Xie S Q, Mason P S, Wilkes D, Goldspink G, Fauconneau B, Stickland N C
Department of Veterinary Basic Sciences, The Royal Veterinary College, University of London, UK.
Differentiation. 2001 Sep;68(2-3):106-14. doi: 10.1046/j.1432-0436.2001.680204.x.
The effect of different temperatures (4 degrees C and 12 degrees C) on myogenic regulatory factors (MyoD and myogenin) and myosin heavy chain (MyHC) expression was investigated in rainbow trout (Onchrhynchus mykiss) during early development. MyoD is first switched on at stage 14 [about 5 somites are formed (1/2 epiboly)] while myogenin mRNA is expressed at stage 15 [around 15 somites are visible (2/3 epiboly)] at both temperatures. Subsequently (up to at least stage 20), the most caudal somites exhibit less myogenin mRNA at 4 degrees C compared to 12 degrees C. At the eyed stage (stage 23-24), both myogenin mRNA and protein are present in greater amounts throughout all myotomes at the lower temperature, with mRNA levels in warmer (12 degrees C) embryos at 83% for MyoD and 72% for myogenin of the levels seen in 4 degrees C embryos. Conversely, however, at this same stage, fast-MyHC mRNA and protein are more abundant in 12 degrees C than in 4 degrees C embryos. This indicates relatively advanced muscle differentiation at the warmer temperature. At hatching, myogenin-positive cells are concentrated within the myosepta at both temperatures and they are also sparsely distributed in the myotome at 4 degrees C, but not at 12 degrees C. MyoD, myogenin, and MyHC levels provide an indication of differentiation of muscle cells. These findings suggest that myogenic regulatory factor expression is delayed but prolonged by the lowering of temperature.
研究了不同温度（4摄氏度和12摄氏度）对虹鳟（Onchrhynchus mykiss）早期发育过程中生肌调节因子（MyoD和肌细胞生成素）以及肌球蛋白重链（MyHC）表达的影响。在两个温度条件下，MyoD在第14阶段（约形成5对体节[1/2外包]）首次开启表达，而肌细胞生成素mRNA在第15阶段（约可见15对体节[2/3外包]）表达。随后（至少到第20阶段），与12摄氏度相比，在4摄氏度时最尾端的体节中肌细胞生成素mRNA较少。在眼点期（第23 - 24阶段），在较低温度下，整个所有肌节中肌细胞生成素mRNA和蛋白质的含量都更高，在较温暖（12摄氏度）胚胎中，MyoD的mRNA水平为4摄氏度胚胎中所见水平的83%，肌细胞生成素为72%。然而，相反的是，在同一阶段，快速型MyHC mRNA和蛋白质在12摄氏度胚胎中比在4摄氏度胚胎中更丰富。这表明在较温暖温度下肌肉分化相对更高级。在孵化时，在两个温度条件下肌细胞生成素阳性细胞都集中在肌隔内，并且在4摄氏度时它们也稀疏分布在肌节中，但在12摄氏度时则不然。MyoD、肌细胞生成素和MyHC水平可指示肌肉细胞的分化。这些发现表明，生肌调节因子的表达会因温度降低而延迟但延长。
