1A6/DRIM, a Novel t-UTP, Activates RNA Polymerase I Transcription and Promotes Cell Proliferation
Figure 4
1A6/DRIM was associated with hALP and knockdown of 1A6/DRIM inhibited UBF acetylation.
A. Immunoprecipitation was performed with the 1A6/DRIM-specific monoclonal antibody 6D9. Proteins from the immunoprecipitates were separated by SDA-PAGE and transferred onto a PVDF membrane. The upper part of the blot was hybridized with 1A6/DRIM antibody and the lower part was probed with anti-hALP antibody. B. Indirect immunofluorescence staining was performed with a monoclonal antibody directed against 1A6/DRIM and a hALP-specific polyclonal antibody. 1A6/DRIM specific immunocomplexes were detected with TRITC-conjugated anti-mouse IgG and hALP specific immunocomplexes were detected with FITC-conjugated anti-rabbit IgG. Images were photographed under confocal microscopy after the nucleus was stained with DAPI. C. A 1A6/DRIM specific siRNA (si2-8) was transfected into U2OS cells. Cell lysate was prepared 72 hours posttransfection. Immunoprecipitation was performed with anti-acetyl-lysine on the cell lysates. Proteins from the immunoprecipitates were separated on SDS-PAGE and transferred onto a PVDF membrane. Blots were probed with anti-UBF antibody or anti-RB antibody (upper panel). Proteins from the whole cell lysates (WCE) were directly subjected to Western blotting to detect protein levels of indicated proteins (lower panel). Topoisomerase I (Topo I) was used as a loading control.