Fig. 4

WTAP forms a complex with BCL6 via Hsp90. a OCI-Ly10 and OCI-Ly19 nuclear and cytoplasmic extracts were detected by Western blotting. b Co-localization of endogenous WTAP (red) and BCL6 (green) in DLBCL cells was detected by antibody stainings and confocal microscopy. When indicated, cells had been treated with PU-H71 (1 μM). Co-localization is shown by merge (yellow or orange). Nuclei were counterstained with DAPI (blue). c OCI-Ly19 cell lysates were supplemented with anti-WTAP, anti-BCL6 and negative control IgG antibodies. The protein complex was assessed against indicated antibodies. d Exogenous expression of WTAP and BCL6 was achieved by expression plasmids (pcDNA3.1-WTAP and BCL6-His) transfected into HEK293T cells and cultured for 24 h. PU-H71 (1.5 μM) or DMSO was added for another 24 h. Whole cell lysates were precipitated by anti-WTAP antibodies. WTAP, BCL6 and Hsp90 protein level were detected by the respective antibodies. LaminA/C as a nuclear protein served as a negative control. e, f GST pull-down assay to determine if WTAP interacts with BCL6 via Hsp90, either with GST-WTAP and BCL6-His only (e) or in the presence of whole cell extracts (f)