Journal: The Journal of Biological Chemistry
Article Title: P300/RNA polymerase II mediates induction of the teleost viral RNA sensor MDA5 through the interferon regulatory factor IRF11
doi: 10.1016/j.jbc.2025.108193
Figure Lengend Snippet: Lc IRF11 regulates Lc MDA5 promoter activity through binding to its promoter via its DBD domain. A , sequence alignments of the ISRE motif in the promoter region of fish MDA5. B , diagram of the Lc MDA5 promoter reporter plasmids showing WT and mutant type (mut) ISRE motifs. C , poly(I:C)-induced activation of Lc MDA5 promoter activity. EPC cells (1 × 10 6 ) in 24-well plates were transfected with the Lc MDA5 promoter reporter (250 ng) and pRL-TK (25 ng) for 6 h, followed by transfection with 1250 ng of poly(I:C) for 24 h to assess luciferase activity. D , Lc IRF11 induced Lc MDA5 promoter activity. EPC cells were cotransfected with pRL-TK, Lc MDA5 promoter reporter, and either Lc IRF11, Lc STAT1 expression plasmids, or control plasmid (pCMV-FLAG). Luciferase activity was measured at 24 h later. E , activation of Lc MDA5pro-luc and its ISRE mutant ( Lc MDA5pro-mut) by Lc IRF11. EPC cells were cotransfected with expression plasmids of pRL-TK, Lc IRF11, and either Lc MDA5pro-luc or its mutant for luciferase activity assay. F , activation of Lc MDA5 promoter by Lc IRF11-WT, but not Lc IRF11-ΔDBD. EPC cells were cotransfected with expression plasmids of pRL-TK, Lc MDA5 promoter reporter, Lc IRF11-WT, Lc IRF11-ΔDBD, or control plasmid. Luciferase activity was measured at 24 h post-transfection. G , Lc IRF11 bound to Lc MDA5 promoter DNA via its DBD domain. HEK293T cells (1 × 10 7 ) were transfected with 10 μg of indicated plasmids. After 24 h, cell lysates were mixed with 100 ng of biotinylated Lc MDA5 promoter DNA. Protein–DNA interactions were analyzed by Western blot. H , ChIP analysis confirmed the binding of Lc IRF11 to the Lc MDA5 promoter. HEK293T cells (1 × 10 7 ) were cotransfected with Lc MDA5 promoter reporter and Flag-tagged Lc IRF11-WT or Lc IRF11-ΔDBD (5 μg each) for 24 h. Following transfection, protein-bound DNA was immunoprecipitated using an anti-FLAG Ab. Subsequently, ChIP-enriched DNA was quantified by qPCR. I , Lc IRF11 binds to the ISRE motif of the Lc MDA5 promoter. HEK293T cells were transfected with the indicated plasmids. After incubating the biotinylated Lc MDA5 promoter DNA, the interaction of protein–DNA was detected by Western blot. Data represent the mean ± SD from three biological replicates. Asterisks indicate statistical significance (∗ p < 0.05, two-tailed unpaired Student's t test).
Article Snippet: The Abs utilized in this study were as follows: Flag mouse monoclonal Ab (MBL, cat#M185-3L, 1:10,000 for Western blot); STAT1 rabbit polyclonal Ab (Cell Signaling Technology, cat#9172S, 1:1000 for Western blot); H3K4me3 rabbit polyclonal Ab (Thermo Fisher Scientific, cat#711958, 3 μg for ChIP); H3K27ac rabbit polyclonal Ab (Thermo Fisher Scientific, cat#PA5-96618, 3 μg for ChIP); p300 rabbit monoclonal Ab (Cell Signaling Technology, cat#57625, 1:100 for ChIP, 1:1000 for Western blot); POLR1A mouse monoclonal Ab (Pol II subunit RPB1, 8WG16, Thermo Fisher Scientific, cat#MA1-26249, 3 μg for ChIP, 1:1000 for Western blot); β-tubulin mouse monoclonal Ab (Beyotime; cat#AF2839, 1:1000 for Western blot), and HRP-conjugated goat anti mouse/rabbit secondary Abs (Proteintech, cat#SA00001-1, cat#SA00001-2, 1:10,000).
Techniques: Activity Assay, Binding Assay, Sequencing, Mutagenesis, Activation Assay, Transfection, Luciferase, Expressing, Control, Plasmid Preparation, Western Blot, Immunoprecipitation, Two Tailed Test