Transient cotransfections of HD-derived L428 cells.

(A) L428 cells were cotransfected with immunoglobulin promoter/enhancer-driven luciferase reporters and expression vectors for BOB.1/OBF.1 and/or Oct2 as indicated. μET1.luc represents reporter wild type promoter element extending from +19 to −131, μEtm.luc contains the same promoter element with point mutations in the octamer motif (see C). Relative activity is shown and the cotransfections with empty expression vectors were arbitrarily set to 1. (B) L428 cells were cotransfected with wild type (4 × wt) or mutant (4 × mut) octamer-dependent luciferase reporters together with expression vectors for BOB.1/OBF.1 and/or Oct2 as indicated. Relative activity is shown and the cotransfections with empty expression vectors were arbitrarily set to 1. (C) Schematic representation of the reporter constructs used in A and B. Wild-type octamer motifs in the immunoglobulin promoter or synthetic promoter are indicated as filled circles; mutant octamer motifs are shown as open circles. Details about the reporter constructs can be found in Laumen et al12 (for μET1.luc and μET1m.luc) or Pfisterer et al19 (for 4 × wt and 4 × mut).