Serio T R, Angeloni A, Kolman J L, Gradoville L, Sun R, Katz D A, Van Grunsven W, Middeldorp J, Miller G
Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut 06520, USA.
J Virol. 1996 Nov;70(11):8047-54. doi: 10.1128/JVI.70.11.8047-8054.1996.
The viral capsid antigen complex of Epstein-Barr virus (EBV), an important serodiagnostic marker of infection with the virus, consists of at least four components, with molecular masses of 150, 110, 40, and 21 kDa. Here we show that the 21-kDa component of the viral capsid antigen consists of products of two EBV genes, BFRF3 and BLRF2. Both products were expressed from late transcripts, were recognized by human antisera, and were present in virions. The BFRF3 product, but not that of BLRF2, fulfilled the definition of ZEBRA-associated protein p21 (ZAP21). In cells in which EBV was lytically replicating, BFRF3 protein was coimmunoprecipitated together with ZEBRA by a rabbit antiserum directed against amino acids 197 to 245 of BZLF1. In EBV-negative cells cotransfected with BZLF1 and BFRF3 expression vectors, BFRF3 was also coimmunoprecipitated with this antiserum. Although this antiserum could not detect BFRF3 on an immunoblot, it was able to immunoprecipitate BFRF3 in the absence of ZEBRA expression. The rabbit antiserum to amino acids 197 to 245 of BZLF1 was found to detect the same epitope at the carboxy end of BFRF3 as was recognized by rabbit antiserum to BFRF3 itself. Thus, coimmunoprecipitation of BFRF3 p21 with ZEBRA appeared to be due to cross-reactivity of the immunoprecipitating antiserum rather than to direct association of ZEBRA and BFRF3 p21.
爱泼斯坦-巴尔病毒(EBV)的病毒衣壳抗原复合物是该病毒感染的重要血清学诊断标志物,它至少由四种成分组成,分子量分别为150、110、40和21 kDa。在此我们表明,病毒衣壳抗原的21-kDa成分由EBV的两个基因BFRF3和BLRF2的产物组成。这两种产物均从晚期转录本表达,可被人抗血清识别,并存在于病毒颗粒中。BFRF3产物而非BLRF2产物符合ZEBRA相关蛋白p21(ZAP21)的定义。在EBV进行裂解复制的细胞中,BFRF3蛋白可被针对BZLF1第197至245位氨基酸的兔抗血清与ZEBRA一起共免疫沉淀。在与BZLF1和BFRF3表达载体共转染的EBV阴性细胞中,BFRF3也可被该抗血清共免疫沉淀。尽管该抗血清在免疫印迹上无法检测到BFRF3,但在没有ZEBRA表达的情况下它能够免疫沉淀BFRF3。发现针对BZLF1第197至245位氨基酸的兔抗血清与针对BFRF3自身的兔抗血清识别BFRF3羧基末端的相同表位。因此,BFRF3 p21与ZEBRA的共免疫沉淀似乎是由于免疫沉淀抗血清的交叉反应性,而非ZEBRA与BFRF3 p21的直接关联。