B.S., 1989, Chemical Engineering, Purdue University
M.D., 1995, Medicine, Harvard Medical School
Postdoctoral research: Harvard Medical School and Brigham and Women's Hospital
Our research focuses on the molecular biology of Epstein-Barr virus (EBV) nuclear proteins, their role in the virus lifecycle and the pathogenesis of EBV associated malignancies. Herpesviruses infect their hosts for life and EBV precisely manipulates growth and survival signaling pathways of B lymphocytes, resulting in their immortalization. Understanding the mechanisms that EBV has evolved to exploit infected cells is an important basis for therapy of EBV associated diseases and offers a unique vantage from which to view and understand complex cellular pathways.
EBNA3 proteins in EBV latent infection. EBV expresses four nuclear proteins (EBNA2, EBNA3A, 3B, and 3C) that target a single DNA binding protein in the Notch signaling pathway. This protein, called RBP-Jk (also CBF1 or CSL), binds to the DNA sequence GTGGGAAA and is normally complexed with repressor proteins that render it transcriptionally inactive. In the Notch signaling pathway, the intracellular portion of the Notch (ICN) receptor is released upon ligand binding. ICN travels to the nucleus, binds to RBP-Jk, displacing the repressor complex and recruiting the activator protein Mastermind, resulting in transcription of Notch regulated genes. The EBV nuclear protein EBNA2 mimics ICN, binding to RBP-Jk and upregulating expression of EBV latent genes and many cell genes usually regulated by Notch.
The EBNA3 proteins are also expressed during latent infection of B cells and bind to RBP-Jk with their highly homologous N-terminal domains. The EBNA3 proteins can compete with EBNA2 for RBP-Jk binding and repress EBNA2 activation of the EBNA (Cp) promoter. Thus, one role for EBNA3 proteins may be to limit “feed forward” upregulation of EBNA2 expression. This shared ability to compete with EBNA2 is unlikely to explain the unique roles of EBNA3A and EBNA3C in promoting lymphocyte growth. Although non-transcriptional activities of the EBNA3 proteins have been proposed to explain this requirement, our recent studies suggest that EBNA3 proteins are, like EBNA2, manipulators of the Notch signaling pathway. We have shown that EBNA3A, 3B, and 3C regulate distinct subsets of cell genes. Further, we have demonstrated that EBNA3A and EBNA3C mutants unable to bind to RBP-Jk fail to support B lymphocyte growth. Our data suggests that the complexity of EBV RBP-Jk binding proteins (EBNA3A, 3B, and 3C) exists in part to “fine tune” the strong positive signal initiated in the Notch pathway by EBNA2.
LF2 protein in EBV replication (lytic infection). EBV replication is controlled by two immediate early tranactivators, Rta and Zta. In a genome wide screen designed to identify all interactions among EBV proteins we discovered that Rta interacted with LF2, an EBV protein of unknown function. LF2 is encoded by one of three genes (LF1, LF2, and LF3) present in wildtype EBV, but deleted from the EBV reference strain, B95-8. We subsequently discovered that LF2 profoundly inhibited Rta’s ability to upregulate EBV replication genes. In cell based assays, LF2 can inhibit EBV DNA replication, lytic protein expression, and production of extracellular viral particles (virions), normally induced by Rta. LF2 homologs are present in all gamma herpesviruses sequenced to date and are incorporated into virions of many of these viruses, including the Kaposi Sarcoma Herpesvirus (KSHV). We speculate that LF2 homologs are incorporated gamma herpesvirus particles to prevent replication upon initial infection, just as alpha and beta herpesviruses incorporate transcriptional activators into their virions to promote it.
Kraus RJ, Yu X, Cordes BA, Sathiamoorthi S, Iempridee T, Nawandar DM, Ma S, Romero-Masters JC, McChesney KG, Lin Z, Makielski KR, Lee DL, Lambert PF, Johannsen EC, Kenney SC, Mertz JE. Hypoxia-inducible factor-1α plays roles in Epstein-Barr virus's natural life cycle and tumorigenesis by inducing lytic infection through direct binding to the immediate-early BZLF1 gene promoter. PLoS Pathog. 2017 Jun 15;13(6):e1006404. doi: 10.1371/journal.ppat.1006404. eCollection 2017 Jun. PubMed PMID: 28617871; PubMed Central PMCID: PMC5487075.
