Casp4^del

RT-PCR confirmed that five 129 substrains (129X1/SvJ, 129S1/SvImJ, 129S2/SvPas, 129S6/SvEvTac and 129P3/J) express a transcript that lacks exon 7 (delta110 isoform). Sequencing identified a 5 bp deletion in exon 7 that results in the fusion of exon 6 and 8, a frame-shift after proline 304 and a stop codon after 5 aberrant amino acids. This deletion is not present in C57BL/6. Western blot analysis confirmed the absence of protein expression in LPS-primed macrophage. (J:193522)