Fanzani A, Giuliani R, Colombo F, Zizioli D, Presta M, Preti A, Marchesini S
Unit of Biochemistry, Department of Biomedical Sciences and Biotechnology, University of Brescia, Brescia, Italy.
FEBS Lett. 2003 Jul 17;547(1-3):183-8. doi: 10.1016/s0014-5793(03)00709-9.
Cytosolic sialidase Neu2 has been implicated in myoblast differentiation. Here we observed a significant upregulation of Neu2 expression during differentiation of murine C2C12 myoblasts. This was evidenced both as an increase in Neu2 mRNA steady-state levels and in the cytosolic sialidase enzymatic activity. To understand the biological significance of Neu2 upregulation in myoblast differentiation, C2C12 cells were stably transfected with the rat cytosolic sialidase Neu2 cDNA. Neu2 overexpressing clones were characterized by a marked decrement of cell proliferation and by the capacity to undergo spontaneous myoblast differentiation also when maintained under standard growth conditions. This was evidenced by the formation of myogenin-positive myotubes and by a significant decrease in the nuclear levels of cyclin D1 protein. No differentiation was on the contrary observed in parental and mock-transfected cells under the same experimental conditions. The results indicate that Neu2 upregulation per se is sufficient to trigger myoblast differentiation in C2C12 cells.
胞质唾液酸酶Neu2与成肌细胞分化有关。在此我们观察到，在小鼠C2C12成肌细胞分化过程中Neu2表达显著上调。这一点在Neu2 mRNA稳态水平的增加以及胞质唾液酸酶活性方面均得到证实。为了解Neu2上调在成肌细胞分化中的生物学意义，用大鼠胞质唾液酸酶Neu2 cDNA稳定转染C2C12细胞。Neu2过表达克隆的特征在于细胞增殖显著减少，并且即使在标准生长条件下培养时也具有自发成肌细胞分化的能力。这通过生成肌细胞生成素阳性的肌管以及细胞周期蛋白D1蛋白核水平的显著降低得到证实。相反，在相同实验条件下，亲本细胞和mock转染细胞未观察到分化现象。结果表明，Neu2上调本身足以触发C2C12细胞中的成肌细胞分化。
