Fig. 6. UBR5 interacts with TRIM28, an epigenetic repressor of RLR.

a The immunoblots of indicated proteins in 2fTGH cells transfected with poly (I:C) or infected with VSV-GFP at a MOI of 0.5. b The fluorescent images of VSV-GFP in 2fTGH cells at 12 h p.i. Scale bar: 50 µM. Quantification of the (c) IFIH1/DDX58 (gene symbol for MDA5/RIG-I) and (d) IFNB1 mRNA levels by qRT-PCR in 2fTGH cells infected with VSV for 12 h. Data shown in c and d are presented as mean ± S.E.M, two-tailed Student’s t test, n = 3 biologically independent experiments; *p = 0.0492, *p = 0.0189 in sequence for IFIH1, *p = 0.0286, *p = 0.0483 in sequence for DDX58 in c; *p = 0.0489 in d. Adjusted p values are presented. e Scatter plot showing the 49 proteins identified by FLAG-UBR5- immunoprecipitated (IP)-mass spectrometer (MS) analysis. The 17 proteins validated at Harmonizome database are labeled. Positive proteins: log₂(FC of A.P.I) > 1, two-tailed Student’s t test with Benjamini–Hochberg, p < 0.05, FC of A.P.I: fold change of Average Precursor Intensity. f, g FLAG-UBR5 co-immunoprecipitated (IP) with endogenous TRIM28, and vice versa. FLAG-UBR5/TRIM28 or vector plasmid was expressed in HEK293T cells, and immunoprecipitated with an anti-FLAG antibody. The indicated proteins were immunoblotted (IB) with specific antibodies. WCL: whole cell lysate. The immunoblots of indicated proteins in HEK293T cells transfected with (h) a negative siRNA (Ctrl) or UBR5 siRNA for 48 h, (i) with a UBR5 expression or vector plasmid for 24 h. The data are representative of two independent experiments with similar results (a, f–i). Source data are provided as a Source Data file.