Yamamoto Y, Tomida M, Hozumi M, Ayusawa D, Seno T, Tamura G
Cancer Res. 1981 Jun;41(6):2534-9.
Mouse myeloid leukemic M1 cells can be induced to differentiate into macrophages and granulocytes in vitro by a factor(s) stimulating differentiation of the cells (D-factor), which is suggested to be a glycoprotein. On the other hand, growth and differentiation of normal precursor cells of macrophages and granulocytes can be stimulated by a glycoprotein termed colony-stimulating factor (CSF). Mouse fibroblast L929 cells were found to produce both the D-factor and CSF. The properties of the D-factor and CSF and the roles of carbohydrates in the molecules of these factors were examined using tunicamycin, a specific inhibitor of asparaginase-linked glycosylation. Although both the D-factor and CSF were produced by L-cells in usual medium containing fetal calf serum, production of D-factor, but not CSF, was reduced by omission of serum from the medium. The activity of the D-factor was slightly decreased by treating the L-cells with tunicamycin (0.5 microgram/ml) in the presence of 2% fetal calf serum, without any decrease in CSF activity. Conditioned medium of L-cells incubated with or without tunicamycin was fractionated by gel filtration on a Sephadex G-200 column. Normal D-factor appeared as a single peak with an apparent molecular weight of 67,000. D-factor produced in the presence of tunicamycin had an apparent molecular weight of 25,000. On the other hand, most of the CSF was eluted in the void volume, even when it was produced in the presence of tunicamycin. The D-factor produced in the presence of tunicamycin was more sensitive than normal D-factor was to trypsin or heat treatment at 70 degrees. The CSF produced in the presence of tunicamycin was resistant to these treatments. These results indicate that the D-factor is distinct from CSF. Furthermore, the results suggest that the D-factor produced by L-cells is also a glycoprotein and that, although carbohydrate is not essential for production or activity of the D-factor, it contributes to stabilizing the protein portion of D-factor.
小鼠髓性白血病M1细胞可在体外被刺激细胞分化的因子（D因子）诱导分化为巨噬细胞和粒细胞，D因子被认为是一种糖蛋白。另一方面，巨噬细胞和粒细胞的正常前体细胞的生长和分化可被一种称为集落刺激因子（CSF）的糖蛋白刺激。发现小鼠成纤维细胞L929细胞可产生D因子和CSF。使用天冬酰胺连接糖基化的特异性抑制剂衣霉素，研究了D因子和CSF的特性以及碳水化合物在这些因子分子中的作用。虽然D因子和CSF在含有胎牛血清的常规培养基中均由L细胞产生，但从培养基中去除血清会降低D因子的产生，而不会降低CSF的产生。在2%胎牛血清存在的情况下，用衣霉素（0.5微克/毫升）处理L细胞，D因子的活性略有下降，而CSF活性没有任何下降。将用或不用衣霉素孵育的L细胞的条件培养基在Sephadex G-200柱上进行凝胶过滤分级分离。正常D因子表现为一个单一峰，表观分子量为67000。在衣霉素存在下产生的D因子表观分子量为25000。另一方面，即使CSF是在衣霉素存在下产生的，大部分CSF也在空体积中洗脱。在衣霉素存在下产生的D因子比正常D因子对胰蛋白酶或70℃热处理更敏感。在衣霉素存在下产生的CSF对这些处理有抗性。这些结果表明D因子与CSF不同。此外，结果表明L细胞产生的D因子也是一种糖蛋白，虽然碳水化合物对于D因子的产生或活性不是必需的，但它有助于稳定D因子的蛋白质部分。
