Figure 3.

Induction of antimicrobial peptide promoters by chimeric Toll receptors. (A) Schematic representation of the chimeric molecules. The constructs are based on a constitutively active version of Toll in which all LRR motifs have been deleted. The truncated ectodomain of Toll (black rectangle) is fused to the transmembrane and intracytoplasmic domains of the Toll-related molecules. EC, ectodomain; TM, transmembrane domain; CTE, C-terminal extension. (B) Expression of the chimeric proteins in transfected cells. Protein extracts prepared from S2 cells transfected by expression vectors either empty (Vector) or expressing Toll^ΔLRR (Toll) or the various chimerae (18W, Toll-3 to -8) were submitted to Western blot analysis with an anti-FLAG mAb. Expected sizes for the various molecules are as follows: Toll, 50 kDa; 18W, 63 kDa; Toll-3, 40 kDa; Toll-4, 41 kDa; Toll-5, 41 kDa; Toll-6, 69 kDa; Toll-7, 63 kDa; and Toll-8, 57 kDa. (C) Induction of antimicrobial peptide promoters in transfected cells. S2 cells were cotransfected with 1 μg of expression vector either empty or expressing Toll^ΔLRR (Toll) or the various chimerae (18W, Toll-5 to -8) and 0.1 μg of reporter plasmid encoding luciferase under the control of the diptericin (Dipt), drosocin (Droc), defensin (Def), cecropin (Cec), attacin (Att), or drosomycin (Drom) promoters. Transfections were repeated twice in S2 cells and l(2)mbn cells with identical results. A representative experiment is shown.