title: Porcine reproductive and respiratory syndrome virus inhibition of interferon-β transcription by IRF3-independent mechanisms in MARC-145 cells in early infection.
abstract: Interferon β is an important antiviral molecule whose expression is triggered through recognition of viral components by pattern recognition receptors via a cascade of signaling molecules, while viruses could target these molecules to evade from innate immunity. IFN regulatory factor 3 (IRF3) plays a crucial role in innate immune responses. Here, we demonstrate that PRRSV infection did not induce IFN-β gene transcription in MARC-145 cells, but inhibited poly (I:C) stimulated IFN-β gene transcription instead. Such inhibition is time-dependent with the progression of PRRSV infection. We also show that the inhibition of IFN-β transcription in the early stage of infection could not be due to inhibition of phosphorylation and nuclear translocation of IRF3, though significant decrease of p-IRF3 and its nuclear translocation in PRRSV-infected and poly (I:C) cells was observed later at 48 h post-infection. The different patterns of inhibition for IFN-β transcription and IRF3 phosphorylation have important implications as to the mechanism(s) by which PRRSV suppresses the type I IFN signaling at early stage of infection. There could be mechanism(s) other than effecting on IRF3 or molecules upstream that require further investigation.
authors.affiliation: Institute of Preventive Veterinary Medicine and Zhejiang Provincial Key Laboratory of Preventive Veterinary Medicine, Zhejiang University, Hangzhou 310058, China.
authors.forename: Hongxia
authors.initials: H
authors.lastname: Hu
authors.forename: Xian
authors.initials: X
authors.lastname: Zhang
authors.forename: Hansong
authors.initials: H
authors.lastname: Zhang
authors.forename: Guilan
authors.initials: G
authors.lastname: Wen
authors.forename: Qianqian
authors.initials: Q
authors.lastname: Zhang
authors.forename: Xiaoliang
authors.initials: X
authors.lastname: Li
authors.forename: Weihuan
authors.initials: W
authors.lastname: Fang
mesh_terms: D000818:Animals; D050838:Interferon Regulatory Factor-3 / Q000502:physiology*; D016899:Interferon-beta / Q000235:genetics*; D011070:Poly I-C / Q000494:pharmacology; D019318:Porcine Reproductive and Respiratory Syndrome / Q000276:immunology*; D019316:Porcine respiratory and reproductive syndrome virus / Q000472:pathogenicity; D013552:Swine; D014158:Transcription, Genetic
chemical_list: D050838:Interferon Regulatory Factor-3; D016899:Interferon-beta; D011070:Poly I-C
keywords: IFN regulatory factor 3; IFN-β; Innate immunity; Porcine reproductive and respiratory syndrome virus