Figure 9.

MyD88 is poised to undergo alternative pre-mRNA splicing. A, WT sequence at the 3′ end of intron 1 in the mouse MyD88 gene. Marked is the 3′ splice site (3′SS), the polypyrimidine tract (pY), and the branch point adenosine residue (BP). Also depicted are 10 bp that were mutated (Mutant) highlighted in red to improve the strength of the branch point and pY tract sequences in a mutagenized MyD88 minigene construct. B and C, the MyD88 minigene plasmid (either WT or mutant (MUT)) was transiently transfected into RAW264.7 cells; after 24 h, the cells were stimulated with LPS (red) or were left unstimulated (no treatment (NT), black) for 48 h, and MyD88-L(minigene) and MyD88-S(minigene) mRNA levels were quantitated by qPCR. Data are normalized so that MyD88-L(mini) and MyD88-S(mini) in the WT minigene in the absence of LPS are set to 1. *, p < 0.05.