Maytin E V, Balduzzi P C, Notter M F, Young D A
J Biol Chem. 1984 Oct 10;259(19):12135-43.
35S- and 32P-labeled proteins from control chick embryo fibroblasts and from fibroblasts transformed by UR2 sarcoma virus, or by a temperature-sensitive mutant (tsLA29) of Rous sarcoma virus, were separated by two-dimensional electrophoresis on giant gels to detect transformation-specific changes in protein synthesis and total phosphorylation. A nontransforming avian retrovirus, UR2-associated virus (UR2AV), was also studied. Virus-coded proteins appear in whole cell lysates of all infected cells. The structural proteins can be identified by comparison with proteins immunoprecipitated with antivirus serum. The transforming proteins pp60src and p68ros, present in cells transformed with Rous sarcoma virus and UR2, respectively, are phosphorylated in vivo. Eighteen increases and eight decreases in cellular phosphoproteins are associated with transformation, and revert toward normal levels when cells infected with tsLA29 are incubated at 42 degrees C. These changes are more extensive than previously reported, but none represent new phosphorylations, since all phosphoproteins seen in transformed cells also appear to be phosphorylated to a certain extent in control cells. Fifteen cellular proteins show increased relative rates of synthesis apparently related either to transformation or to growth at 42 degrees C. Four other proteins are increased exclusively in cells incubated at 42 degrees C, but not at 37 degrees C, whether transformed or not. Eleven additional increases in the synthesis of cellular proteins, many quite large, and one seemingly a de novo induction, appear to be specific for transformation. These changes occur in cells transformed by either UR2 or Rous sarcoma virus at 37 degrees C, do not occur with UR2AV infection, and tend to revert in cells infected with tsLA29 incubated at 42 degrees C. These 11 changes may represent increases in cellular gene expression that are related specifically to the maintenance of the transformed state.
用35S和32P标记来自对照鸡胚成纤维细胞以及由UR2肉瘤病毒或劳氏肉瘤病毒的温度敏感突变体（tsLA29）转化的成纤维细胞的蛋白质，通过在巨型凝胶上进行二维电泳来检测蛋白质合成和总磷酸化中转化特异性的变化。还研究了一种非转化性禽逆转录病毒，即UR2相关病毒（UR2AV）。病毒编码的蛋白质出现在所有感染细胞的全细胞裂解物中。通过与用抗病毒血清免疫沉淀的蛋白质进行比较，可以鉴定出结构蛋白。分别存在于用劳氏肉瘤病毒和UR2转化的细胞中的转化蛋白pp60src和p68ros在体内被磷酸化。细胞磷酸化蛋白中有18种增加和8种减少与转化相关，当感染tsLA29的细胞在42℃孵育时会恢复到正常水平。这些变化比以前报道的更为广泛，但没有一个代表新的磷酸化，因为在转化细胞中看到的所有磷酸化蛋白在对照细胞中似乎也在一定程度上被磷酸化。15种细胞蛋白显示出相对合成速率增加，这显然与转化或在42℃下的生长有关。另外4种蛋白仅在42℃孵育的细胞中增加，而在37℃时无论是否转化都不增加。细胞蛋白合成中还有11种增加，其中许多增加幅度很大，还有一种似乎是从头诱导，似乎是转化特有的。这些变化发生在37℃下被UR2或劳氏肉瘤病毒转化的细胞中，在UR2AV感染时不发生，并且在42℃孵育的感染tsLA29的细胞中倾向于恢复。这11种变化可能代表与维持转化状态特异性相关的细胞基因表达增加。
