Epstein–Barr virus LMP1 oncogene polymorphism in tatar and slavic populations in Russian Federation impacting on some malignant tumours

Objective: To compare genetic structure of the main Epstein–Barr virus (EBV) oncogene, latent membrane protein 1 (LMP1), in EBV strains circulating in two genetically distinct ethnic populations in Russian Federation, Tatars and Slavs, as well as assess an impact of diverse LMP1 variants on incidence and mortality rate for some malignant tumors partially associated with EBV infection. Materials and methods. Oral washing samples were collected from 60 ethnic Kazan Tatars and 65 ethnic Moscow Slavics. Carboxy-terminal nucleotide sequences (41 and 40 sequences, respectively) derived from hypervariable LMP1 gene region were amplified from EBV DNA samples. Next, final nucleotide sequences were translated into amino acid sequences and analyzed according to classification by Edwards et al. Results. Analysis of 41 and 40 LMP1 samples obtained from ethnic Kasan Tatars and ethnic Moscow Slavics, respectively, revealed significant difference in relevant amino acid structures. In particular, all LMP1 samples derived from Moscow Slavics were found to belong to the four protein variants: B95.8/A, Med–, China1 and NC. Among them, low-transforming variant B95.8/A was dominant (82.5%). In contrast, solely 21 out of 41 LMP1 samples derived from ethnic Tatars were classified as B95.8/A, Med– and China1 variants. Importantly, the percentage of low-transforming B95.8/A variant among ethnic Tatar samples was significantly lower compared to that one found in Moscow Slavics (29.3% vs. 82.5%). On the other hand, seven (17.1%) out of 20 other samples formed a unique protein mono group characterized by LMP1 amino acid sequence differed from that one available in the GenBank database. Such group of variants was designated as LMP1-TatK. The remaining 13 samples (31.7%) did not match either protein variants, thereby forming the “beyond classification” (LMP1-TatBC) group. Conclusion. The data obtained suggest that various LMP1 variants exist in EBV strains persisting in ethnic Tatrs and ethnic Slavics examined in Russian Federation. It was also found that EBV strains isolated from ethnic Tatars contained a unique LMP1 gene variant encoding protein LMP1-TatK lacked in EBV strains derived from ethnic Moscow Slavics. Taking into account the genealogy of Tatars, it cannot be ruled out that EBV strain bearing LMP1-TatK variant represented ethnically specific EBV strain that might circulate many centuries ago among their historical human predecessors called Mongol-Tatar tribes. In addition, it was shown that the LMP1 variants in EBV strains isolated from ethnic Kazan Tatars and ethnic Moscow Slavics did not affect the incidence and mortality of different forms of cancer consisting of EBV-associated cases

Распределение генов HLA II у больных раком носоглотки, ассоциированным с вирусом Эпштейна–Барр, и другими опухолями ротовой полости в России

