title: Human bocavirus NP1 inhibits IFN-β production by blocking association of IFN regulatory factor 3 with IFNB promoter.
abstract: Human bocavirus (HBoV) mainly infects young children. Although many infected children suffer from respiratory or gastroenteric tract diseases, an association between HBoV and these diseases is not definite. Because modulation of type I IFN is crucial for viruses to establish efficient replication, in this study, we tested whether HBoV modulates type I IFN production. We observed that a nearly full-length HBoV clone significantly reduced both Sendai virus (SeV)- and poly(deoxyadenylic-thymidylic) acid-induced IFN-β production. Further study showed that NP1 blocked IFN-β activation in response to SeV, poly(deoxyadenylic-thymidylic) acid, and IFN-β pathway inducers, including retinoic acid-inducible protein I, mitochondrial antiviral signaling protein, inhibitor of κB kinase ε, and TANK-binding kinase 1. In addition, NP1 interfered with IRF-3-responsive PRD(III-I) promoter activated by SeV and a constitutively active mutant of IRF-3 (IRF-3/5D). Although NP1 suppressed the IRF-3 pathway, it did not affect IRF-3 activation processes, including phosphorylation, dimerization, and nuclear translocation. Coimmunoprecipitation assays confirmed the interaction between NP1 and IRF-3. Additional deletion mutagenesis and coimmunoprecipitation assays revealed that NP1 bound to the DNA-binding domain of IRF-3, resulting in the interruption of an association between IRF-3 and IFNB promoter. Altogether, our results indicate that HBoV NP1 blocks IFN production through a unique mechanism. To our knowledge, this is the first study to investigate the modulation of innate immunity by HBoV. Our findings suggest a potential immune-evasion mechanism used by HBoV and provide a basis for better understanding HBoV pathogenesis.
authors: State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan 430071, China.
authors: Zhenfeng
authors: Z
authors: Zhang
authors: Zhenhua
authors: Z
authors: Zheng
authors: Huanle
authors: H
authors: Luo
authors: Jin
authors: J
authors: Meng
authors: Hongxia
authors: H
authors: Li
authors: Qian
authors: Q
authors: Li
authors: Xiaowei
authors: X
authors: Zhang
authors: Xianliang
authors: X
authors: Ke
authors: Bingke
authors: B
authors: Bai
authors: Panyong
authors: P
authors: Mao
authors: Qinxue
authors: Q
authors: Hu
authors: Hanzhong
authors: H
authors: Wang
mesh_terms: D052660:Bocavirus / Q000276:immunology*; D045744:Cell Line, Tumor; D057809:HEK293 Cells; D054884:Host-Pathogen Interactions; D006801:Humans; D050838:Interferon Regulatory Factor-3 / Q000037:antagonists & inhibitors* / Q000378:metabolism*; D016899:Interferon-beta / Q000037:antagonists & inhibitors* / Q000096:biosynthesis* / Q000235:genetics; D011401:Promoter Regions, Genetic / Q000276:immunology*; D015398:Signal Transduction / Q000276:immunology; D017361:Viral Nonstructural Proteins / Q000502:physiology*
chemical_list: D050838:Interferon Regulatory Factor-3; D017361:Viral Nonstructural Proteins; D016899:Interferon-beta