Schematic representation of adenoviral vectors used in this study. All vectors were based on the Ad5-derived vector, pAd/PL-DEST™ (Life Technologies), and they lack the E1 and E3 genes. Expression cassettes were inserted into the deleted E1 region in the antisense orientation with respect to the left inverted terminal repeat (ITR). Expression cassettes contained the indicated open reading frames (light grey) for the enhanced green fluorescent protein (EGFP) or the herpes simplex virus 1 thymidine kinase (HSV-TK). Gene expression was driven by the cytomegalovirus promoter (CMV) or the adenoviral E4 promoter (E4). Promoters are indicated as boxed grey arrows. The 2 copies of the tetracycline repressor-binding sequence are indicated as 2xTetO2. Mmu-miR-155-derived sequences flanking the hairpins that give rise to mature amiRNAs are indicated as small, dark grey boxes. Polyadenylation sequences are indicated as p(A).