针对幼虫型（抗MHC-La）和一种快速肌球蛋白（MHC-IIA）异构体的多克隆抗体，并通过蛋白质免疫印迹分析证实了它们的特异性。然后对处于不同发育阶段的钝口螈躯干背肌冰冻切片进行了免疫组织化学分析。从第44阶段开始，就可以证明在肌肉周边的小直径纤维中存在MHC-IIA；当解剖学变态完成时，从第44阶段到第56阶段，这些纤维的数量和直径都增加了。到第56阶段，使用标准组织化学技术也可以很容易地将这些纤维鉴定为IIA型纤维。我们得出结论，快速IIA型肌球蛋白在最终的成年肌肉表型建立之前就已大量表达，因此其表达独立于甲状腺激素。
