Saadi A, Gallien C L, Guyot-Lenfant M, Chanoine C
Laboratoire de Biologie du Développement, U.A. CNRS 1188, Université René Descartes, Paris, France.
Mech Dev. 1993 Sep;43(1):49-56. doi: 10.1016/0925-4773(93)90022-p.
In P. waltlii, an urodele amphibian species which undergoes spontaneous metamorphosis, study of native myosin in pyrophosphate gels at various stages of normal development demonstrates a complete larval to fast myosin isoforms transition, which occurs more precociously in forelimb muscles than in the dorsal and ventral muscles. In the neotenic species A. mexicanum, forelimb muscles development also presents a complete myosin isoforms transition which is in contrast with the partial myosin isoforms transition observed in the dorsal muscle. In metamorphosed or neotenic animals of both species aged 1 year, forelimb regeneration is characterized by a complete transition from larval to fast myosin isoforms, that occurs earlier and more rapidly than in normal forelimb development. When forelimb regeneration is studied in P. waltlii aged 4 years, the adult fast and slow isomyosins are expressed very early in the regeneration process. In experimental hypothyroidian P. waltlii, the larval to fast isoforms transition in regenerating forelimb muscles is slightly delayed. Experimental hyperthyroidism accelerates the disappearance of larval isomyosins in regenerating forelimb muscles, both in P. waltlii and A. mexicanum aged 1 year. This work demonstrates that changes in myosin isoform pattern during forelimb regeneration in adult urodele amphibians are different from changes occurring in the normal forelimb development. They take place without any thyroid hormone influence, as opposed to normal development, and appear to be age-dependent.
在自发变态的有尾两栖动物华氏钝口螈中，对正常发育各阶段焦磷酸凝胶中的天然肌球蛋白进行研究发现，其从幼虫型肌球蛋白到快肌球蛋白同工型发生了完全转变，这种转变在前肢肌肉中比在背肌和腹肌中出现得更早。在幼态延续物种墨西哥钝口螈中，前肢肌肉发育也呈现出肌球蛋白同工型的完全转变，这与在背肌中观察到的部分肌球蛋白同工型转变形成对比。在这两个物种1岁的变态或幼态延续动物中，前肢再生的特征是从幼虫型肌球蛋白到快肌球蛋白同工型的完全转变，这种转变比正常前肢发育更早且更迅速。当对4岁的华氏钝口螈进行前肢再生研究时，成年快肌和慢肌同功酶在再生过程中很早就表达了。在实验性甲状腺功能减退的华氏钝口螈中，再生前肢肌肉中从幼虫型到快肌同工型的转变略有延迟。实验性甲状腺功能亢进加速了1岁的华氏钝口螈和墨西哥钝口螈再生前肢肌肉中幼虫型肌球蛋白同工型的消失。这项研究表明，成年有尾两栖动物前肢再生过程中肌球蛋白同工型模式的变化与正常前肢发育过程中的变化不同。与正常发育不同，它们在没有任何甲状腺激素影响的情况下发生，并且似乎与年龄有关。
