Maréchal G, Beckers-Bleukx G, Berquin A, Coulton G
Départment de Physiologie, Faculté de Médecine, UCL 5540, Brussels, Belgium.
Eur J Biochem. 1996 Nov 1;241(3):916-22. doi: 10.1111/j.1432-1033.1996.00916.x.
Kyphoscoliotic (ky) mice are spontaneous mutants of the BDL strain whose postural muscles atrophy during post-natal growth, resulting in extensive kyphoscoliosis in adult animals. At 21 days of age, the seven muscles examined were already well differentiated into fast, slow and mixed type on the basis of the proportions of their native myosin isoforms or their subunits. During post-natal growth, from 21 to 120 days of age, the normal pattern of myosin maturation was essentially respected by the ky mutation: fast muscles became faster, slow muscles became slower and mixed muscles specialized in both directions. However, the post-natal increases of myosin heavy chain 2B and fast myosin light chain LC3f were depressed in ky muscles, whilst there was novel expression of slow myosin light chains, LC1s and LC2s in muscles which normally did not express them. Intermediate native myosin IM was absent in adult ky soleus, but it increased in adult ky tibialis anterior. We conclude that the ky mutation depresses the normal post-natal transition towards faster muscles and results in adult muscles whose myosin isoforms are generally shifted in a fast-to-slow direction.
脊柱后侧凸（ky）小鼠是BDL品系的自发突变体，其姿势性肌肉在出生后生长过程中发生萎缩，导致成年动物出现广泛的脊柱后侧凸。在21日龄时，根据其天然肌球蛋白同工型或其亚基的比例，所检查的七块肌肉已很好地分化为快肌、慢肌和混合肌。在出生后生长过程中，从21日龄到120日龄，ky突变基本遵循了肌球蛋白成熟的正常模式：快肌变得更快，慢肌变得更慢，混合肌在两个方向上都发生特化。然而，ky肌肉中肌球蛋白重链2B和快肌球蛋白轻链LC3f的出生后增加受到抑制，而在正常情况下不表达慢肌球蛋白轻链LC1s和LC2s的肌肉中出现了它们的新表达。成年ky比目鱼肌中不存在中间天然肌球蛋白IM，但在成年ky胫前肌中它有所增加。我们得出结论，ky突变抑制了出生后向更快肌肉的正常转变，并导致成年肌肉的肌球蛋白同工型总体上向快到慢的方向转变。
