The locus of Epstein-Barr virus terminal repeat processing is bound with enhanced affinity by Sp1 and Sp3.-猫眼课题宝

Epstein-Barr 病毒末端重复加工的位点与 Sp1 和 Sp3 结合，亲和力增强。

DOI：

10.1006/viro.1997.8770

发表时间：

1997

期刊：

Virology.

影响因子：

--

通讯作者：

中科院分区：

--

文献类型：

--

作者：

Spain,TA;Sun,R;Miller,G

EBV DNA含有富含G的重复区域，其参与重排和重组事件，包括EBV株P3 HR-1中的末端重复（TR）加工和EBNA-2缺失。细胞蛋白，称为末端或串联重复结合蛋白（TRBP），识别这些重组事件的连接处的序列。在这项研究中，使用抗体supershift测定和重组蛋白的表达，我们表明，Sp1和Sp3的序列特异性组件的TRBP和Ku是非特异性结合组件。Sp1结合EBV DNA的其他重组区域，但Sp3不结合大的内部重复序列。序列GGGGTGGGG是Sp1和Sp3的低亲和力位点，是末端重复序列结合位点1（TRBS 1）内的最小结合位点。然而，序列GGGGTGGGGCATGGGG中的3′侧翼序列增强了Sp1和Sp3的结合，使得它们的结合亲和力相对于经典的高亲和力Sp1位点增加了约两倍。EBV裂解周期诱导不改变TRBP的三种鉴定组分中的任何一种的丰度或结合活性。Sp1和Sp3可以反式促进EBV末端重复序列的加工和可能的其他病毒和细胞重组事件。

EBV DNA contains G-rich, repeat regions that are involved in rearrangement and recombination events including terminal repeat (TR) processing and the EBNA-2 deletion in the EBV strain P3HR-1. Cellular proteins, called terminal or tandem repeat binding proteins (TRBPs), recognize sequences at the junctions of these recombination events. In this study, using antibody supershift assays and expression of recombinant proteins, we show that Sp1 and Sp3 are the sequence-specific components of TRBP and that Ku is the nonspecific binding component. Sp1 binds other recombinogenic regions of EBV DNA, but Sp3 does not bind to the large internal repeat. The sequence GGGGTGGGG, a low affinity site for Sp1 and Sp3, is the minimal binding site within terminal repeat binding site 1 (TRBS1). However, 3′ flanking sequences in the sequence GGGGTGGGGCATGGGG augment binding of Sp1 and Sp3 so that their affinity of binding is increased approximately twofold relative to a classical high-affinity Sp1 site. EBV lytic cycle induction does not alter the abundance or binding activity of any of the three identified components of TRBP. Sp1 and Sp3 may actin transto promote EBV terminal repeat processing and possibly other viral and cellular recombination events.