Upstream ORFs (uORFs) in the 5'UTR of the alternative NOD2 transcripts have an effect on translational efficacy. (A) Reporter gene constructs containing the differentially spliced alternative 5'UTRs of NOD2 (alt 5' UTR NOD2 a, containing only exon 1a and alt 5' UTR NOD2 b containing exon 1a and 1b) cloned in front of a luciferase reporter gene (pGL Basic) ATG1-3 denote the uAUGs and STP the respective stop codons. (B) Constitutive luciferase activities of the two constructs in transfected HEK293 cells. (C) Sequential deletion of the uAUGs (e.g. ΔATG 1 denotes deletion of the first uAUG) abolishes the inhibitory activity of the long alternative 5'UTR (alt 5' UTR NOD2 b). All values correspond to mean ± SD calculated from at least three independent experiments. RLU, relative luciferase units, determined by dual luciferase assay *p < 0.05, **p < 0.01, Student's T-Test).