Genetic and cellular/biochemical data for mouse Pycard gene differences altering mRNA turnover and IL-1b release

Quantitative trait locus mapping for interleukin-1b release after
inflammasome priming and activation was performed on bone marrow-derived
macrophages (BMDM) from an AKRxDBA/2 strain intercross.  The
strongest associated locus mapped very close to the Pycard gene on
chromosome 7, which codes for the inflammasome adaptor protein
apoptosis-associated speck-like protein containing a CARD (ASC). 
The DBA/2 and AKR Pycard genes only differ at single nucleotide
polymorphism (SNP) in their 3’ untranslated region (UTR).  DBA/2
vs. AKR BMDM had increased levels of Pycard mRNA expression and ASC
protein, and increased inflammasome speck formation, which was associated
with increased Pycard mRNA stability without an increased transcription
rate.  CRIPSR/Cas9 gene editing was performed on DBA/2 embryonic
stem cells to change the Pycard 3’UTR SNP from the DBA/2 to the AKR
allele.  This single base change significantly reduced Pycard
expression and inflammasome activity after cells were differentiated into
macrophages due to reduced Pycard mRNA stability.