Linzer D I, Levine A J
Cell. 1979 May;17(1):43-52. doi: 10.1016/0092-8674(79)90293-9.
SV40 infection or transformation of murine cells stimulated the production of a 54K dalton protein that was specifically immunoprecipitated, along with SV40 large T and small t antigens, with sera from mice or hamsters bearing SV40-induced tumors. The same SV40 anti-T sera immunoprecipitated a 54K dalton protein from two different, uninfected murine embryonal carcinoma cell lines. These 54K proteins from SV40-transformed mouse cells and the uninfected embryonal carcinomas cells had identical partial peptide maps which were completely different from the partial peptide map of SV40 large T antigen. An Ad2+ND4-transformed hamster cell line also expressed a 54K protein that was specifically immunoprecipitated by SV40 T sera. The partial peptide maps of the mouse and hamster 54K protein were different, showing the host cell species specificity of these proteins. The 54K hamster protein was also unrelated to the Ad2+ND4 SV40 T antigen. Analogous proteins immunoprecipitated by SV40 T sera, ranging in molecular weight from 44K to 60K, were detected in human and monkey SV40-infected or -transformed cells. A wide variety of sera from hamsters and mice bearing SV40-induced tumors immunoprecipitated the 54K protein of SV40-transformed cells and murine embryonal carcinoma cells. Antibody produced by somatic cell hybrids between a B cell and a myeloma cell (hybridoma) against SV40 large T antigen also immunoprecipitated the 54K protein in virus-infected and -transformed cells, but did not do so in the embryonal carcinoma cell lines. We conclude that SV40 infection or transformation of mouse cells stimulates the synthesis or enhances the stability of a 54K protein. This protein appears to be associated with SV40 T antigen in SV40-infected and -transformed cells, and is co-immunoprecipitated by hybridomas sera to SV40 large T antigen. The 54K protein either shares antigenic determinants with SV40 T antigen or is itself immunogenic when in association with SV40 large T antigen. The protein varies with host cell species, and analogous proteins were observed in hamster, monkey and human cells. The role of this protein in transformation is unclear at present.
SV40对鼠细胞的感染或转化刺激产生了一种54K道尔顿的蛋白质，该蛋白质与SV40大T抗原和小t抗原一起，被携带SV40诱导肿瘤的小鼠或仓鼠血清特异性免疫沉淀。相同的SV40抗T血清从两种不同的未感染鼠胚胎癌细胞系中免疫沉淀出一种54K道尔顿的蛋白质。来自SV40转化的小鼠细胞和未感染的胚胎癌细胞的这些54K蛋白质具有相同的部分肽图谱，这与SV40大T抗原的部分肽图谱完全不同。一种Ad2+ND4转化的仓鼠细胞系也表达一种54K蛋白质，该蛋白质被SV40 T血清特异性免疫沉淀。小鼠和仓鼠54K蛋白质的部分肽图谱不同，显示出这些蛋白质的宿主细胞物种特异性。仓鼠的54K蛋白质也与Ad2+ND4 SV40 T抗原无关。在人类和猴的SV40感染或转化细胞中检测到了被SV40 T血清免疫沉淀的类似蛋白质，其分子量在44K到60K之间。多种来自携带SV40诱导肿瘤的仓鼠和小鼠的血清免疫沉淀了SV40转化细胞和鼠胚胎癌细胞的54K蛋白质。由B细胞和骨髓瘤细胞（杂交瘤）之间的体细胞杂交产生的针对SV40大T抗原的抗体也免疫沉淀了病毒感染和转化细胞中的54K蛋白质，但在胚胎癌细胞系中未出现这种情况。我们得出结论，SV40对小鼠细胞的感染或转化刺激了一种54K蛋白质的合成或增强了其稳定性。这种蛋白质在SV40感染和转化的细胞中似乎与SV40 T抗原相关，并被针对SV40大T抗原的杂交瘤血清共免疫沉淀。54K蛋白质要么与SV40 T抗原共享抗原决定簇，要么在与SV40大T抗原结合时本身具有免疫原性。该蛋白质因宿主细胞物种而异，并且在仓鼠、猴和人类细胞中观察到了类似的蛋白质。目前尚不清楚这种蛋白质在转化中的作用。