Background. It has been proved that for the nasopharyngeal carcinoma (NPC) the etiological agent is the Epstein–Barr virus (EBV). Being an ubiquitous infection, EBV, under certain conditions, is able to display its oncogenic potential. Among a wide range of tumors associated with EBV, the NPC occupies a special place because it is characterized by a geographically and ethnically heterogeneous distribution, suggesting that in the pathogenesis of NPC, in addition to EBV, an important role is played by other factors, such as genetic predisposition to this neoplasm. Among known genetic factors influencing the frequency of NPC development, the human leukocyte antigen (HLA) complex occupies an important place, as it plays a central role in the presentation of viral antigens to the immune system. In Russia, the association of HLA alleles with the risk of EBV associated forms of NPC development and with development of other oral cavity tumors (OOCT), not associated with the virus, has not been studied. In the literature there are contradictory information about HLA genes, which determine the predisposition to the emergence of these tumors, and their role in the initiation and formation an immune response to EBV proteins.Objective: to study the distribution of the of DQA1-, DQB1-, DRB1-HLA class II gene variants associated with respectively the risk or resistance to the development of NPC and OOCT and with a high and low level of antibody response to EBV main proteins. A group of healthy persons served as a control.Materials and methods. Blood samples from 62 patients with NPC, 44 patients with OOCT, and as control, 300 healthy individuals, were used in the study. The blood serum samples of NPC and OOCT patients were tested for the presence of immunoglobulin classes G and A antibodies to capsid and early EBV antigens by indirect immunofluorescence. All serum samples of patients and healthy individuals were genotyped on HLA-DQA1, -DQB1 and -DRB1 by the method of multi-primer amplification by sequence-specific primers by real-time polymerase chain reaction.Results. In NPC patients, an increase in the frequency of HLA-DRB1*08 was found when compared with the frequency of a similar allele in healthy individuals (5.6 % vs 1.8 %; odds ratio (OR) 3.2; 95 % confidence interval (CI) 1.1–9.1; p = 0.02), and, on the contrary, a lower HLA-DQB1*0301 frequency was detected (16.1 % vs 25.3 %; p <0.05) than in healthy individuals. The data obtained suggest that the HLA-DRB1*08 gene is associated with an increased sensitivity to NPC.In OOCT patients, HLA-DQB1*0502–4 and HLA-DRB1*16 variants were less common than in healthy individuals (1.1 % vs 6.8 %; p <0.05 and 1.1 % vs 6.7 %; OR 0.16; 95 % CI 0.01–1.08; p <0.05, respectively), suggesting that the HLA-DQB1*0301 gene is associated with resistance to NPC, and HLA-DQB1*0502–4 and HLA-DRB1*16 variants – with resistance to OOCT. It is interesting to note the difference in the frequency of HLA-DRB1*13 between NPC and OOCT patients (17.7 % vs 6.8 %; OR 2.9; 95 %CI 1.1–8.6; p <0.05). One can suggest that this difference is related to the proven involvement of EBV in the NPC development. There were no other differences in the frequencies of class II HLA genes between the groups of NPC and OOCT patients. For the first time in Russia the importance of alleles DQA1, DQB1 and DRB1 of the HLA gene for the NPC and OOCT development, malignant tumors, respectively associated and non-associated with EBV, was studied. The results of the investigation completed together with known literature data allow us to conclude that the above alleles of the HLA class II gene can serve as a factor predisposing to the development of NPC in Russia.Conclusion. However, in order to establish a strict association between a specific HLA haplotype and the NPC and OOCT incidence, the information obtained is insufficient due to the complexity and variability of the genetic control of immune responses controlling the tumor process. A comprehensive study of this issue using different immune response genes and populations of different ethnic origins will probably help to elucidate the effect of genetic polymorphism on the risk of NPC and OOCT development in Russia.Введение. Назофарингеальная карцинома (рак носоглотки, РНГ), как известно, строго ассоциирована с вирусом Эпштейна–Барр (ВЭБ). Однако ВЭБ является убиквитарной инфекцией, тогда как РНГ развивается довольно редко и характеризуется географически и этнически неоднородным распространением, что позволяет предположить важную роль других кофакторов в патогенезе РНГ, таких как окружающая среда и генетическая предрасположенность. Среди известных генетических факторов, ассоциированных с РНГ, главный комплекс гистосовместимости (лейкоцитарный антиген человека, human leukocyte antigen (HLA)) занимает важное положение, так как играет ключевую роль в презентации вирусных антигенов иммунной системы. В России изучение ассоциации аллелей HLA с риском развития РНГ, связанного с ВЭБ, не проводилось, а в литературе существуют противоречивые сведения о роли разных HLA-генов как в возникновении и развитии РНГ, так и в инициации и особенностях иммунного ответа к белкам ВЭБ.Цель исследования – изучение распределения вариантов DQA1-, DQB1-, DRB1-генов HLA класса II у больных РНГ и пациентов с другими опухолями полости рта (ДОПР), ассоциированными и не ассоциированными с ВЭБ, в группах с высоким и низким уровнем гуморального иммунного ответа к основным белкам ВЭБ по сравнению с контрольной группой здоровых лиц.Материалы и методы. Всего в исследование вошли 62 больных недифференцированным РНГ и 44 пациента с ДОПР, а также 300 здоровых лиц. Сыворотка крови всех больных была протестирована на наличие антител иммуноглобулинов классов G и А к капсидному и раннему антигенам ВЭБ методом непрямой иммунофлюоресценции. Все образцы генотипированы на HLA-DQA1, -DQB1 и -DRB1 с помощью мультипраймерной амплификации сиквенс-специфическими праймерами методом полимеразной цепной реакции в режиме реального времени.Результаты. Показано увеличение частоты HLA-DRB1*08 у пациентов с РНГ по сравнению с контролем (5,6 % против 1,8 %; отношение шансов (ОШ) 3,2; 95 % доверительный интервал (ДИ) 1,1–9,1; р = 0,02). Возможно, ген HLA-DRB1*08 ассоциирован с повышенной чувствительностью к РНГ. В то же время у пациентов с РНГ была выявлена более низкая, чем в контроле, частота HLA-DQB1*0301 (16,1 % против 25,3 %; р <0,05). Вариант HLA-DQB1*0502–4, наоборот, реже встречался у пациентов с ДОПР, чем в контроле (1,1 % против 6,8 %; р <0,05). Аналогичные наблюдения касаются HLA-DRB1*16, частота которого у пациентов с ДОПР была ниже, чем в контроле (1,1 % против 6,7 %; ОШ 0,16; 95 % ДИ 0,01–1,08; р <0,05), т. е. ген HLA-DQB1*0301 ассоциирован с резистентностью к РНГ, а варианты HLA-DQB1*0502–4 и HLA-DRB1*16 – с резистентностью к ДОПР.Интересен факт обнаружения различий в частоте HLA-DRB1*13 у пациентов с РНГ и ДОПР (17,7 % против 6,8 %; ОШ 2,9; 95 % ДИ 1,1–8,6; р <0,05). Эти различия могут быть связаны с доказанным участием ВЭБ в развитии РНГ. Других различий по частотам генов HLA класса II между группами пациентов с РНГ и ДОПР не выявлено. Впервые в России проведено изучение связи аллелей DQA1, DQB1 и DRB1 гена HLA с развитием назофарингеальной карциномы (РНГ) и ДОПР, ассоциированных и не ассоциированных с ВЭБ.Заключение. Наши исследования в совокупности с уже известными данными позволяют заключить, что имеется определенная связь генов HLA класса II c развитием РНГ, однако для установления строгой ассоциации аллелей HLA класса II с РНГ и другими опухолями области головы и шеи полученных сведений недостаточно из-за сложности и вариабельности генетического контроля иммунных реакций, контролирующих опухолевый процесс

