POSTTRANSLATIONAL PROCESSING OF AN EPSTEIN-BARR VIRUS-ENCODED MEMBRANE-PROTEIN EXPRESSED IN CELLS TRANSFORMED BY EPSTEIN-BARR-VIRUS
POSTTRANSLATIONAL PROCESSING OF AN EPSTEIN-BARR VIRUS-ENCODED MEMBRANE-PROTEIN EXPRESSED IN CELLS TRANSFORMED BY EPSTEIN-BARR-VIRUS
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DOI：
10.1128/jvi.61.3.866-875.1987
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发表时间：
1987-03-01
影响因子：
5.4
通讯作者：
SUGDEN, B
中科院分区：
文献类型：
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作者：
BAICHWAL, VR;SUGDEN, B
EB病毒（EBV）B958株的BamHI Nhet片段编码存在于由EBV转化的细胞中的膜蛋白（BNLF-1）。我们制备了一种杂合蛋白，其中来自BNLF-1羧基末端部分的多肽序列融合到大肠杆菌β-半乳糖苷酶。将该杂交蛋白免疫家兔，用免疫亲和层析法纯化得到的抗血清。抗血清能够从细胞裂解物中免疫沉淀BNLF-1。我们发现，在EBV基因组阳性的B细胞系中，BNF-1的丝氨酸被磷酸化。用[35S]甲硫氨酸进行的脉冲追踪分析表明，BNLF-1在淋巴母细胞中的半衰期约为5小时。EB病毒基因组阳性B细胞系的蛋白质免疫印迹显示了与BNLF-1对应的62，000分子量条带和无数的低分子量条带。我们推测这些低分子量条带是细胞中BNLF-1周转产生的降解产物。BNLF-1基因在COS细胞中表达，并且该蛋白在这些细胞中既被磷酸化又被翻转。
The BamHI Nhet fragment of the B958 strain of Epstein-Barr virus (EBV) encodes a membrane protein (BNLF-1) that is present in cells transformed by EBV. We made a hybrid protein in which a polypeptide sequence from the carboxyl-terminal part of BNLF-1 is fused to Escherichia coli .beta.-galactosidase. This hybrid protein was used to immunize rabbits, and the resulting antiserum was purified by immunoaffinity chromatography. The antiserum was able to immunoprecipitate BNLF-1 from cell lysates. We found that BNF-1 is phosphorylated at serines in EBV genome-positive B-cell lines. Pulse-chase analysis with [35S]methionine indicated that BNLF-1 is turned over in lymphoblasts with a half-life of approximately 5 h. Protein immunoblots of EBV genome-positive B-cell lines revealed both a 62,000-molecular-mass band corresponding to BNLF-1 and a myriad of lower-molecular-mass bands. We postulate that these lower-molecular-mass bands are degradation products resulting from the turnover of BNLF-1 in cells. The BNLF-1 gene was expressed in COS cells, and the protein was both phosphorylated and turned over in these cells.