Journal: Nucleic Acids Research
Article Title: Control of retrotransposon-driven activation of the interferon response by the double-stranded RNA binding protein DGCR8
doi: 10.1093/nar/gkag190
Figure Lengend Snippet: Loss of DGCR8 leads to immune system activation in 22qDS cells. ( A ) Western blot analyses of DGCR8 protein levels in PA-1 WT, DGCR8 HET, and DGCR8 KO cells. GAPDH serves as loading control (left). Quantification of three independent biological replicates (right). The dashed line represents the WT mean. ( B ) Quantification of IFNB1 mRNA levels by RT-qPCR in PA-1 WT, DGCR8 HET, and DGCR8 KO cells, both untreated and after stimulation with poly(I:C). Expression is represented as 2^-ΔCt, using GAPDH as a normaliser. ( C ) Influenza A Virus RNA levels by RT-qPCR after infection of PA-1 WT, DGCR8 HET, and DGCR8 KO. Expression was normalised to 18S rRNA and plotted relative to WT cells. ( D ) DGCR8 mRNA levels by RT-qPCR in control (healthy cells) and 22qDS immortalised fibroblasts (GM07215F). Data are normalised to GAPDH and expressed relative to WT cells. ( E ) IFNB1 expression levels by RT-qPCR in control (healthy cells) versus 22qDS immortalised fibroblasts (GM07215F), after poly(I:C) stimulation. Data are normalised to RN7SK and represented relative to stimulated healthy (WT) fibroblasts. ( F ) IFNB1 expression levels by RT-qPCR in control (healthy cells) versus 22qDS-derived primary fibroblasts (GM02944), after poly(I:C) stimulation. Data are normalised to GAPDH and represented relative to healthy stimulated cells. ( G ) Percentage of ISGs with a log2FC (22qDS/control) > 0 (up) or log2FC (22qDS/control) < 0 (down) from the following datasets: blood (Lin et al. ), T-lymphocytes (Raje et al. 2022), iPSCs-derived neurons (Lin et al. ), and cerebral cortex organoids from 22qDS-iPSCs (Khan et al. ). ( H ) Correlation between the log2FC (22qDS/control) of 22q11.2 deleted genes and ISGs. The log2FC of the mean of ISGs is plotted on the y -axis. The log2FC of the mean of 22q11.2 genes or the DGCR8 gene is plotted on the x -axis. Each dot represents one dataset, these being: blood ( n = 79 patients, n = 68 controls) (Lin et al. 2021), T-lymphocytes ( n = 13 patients, n = 6 controls) (Raje et al. 2022), iPSCs-derived neurons ( n = 8 patients, n = 7 controls) (Lin et al. 2016), hPSCs, NPCs and neurons ( n = 20 patients, n = 29 controls) (Nehme et al. ) and cerebral cortex organoids differentiated from 22qDS-iPSCs after 25, 50, 50, and 100 days ( n = 15 patients, n = 14 controls) (Khan et al. 2020). On the right, a table representing the top15 22q11.2 genes with the highest correlation index (all genes in ). ( I ) In homeostasis, DGCR8 and dsRNA-BPs such as DHX9 bind and resolve dsRNA structures of TE-rich mRNAs. After unwinding, RNAs are exported to the cytoplasm, where they are unseen by dsRNA receptors (left). In the absence of DGCR8, dsRNA structures remain unresolved. In the cytoplasm, these TE-rich RNAs are recognised by the MDA5 sensor, triggering IFN activation (right). Figure was created in BioRender ( https://BioRender.com/jt7uab7 ). In RT-qPCR, bars represent the average of three biological replicates. Error bars plot mean ± SD. * P < 0.05, ** P < 0.01, *** P < 0.001, **** P < 0.0001. P -values are determined by one-way ANOVA followed by Dunnett multiple comparison post-hoc test.
Article Snippet: Cells were transfected at 70% confluency, in six-well plates, and transfected with 5 μl of Invitrogen Lipofectamine 2000 Transfection Reagent and 1 μg of Y-shaped-DNA cGAS agonist (G3-YSD) (#tlrl-ydna, Invivogen) or dsRNA analogue polyinosinic:polycytidylic acid (poly(I:C)) (HMW #tlrl-pic, Invivogen).
Techniques: Activation Assay, Western Blot, Control, Quantitative RT-PCR, Expressing, Virus, Infection, Derivative Assay, Comparison