Вирус Эпштейна–Барр у этнических татар: инфицированность и сиквенсные варианты онкогена LMP1

Objective of the investigation was to study the infection of ethnic Tatars with the Epstein–Barr virus (EBV) and to analyze the genetic structure of the oncogene of the virus, the latent membrane protein 1 (LMP1), in the virus strains of Tatar origin. Materials and methods. The materials for the study were samples of boucle flushes of 60 students from the Kazan State Medical University who are ethnic Tatars (Tatars no less than in the 3rd generation). Amplified from DNA of boucle flushes the nucleotide sequences of the LMP1 samples translated into DNA amino acid sequences, have undergone classification based on the well-known and widely used in literature the R.H. Edwards et al. classification. Results. The analysis of nucleotide and deductive amino acid sequences of the 41 LMP1 amplicons revealed their homology with only three gene variants from the R.H. Edwards et al. classification (1999): 95.8/A (29.3 %; 12/41), Med– (14.6 %; 6/41) and China1 (7.3 %, 3/41). Such variants of LMP1 as Alaskan, Med+, Chinа2, China3 and NC, were not found. Among the LMP1 samples of Tatar origin in 20 cases (48.8 %), the composition of the mutations found did not allow them to be assigned to any of the oncogene variants listed above. Out of this number, in 7 (17.1 %) cases a mono group of LMP1 samples was found, differing not only from representatives of the Slavs, inhabitants of the European part of Russia, but also from other Kazan samples, and was designated as LMP1-TatK. The remaining 13 samples of LMP1 (31.7 %), not belonging to any of the known classifications, formed the group designated by us as an LMP1 group beside the classification (LMP1BC). Conclusion. Continuation of the study of the molecular-biological and functional properties of LMP1 in TatK and BC groups, which constitute 48.8 % of the number of gene samples studied, and an analysis of the peculiarities of the ethnic Tatar genotype, will probably help to clarify whether certain EBV strains influence morbidity and mortality in Tatar population with malignant neoplasms, which include EBVassociated cases.Цель исследования – изучение инфицированности вирусом Эпштейна–Барр (ВЭБ) этнических татар и анализ генетической структуры онкогена вируса, латентного мембранного белка 1 (LMP1), в штаммах вируса татарского происхождения. Материалы и методы. Материалом для исследования служили буккальные смывы 60 студентов Казанского государственного медицинского университета, являющихся этническими татарами (не менее чем в III поколении). Выделенную из смывов ДНК использовали для амплификаци LMP1. Амплифицированные из ДНК буккальных смывов нуклеотидные последовательности образцов LMP1, транслированные в аминокислотные последовательности, подверглись классификации на основании известной и широко используемой в литературе классификации R.H. Edwards и соавт. Результаты. Анализ нуклеотидных и транслированных аминокислотных последовательностей 41-го ампликона LMP1 выявил их гомологию только с 3 вариантами гена из классификации R.H. Edwards и соавт.: 95.8/А (29,3 %; 12/41), Med– (14,6 %; 6/41) и China1 (7,3 %; 3/41). Такие варианты LMP1, как Alaskan, Med+, Chinа2, China3 и NC, не обнаружены. В остальных 20 случаях (48,8 %) спектр обнаруженных мутаций в образцах LMP1 татарского происхождения не позволил их отнести ни к одному из перечисленных выше вариантов онкогена. Из них в 7 случаях (17,1 % всех исследованных образцов) обнаружена моногруппа вариантов LMP1, отличающаяся не только от представителей славян, жителей европейской части России, но и от других казанских образцов, и обозначенная нами, как LMP1-TatK. Остальные 13 образцов LMP1 (31,7 %), не относящихся ни к одной из известных классификаций, сформировали группу, обозначенную нами, как группа LMP1 вне классификации (LMP1ВК). Заключение. Дальнейшее изучение молекулярно-биологических и функциональных свойств LMP1 в группах ВК и TatK, составляющих 48,8 % от числа изученных образцов онкобелка, и анализ особенностей генотипа этнических татар, вероятно, позволят выяснить, оказывают ли определенные штаммы ВЭБ влияние на показатели заболеваемости и смертности злокачественными новообразованиями, в состав которых входят ВЭБ-ассоциированные случаи, у татарского населения

