Parvovirus B19 NS1 protein induces cell cycle arrest at G2-phase by activating the ATR-CDC25C-CDK1 pathway.

Peng Xu,Shengqi Wang,Jianxin Peng,Kaiyu Liu,Jianming Qiu,Safder S Ganaie,Min Xiong,Xuefeng Deng,Steve Kleiboeker,Shui Qing Ye,Wei Zou,Zhe Zhou,Colin Parrish

doi:10.1371/journal.ppat.1006266

Abstract

Human parvovirus B19 (B19V) infection of primary human erythroid progenitor cells (EPCs) arrests infected cells at both late S-phase and G2-phase, which contain 4N DNA. B19V infection induces a DNA damage response (DDR) that facilitates viral DNA replication but is dispensable for cell cycle arrest at G2-phase; however, a putative C-terminal transactivation domain (TAD2) within NS1 is responsible for G2-phase arrest. To fully understand the mechanism underlying B19V NS1-induced G2-phase arrest, we established two doxycycline-inducible B19V-permissive UT7/Epo-S1 cell lines that express NS1 or NS1mTAD2, and examined the function of the TAD2 domain during G2-phase arrest. The results confirm that the NS1 TAD2 domain plays a pivotal role in NS1-induced G2-phase arrest. Mechanistically, NS1 transactivated cellular gene expression through the TAD2 domain, which was itself responsible for ATR (ataxia-telangiectasia mutated and Rad3-related) activation. Activated ATR phosphorylated CDC25C at serine 216, which in turn inactivated the cyclin B/CDK1 complex without affecting nuclear import of the complex. Importantly, we found that the ATR-CHK1-CDC25C-CDK1 pathway was activated during B19V infection of EPCs, and that ATR activation played an important role in B19V infection-induced G2-phase arrest.

Highlights

Human parvovirus B19 (B19V) is a small, non-enveloped, single stranded DNA virus belonging to the genus Erythroparvovirus within the family Parvoviridae [1]
B19V infection results in several hematological disorders, which are a direct consequence of the infection and death of infected erythroid progenitor cells (EPCs)
We previously showed that the B19V NS1 protein is a key factor for disrupting the cell cycle via the putative transactivation domain Transactivation Domain 2 (TAD2), and that viral DNA replication-induced DNA damage response (DDR) is not necessary for cell cycle arrest of cells containing 4N DNA [36]

Summary

Introduction

Human parvovirus B19 (B19V) is a small, non-enveloped, single stranded DNA (ssDNA) virus belonging to the genus Erythroparvovirus within the family Parvoviridae [1]. B19V causes fifth disease or slapped cheek syndrome in children; B19V infection can cause hematological disorders [2,3,4,5,6]. B19V infection of immunocompromised patients, such as those with HIV/AIDS, transplant recipients, and infants, leads to a persistent viremia that is associated with chronic anemia and pure red-cell aplasia. Acute B19V infection of patients experiencing increased destruction of erythrocytes, and having a high demand for erythrocyte production (e.g., those with sickle-cell disease), can cause a transient aplastic crisis, whereas B19V infection of pregnant women can cause non-immune hydrops fetalis. There are no vaccines or specific antiviral therapeutics that can prevent or treat B19V-induced hematological disorders

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