Reactivation of Epstein–Barr virus by a dual-responsive fluorescent EBNA1-targeting agent with Zn2+-chelating function

Lijun Jiang,Cecilia Boreström,Sai Wah Tsao,Lai Sheung Chan,Hong Lok Lung,Alan Kwok Shing Chiang,Shuai Zha,Wai Yin Chau,Jaap M Middeldorp,Tao Huang,Yujun Du,Steven L Cobb,Waygen Thor,Rongfeng Lan,Nai Ki Mak,Nicholas J Long,Lucas Tang ,Zhao Xiang Bian ,Kwok Wai Lo ,Ho Fai Chau ,Tik Hung Tsoi ,William Tai ,Ga Lai Law ,Wing Tak Wong ,Ka Leung Wong

doi:10.1073/pnas.1915372116

Abstract

Epstein-Barr nuclear antigen 1 (EBNA1) plays a vital role in the maintenance of the viral genome and is the only viral protein expressed in nearly all forms of Epstein-Barr virus (EBV) latency and EBV-associated diseases, including numerous cancer types. To our knowledge, no specific agent against EBV genes or proteins has been established to target EBV lytic reactivation. Here we report an EBNA1- and Zn2+-responsive probe (ZRL5P4) which alone could reactivate the EBV lytic cycle through specific disruption of EBNA1. We have utilized the Zn2+ chelator to further interfere with the higher order of EBNA1 self-association. The bioprobe ZRL5P4 can respond independently to its interactions with Zn2+ and EBNA1 with different fluorescence changes. It can selectively enter the nuclei of EBV-positive cells and disrupt the oligomerization and oriP-enhanced transactivation of EBNA1. ZRL5P4 can also specifically enhance Dicer1 and PML expression, molecular events which had been reported to occur after the depletion of EBNA1 expression. Importantly, we found that treatment with ZRL5P4 alone could reactivate EBV lytic induction by expressing the early and late EBV lytic genes/proteins. Lytic induction is likely mediated by disruption of EBNA1 oligomerization and the subsequent change of Dicer1 expression. Our probe ZRL5P4 is an EBV protein-specific agent that potently reactivates EBV from latency, leading to the shrinkage of EBV-positive tumors, and our study also suggests the association of EBNA1 oligomerization with the maintenance of EBV latency.

Highlights

CELL BIOLOGY Correction for “Reactivation of Epstein–Barr virus by a dualresponsive fluorescent Epstein–Barr nuclear antigen 1 (EBNA1)-targeting agent with Zn2+chelating function,” by Lijun Jiang, Hong Lok Lung, Tao Huang, Rongfeng Lan, Shuai Zha, Lai Sheung Chan, Waygen Thor, Tik-Hung Tsoi, Ho-Fai Chau, Cecilia Boreström, Steven L
Interactions between ZRL5P4 and EBNA1 DBD were initially determined by molecular dynamics (MD) simulations
As only the Xray crystal structure of the dimeric EBNA1 DBD is available, we decided to use this partial structure of EBNA1 to check whether the presence of the Zn2+-chelating fluorophore ZRL5 in ZRL5P4 would affect its P4 to bind to an EBNA1 monomer

Summary

Introduction

CELL BIOLOGY Correction for “Reactivation of Epstein–Barr virus by a dualresponsive fluorescent EBNA1-targeting agent with Zn2+chelating function,” by Lijun Jiang, Hong Lok Lung, Tao Huang, Rongfeng Lan, Shuai Zha, Lai Sheung Chan, Waygen Thor, Tik-Hung Tsoi, Ho-Fai Chau, Cecilia Boreström, Steven L. Epstein–Barr nuclear antigen 1 (EBNA1) plays a vital role in the maintenance of the viral genome and is the only viral protein expressed in most forms of Epstein–Barr virus (EBV) latency and EBV-associated diseases, including numerous cancer types. The bioprobe ZRL5P4 can respond independently to its interactions with Zn2+ and EBNA1 with different fluorescence changes It can selectively enter the nuclei of EBV-positive cells and disrupt the oligomerization and oriP-enhanced transactivation of EBNA1. Epstein–Barr nuclear antigen 1 (EBNA1) is the only viral protein expressed in most forms of EBV latency and its associated cancers which plays a vital role in the maintenance of viral genome [3].

Methods

Results

Conclusion