Tong X, Drapkin R, Reinberg D, Kieff E
Department of Medicine and Microbiology and Molecular Genetics, Harvard Medical School, Boston, MA 02115, USA.
Proc Natl Acad Sci U S A. 1995 Apr 11;92(8):3259-63. doi: 10.1073/pnas.92.8.3259.
EBNA 2 (Epstein-Barr virus nuclear antigen 2) is an acidic transactivator essential for EBV transformation of B lymphocytes. We show that EBNA 2 directly interacts with general transcription factor IIH. Glutathione S-transferase (GST)-EBNA 2 acidic domain fusion protein depleted transcription factor IIH activity from a TFIIH nuclear fraction. The p89 (ERCC3), p80 (ERCC2), and p62 subunits of TFIIH were among the proteins retained by GST-EBNA 2. Eluates from the GST-EBNA 2 beads reconstituted activity in a TFIIH-dependent in vitro transcription assay. The p62 and p80 subunits of TFIIH independently bound to GST-EBNA 2, whereas the p34 subunit of TFIIH only bound in the presence of p62. A Trp-->Thr mutation in the EBNA 2 acidic domain abolishes EBNA 2 transactivation in vivo and greatly compromised EBNA 2 association with TFIIH activity and with the p62 and p80 subunits, providing a link between EBNA 2 transactivation and these interactions. Antibodies directed against the p62 subunit of TFIIH coimmunoprecipitated EBNA 2 from EBV-transformed B lymphocytes, indicating that EBNA 2 associates with TFIIH in vivo.
EBNA 2（爱泼斯坦-巴尔病毒核抗原2）是一种酸性反式激活因子，对B淋巴细胞的EBV转化至关重要。我们发现EBNA 2直接与通用转录因子IIH相互作用。谷胱甘肽S-转移酶（GST）-EBNA 2酸性结构域融合蛋白使TFIIH核组分中的转录因子IIH活性降低。TFIIH的p89（ERCC3）、p80（ERCC2）和p62亚基是被GST-EBNA 2保留的蛋白质。从GST-EBNA 2磁珠洗脱的物质在依赖TFIIH的体外转录试验中恢复了活性。TFIIH的p62和p80亚基独立地与GST-EBNA 2结合，而TFIIH的p34亚基仅在p62存在时结合。EBNA 2酸性结构域中的色氨酸向苏氨酸突变消除了EBNA 2在体内的反式激活作用，并极大地损害了EBNA 2与TFIIH活性以及与p62和p80亚基的结合，这在EBNA 2反式激活与这些相互作用之间建立了联系。针对TFIIH的p62亚基的抗体从EBV转化的B淋巴细胞中共免疫沉淀出EBNA 2，表明EBNA 2在体内与TFIIH相关联。
