Deciphering the mechanism of the viral telomerase RNA in Marek’s disease virus pathogenesis and tumorigenesis

• Applicant: Professor Dr. Benedikt Bertold Kaufer, Ph.D.
• Subject Area: Veterinary Medical Science
• Term: from 2020 to 2023
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 438108354

Marek’s disease virus (MDV) is a highly oncogenic alphaherpesvirus that causes deadly T cell lymphoma in chickens. MDV encodes a telomerase RNA (vTR) that plays a crucial role in MDV-induced tumor formation. It shares an 88% sequence identity with the cellular TR in chickens (cTR) and promotes telomerase activity. We previously demonstrated that the tumor-promoting functions of vTR act independent of its role in the telomerase complex. Furthermore, we showed that vTR interacts with and re-localizes the cellular protein RpL22, which is an important factor in T-cell development and transformation. Until now, the role of this vTR-RpL22 interaction in MDV-induced tumor formation remains elusive. In addition, we provide preliminary data that vTR has additional interaction partners and possesses anti-apoptotic functions. Considering these aspects, we hypothesize that the interaction of vTR with RpL22 and/or other interaction partners as well as vTR-mediated inhibition of apoptosis contribute to tumor formation. We will address this hypothesis in three specific aims. Specifically, we will 1) decipher the role of the vTR-RpL22 interaction in MDV-induced tumorigenesis, 2) identify novel vTR interaction partners and determine if they contribute to tumor cell proliferation, and 3) investigate the mechanism that allows vTR to inhibit apoptosis. To address aim 1, we will mutate the RpL22-consensus binding sites in vTR and assess the ability of these vTR mutants to interact with and re-localize RpL22. In addition, we will generate recombinant viruses harboring these mutations to determine if the vTR-RpL22 interaction plays a role in MDV-induced tumorigenesis. To achieve aim 2, we will perform RNA-Protein precipitation assays and identify novel interaction partners by mass spectrometry. We will assess if vTR affects the localization of these novel interaction partners and if they contribute to MDV-induced tumor cell proliferation. In aim 3, we will further investigate the anti-apoptotic properties of vTR and assess if it is dependent on the telomerase complex. In addition, we will determine if vTR acquired this function during virus evolution or if the cellular homologue cTR already possesses this activity. This proposal will define the molecular mechanism(s) of vTR and its interaction partners in MDV-induced tumorigenesis, providing a deeper understanding of the pathogenesis of this deadly pathogen.

• DFG Programme: Research Grants