Epstein-Barr Virus nuclear antigen leader protein in transcription regulation

Abstract: Epstein-Barr virus (EBV) associated diseases remain a huge burden in human health. As an orally transmitted pathogen, EBV infection causes infectious mononucleosis and ~200,000 cases of various cancers, including nasopharyngeal carcinoma that occurs in a space immediately adjacent to the oral cavity, some B cell malignancies, and ~10% of gastric cancer. In HIV infected people, EBV causes oral hairy leukoplakia of tongue. To understand the molecular mechanisms through which EBV contributes to disease development, EBV-transformed lymphoblastoid cell lines are used as a model system. EBV nuclear antigen leader protein (EBNALP) is essential for EBV to transform naïve B lymphocytes. Most of its known functions are linked to EBV transcription activator EBNA2. However, EBNALP binds to many enhancer and promoter sites independent of EBNA2. Perturbations of these EBNALP sites with CRISPRi significantly decreased these enhancers’ linked gene expression. Little is known about how EBNALP exerts its EBNA2 independent functions. It is also not known how EBNALP is tethered to the enhancer/promoter sites and how they affect transcription. Therefore, we hypothesize that EBNALP exploits host transcription programs to gain access to host enhancers/promoters, and contributes to EBV transformation through EBNA2-independent mechanisms. During my mentored period, I will address the fundamental question of how EBNALP binds to DNA. We will use CRISPR-based assays to identify host proteins essential for EBNALP enhancer activation. I will first focus on sequence-specific transcription factors (TFs). Chromatin immune precipitation (ChIP) based assays will be used to test the effects of knockout on EBNALP DNA binding. During my R00 phase, I will perform research independently and distinguish my work from my mentor’s by studying different aspects of EBNALP. I will focus my studies on characterizing the enhancer protein complexes assembled by EBNALP onto the enhancers to regulate transcription activity. I will focus on transcription cofactors, basal transcription factors, and histone modifying enzymes. Understanding the mechanisms through which EBNALP binds to DNA and regulates gene transcription may provide promising targets for treating EBV-associated diseases.