OBJECTIVE
To study the structural characteristics of the mouse DNA-dependent activator of interferon-regulatory factors (DAI) and its related molecular mechanism in anti-viral innate immune responses and signal transduction.
METHODS
The coding sequence of mouse DAI gene was amplified from splenic mononuclear cells by reverse transcription-PCR, and the genetic evolution and molecular structure of the mouse DAI gene were analyzed by bioinformatics softwares. After mouse DAI was stimulated by poly(dA-dT) and poly(dG-dC), the nuclear factor κB (NF-κB) and interferon-beta (IFN-β) promoter-driven luciferase activity were detected by dual-luciferase reporter assay system.
RESULTS
The open reading frame (ORF) of the cloned mouse DAI sequence was 1236 bp, encoding 411 amino acids, which exhibited identity with the corresponding sequences of cattle, pig, rat and other mammals ranging from 60%, 63.1%, 84%, and it contained two Z-DNA domains (Zα and Zβ), DNA binding region (D3) and signaling domain (SD). The stimulation of poly (dA-dT) increased the expressions of mouse DAI activated transcription factors NF-κB and IFN-β promoter. However, the stimulation of poly(dG-dC) only induced the activation of NF-κB but not IFN-β promoter.
CONCLUSION
Mouse DAI as an important cytosolic DNA sensor, is responsible for the recognition of A/T or G/C-rich DNA derived from DNA virus. It may play an important role in anti-viral innate immune responses.