What is IRF3 and IRF7?
IRF3 and IRF7, the two family-members with greatest structural homology, are now known to be the principal mediators of IFN induction, acting downstream of cytosolic RNA and DNA receptors and the TLRs (TLR3, TLR4, TLR7, and TLR9) (9).
Where does IRF3 bind?
We show that IRF3 and IRF7 bind to many interferon-stimulated response element (ISRE)-type sites in the virus-response elements (VREs) of IFN promoters.
Is IRF7 an ISG?
While IRF-3 is constitutively expressed in many tissues, IRF-7 is an ISG required for the expression of most IFN-α subtypes, and thus a key mediator of the type I IFN amplification loop [2], [9], [10].
What activates IRF7?
IRF7 is activated by pathogenic nuclei acids through pathways mediated by TLR3, -7 and -9, RIG-I and likely DNA-dependent activator of IRF and IFI16, as well as by TLR2-mediated signaling pathway.
What does IRF3 produce?
IRF3 also functions as a negative regulator of gene expression, where, for example, IRF3 is directly recruited to the Il12b gene promoter and enhancer on RLR or cytosolic DNA sensor stimulation, where it suppresses Il12b mRNA induction by competing with IRF5, the bona fide transcriptional activator for the gene …
What activates IRF3?
IRF3 is a transcription factor that controls multiple IFN-inducing pathways, including the TLR3 pathway, which can be triggered by dsRNA, and the pathways triggered by other RNA and DNA sensors. IRF3 is normally activated by TBK1 and/or IKKε kinases.
What is irf7 gene?
This gene encodes interferon regulatory factor 7, a member of the interferon regulatory transcription factor (IRF) family. It has been shown to play a role in the transcriptional activation of virus-inducible cellular genes, including interferon beta chain genes.
What is the role of interferon gamma?
Interferon gamma (IFN-γ) is a cytokine critical to both innate and adaptive immunity, and functions as the primary activator of macrophages, in addition to stimulating natural killer cells and neutrophils.
What cell produces interferon-gamma?
IFN-γ is secreted by T helper cells (specifically, Th1 cells), cytotoxic T cells (TC cells), macrophages, mucosal epithelial cells and NK cells. IFN-γ is both an important autocrine signal for professional APCs in early innate immune response, and an important paracrine signal in adaptive immune response.
What does interferon do in the human body?
Interferons were first described as an antiviral factor that interferes with viral replication in mammalian cells (10). They are secreted from infected cells and activate innate immune response that promotes not only cytokine production but also natural killer cell functions and antigen presentation (11, 12).
Which cells secrete interferon-gamma?
IFN‐γ is primarily secreted by activated T cells and natural killer (NK) cells, and can promote macrophage activation, mediate antiviral and antibacterial immunity, enhance antigen presentation, orchestrate activation of the innate immune system, coordinate lymphocyte–endothelium interaction, regulate Th1/Th2 balance.