Nawandar DM, Ohashi M, Djavadian R, Barlow E, Makielski K, Ali A, Lee D, Lambert PF, Johannsen E, Kenney SC. Differentiation-Dependent LMP1 Expression Is Required for Efficient Lytic Epstein-Barr Virus Reactivation in Epithelial Cells. J Virol. 2017 Mar 29;91(8). pii: e02438-16. doi: 10.1128/JVI.02438-16. Print 2017 Apr 15. PubMed PMID: 28179525; PubMed Central PMCID: PMC5375685.
Price AM, Dai J, Bazot Q, Patel L, Nikitin PA, Djavadian R, Winter PS, Salinas CA, Barry AP, Wood KC, Johannsen EC, Letai A, Allday MJ, Luftig MA. Epstein-Barr virus ensures B cell survival by uniquely modulating apoptosis at early and late times after infection. Elife. 2017 Apr 20;6. pii: e22509. doi: 10.7554/eLife.22509. PubMed PMID: 28425914; PubMed Central PMCID: PMC5425254.
Wille CK, Li Y, Rui L, Johannsen EC, Kenney SC. Restricted TET2 Expression in Germinal Center Type B Cells Promotes Stringent Epstein-Barr Virus Latency. J Virol. 2017 Feb 14;91(5). pii: e01987-16. doi: 10.1128/JVI.01987-16. PubMed PMID: 28003489. PubMed Central PMCID: PMC5309966.
Djavadian R, Chiu YF, Johannsen E. An Epstein-Barr Virus-Encoded Protein Complex Requires an Origin of Lytic Replication In Cis to Mediate Late Gene Transcription. PLoS Pathog. 2016 Jun 27;12(6):e1005718. doi: 10.1371/journal.ppat.1005718. eCollection 2016 Jun. PubMed PMID: 27348612; PubMed Central PMCID: PMC4922670.
Wang A, Welch R, Zhao B, Ta T, Keles S, Johannsen E. Epstein-Barr Virus Nuclear Antigen 3 (EBNA3) Proteins Regulate EBNA2 Binding to Distinct RBPJ Genomic Sites. J Virol. 2016 Dec 30(2015);90(6):2906-19. doi: 10.1128/JVI.02737-15. PubMed PMID: 26719268; PubMed Central PMCID: PMC4810642.
Nawandar DM, Wang A, Makielski K, Lee D, Ma S, Barlow E, Reusch J, Jiang R, Wille CK, Greenspan D, Greenspan JS, Mertz JE, Hutt-Fletcher L, Johannsen EC, Lambert PF, Kenney SC. Differentiation-Dependent KLF4 Expression Promotes Lytic Epstein-Barr Virus Infection in Epithelial Cells. PLoS Pathog. 2015 Oct 2;11(10):e1005195. doi: 10.1371/journal.ppat.1005195. eCollection 2015 Oct. PubMed PMID: 26431332; PubMed Central PMCID: PMC4592227.
Ohashi M, Holthaus AM, Calderwood MA, Lai CY, Krastins B, Sarracino D, Johannsen E. The EBNA3 family of Epstein-Barr virus nuclear proteins associates with the USP46/USP12 deubiquitination complexes to regulate lymphoblastoid cell line growth. PLoS Pathog. 2015 Apr 9;11(4):e1004822. doi: 10.1371/journal.ppat.1004822. eCollection 2015 Apr. PubMed PMID: 25855980; PubMed Central PMCID: PMC4391933.
Schmidt SC, Jiang S, Zhou H, Willox B, Holthaus AM, Kharchenko PV, Johannsen EC, Kieff E, Zhao B. Epstein-Barr virus nuclear antigen 3A partially coincides with EBNA3C genome-wide and is tethered to DNA through BATF complexes. Proc Natl Acad Sci U S A. 2015 Jan 13;112(2):554-9. doi: 10.1073/pnas.1422580112. Epub 2014 Dec 24. PubMed PMID: 25540416; PubMed Central PMCID: PMC4299249.
