Hayman M J, Beug H
Nature. 1984;309(5967):460-2. doi: 10.1038/309460a0.
Avian erythroblastosis virus (AEV) induces both erythroblastosis and fibrosarcoma in chickens. The viral oncogene responsible for these diseases, erb, is divided into two regions, erb-A and erb-B, although recent evidence suggests that it is primarily the erb-B gene product that is responsible for the transforming activity. The erb-B gene product has been reported previously to be a membrane glycoprotein of 68,000 molecular weight (MW), gp68erb -B. However, we show here that gp68erb -B is an intracellular precursor which is modified further to a 74,000 MW protein, gp74erb -B. By the criteria of resistance to digestion with endoglycosidase H, subcellular fractionation and inhibition of biosynthesis by the ionophore monensin, gp74erb -B appears to be located at the cell surface. Recently, a comparison of the erb-B sequence with that of the epidermal growth factor (EGF) receptor has shown that these two genes are highly homologous, and that erb-B appears to represent a truncated form of this growth factor. In light of these data the identification of gp74erb -B at the plasma membrane suggests that this may be the functionally important form of the erb-B gene product.
禽成红细胞增多症病毒（AEV）可在鸡体内引发成红细胞增多症和纤维肉瘤。引发这些疾病的病毒癌基因erb可分为两个区域，即erb - A和erb - B，不过最近有证据表明，主要是erb - B基因产物具有转化活性。此前有报道称，erb - B基因产物是一种分子量为68,000的膜糖蛋白，即gp68erb - B。然而，我们在此表明，gp68erb - B是一种细胞内前体，它会进一步被修饰为一种分子量为74,000的蛋白质，即gp74erb - B。根据对糖苷内切酶H消化的抗性、亚细胞分级分离以及离子载体莫能菌素对生物合成的抑制等标准判断，gp74erb - B似乎位于细胞表面。最近，erb - B序列与表皮生长因子（EGF）受体序列的比较表明，这两个基因高度同源，而且erb - B似乎代表了这种生长因子的一种截短形式。鉴于这些数据，在质膜上鉴定出gp74erb - B表明，这可能是erb - B基因产物的功能重要形式。
