Biochemical characterization of nuclear and cytoplasmic forms of SV40 tumor antigens encoded by parental and transport-detective mutant SV40-adenovirus 7 hybrid viruses.
Biochemical characterization of nuclear and cytoplasmic forms of SV40 tumor antigens encoded by parental and transport-detective mutant SV40-adenovirus 7 hybrid viruses.
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由亲本和转运检测突变体 SV40-腺病毒 7 杂交病毒编码的 SV40 肿瘤抗原的核和细胞质形式的生化特征。
DOI：
10.1016/0042-6822(80)90033-1
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发表时间：
1980
期刊：
影响因子：
3.7
通讯作者：
Butel,JS
中科院分区：
文献类型：
--
作者：
Lanford,RE;Butel,JS
比较了缺陷型SV40-腺病毒7型杂合病毒PARA和突变株[PARA(2cT)j]编码的核(NT-Ag)和胞浆(Ct-Ag)SV40肿瘤抗原的生化特性。免疫沉淀和SDS-聚丙烯酰胺凝胶电泳法显示，亲本(NT)、ParA和ParA(2cT)感染和转化的细胞均含有正常大小的大T(92K)和小的t(19K)多肽。此外，Para(2cT)感染和转化的细胞产生了一种相对分子质量(94K)略高的T相关多肽。细胞分级研究表明，这两种形式的大Ct-Ag(92K和94K)主要定位于转化细胞的细胞质中；脉冲追逐分析表明这两种多肽之间没有产物-前体关系。细胞分离研究还表明，由于与颗粒组分有关，转化细胞中的Ct-Ag没有保留在细胞质中。副感染细胞产生稳定的T-Ag(与WT SV40相比)，导致T-Ag在副感染细胞中大量积累。这些结果表明，SV40调节T-Ag合成的转录调控不能与PARA一起起作用。放射免疫法测定DNA结合电位显示，NT-Ag和Ct-Ag之间无差异。(2cT)感染细胞胞质T-Ag的磷酸化程度低于(2cT)诱导的核T-Ag。通过琼脂糖凝胶等电聚焦(IEF)分析，从Para(NT)和Para(2cT)感染的细胞中提取的T-Ag多肽的等电聚焦(IEF)点有微小的差异(分别为pI4.4和pI4.5)。讨论了SV40T-Ag的磷酸化、Ct突变和核转运之间的可能关系。
The biochemical properties of nuclear (nT-ag) and cytoplasmic (cT-ag) SV40 tumor antigens encoded by the defective SV40-adenovirus 7 hybrid virus, PARA, and a mutant [PARA(2cT)j which induces the synthesis of T-ag that is not transported to the nucleus but accumulates in the cytoplasm of infected and transformed cells were compared. Immunoprecipitation and SDS-polyacrylamide gel electrophoresis revealed that parental (nT) PARA and PARA(2cT)-infected and -transformed cells all contained normal-sized large T (92K) and small t(19K) polypeptides. In addition, PARA(2cT)-infected and -transformed cells produced a T-related polypeptide with a slightly higher molecular weight (94K). Cellular fractionation studies demonstrated that both forms of large cT-ag (92K and 94K) were localized predominantly in the cytoplasm of transformed cells; pulse-chase analyses revealed no product-precursor relationship between the two polypeptides. Cell fractionation studies also indicated that cT-ag in PARA(2eT)-transformed cells was not retained in the cytoplasm due to an association with a particulate fraction. PARA-infected cells overproduced T-ag (in comparison to WT SV40) which was stable, resulting in the accumulation of large amounts of T-ag in PARA-infected cells. These results suggest that the transcriptional controls regulating T-ag synthesis by SV40 are not operative with PARA. Quantitation of DNA-binding potentials by radioimmunoassay revealed no differences between nT-ag and cT-ag. Cytoplasmic T-ag from PARA(2cT)-infected cells was phosphorylated to a lesser extent than the nuclear T-ag induced by PARA(nT). Analysis by isoelectric focusing (IEF) in agarose gels of T-ag polypeptides extracted from PARA(nT)- and PARA(2cT)-infected cells revealed a small difference in IEF points (pI4.4 and pI4.5, respectively). The possible relationships between phosphorylation, the cT mutation, and the nuclear transport of SV40 T-ag are discussed.