Sequence differences in the EBNA-2 protein mediate the superior ability of

Sequence differences in the EBNA-2 protein mediate the superior ability of type 1 Epstein-Barr computer virus (EBV) to transform human W cells into lymphoblastoid cell lines compared to that of type 2 EBV. induction of EBV LMP-1 and about 10 cell genes, including CXCR7. In chromatin immunoprecipitation assays, type 1 EBNA-2 is usually shown to associate more strongly with EBNA-2 binding sites near the LMP-1 and CXCR7 genes. Unbiased motif searching of the EBNA-2 binding regions of the differentially regulated cell genes identified an ETS-interferon regulatory factor composite element motif that closely corresponds to the sequences known to mediate EBNA-2 rules of the LMP-1 promoter. It appears Abiraterone Acetate that the superior induction by type 1 EBNA-2 of the cell genes contributing to cell growth is usually due to their being regulated in a manner different from that for most EBNA-2-responsive genes and in a way comparable to that for the LMP-1 gene. IMPORTANCE The EBNA-2 transcription factor plays a key role in W cell transformation by EBV and defines the two EBV types. Here we identify a single amino acid (Ser in type 1 EBV, Asp in type 2 EBV) of EBNA-2 that determines the superior ability of type 1 EBNA-2 to induce a key group of cell genes and the EBV LMP-1 gene, which mediate the growth advantage of W cells infected with type 1 EBV. The EBNA-2 binding sites in these cell genes have a sequence motif comparable to the sequence known to mediate rules of the EBV LMP-1 promoter. Further detailed analysis of transactivation and promoter binding provides new insight into the physiological rules of cell genes by EBNA-2. INTRODUCTION Epstein-Barr computer virus (EBV) is usually the main cause of infectious mononucleosis in Western countries and also contributes to several types of human malignancy. Some of these diseases vary in incidence dramatically in different parts of the world, and it is usually possible that natural variance in EBV contributes to differences in disease incidence. It has recently been proposed that differences in the properties of an EBV strain isolated from a Chinese nasopharyngeal carcinoma might contribute to its role in that disease (1). Mutations in the EBNA-3W gene linked to diffuse large W cell lymphoma also support the idea that variance in EBV sequence may be Abiraterone Acetate linked to human disease (2). Type 1 and type 2 strains are the main natural functional variance known in Epstein-Barr computer virus (3, 4). The types are defined by sequence differences in the EBNA-2 gene, but there are also linked sequence changes in the EBNA-3 family of genes (3). Although both computer virus types activate human W cells Mouse monoclonal to CK17 upon contamination, type 1 strains are much better than type 2 strains at transforming human W cells into proliferating lymphoblastoid cell lines (LCLs) (5). Type 1 is usually the main EBV type prevalent all over the world, but type 2 EBV is usually frequently found in sub-Saharan Africa, where it can be as abundant as type 1 EBV. At present the biological significance of the two types of EBV is usually not comprehended, and there is usually no specific link of these types to human disease. However, the difference in growth transformation remains the clearest example of the functional variance of EBV. Most genes of EBV have a low level of natural sequence variance (less than 5% at the amino acid level), but type 1 EBNA-2 and type 2 EBNA-2 are only 56% identical at the amino acid level. Replacement of the EBNA-2 gene in type 2 EBV with the type 1 EBNA-2 gene confers a type 1 transformation efficiency on the type 2 strain (6), showing that EBNA-2 is usually the gene functionally important for the growth transformation phenotype. EBNA-2 is usually a transcription factor for viral and cell genes transcribed by RNA Abiraterone Acetate polymerase II but does not hole DNA directly. EBNA-2 forms a complex with cell DNA-binding protein, which target it to promoters. The best characterized of these cell protein is usually RBP-J (also known as CSL), but PU.1 Abiraterone Acetate (7, 8), ATF/CRE (9), and EBF1 binding sites (10) have also been shown to mediate EBNA-2 function at certain promoters. Early studies of EBNA-2 function focused on viral promoters or artificial promoters where the binding sites are.