Fig. 5

Interaction network of RBM22 between RNAPII and inhibitory 7SK-P-TEFb complex. a Cytoscape network analysis of the RBM22 protein interactome in HepG2 cells. Orange diamond, RBM22; light blue oval, spliceosome complex; pink oval, transcription; purple oval, DNA repair. b Western blot results showing co-immunoprecipitation of HA-tagged RBM22 and FLAG-tagged RPB3 in HEK293T cells. c Western blot results showing co-immunoprecipitation of FLAG-tagged RBM22 and RNAPII with different phosphorylation status, SPT5, CDK9 in HepG2 cells. d–f Reciprocal co-immunoprecipitation results showing the distinct interaction between RBM22 and unphosphorylated (d), Ser5P (e), and Ser2P (f) RNAPII in HepG2 cells. g Effect of CDK7, CDK9, and CDK12 knockdown on the interaction between RBM22 and RPB3 in HepG2 cells. h Effect of DRB and flavopiridol treatment on the interaction between RBM22 and RPB3 in HepG2 cells. i Effect of Actinomycin D treatment on the interaction between RBM22 and RNAPII in HepG2 cells. j–k Reciprocal co-IP results in HepG2 cells inducibly expressing FLAG-HRV-tagged RBM22 (j) and wild-type HepG2 cells (k) showing the association between RBM22 and 7SK-P-TEFb complex. l RBM22 co-fractionation with RNAPII and spliceosome and identification of separate RBM22-7SK complex. HepG2 cell lysate was analyzed by glycerol gradient sedimentation. Collected fractions were detected by Western blotting. The dashed box highlights a large complex (LC) and a small complex (SC) associated with RBM22. The asterisk indicates a non-specific signal