Wille CK, Nawandar DM, Henning AN, Ma S, Oetting KM, Lee D, Lambert P, Johannsen EC, Kenney SC. 5-hydroxymethylation of the EBV genome regulates the latent to lytic switch. Proc Natl Acad Sci U S A. 2015 Dec 29;112(52):E7257-65. doi: 10.1073/pnas.1513432112. Epub 2015 Dec 9. PubMed PMID: 26663912; PubMed Central PMCID: PMC4703011.
Zhou H, Schmidt SC, Jiang S, Willox B, Bernhardt K, Liang J, Johannsen EC, Kharchenko P, Gewurz BE, Kieff E, Zhao B. Epstein-Barr virus oncoproteins super-enhancers control B cell growth. Cell Host Microbe. 2015 Feb 11;17(2):205-16. doi: 10.1016/j.chom.2014.12.013. Epub 2015 Jan 29. PubMed PMID: 25639793; PubMed Central PMCID: PMC4539236.
Iempridee, T., Reusch, J. A., Riching, A., Johannsen, E. C., Dovat, S., Kenney, S. C., and Mertz, J. E. Epstein-Barr Virus Utilizes Ikaros in Regulating Its Latent-Lytic Switch in B Cells. J. Virol., 88(9): 4811-4827, 2014.
Jiang, S., Willox, B., Zhou, H., Holthaus, A. M., Wang, A., Shi, T. T., Maruo, S., Kharchenko, P. V., Johannsen, E. C., Kieff, E., and Zhao, B. Epstein-Barr Virus Nuclear Antigen 3C Binds to BATF/IRF4 or SPI1/IRF4 Composite Sites and Recruits Sin3A to Repress CDKN2A. Proc. Natl. Acad. Sci. USA, 111(1): 421-426, 2014.
Duarte, M., Wang, L., Calderwood, M. A., Adelmant, G., Ohashi, M., Roecklein-Canfield, J., Marto, J. A., Hill, D. E., Deng, H., and Johannsen, E. An RS Motif within the Epstein-Barr Virus BLRF2 Tegument Protein Is Phosphorylated by SRPK2 and Is Important for Viral Replication. PLoS One, 8(1):e53512, 2013.
Johannsen, E., and Lambert, P. F. Epigenetics of Human Papillomaviruses. Virology, 445(1-2): 205-212, 2013.
Heilmann, A. M. F., Calderwood, M. A., Portal, D., Lu, Y., and Johannsen, E. Genome-Wide Analysis of Epstein-Barr Virus Rta DNA Binding. J. Virol., 86: 5151-5164, 2012.
Rozenblatt-Rosen, O., Deo, R. C., Padi, M., Adelmant, G., Calderwood, M. A., Rolland, T., Grace, M., Dricot, A., Askenazi, M., Tavares, M., Pevzner, S. J., Abderazzaq, F., Byrdsong, D., Carvunis, A.-R., Chen, A. A., Cheng, J., Correll, M., Duarte, M., Fan, C., Feltkamp, M. C., Ficarro, S. B., Franchi, R., Garg, B. K., Gulbahce, N., Hao, T., Holthaus, A. M., James, R., Korkhin, A., Litovchick, L., Mar, J. C., Pak, T. R., Rabello, S., Rubio, R., Shen, Y., Singh, S., Spangle, J. M., Tasan, M., Wanamaker, S., Webber, J. T., Roecklein-Canfield, J., Johannsen, E., Barbási, A.-L., Beroukhim, R., Kieff, E., Cusick, M. E., Hill, D. E., Münger, K., Marto, J. A., Quackenbush, J., Roth, F. P., DeCaprio, J. A., and Vidal, M. Interpreting Cancer Genomes Using Systematic Host Network Perturbations by Tumour Virus Proteins. Nature, 487: 491-495, 2012.