Cellular Zinc Finger Protein 622 Hinders Human Adenovirus Lytic Growth and Limits Binding of the Viral pVII Protein to Virus DNA

Abstract

Human adenovirus (HAdV) encodes a multifunctional DNA-binding protein pVII, which is involved in virus DNA packaging and extracellular immune signaling regulation. Although the pVII is an essential viral protein, its exact role in the virus life cycle and interplay with cellular proteins have remained to a large extent unclear. We have recently identified the cellular zinc finger protein 622 (ZNF622) as a potential pVII-interacting protein. In this study, we describe the functional consequences of the ZNF622-pVII interplay and the role of ZNF622 in the HAdV life cycle. ZNF622 protein expression increased, and it accumulated similarly to the pVII protein in the nuclei of virus-infected cells. The lack of the ZNF622 protein specifically increased pVII binding to viral DNA in the infected cells and elevated the pVII protein levels in the purified virions. In addition, ZNF622 knockout cells showed an increased cell lysis and enhanced accumulation of the infectious virus particles. Protein interaction studies revealed that ZNF622 forms a trimeric complex with the pVII protein and the cellular histone chaperon protein nucleophosmin 1 (NPM1). The integrity of this complex is important since ZNF622 mutations and NPM1 deficiency changed pVII ability to bind viral DNA. Collectively, our results implicate that ZNF622 may act as a cellular antiviral protein hindering lytic HAdV growth and limiting pVII protein binding to viral DNA.IMPORTANCE Human adenoviruses (HAdVs) are common human pathogens causing a wide range of acute infections. To counteract viral pathogenicity, cells encode a variety of antiviral proteins and noncoding RNAs to block virus growth. In this study, we show that the cellular zinc finger protein 622 (ZNF622) interacts with an essential HAdV protein known as pVII. This mutual interaction limits pVII binding to viral DNA. Further, ZNF622 has a role in HAdV life cycle since the lack of ZNF622 correlates with increased lysis of the infected cells and accumulation of the infectious virions. Together, our study reveals a novel cellular antiviral protein ZNF622, which may impede lytic HAdV growth.

Keywords: adenoviruses; chromatin remodeling.