FIG 1.

Distinct intranuclear localizations of ectopically expressed Sp100 isoforms. (A) Schematics of protein domains of SP100 splice variants. Destruction-box (D-box), trans-activating region (TR), high mobility group (HMG), bromodomain (BRD) and plant homeodomain (PHD). (B) HEp-2 cells were transfected with plasmids coding for tagged Sp100 isoforms A, B, C, and HMG in pairs. At 24 h posttransfection, cells were fixed, permeabilized, and reacted with antibodies labeled with fluorophores, as indicated. White arrowheads indicate differential intranuclear localizations of Sp100A from the other three Sp100 isoforms. (C to F) HEp-2 cells were transfected with individual plasmids encoding Sp100C (C), Sp100HMG (D), Sp100B (E), or Sp100A (F). At 24 h posttransfection, cells were mock treated (control [Con]) or treated with IFN-β at 1,000 U/mL for 2 h, fixed, permeabilized, and reacted with anti-Flag and anti-PML antibodies. Representative images are shown.