Epstein–Barr virus nuclear antigen 3A protein regulates CDKN2B transcription via interaction with MIZ-1

Quentin Bazot (1) , Thibaut Deschamps (1) , Lionel Tafforeau (2) , Maha Siouda (3) , Pascal Leblanc (4) , Marie L Harth-Hertle (5) , Chantal Rabourdin-Combe (2) , Vincent Lotteau (6) , Bettina Kempkes (5) , Massimo Tommasino (3) , Henri Gruffat (1) , Evelyne Manet (1)

1 Herpesvirus oncogènes – Oncogenic Herpesviruses [CIRI]
2 CIRI - Centre International de Recherche en Infectiologie
3 CIRC - IARC - Centre International de Recherche contre le Cancer - International Agency for Research on Cancer
4 INMG - Institut NeuroMyoGène
5 Institute of Virology, Helmholtz Zentrum Munich, German Research Center for Environmental Health
6 Biologie cellulaire des infections virales – Cell biology of viral infection [CIRI]

The Epstein-Barr virus (EBV) nuclear antigen 3 family of protein is critical for the EBV-induced primary B-cell growth transformation process. Using a yeast two-hybrid screen we identified 22 novel cellular partners of the EBNA3s. Most importantly, among the newly identified partners, five are known to play direct and important roles in transcriptional regulation. Of these, the Myc-interacting zinc finger protein-1 (MIZ-1) is a transcription factor initially characterized as a binding partner of MYC. MIZ-1 activates the transcription of a number of target genes including the cell cycle inhibitor CDKN2B. Focusing on the EBNA3A/MIZ-1 interaction we demonstrate that binding occurs in EBV-infected cells expressing both proteins at endogenous physiological levels and that in the presence of EBNA3A, a significant fraction of MIZ-1 translocates from the cytoplasm to the nucleus. Moreover, we show that a trimeric complex composed of a MIZ-1 recognition DNA element, MIZ-1 and EBNA3A can be formed, and that interaction of MIZ-1 with nucleophosmin (NPM), one of its coacti-vator, is prevented by EBNA3A. Finally, we show that, in the presence of EBNA3A, expression of the MIZ-1 target gene, CDKN2B, is downregulated and repressive H3K27 marks are established on its promoter region suggesting that EBNA3A directly counteracts the growth inhibitory action of MIZ-1.

Domaines: Virologie; Biologie moléculaire

Quentin Bazot, Thibaut Deschamps, Lionel Tafforeau, Maha Siouda, Pascal Leblanc, et al.. Epstein–Barr virus nuclear antigen 3A protein regulates CDKN2B transcription via interaction with MIZ-1. Nucleic Acids Research, 2014, 42 (15), pp.9700 - 9716. ⟨10.1093/nar/gku697⟩. ⟨hal-01927905⟩