Epigenetic mechanisms in virus-induced tumorigenesis

About 15–20% of human cancers worldwide have viral etiology. Emerging data clearly indicate that several human DNA and RNA viruses, such as human papillomavirus, Epstein–Barr virus, Kaposi’s sarcoma-associated herpesvirus, hepatitis B virus, hepatitis C virus, and human T-cell lymphotropic virus, contribute to cancer development. Human tumor-associated viruses have evolved multiple molecular mechanisms to disrupt specific cellular pathways to facilitate aberrant replication. Although oncogenic viruses belong to different families, their strategies in human cancer development show many similarities and involve viral-encoded oncoproteins targeting the key cellular proteins that regulate cell growth. Recent studies show that virus and host interactions also occur at the epigenetic level. In this review, we summarize the published information related to the interactions between viral proteins and epigenetic machinery which lead to alterations in the epigenetic landscape of the cell contributing to carcinogenesis

P20

The Epstein–Barr virus (EBV) represents an etiological agent for a number of human benign and malignant tumors. One of the EBV encoded proteins, the latent membrane protein 1 (LMP1), is involved in activation of many signaling pathways and transcription factors leading EBV infected cells to immortalization and transformation. It’s well known that almost all worlds’ population is infected with EBV. As usually, infection occurs during early childhood without serious consequences for infected people. At the same time a secondary infection by additional EBV strain(s) occurs quite often. During the in vitro cultivation of peripheral blood lymphocyte from persons infected with multiple strains of the virus, only one of them having LMP1 oncogene with highest transforming potential becomes dominant while the others are eliminated. To figure out whether pattern of LMP1 expressions reflects the origin of EBV strains, six cell lines from patients with tumors, associated and not-associated with the virus and healthy individuals were established. The nucleotide and deductive amino acid (a.a.) sequences of LMP1 isolates tested were analyzed and compared with those of LMP1 isolates obtained from eight cell lines of African and Japanese EBV-associated Burkitt’s lymphomas (BL) origin. As the result, in four out of six cell lines of Russian origin (2 from patients with lymphoid pathology and 2 from PBLs of blood donors) the low divergent LMP1 B95.8/A variant characterized by a low transforming activity and a small number of a.a. substitutions was detected. For other two cell lines originated from EBV-associated patient with nasopharyngeal carcinoma and not virus-associated Hodgkin’s lymphoma patient the LMP1Med- and LMP1China1 variants, characterized by a larger set of mutations and high transforming potential, were found. Low divergent LMP1 variants (B95.8 or B95.8/A) were observed for 13 of 15 LMP1 samples from PBLs of Russian blood donors; in 2 donors highly divergent China1 and NC LMP1 variants were also detected. Among eight cell lines of BL origin three lines were the sources of the prototype EBV strain B95.8 (Jijoye, P3HR1, Raji). From other five cell lines (Daudi, Namalva, Ag 876, NC37 and Akata) LMP1 variants Med- and China1, characterized by a significant number of mutations and high transforming capacity were obtained. Genetic relationship between LMP1 isolates from cell lines of Russian and BL origin were analyzed by the phylogenetic tree. It follows from the constructed tree that cell lines of Russian and BL lymphoma origin formed two separate clusters located at the tree a distance from each other, indicating genetic proximity for respective groups of cell lines. The data obtained complemented with the results of our previous studies suggest that among Russians represented by cancer patients and healthy individuals, EBV strains with predominantly low transforming capacity of LMP1 are persisting. These findings are likely can explain the non-endemic nature of the EBV-associated pathologies in Russia.On the other hand, one can speculate that in African countries which are endemic for BL highly oncogenic strains of EBV are dominated, the indirect confirmation of what is the detection in cell lines of BL origin LMP1 isolates having high transforming activity. The results of this study let us also to suggest that LMP1 expression pattern in non-endemic region like Russia does not reflect the type of malignancy but rather reflect their geographic origin

