Fig. 4

RNF8 interacts with RARA and downregulates RARA protein expression. a Western blot results of RNF8, RARA, and RXRA in GTF2I-RARA-positive HL60 cells. RARA expression was reduced in GTF2I-RARA-positive HL60 cells, while RXRA remain unchanged. b Coimmunoprecipitation assays of endogenous RARA, RXRA, GTF2I-RARA, and RNF8 in GTF2I-RARA-positive HL60 cells showed RNF8 interacted with both RARA and RXRA but had no association with GTF2I-RARA. c Immunofluorescent colocalization analysis of RNF8, RARA, and RXRA in GTF2I-RARA-positive HL60 cells (GFP free). DAPI was used as nuclear staining. Results indicated GTF2I-RARA might precipitate the nuclear transcript of RNF8 and the formation of RNF8/RXRA or RNF8/RARA heterodimers. At least 100 cells were counted for colocalization analysis. Scale bar = 8 μm. d HL60 cells were transfected with plasmid-expressed RNF8, and total mRNA and protein were extracted and assessed by qPCR and Western blot. e HL60 cells were transfected with siRNF8 and control siRNA, and mRNA and proteins were assessed by qPCR and western blot, respectively. The RARA mRNA level remained unchanged, while RARA protein expression significantly increased in siRNF8-HL60 cells