(A) Schematic overview of the Nlrp1b (splice) variants deposited prior to this study (roughly to scale). A representative mouse strain whose macrophages express a particular variant is shown on the right, and LT-sensitivity is indicated in red. The number of amino acid polymorphisms relative to the 129S1/SvImJ variant is indicated in (or below) the respective exons. Exon numbers are given on the top. Nlrp1b 129S1/SvImJ has exons 6 and 7 duplicated and transcribed, a unique feature not known to be present in other Nlrp1b genes. CAST/EiJ splice variant (SV) 2 contains an additional exon indicated in orange. GenBank accession numbers are shown on the right. NBD and other domain identifiers are as in Figure 2. Locations of domains were determined according to the annotated Nlrp1b C57-SV1 sequence. Schematic was adapted from . (B) Expression profile of Nlrp1b splice variants. LT-resistant (black) or sensitive (red) macrophages of indicated mouse strains were PCR analyzed for expression of Nlrp1b using cDNA as template. The upper panel shows the expression profile of C57-SV1 and SV2 of Nlrp1b, the lower panel depicts the expression profile of all other variants.