HLA II genes distribution in Epstein–Barr virus-associated nasopharyngeal carcinoma and other tumors of the oral cavity patients in Russia

Background. It has been proved that for the nasopharyngeal carcinoma (NPC) the etiological agent is the Epstein–Barr virus (EBV). Being an ubiquitous infection, EBV, under certain conditions, is able to display its oncogenic potential. Among a wide range of tumors associated with EBV, the NPC occupies a special place because it is characterized by a geographically and ethnically heterogeneous distribution, suggesting that in the pathogenesis of NPC, in addition to EBV, an important role is played by other factors, such as genetic predisposition to this neoplasm. Among known genetic factors influencing the frequency of NPC development, the human leukocyte antigen (HLA) complex occupies an important place, as it plays a central role in the presentation of viral antigens to the immune system. In Russia, the association of HLA alleles with the risk of EBV associated forms of NPC development and with development of other oral cavity tumors (OOCT), not associated with the virus, has not been studied. In the literature there are contradictory information about HLA genes, which determine the predisposition to the emergence of these tumors, and their role in the initiation and formation an immune response to EBV proteins.Objective: to study the distribution of the of DQA1-, DQB1-, DRB1-HLA class II gene variants associated with respectively the risk or resistance to the development of NPC and OOCT and with a high and low level of antibody response to EBV main proteins. A group of healthy persons served as a control.Materials and methods. Blood samples from 62 patients with NPC, 44 patients with OOCT, and as control, 300 healthy individuals, were used in the study. The blood serum samples of NPC and OOCT patients were tested for the presence of immunoglobulin classes G and A antibodies to capsid and early EBV antigens by indirect immunofluorescence. All serum samples of patients and healthy individuals were genotyped on HLA-DQA1, -DQB1 and -DRB1 by the method of multi-primer amplification by sequence-specific primers by real-time polymerase chain reaction.Results. In NPC patients, an increase in the frequency of HLA-DRB1*08 was found when compared with the frequency of a similar allele in healthy individuals (5.6 % vs 1.8 %; odds ratio (OR) 3.2; 95 % confidence interval (CI) 1.1–9.1; p = 0.02), and, on the contrary, a lower HLA-DQB1*0301 frequency was detected (16.1 % vs 25.3 %; p <0.05) than in healthy individuals. The data obtained suggest that the HLA-DRB1*08 gene is associated with an increased sensitivity to NPC.In OOCT patients, HLA-DQB1*0502–4 and HLA-DRB1*16 variants were less common than in healthy individuals (1.1 % vs 6.8 %; p <0.05 and 1.1 % vs 6.7 %; OR 0.16; 95 % CI 0.01–1.08; p <0.05, respectively), suggesting that the HLA-DQB1*0301 gene is associated with resistance to NPC, and HLA-DQB1*0502–4 and HLA-DRB1*16 variants – with resistance to OOCT. It is interesting to note the difference in the frequency of HLA-DRB1*13 between NPC and OOCT patients (17.7 % vs 6.8 %; OR 2.9; 95 %CI 1.1–8.6; p <0.05). One can suggest that this difference is related to the proven involvement of EBV in the NPC development. There were no other differences in the frequencies of class II HLA genes between the groups of NPC and OOCT patients. For the first time in Russia the importance of alleles DQA1, DQB1 and DRB1 of the HLA gene for the NPC and OOCT development, malignant tumors, respectively associated and non-associated with EBV, was studied. The results of the investigation completed together with known literature data allow us to conclude that the above alleles of the HLA class II gene can serve as a factor predisposing to the development of NPC in Russia.Conclusion. However, in order to establish a strict association between a specific HLA haplotype and the NPC and OOCT incidence, the information obtained is insufficient due to the complexity and variability of the genetic control of immune responses controlling the tumor process. A comprehensive study of this issue using different immune response genes and populations of different ethnic origins will probably help to elucidate the effect of genetic polymorphism on the risk of NPC and OOCT development in Russia

