DE Pomerai D I, Gali M A H
Department of Zoology, University of Nottingham, Nottingham, NG7 2RD, UK.
Dev Growth Differ. 1982;24(3):233-243. doi: 10.1111/j.1440-169X.1982.00233.x.
The accumulation of δ crystallin (chick lens marker) in cultures of 9 day chick embryo neuroretinal cells is strongly promoted by chick embryo extract (CEE) or foetal calf serum (FCS), but much less so by adult sera (horse, chicken and newborn bovine serum). The "transdifferentiation-promoting" (TP) activity of FCS is absent from dialysed FCS but is largely recovered in the initial dialysis medium (F ). Similarly, the initial dialysis medium from CEE (E ) shows strong TP activity, whereas that from chicken or from horse serum does not. We conclude that the proposed TP factor(s) is (are) of relatively low molecular weight. By contrast, horse serum contains macromolecular factor(s) able to inhibit the TP activity of E or F . Rapid loss of neuronal cells (including those expressing choline acetyltransferase activity) is also observed in media based on F , though whether this effect is mediated by the proposed TP factor(s) has not been determined. The TP activity is not directly related to growth rate or cell density, since cultures in F alone grow poorly yet still accumulate δ crystallin.
δ晶状体蛋白（鸡晶状体标志物）在9日龄鸡胚神经视网膜细胞培养物中的积累受到鸡胚提取物（CEE）或胎牛血清（FCS）的强烈促进，但成年血清（马、鸡和新生牛血清）的促进作用则小得多。FCS的“促进转分化”（TP）活性在透析后的FCS中不存在，但在初始透析培养基（F）中大部分得以恢复。同样，CEE的初始透析培养基（E）显示出很强的TP活性，而鸡血清或马血清的初始透析培养基则没有。我们得出结论，所提出的TP因子分子量相对较低。相比之下，马血清含有能够抑制E或F的TP活性的大分子因子。在基于F的培养基中也观察到神经元细胞（包括那些表达胆碱乙酰转移酶活性的细胞）的快速损失，不过这种效应是否由所提出的TP因子介导尚未确定。TP活性与生长速率或细胞密度没有直接关系，因为仅在F中培养的细胞生长不佳，但仍会积累δ晶状体蛋白。