Epstein–Barr virus in the ethnic Tatars population: the infection and sequence variants of LMP1 oncogene

Objective of the investigation was to study the infection of ethnic Tatars with the Epstein–Barr virus (EBV) and to analyze the genetic structure of the oncogene of the virus, the latent membrane protein 1 (LMP1), in the virus strains of Tatar origin. Materials and methods. The materials for the study were samples of boucle flushes of 60 students from the Kazan State Medical University who are ethnic Tatars (Tatars no less than in the 3rd generation). Amplified from DNA of boucle flushes the nucleotide sequences of the LMP1 samples translated into DNA amino acid sequences, have undergone classification based on the well-known and widely used in literature the R.H. Edwards et al. classification. Results. The analysis of nucleotide and deductive amino acid sequences of the 41 LMP1 amplicons revealed their homology with only three gene variants from the R.H. Edwards et al. classification (1999): 95.8/A (29.3 %; 12/41), Med– (14.6 %; 6/41) and China1 (7.3 %, 3/41). Such variants of LMP1 as Alaskan, Med+, Chinа2, China3 and NC, were not found. Among the LMP1 samples of Tatar origin in 20 cases (48.8 %), the composition of the mutations found did not allow them to be assigned to any of the oncogene variants listed above. Out of this number, in 7 (17.1 %) cases a mono group of LMP1 samples was found, differing not only from representatives of the Slavs, inhabitants of the European part of Russia, but also from other Kazan samples, and was designated as LMP1-TatK. The remaining 13 samples of LMP1 (31.7 %), not belonging to any of the known classifications, formed the group designated by us as an LMP1 group beside the classification (LMP1BC). Conclusion. Continuation of the study of the molecular-biological and functional properties of LMP1 in TatK and BC groups, which constitute 48.8 % of the number of gene samples studied, and an analysis of the peculiarities of the ethnic Tatar genotype, will probably help to clarify whether certain EBV strains influence morbidity and mortality in Tatar population with malignant neoplasms, which include EBVassociated cases

The NP9 protein encoded by the human endogenous retrovirus HERV-K(HML-2) negatively regulates gene activation of the Epstein-Barr virus nuclear antigen 2 (EBNA2).

Epstein-Barr virus (EBV) is a human tumour virus that efficiently growth-transforms primary human B-lymphocytes in vitro. The viral nuclear antigen 2 (EBNA2) is essential for immortalisation of B-cells and stimulates viral and cellular gene expression through interaction with DNA-bound transcription factors. Like its cellular homologue Notch, it associates with the DNA-bound repressor RBPJκ (CSL/CBF1) thereby converting RBPJκ into the active state. For instance, both EBNA2 and Notch activate the cellular HES1 promoter. In EBV-transformed lymphocytes, the RNA of the NP9 protein encoded by human endogenous retrovirus HERV-K(HML-2) Type 1 is strongly up-regulated. The NP9 protein is detectable both in EBV-positive Raji cells, a Burkitt's lymphoma cell line, and in IB4, an EBV-transformed human lymphoblastoid cell line. NP9 binds to LNX that forms a complex with the Notch regulator Numb. Therefore, the function of NP9 vis-à-vis Notch and EBNA2 was analysed. Here, we show that NP9 binds to EBNA2 and negatively affects the EBNA2-mediated activation of the viral C- and LMP2A promoters. In contrast, NP9 did neither interfere in the activation of the HES1 promoter by Notch nor the induction of the viral LMP1 promoter by EBNA2. In an electrophoretic mobility shift analysis, NP9 reduced the binding of EBNA2 to DNA-bound RBPJκ by about 50%. The down-regulation of EBNA2-activity by NP9 might represent a cellular defence mechanism against viral infection or could, alternatively, represent an adaptation of the virus to prevent excessive viral protein production that might otherwise be harmful for the infected cell